update_display_cursor: take view as arg

[tig] / tig.c

/* Copyright (c) 2006 Jonas Fonseca <fonseca@diku.dk>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#ifndef VERSION
#define VERSION "tig-0.4.git"
#endif

#ifndef DEBUG
#define NDEBUG
#endif

#include <assert.h>
#include <errno.h>
#include <ctype.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>

#include <sys/types.h>
#include <regex.h>

#include <locale.h>
#include <langinfo.h>
#include <iconv.h>

#include <curses.h>

#if __GNUC__ >= 3
#define __NORETURN __attribute__((__noreturn__))
#else
#define __NORETURN
#endif

static void __NORETURN die(const char *err, ...);
static void report(const char *msg, ...);
static int read_properties(FILE *pipe, const char *separators, int (*read)(char *, int, char *, int));
static void set_nonblocking_input(bool loading);
static size_t utf8_length(const char *string, size_t max_width, int *coloffset, int *trimmed);

#define ABS(x)          ((x) >= 0  ? (x) : -(x))
#define MIN(x, y)       ((x) < (y) ? (x) :  (y))

#define ARRAY_SIZE(x)   (sizeof(x) / sizeof(x[0]))
#define STRING_SIZE(x)  (sizeof(x) - 1)

#define SIZEOF_STR      1024    /* Default string size. */
#define SIZEOF_REF      256     /* Size of symbolic or SHA1 ID. */
#define SIZEOF_REV      41      /* Holds a SHA-1 and an ending NUL */
#define SIZEOF_REVGRAPH 19      /* Size of revision ancestry graphics. */

/* This color name can be used to refer to the default term colors. */
#define COLOR_DEFAULT   (-1)

#define ICONV_NONE      ((iconv_t) -1)

/* The format and size of the date column in the main view. */
#define DATE_FORMAT     "%Y-%m-%d %H:%M"
#define DATE_COLS       STRING_SIZE("2006-04-29 14:21 ")

#define AUTHOR_COLS     20

/* The default interval between line numbers. */
#define NUMBER_INTERVAL 1

#define TABSIZE         8

#define SCALE_SPLIT_VIEW(height)        ((height) * 2 / 3)

#define TIG_LS_REMOTE \
        "git ls-remote . 2>/dev/null"

#define TIG_DIFF_CMD \
        "git show --root --patch-with-stat --find-copies-harder -B -C %s 2>/dev/null"

#define TIG_LOG_CMD     \
        "git log --cc --stat -n100 %s 2>/dev/null"

#define TIG_MAIN_CMD \
        "git log --topo-order --pretty=raw %s 2>/dev/null"

#define TIG_TREE_CMD    \
        "git ls-tree %s %s"

#define TIG_BLOB_CMD    \
        "git cat-file blob %s"

/* XXX: Needs to be defined to the empty string. */
#define TIG_HELP_CMD    ""
#define TIG_PAGER_CMD   ""

/* Some ascii-shorthands fitted into the ncurses namespace. */
#define KEY_TAB         '\t'
#define KEY_RETURN      '\r'
#define KEY_ESC         27


struct ref {
        char *name;             /* Ref name; tag or head names are shortened. */
        char id[SIZEOF_REV];    /* Commit SHA1 ID */
        unsigned int tag:1;     /* Is it a tag? */
        unsigned int next:1;    /* For ref lists: are there more refs? */
};

static struct ref **get_refs(char *id);

struct int_map {
        const char *name;
        int namelen;
        int value;
};

static int
set_from_int_map(struct int_map *map, size_t map_size,
                 int *value, const char *name, int namelen)
{

        int i;

        for (i = 0; i < map_size; i++)
                if (namelen == map[i].namelen &&
                    !strncasecmp(name, map[i].name, namelen)) {
                        *value = map[i].value;
                        return OK;
                }

        return ERR;
}


/*
 * String helpers
 */

static inline void
string_ncopy_do(char *dst, size_t dstlen, const char *src, size_t srclen)
{
        if (srclen > dstlen - 1)
                srclen = dstlen - 1;

        strncpy(dst, src, srclen);
        dst[srclen] = 0;
}

/* Shorthands for safely copying into a fixed buffer. */

#define string_copy(dst, src) \
        string_ncopy_do(dst, sizeof(dst), src, sizeof(dst))

#define string_ncopy(dst, src, srclen) \
        string_ncopy_do(dst, sizeof(dst), src, srclen)

static char *
chomp_string(char *name)
{
        int namelen;

        while (isspace(*name))
                name++;

        namelen = strlen(name) - 1;
        while (namelen > 0 && isspace(name[namelen]))
                name[namelen--] = 0;

        return name;
}

static bool
string_nformat(char *buf, size_t bufsize, size_t *bufpos, const char *fmt, ...)
{
        va_list args;
        size_t pos = bufpos ? *bufpos : 0;

        va_start(args, fmt);
        pos += vsnprintf(buf + pos, bufsize - pos, fmt, args);
        va_end(args);

        if (bufpos)
                *bufpos = pos;

        return pos >= bufsize ? FALSE : TRUE;
}

#define string_format(buf, fmt, args...) \
        string_nformat(buf, sizeof(buf), NULL, fmt, args)

#define string_format_from(buf, from, fmt, args...) \
        string_nformat(buf, sizeof(buf), from, fmt, args)

static int
string_enum_compare(const char *str1, const char *str2, int len)
{
        size_t i;

#define string_enum_sep(x) ((x) == '-' || (x) == '_' || (x) == '.')

        /* Diff-Header == DIFF_HEADER */
        for (i = 0; i < len; i++) {
                if (toupper(str1[i]) == toupper(str2[i]))
                        continue;

                if (string_enum_sep(str1[i]) &&
                    string_enum_sep(str2[i]))
                        continue;

                return str1[i] - str2[i];
        }

        return 0;
}

/* Shell quoting
 *
 * NOTE: The following is a slightly modified copy of the git project's shell
 * quoting routines found in the quote.c file.
 *
 * Help to copy the thing properly quoted for the shell safety.  any single
 * quote is replaced with '\'', any exclamation point is replaced with '\!',
 * and the whole thing is enclosed in a
 *
 * E.g.
 *  original     sq_quote     result
 *  name     ==> name      ==> 'name'
 *  a b      ==> a b       ==> 'a b'
 *  a'b      ==> a'\''b    ==> 'a'\''b'
 *  a!b      ==> a'\!'b    ==> 'a'\!'b'
 */

static size_t
sq_quote(char buf[SIZEOF_STR], size_t bufsize, const char *src)
{
        char c;

#define BUFPUT(x) do { if (bufsize < SIZEOF_STR) buf[bufsize++] = (x); } while (0)

        BUFPUT('\'');
        while ((c = *src++)) {
                if (c == '\'' || c == '!') {
                        BUFPUT('\'');
                        BUFPUT('\\');
                        BUFPUT(c);
                        BUFPUT('\'');
                } else {
                        BUFPUT(c);
                }
        }
        BUFPUT('\'');

        return bufsize;
}


/*
 * User requests
 */

#define REQ_INFO \
        /* XXX: Keep the view request first and in sync with views[]. */ \
        REQ_GROUP("View switching") \
        REQ_(VIEW_MAIN,         "Show main view"), \
        REQ_(VIEW_DIFF,         "Show diff view"), \
        REQ_(VIEW_LOG,          "Show log view"), \
        REQ_(VIEW_TREE,         "Show tree view"), \
        REQ_(VIEW_BLOB,         "Show blob view"), \
        REQ_(VIEW_HELP,         "Show help page"), \
        REQ_(VIEW_PAGER,        "Show pager view"), \
        \
        REQ_GROUP("View manipulation") \
        REQ_(ENTER,             "Enter current line and scroll"), \
        REQ_(NEXT,              "Move to next"), \
        REQ_(PREVIOUS,          "Move to previous"), \
        REQ_(VIEW_NEXT,         "Move focus to next view"), \
        REQ_(VIEW_CLOSE,        "Close the current view"), \
        REQ_(QUIT,              "Close all views and quit"), \
        \
        REQ_GROUP("Cursor navigation") \
        REQ_(MOVE_UP,           "Move cursor one line up"), \
        REQ_(MOVE_DOWN,         "Move cursor one line down"), \
        REQ_(MOVE_PAGE_DOWN,    "Move cursor one page down"), \
        REQ_(MOVE_PAGE_UP,      "Move cursor one page up"), \
        REQ_(MOVE_FIRST_LINE,   "Move cursor to first line"), \
        REQ_(MOVE_LAST_LINE,    "Move cursor to last line"), \
        \
        REQ_GROUP("Scrolling") \
        REQ_(SCROLL_LINE_UP,    "Scroll one line up"), \
        REQ_(SCROLL_LINE_DOWN,  "Scroll one line down"), \
        REQ_(SCROLL_PAGE_UP,    "Scroll one page up"), \
        REQ_(SCROLL_PAGE_DOWN,  "Scroll one page down"), \
        \
        REQ_GROUP("Searching") \
        REQ_(SEARCH,            "Search the view"), \
        REQ_(SEARCH_BACK,       "Search backwards in the view"), \
        REQ_(FIND_NEXT,         "Find next search match"), \
        REQ_(FIND_PREV,         "Find previous search match"), \
        \
        REQ_GROUP("Misc") \
        REQ_(NONE,              "Do nothing"), \
        REQ_(PROMPT,            "Bring up the prompt"), \
        REQ_(SCREEN_REDRAW,     "Redraw the screen"), \
        REQ_(SCREEN_RESIZE,     "Resize the screen"), \
        REQ_(SHOW_VERSION,      "Show version information"), \
        REQ_(STOP_LOADING,      "Stop all loading views"), \
        REQ_(TOGGLE_LINENO,     "Toggle line numbers"), \
        REQ_(TOGGLE_REV_GRAPH,  "Toggle revision graph visualization")


/* User action requests. */
enum request {
#define REQ_GROUP(help)
#define REQ_(req, help) REQ_##req

        /* Offset all requests to avoid conflicts with ncurses getch values. */
        REQ_OFFSET = KEY_MAX + 1,
        REQ_INFO,
        REQ_UNKNOWN,

#undef  REQ_GROUP
#undef  REQ_
};

struct request_info {
        enum request request;
        char *name;
        int namelen;
        char *help;
};

static struct request_info req_info[] = {
#define REQ_GROUP(help) { 0, NULL, 0, (help) },
#define REQ_(req, help) { REQ_##req, (#req), STRING_SIZE(#req), (help) }
        REQ_INFO
#undef  REQ_GROUP
#undef  REQ_
};

static enum request
get_request(const char *name)
{
        int namelen = strlen(name);
        int i;

        for (i = 0; i < ARRAY_SIZE(req_info); i++)
                if (req_info[i].namelen == namelen &&
                    !string_enum_compare(req_info[i].name, name, namelen))
                        return req_info[i].request;

        return REQ_UNKNOWN;
}


/*
 * Options
 */

static const char usage[] =
VERSION " (" __DATE__ ")\n"
"\n"
"Usage: tig [options]\n"
"   or: tig [options] [--] [git log options]\n"
"   or: tig [options] log  [git log options]\n"
"   or: tig [options] diff [git diff options]\n"
"   or: tig [options] show [git show options]\n"
"   or: tig [options] <    [git command output]\n"
"\n"
"Options:\n"
"  -l                          Start up in log view\n"
"  -d                          Start up in diff view\n"
"  -n[I], --line-number[=I]    Show line numbers with given interval\n"
"  -b[N], --tab-size[=N]       Set number of spaces for tab expansion\n"
"  --                          Mark end of tig options\n"
"  -v, --version               Show version and exit\n"
"  -h, --help                  Show help message and exit\n";

/* Option and state variables. */
static bool opt_line_number             = FALSE;
static bool opt_rev_graph               = TRUE;
static int opt_num_interval             = NUMBER_INTERVAL;
static int opt_tab_size                 = TABSIZE;
static enum request opt_request         = REQ_VIEW_MAIN;
static char opt_cmd[SIZEOF_STR]         = "";
static char opt_path[SIZEOF_STR]        = "";
static FILE *opt_pipe                   = NULL;
static char opt_encoding[20]            = "UTF-8";
static bool opt_utf8                    = TRUE;
static char opt_codeset[20]             = "UTF-8";
static iconv_t opt_iconv                = ICONV_NONE;
static char opt_search[SIZEOF_STR]      = "";

enum option_type {
        OPT_NONE,
        OPT_INT,
};

static bool
check_option(char *opt, char short_name, char *name, enum option_type type, ...)
{
        va_list args;
        char *value = "";
        int *number;

        if (opt[0] != '-')
                return FALSE;

        if (opt[1] == '-') {
                int namelen = strlen(name);

                opt += 2;

                if (strncmp(opt, name, namelen))
                        return FALSE;

                if (opt[namelen] == '=')
                        value = opt + namelen + 1;

        } else {
                if (!short_name || opt[1] != short_name)
                        return FALSE;
                value = opt + 2;
        }

        va_start(args, type);
        if (type == OPT_INT) {
                number = va_arg(args, int *);
                if (isdigit(*value))
                        *number = atoi(value);
        }
        va_end(args);

        return TRUE;
}

/* Returns the index of log or diff command or -1 to exit. */
static bool
parse_options(int argc, char *argv[])
{
        int i;

        for (i = 1; i < argc; i++) {
                char *opt = argv[i];

                if (!strcmp(opt, "-l")) {
                        opt_request = REQ_VIEW_LOG;
                        continue;
                }

                if (!strcmp(opt, "-d")) {
                        opt_request = REQ_VIEW_DIFF;
                        continue;
                }

                if (check_option(opt, 'n', "line-number", OPT_INT, &opt_num_interval)) {
                        opt_line_number = TRUE;
                        continue;
                }

                if (check_option(opt, 'b', "tab-size", OPT_INT, &opt_tab_size)) {
                        opt_tab_size = MIN(opt_tab_size, TABSIZE);
                        continue;
                }

                if (check_option(opt, 'v', "version", OPT_NONE)) {
                        printf("tig version %s\n", VERSION);
                        return FALSE;
                }

                if (check_option(opt, 'h', "help", OPT_NONE)) {
                        printf(usage);
                        return FALSE;
                }

                if (!strcmp(opt, "--")) {
                        i++;
                        break;
                }

                if (!strcmp(opt, "log") ||
                    !strcmp(opt, "diff") ||
                    !strcmp(opt, "show")) {
                        opt_request = opt[0] == 'l'
                                    ? REQ_VIEW_LOG : REQ_VIEW_DIFF;
                        break;
                }

                if (opt[0] && opt[0] != '-')
                        break;

                die("unknown option '%s'\n\n%s", opt, usage);
        }

        if (!isatty(STDIN_FILENO)) {
                opt_request = REQ_VIEW_PAGER;
                opt_pipe = stdin;

        } else if (i < argc) {
                size_t buf_size;

                if (opt_request == REQ_VIEW_MAIN)
                        /* XXX: This is vulnerable to the user overriding
                         * options required for the main view parser. */
                        string_copy(opt_cmd, "git log --stat --pretty=raw");
                else
                        string_copy(opt_cmd, "git");
                buf_size = strlen(opt_cmd);

                while (buf_size < sizeof(opt_cmd) && i < argc) {
                        opt_cmd[buf_size++] = ' ';
                        buf_size = sq_quote(opt_cmd, buf_size, argv[i++]);
                }

                if (buf_size >= sizeof(opt_cmd))
                        die("command too long");

                opt_cmd[buf_size] = 0;

        }

        if (*opt_encoding && strcasecmp(opt_encoding, "UTF-8"))
                opt_utf8 = FALSE;

        return TRUE;
}


/*
 * Line-oriented content detection.
 */

#define LINE_INFO \
LINE(DIFF_HEADER,  "diff --git ",       COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(DIFF_CHUNK,   "@@",                COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(DIFF_ADD,     "+",                 COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(DIFF_DEL,     "-",                 COLOR_RED,      COLOR_DEFAULT,  0), \
LINE(DIFF_INDEX,        "index ",         COLOR_BLUE,   COLOR_DEFAULT,  0), \
LINE(DIFF_OLDMODE,      "old file mode ", COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_NEWMODE,      "new file mode ", COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_COPY_FROM,    "copy from",      COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_COPY_TO,      "copy to",        COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_RENAME_FROM,  "rename from",    COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_RENAME_TO,    "rename to",      COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_SIMILARITY,   "similarity ",    COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_DISSIMILARITY,"dissimilarity ", COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_TREE,         "diff-tree ",     COLOR_BLUE,   COLOR_DEFAULT,  0), \
LINE(PP_AUTHOR,    "Author: ",          COLOR_CYAN,     COLOR_DEFAULT,  0), \
LINE(PP_COMMIT,    "Commit: ",          COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(PP_MERGE,     "Merge: ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(PP_DATE,      "Date:   ",          COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(PP_ADATE,     "AuthorDate: ",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(PP_CDATE,     "CommitDate: ",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(PP_REFS,      "Refs: ",            COLOR_RED,      COLOR_DEFAULT,  0), \
LINE(COMMIT,       "commit ",           COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(PARENT,       "parent ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(TREE,         "tree ",             COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(AUTHOR,       "author ",           COLOR_CYAN,     COLOR_DEFAULT,  0), \
LINE(COMMITTER,    "committer ",        COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(SIGNOFF,      "    Signed-off-by", COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(ACKED,        "    Acked-by",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(DEFAULT,      "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  A_NORMAL), \
LINE(CURSOR,       "",                  COLOR_WHITE,    COLOR_GREEN,    A_BOLD), \
LINE(STATUS,       "",                  COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(TITLE_BLUR,   "",                  COLOR_WHITE,    COLOR_BLUE,     0), \
LINE(TITLE_FOCUS,  "",                  COLOR_WHITE,    COLOR_BLUE,     A_BOLD), \
LINE(MAIN_DATE,    "",                  COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(MAIN_AUTHOR,  "",                  COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(MAIN_COMMIT,  "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  0), \
LINE(MAIN_DELIM,   "",                  COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(MAIN_TAG,     "",                  COLOR_MAGENTA,  COLOR_DEFAULT,  A_BOLD), \
LINE(MAIN_REF,     "",                  COLOR_CYAN,     COLOR_DEFAULT,  A_BOLD), \
LINE(TREE_DIR,     "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  A_NORMAL), \
LINE(TREE_FILE,    "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  A_NORMAL)

enum line_type {
#define LINE(type, line, fg, bg, attr) \
        LINE_##type
        LINE_INFO
#undef  LINE
};

struct line_info {
        const char *name;       /* Option name. */
        int namelen;            /* Size of option name. */
        const char *line;       /* The start of line to match. */
        int linelen;            /* Size of string to match. */
        int fg, bg, attr;       /* Color and text attributes for the lines. */
};

static struct line_info line_info[] = {
#define LINE(type, line, fg, bg, attr) \
        { #type, STRING_SIZE(#type), (line), STRING_SIZE(line), (fg), (bg), (attr) }
        LINE_INFO
#undef  LINE
};

static enum line_type
get_line_type(char *line)
{
        int linelen = strlen(line);
        enum line_type type;

        for (type = 0; type < ARRAY_SIZE(line_info); type++)
                /* Case insensitive search matches Signed-off-by lines better. */
                if (linelen >= line_info[type].linelen &&
                    !strncasecmp(line_info[type].line, line, line_info[type].linelen))
                        return type;

        return LINE_DEFAULT;
}

static inline int
get_line_attr(enum line_type type)
{
        assert(type < ARRAY_SIZE(line_info));
        return COLOR_PAIR(type) | line_info[type].attr;
}

static struct line_info *
get_line_info(char *name, int namelen)
{
        enum line_type type;

        for (type = 0; type < ARRAY_SIZE(line_info); type++)
                if (namelen == line_info[type].namelen &&
                    !string_enum_compare(line_info[type].name, name, namelen))
                        return &line_info[type];

        return NULL;
}

static void
init_colors(void)
{
        int default_bg = COLOR_BLACK;
        int default_fg = COLOR_WHITE;
        enum line_type type;

        start_color();

        if (use_default_colors() != ERR) {
                default_bg = -1;
                default_fg = -1;
        }

        for (type = 0; type < ARRAY_SIZE(line_info); type++) {
                struct line_info *info = &line_info[type];
                int bg = info->bg == COLOR_DEFAULT ? default_bg : info->bg;
                int fg = info->fg == COLOR_DEFAULT ? default_fg : info->fg;

                init_pair(type, fg, bg);
        }
}

struct line {
        enum line_type type;

        /* State flags */
        unsigned int selected:1;

        void *data;             /* User data */
};


/*
 * Keys
 */

struct keybinding {
        int alias;
        enum request request;
        struct keybinding *next;
};

static struct keybinding default_keybindings[] = {
        /* View switching */
        { 'm',          REQ_VIEW_MAIN },
        { 'd',          REQ_VIEW_DIFF },
        { 'l',          REQ_VIEW_LOG },
        { 't',          REQ_VIEW_TREE },
        { 'f',          REQ_VIEW_BLOB },
        { 'p',          REQ_VIEW_PAGER },
        { 'h',          REQ_VIEW_HELP },

        /* View manipulation */
        { 'q',          REQ_VIEW_CLOSE },
        { KEY_TAB,      REQ_VIEW_NEXT },
        { KEY_RETURN,   REQ_ENTER },
        { KEY_UP,       REQ_PREVIOUS },
        { KEY_DOWN,     REQ_NEXT },

        /* Cursor navigation */
        { 'k',          REQ_MOVE_UP },
        { 'j',          REQ_MOVE_DOWN },
        { KEY_HOME,     REQ_MOVE_FIRST_LINE },
        { KEY_END,      REQ_MOVE_LAST_LINE },
        { KEY_NPAGE,    REQ_MOVE_PAGE_DOWN },
        { ' ',          REQ_MOVE_PAGE_DOWN },
        { KEY_PPAGE,    REQ_MOVE_PAGE_UP },
        { 'b',          REQ_MOVE_PAGE_UP },
        { '-',          REQ_MOVE_PAGE_UP },

        /* Scrolling */
        { KEY_IC,       REQ_SCROLL_LINE_UP },
        { KEY_DC,       REQ_SCROLL_LINE_DOWN },
        { 'w',          REQ_SCROLL_PAGE_UP },
        { 's',          REQ_SCROLL_PAGE_DOWN },

        /* Searching */
        { '/',          REQ_SEARCH },
        { '?',          REQ_SEARCH_BACK },
        { 'n',          REQ_FIND_NEXT },
        { 'N',          REQ_FIND_PREV },

        /* Misc */
        { 'Q',          REQ_QUIT },
        { 'z',          REQ_STOP_LOADING },
        { 'v',          REQ_SHOW_VERSION },
        { 'r',          REQ_SCREEN_REDRAW },
        { '.',          REQ_TOGGLE_LINENO },
        { 'g',          REQ_TOGGLE_REV_GRAPH },
        { ':',          REQ_PROMPT },

        /* wgetch() with nodelay() enabled returns ERR when there's no input. */
        { ERR,          REQ_NONE },

        /* Using the ncurses SIGWINCH handler. */
        { KEY_RESIZE,   REQ_SCREEN_RESIZE },
};

#define KEYMAP_INFO \
        KEYMAP_(GENERIC), \
        KEYMAP_(MAIN), \
        KEYMAP_(DIFF), \
        KEYMAP_(LOG), \
        KEYMAP_(TREE), \
        KEYMAP_(BLOB), \
        KEYMAP_(PAGER), \
        KEYMAP_(HELP) \

enum keymap {
#define KEYMAP_(name) KEYMAP_##name
        KEYMAP_INFO
#undef  KEYMAP_
};

static struct int_map keymap_table[] = {
#define KEYMAP_(name) { #name, STRING_SIZE(#name), KEYMAP_##name }
        KEYMAP_INFO
#undef  KEYMAP_
};

#define set_keymap(map, name) \
        set_from_int_map(keymap_table, ARRAY_SIZE(keymap_table), map, name, strlen(name))

static struct keybinding *keybindings[ARRAY_SIZE(keymap_table)];

static void
add_keybinding(enum keymap keymap, enum request request, int key)
{
        struct keybinding *keybinding;

        keybinding = calloc(1, sizeof(*keybinding));
        if (!keybinding)
                die("Failed to allocate keybinding");

        keybinding->alias = key;
        keybinding->request = request;
        keybinding->next = keybindings[keymap];
        keybindings[keymap] = keybinding;
}

/* Looks for a key binding first in the given map, then in the generic map, and
 * lastly in the default keybindings. */
static enum request
get_keybinding(enum keymap keymap, int key)
{
        struct keybinding *kbd;
        int i;

        for (kbd = keybindings[keymap]; kbd; kbd = kbd->next)
                if (kbd->alias == key)
                        return kbd->request;

        for (kbd = keybindings[KEYMAP_GENERIC]; kbd; kbd = kbd->next)
                if (kbd->alias == key)
                        return kbd->request;

        for (i = 0; i < ARRAY_SIZE(default_keybindings); i++)
                if (default_keybindings[i].alias == key)
                        return default_keybindings[i].request;

        return (enum request) key;
}


struct key {
        char *name;
        int value;
};

static struct key key_table[] = {
        { "Enter",      KEY_RETURN },
        { "Space",      ' ' },
        { "Backspace",  KEY_BACKSPACE },
        { "Tab",        KEY_TAB },
        { "Escape",     KEY_ESC },
        { "Left",       KEY_LEFT },
        { "Right",      KEY_RIGHT },
        { "Up",         KEY_UP },
        { "Down",       KEY_DOWN },
        { "Insert",     KEY_IC },
        { "Delete",     KEY_DC },
        { "Hash",       '#' },
        { "Home",       KEY_HOME },
        { "End",        KEY_END },
        { "PageUp",     KEY_PPAGE },
        { "PageDown",   KEY_NPAGE },
        { "F1",         KEY_F(1) },
        { "F2",         KEY_F(2) },
        { "F3",         KEY_F(3) },
        { "F4",         KEY_F(4) },
        { "F5",         KEY_F(5) },
        { "F6",         KEY_F(6) },
        { "F7",         KEY_F(7) },
        { "F8",         KEY_F(8) },
        { "F9",         KEY_F(9) },
        { "F10",        KEY_F(10) },
        { "F11",        KEY_F(11) },
        { "F12",        KEY_F(12) },
};

static int
get_key_value(const char *name)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(key_table); i++)
                if (!strcasecmp(key_table[i].name, name))
                        return key_table[i].value;

        if (strlen(name) == 1 && isprint(*name))
                return (int) *name;

        return ERR;
}

static char *
get_key(enum request request)
{
        static char buf[BUFSIZ];
        static char key_char[] = "'X'";
        size_t pos = 0;
        char *sep = "    ";
        int i;

        buf[pos] = 0;

        for (i = 0; i < ARRAY_SIZE(default_keybindings); i++) {
                struct keybinding *keybinding = &default_keybindings[i];
                char *seq = NULL;
                int key;

                if (keybinding->request != request)
                        continue;

                for (key = 0; key < ARRAY_SIZE(key_table); key++)
                        if (key_table[key].value == keybinding->alias)
                                seq = key_table[key].name;

                if (seq == NULL &&
                    keybinding->alias < 127 &&
                    isprint(keybinding->alias)) {
                        key_char[1] = (char) keybinding->alias;
                        seq = key_char;
                }

                if (!seq)
                        seq = "'?'";

                if (!string_format_from(buf, &pos, "%s%s", sep, seq))
                        return "Too many keybindings!";
                sep = ", ";
        }

        return buf;
}


/*
 * User config file handling.
 */

static struct int_map color_map[] = {
#define COLOR_MAP(name) { #name, STRING_SIZE(#name), COLOR_##name }
        COLOR_MAP(DEFAULT),
        COLOR_MAP(BLACK),
        COLOR_MAP(BLUE),
        COLOR_MAP(CYAN),
        COLOR_MAP(GREEN),
        COLOR_MAP(MAGENTA),
        COLOR_MAP(RED),
        COLOR_MAP(WHITE),
        COLOR_MAP(YELLOW),
};

#define set_color(color, name) \
        set_from_int_map(color_map, ARRAY_SIZE(color_map), color, name, strlen(name))

static struct int_map attr_map[] = {
#define ATTR_MAP(name) { #name, STRING_SIZE(#name), A_##name }
        ATTR_MAP(NORMAL),
        ATTR_MAP(BLINK),
        ATTR_MAP(BOLD),
        ATTR_MAP(DIM),
        ATTR_MAP(REVERSE),
        ATTR_MAP(STANDOUT),
        ATTR_MAP(UNDERLINE),
};

#define set_attribute(attr, name) \
        set_from_int_map(attr_map, ARRAY_SIZE(attr_map), attr, name, strlen(name))

static int   config_lineno;
static bool  config_errors;
static char *config_msg;

/* Wants: object fgcolor bgcolor [attr] */
static int
option_color_command(int argc, char *argv[])
{
        struct line_info *info;

        if (argc != 3 && argc != 4) {
                config_msg = "Wrong number of arguments given to color command";
                return ERR;
        }

        info = get_line_info(argv[0], strlen(argv[0]));
        if (!info) {
                config_msg = "Unknown color name";
                return ERR;
        }

        if (set_color(&info->fg, argv[1]) == ERR ||
            set_color(&info->bg, argv[2]) == ERR) {
                config_msg = "Unknown color";
                return ERR;
        }

        if (argc == 4 && set_attribute(&info->attr, argv[3]) == ERR) {
                config_msg = "Unknown attribute";
                return ERR;
        }

        return OK;
}

/* Wants: name = value */
static int
option_set_command(int argc, char *argv[])
{
        if (argc != 3) {
                config_msg = "Wrong number of arguments given to set command";
                return ERR;
        }

        if (strcmp(argv[1], "=")) {
                config_msg = "No value assigned";
                return ERR;
        }

        if (!strcmp(argv[0], "show-rev-graph")) {
                opt_rev_graph = (!strcmp(argv[2], "1") ||
                                 !strcmp(argv[2], "true") ||
                                 !strcmp(argv[2], "yes"));
                return OK;
        }

        if (!strcmp(argv[0], "line-number-interval")) {
                opt_num_interval = atoi(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "tab-size")) {
                opt_tab_size = atoi(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "commit-encoding")) {
                char *arg = argv[2];
                int delimiter = *arg;
                int i;

                switch (delimiter) {
                case '"':
                case '\'':
                        for (arg++, i = 0; arg[i]; i++)
                                if (arg[i] == delimiter) {
                                        arg[i] = 0;
                                        break;
                                }
                default:
                        string_copy(opt_encoding, arg);
                        return OK;
                }
        }

        config_msg = "Unknown variable name";
        return ERR;
}

/* Wants: mode request key */
static int
option_bind_command(int argc, char *argv[])
{
        enum request request;
        int keymap;
        int key;

        if (argc != 3) {
                config_msg = "Wrong number of arguments given to bind command";
                return ERR;
        }

        if (set_keymap(&keymap, argv[0]) == ERR) {
                config_msg = "Unknown key map";
                return ERR;
        }

        key = get_key_value(argv[1]);
        if (key == ERR) {
                config_msg = "Unknown key";
                return ERR;
        }

        request = get_request(argv[2]);
        if (request == REQ_UNKNOWN) {
                config_msg = "Unknown request name";
                return ERR;
        }

        add_keybinding(keymap, request, key);

        return OK;
}

static int
set_option(char *opt, char *value)
{
        char *argv[16];
        int valuelen;
        int argc = 0;

        /* Tokenize */
        while (argc < ARRAY_SIZE(argv) && (valuelen = strcspn(value, " \t"))) {
                argv[argc++] = value;

                value += valuelen;
                if (!*value)
                        break;

                *value++ = 0;
                while (isspace(*value))
                        value++;
        }

        if (!strcmp(opt, "color"))
                return option_color_command(argc, argv);

        if (!strcmp(opt, "set"))
                return option_set_command(argc, argv);

        if (!strcmp(opt, "bind"))
                return option_bind_command(argc, argv);

        config_msg = "Unknown option command";
        return ERR;
}

static int
read_option(char *opt, int optlen, char *value, int valuelen)
{
        int status = OK;

        config_lineno++;
        config_msg = "Internal error";

        /* Check for comment markers, since read_properties() will
         * only ensure opt and value are split at first " \t". */
        optlen = strcspn(opt, "#");
        if (optlen == 0)
                return OK;

        if (opt[optlen] != 0) {
                config_msg = "No option value";
                status = ERR;

        }  else {
                /* Look for comment endings in the value. */
                int len = strcspn(value, "#");

                if (len < valuelen) {
                        valuelen = len;
                        value[valuelen] = 0;
                }

                status = set_option(opt, value);
        }

        if (status == ERR) {
                fprintf(stderr, "Error on line %d, near '%.*s': %s\n",
                        config_lineno, optlen, opt, config_msg);
                config_errors = TRUE;
        }

        /* Always keep going if errors are encountered. */
        return OK;
}

static int
load_options(void)
{
        char *home = getenv("HOME");
        char buf[SIZEOF_STR];
        FILE *file;

        config_lineno = 0;
        config_errors = FALSE;

        if (!home || !string_format(buf, "%s/.tigrc", home))
                return ERR;

        /* It's ok that the file doesn't exist. */
        file = fopen(buf, "r");
        if (!file)
                return OK;

        if (read_properties(file, " \t", read_option) == ERR ||
            config_errors == TRUE)
                fprintf(stderr, "Errors while loading %s.\n", buf);

        return OK;
}


/*
 * The viewer
 */

struct view;
struct view_ops;

/* The display array of active views and the index of the current view. */
static struct view *display[2];
static unsigned int current_view;

#define foreach_displayed_view(view, i) \
        for (i = 0; i < ARRAY_SIZE(display) && (view = display[i]); i++)

#define displayed_views()       (display[1] != NULL ? 2 : 1)

/* Current head and commit ID */
static char ref_blob[SIZEOF_REF]        = "";
static char ref_commit[SIZEOF_REF]      = "HEAD";
static char ref_head[SIZEOF_REF]        = "HEAD";

struct view {
        const char *name;       /* View name */
        const char *cmd_fmt;    /* Default command line format */
        const char *cmd_env;    /* Command line set via environment */
        const char *id;         /* Points to either of ref_{head,commit,blob} */

        struct view_ops *ops;   /* View operations */

        enum keymap keymap;     /* What keymap does this view have */

        char cmd[SIZEOF_STR];   /* Command buffer */
        char ref[SIZEOF_REF];   /* Hovered commit reference */
        char vid[SIZEOF_REF];   /* View ID. Set to id member when updating. */

        int height, width;      /* The width and height of the main window */
        WINDOW *win;            /* The main window */
        WINDOW *title;          /* The title window living below the main window */

        /* Navigation */
        unsigned long offset;   /* Offset of the window top */
        unsigned long lineno;   /* Current line number */

        /* Searching */
        char grep[SIZEOF_STR];  /* Search string */
        regex_t *regex;         /* Pre-compiled regex */

        /* If non-NULL, points to the view that opened this view. If this view
         * is closed tig will switch back to the parent view. */
        struct view *parent;

        /* Buffering */
        unsigned long lines;    /* Total number of lines */
        struct line *line;      /* Line index */
        unsigned long line_size;/* Total number of allocated lines */
        unsigned int digits;    /* Number of digits in the lines member. */

        /* Loading */
        FILE *pipe;
        time_t start_time;
};

struct view_ops {
        /* What type of content being displayed. Used in the title bar. */
        const char *type;
        /* Draw one line; @lineno must be < view->height. */
        bool (*draw)(struct view *view, struct line *line, unsigned int lineno, bool selected);
        /* Read one line; updates view->line. */
        bool (*read)(struct view *view, char *data);
        /* Depending on view, change display based on current line. */
        bool (*enter)(struct view *view, struct line *line);
        /* Search for regex in a line. */
        bool (*grep)(struct view *view, struct line *line);
        /* Select line */
        void (*select)(struct view *view, struct line *line);
};

static struct view_ops pager_ops;
static struct view_ops main_ops;
static struct view_ops tree_ops;
static struct view_ops blob_ops;

#define VIEW_STR(name, cmd, env, ref, ops, map) \
        { name, cmd, #env, ref, ops, map}

#define VIEW_(id, name, ops, ref) \
        VIEW_STR(name, TIG_##id##_CMD,  TIG_##id##_CMD, ref, ops, KEYMAP_##id)


static struct view views[] = {
        VIEW_(MAIN,  "main",  &main_ops,  ref_head),
        VIEW_(DIFF,  "diff",  &pager_ops, ref_commit),
        VIEW_(LOG,   "log",   &pager_ops, ref_head),
        VIEW_(TREE,  "tree",  &tree_ops,  ref_commit),
        VIEW_(BLOB,  "blob",  &blob_ops,  ref_blob),
        VIEW_(HELP,  "help",  &pager_ops, "static"),
        VIEW_(PAGER, "pager", &pager_ops, "static"),
};

#define VIEW(req) (&views[(req) - REQ_OFFSET - 1])

#define foreach_view(view, i) \
        for (i = 0; i < ARRAY_SIZE(views) && (view = &views[i]); i++)

#define view_is_displayed(view) \
        (view == display[0] || view == display[1])

static bool
draw_view_line(struct view *view, unsigned int lineno)
{
        struct line *line;
        bool selected = (view->offset + lineno == view->lineno);

        assert(view_is_displayed(view));

        if (view->offset + lineno >= view->lines)
                return FALSE;

        line = &view->line[view->offset + lineno];

        if (selected) {
                line->selected = TRUE;
                view->ops->select(view, line);
        } else if (line->selected) {
                line->selected = FALSE;
                wmove(view->win, lineno, 0);
                wclrtoeol(view->win);
        }

        return view->ops->draw(view, line, lineno, selected);
}

static void
redraw_view_from(struct view *view, int lineno)
{
        assert(0 <= lineno && lineno < view->height);

        for (; lineno < view->height; lineno++) {
                if (!draw_view_line(view, lineno))
                        break;
        }

        redrawwin(view->win);
        wrefresh(view->win);
}

static void
redraw_view(struct view *view)
{
        wclear(view->win);
        redraw_view_from(view, 0);
}


static void
update_view_title(struct view *view)
{
        assert(view_is_displayed(view));

        if (view == display[current_view])
                wbkgdset(view->title, get_line_attr(LINE_TITLE_FOCUS));
        else
                wbkgdset(view->title, get_line_attr(LINE_TITLE_BLUR));

        werase(view->title);
        wmove(view->title, 0, 0);

        if (*view->ref)
                wprintw(view->title, "[%s] %s", view->name, view->ref);
        else
                wprintw(view->title, "[%s]", view->name);

        if (view->lines || view->pipe) {
                unsigned int view_lines = view->offset + view->height;
                unsigned int lines = view->lines
                                   ? MIN(view_lines, view->lines) * 100 / view->lines
                                   : 0;

                wprintw(view->title, " - %s %d of %d (%d%%)",
                        view->ops->type,
                        view->lineno + 1,
                        view->lines,
                        lines);
        }

        if (view->pipe) {
                time_t secs = time(NULL) - view->start_time;

                /* Three git seconds are a long time ... */
                if (secs > 2)
                        wprintw(view->title, " %lds", secs);
        }

        wmove(view->title, 0, view->width - 1);
        wrefresh(view->title);
}

static void
resize_display(void)
{
        int offset, i;
        struct view *base = display[0];
        struct view *view = display[1] ? display[1] : display[0];

        /* Setup window dimensions */

        getmaxyx(stdscr, base->height, base->width);

        /* Make room for the status window. */
        base->height -= 1;

        if (view != base) {
                /* Horizontal split. */
                view->width   = base->width;
                view->height  = SCALE_SPLIT_VIEW(base->height);
                base->height -= view->height;

                /* Make room for the title bar. */
                view->height -= 1;
        }

        /* Make room for the title bar. */
        base->height -= 1;

        offset = 0;

        foreach_displayed_view (view, i) {
                if (!view->win) {
                        view->win = newwin(view->height, 0, offset, 0);
                        if (!view->win)
                                die("Failed to create %s view", view->name);

                        scrollok(view->win, TRUE);

                        view->title = newwin(1, 0, offset + view->height, 0);
                        if (!view->title)
                                die("Failed to create title window");

                } else {
                        wresize(view->win, view->height, view->width);
                        mvwin(view->win,   offset, 0);
                        mvwin(view->title, offset + view->height, 0);
                }

                offset += view->height + 1;
        }
}

static void
redraw_display(void)
{
        struct view *view;
        int i;

        foreach_displayed_view (view, i) {
                redraw_view(view);
                update_view_title(view);
        }
}

static void
update_display_cursor(struct view *view)
{
        /* Move the cursor to the right-most column of the cursor line.
         *
         * XXX: This could turn out to be a bit expensive, but it ensures that
         * the cursor does not jump around. */
        if (view->lines) {
                wmove(view->win, view->lineno - view->offset, view->width - 1);
                wrefresh(view->win);
        }
}

/*
 * Navigation
 */

/* Scrolling backend */
static void
do_scroll_view(struct view *view, int lines)
{
        bool redraw_current_line = FALSE;

        /* The rendering expects the new offset. */
        view->offset += lines;

        assert(0 <= view->offset && view->offset < view->lines);
        assert(lines);

        /* Move current line into the view. */
        if (view->lineno < view->offset) {
                view->lineno = view->offset;
                redraw_current_line = TRUE;
        } else if (view->lineno >= view->offset + view->height) {
                view->lineno = view->offset + view->height - 1;
                redraw_current_line = TRUE;
        }

        assert(view->offset <= view->lineno && view->lineno < view->lines);

        /* Redraw the whole screen if scrolling is pointless. */
        if (view->height < ABS(lines)) {
                redraw_view(view);

        } else {
                int line = lines > 0 ? view->height - lines : 0;
                int end = line + ABS(lines);

                wscrl(view->win, lines);

                for (; line < end; line++) {
                        if (!draw_view_line(view, line))
                                break;
                }

                if (redraw_current_line)
                        draw_view_line(view, view->lineno - view->offset);
        }

        redrawwin(view->win);
        wrefresh(view->win);
        report("");
}

/* Scroll frontend */
static void
scroll_view(struct view *view, enum request request)
{
        int lines = 1;

        assert(view_is_displayed(view));

        switch (request) {
        case REQ_SCROLL_PAGE_DOWN:
                lines = view->height;
        case REQ_SCROLL_LINE_DOWN:
                if (view->offset + lines > view->lines)
                        lines = view->lines - view->offset;

                if (lines == 0 || view->offset + view->height >= view->lines) {
                        report("Cannot scroll beyond the last line");
                        return;
                }
                break;

        case REQ_SCROLL_PAGE_UP:
                lines = view->height;
        case REQ_SCROLL_LINE_UP:
                if (lines > view->offset)
                        lines = view->offset;

                if (lines == 0) {
                        report("Cannot scroll beyond the first line");
                        return;
                }

                lines = -lines;
                break;

        default:
                die("request %d not handled in switch", request);
        }

        do_scroll_view(view, lines);
}

/* Cursor moving */
static void
move_view(struct view *view, enum request request)
{
        int scroll_steps = 0;
        int steps;

        switch (request) {
        case REQ_MOVE_FIRST_LINE:
                steps = -view->lineno;
                break;

        case REQ_MOVE_LAST_LINE:
                steps = view->lines - view->lineno - 1;
                break;

        case REQ_MOVE_PAGE_UP:
                steps = view->height > view->lineno
                      ? -view->lineno : -view->height;
                break;

        case REQ_MOVE_PAGE_DOWN:
                steps = view->lineno + view->height >= view->lines
                      ? view->lines - view->lineno - 1 : view->height;
                break;

        case REQ_MOVE_UP:
                steps = -1;
                break;

        case REQ_MOVE_DOWN:
                steps = 1;
                break;

        default:
                die("request %d not handled in switch", request);
        }

        if (steps <= 0 && view->lineno == 0) {
                report("Cannot move beyond the first line");
                return;

        } else if (steps >= 0 && view->lineno + 1 >= view->lines) {
                report("Cannot move beyond the last line");
                return;
        }

        /* Move the current line */
        view->lineno += steps;
        assert(0 <= view->lineno && view->lineno < view->lines);

        /* Check whether the view needs to be scrolled */
        if (view->lineno < view->offset ||
            view->lineno >= view->offset + view->height) {
                scroll_steps = steps;
                if (steps < 0 && -steps > view->offset) {
                        scroll_steps = -view->offset;

                } else if (steps > 0) {
                        if (view->lineno == view->lines - 1 &&
                            view->lines > view->height) {
                                scroll_steps = view->lines - view->offset - 1;
                                if (scroll_steps >= view->height)
                                        scroll_steps -= view->height - 1;
                        }
                }
        }

        if (!view_is_displayed(view)) {
                view->offset += steps;
                view->ops->select(view, &view->line[view->lineno]);
                return;
        }

        /* Repaint the old "current" line if we be scrolling */
        if (ABS(steps) < view->height)
                draw_view_line(view, view->lineno - steps - view->offset);

        if (scroll_steps) {
                do_scroll_view(view, scroll_steps);
                return;
        }

        /* Draw the current line */
        draw_view_line(view, view->lineno - view->offset);

        redrawwin(view->win);
        wrefresh(view->win);
        report("");
}


/*
 * Searching
 */

static void search_view(struct view *view, enum request request);

static bool
find_next_line(struct view *view, unsigned long lineno, struct line *line)
{
        assert(view_is_displayed(view));

        if (!view->ops->grep(view, line))
                return FALSE;

        if (lineno - view->offset >= view->height) {
                view->offset = lineno;
                view->lineno = lineno;
                redraw_view(view);

        } else {
                unsigned long old_lineno = view->lineno - view->offset;

                view->lineno = lineno;
                draw_view_line(view, old_lineno);

                draw_view_line(view, view->lineno - view->offset);
                redrawwin(view->win);
                wrefresh(view->win);
        }

        report("Line %ld matches '%s'", lineno + 1, view->grep);
        return TRUE;
}

static void
find_next(struct view *view, enum request request)
{
        unsigned long lineno = view->lineno;
        int direction;

        if (!*view->grep) {
                if (!*opt_search)
                        report("No previous search");
                else
                        search_view(view, request);
                return;
        }

        switch (request) {
        case REQ_SEARCH:
        case REQ_FIND_NEXT:
                direction = 1;
                break;

        case REQ_SEARCH_BACK:
        case REQ_FIND_PREV:
                direction = -1;
                break;

        default:
                return;
        }

        if (request == REQ_FIND_NEXT || request == REQ_FIND_PREV)
                lineno += direction;

        /* Note, lineno is unsigned long so will wrap around in which case it
         * will become bigger than view->lines. */
        for (; lineno < view->lines; lineno += direction) {
                struct line *line = &view->line[lineno];

                if (find_next_line(view, lineno, line))
                        return;
        }

        report("No match found for '%s'", view->grep);
}

static void
search_view(struct view *view, enum request request)
{
        int regex_err;

        if (view->regex) {
                regfree(view->regex);
                *view->grep = 0;
        } else {
                view->regex = calloc(1, sizeof(*view->regex));
                if (!view->regex)
                        return;
        }

        regex_err = regcomp(view->regex, opt_search, REG_EXTENDED);
        if (regex_err != 0) {
                char buf[SIZEOF_STR] = "unknown error";

                regerror(regex_err, view->regex, buf, sizeof(buf));
                report("Search failed: %s", buf);
                return;
        }

        string_copy(view->grep, opt_search);

        find_next(view, request);
}

/*
 * Incremental updating
 */

static void
end_update(struct view *view)
{
        if (!view->pipe)
                return;
        set_nonblocking_input(FALSE);
        if (view->pipe == stdin)
                fclose(view->pipe);
        else
                pclose(view->pipe);
        view->pipe = NULL;
}

static bool
begin_update(struct view *view)
{
        const char *id = view->id;

        if (view->pipe)
                end_update(view);

        if (opt_cmd[0]) {
                string_copy(view->cmd, opt_cmd);
                opt_cmd[0] = 0;
                /* When running random commands, the view ref could have become
                 * invalid so clear it. */
                view->ref[0] = 0;

        } else if (view == VIEW(REQ_VIEW_TREE)) {
                const char *format = view->cmd_env ? view->cmd_env : view->cmd_fmt;

                if (strcmp(view->vid, view->id))
                        opt_path[0] = 0;

                if (!string_format(view->cmd, format, id, opt_path))
                        return FALSE;

        } else {
                const char *format = view->cmd_env ? view->cmd_env : view->cmd_fmt;

                if (!string_format(view->cmd, format, id, id, id, id, id))
                        return FALSE;
        }

        /* Special case for the pager view. */
        if (opt_pipe) {
                view->pipe = opt_pipe;
                opt_pipe = NULL;
        } else {
                view->pipe = popen(view->cmd, "r");
        }

        if (!view->pipe)
                return FALSE;

        set_nonblocking_input(TRUE);

        view->offset = 0;
        view->lines  = 0;
        view->lineno = 0;
        string_copy(view->vid, id);

        if (view->line) {
                int i;

                for (i = 0; i < view->lines; i++)
                        if (view->line[i].data)
                                free(view->line[i].data);

                free(view->line);
                view->line = NULL;
        }

        view->start_time = time(NULL);

        return TRUE;
}

static struct line *
realloc_lines(struct view *view, size_t line_size)
{
        struct line *tmp = realloc(view->line, sizeof(*view->line) * line_size);

        if (!tmp)
                return NULL;

        view->line = tmp;
        view->line_size = line_size;
        return view->line;
}

static bool
update_view(struct view *view)
{
        char in_buffer[BUFSIZ];
        char out_buffer[BUFSIZ * 2];
        char *line;
        /* The number of lines to read. If too low it will cause too much
         * redrawing (and possible flickering), if too high responsiveness
         * will suffer. */
        unsigned long lines = view->height;
        int redraw_from = -1;

        if (!view->pipe)
                return TRUE;

        /* Only redraw if lines are visible. */
        if (view->offset + view->height >= view->lines)
                redraw_from = view->lines - view->offset;

        /* FIXME: This is probably not perfect for backgrounded views. */
        if (!realloc_lines(view, view->lines + lines))
                goto alloc_error;

        while ((line = fgets(in_buffer, sizeof(in_buffer), view->pipe))) {
                size_t linelen = strlen(line);

                if (linelen)
                        line[linelen - 1] = 0;

                if (opt_iconv != ICONV_NONE) {
                        char *inbuf = line;
                        size_t inlen = linelen;

                        char *outbuf = out_buffer;
                        size_t outlen = sizeof(out_buffer);

                        size_t ret;

                        ret = iconv(opt_iconv, &inbuf, &inlen, &outbuf, &outlen);
                        if (ret != (size_t) -1) {
                                line = out_buffer;
                                linelen = strlen(out_buffer);
                        }
                }

                if (!view->ops->read(view, line))
                        goto alloc_error;

                if (lines-- == 1)
                        break;
        }

        {
                int digits;

                lines = view->lines;
                for (digits = 0; lines; digits++)
                        lines /= 10;

                /* Keep the displayed view in sync with line number scaling. */
                if (digits != view->digits) {
                        view->digits = digits;
                        redraw_from = 0;
                }
        }

        if (!view_is_displayed(view))
                goto check_pipe;

        if (view == VIEW(REQ_VIEW_TREE)) {
                /* Clear the view and redraw everything since the tree sorting
                 * might have rearranged things. */
                redraw_view(view);

        } else if (redraw_from >= 0) {
                /* If this is an incremental update, redraw the previous line
                 * since for commits some members could have changed when
                 * loading the main view. */
                if (redraw_from > 0)
                        redraw_from--;

                /* Incrementally draw avoids flickering. */
                redraw_view_from(view, redraw_from);
        }

        /* Update the title _after_ the redraw so that if the redraw picks up a
         * commit reference in view->ref it'll be available here. */
        update_view_title(view);

check_pipe:
        if (ferror(view->pipe)) {
                report("Failed to read: %s", strerror(errno));
                goto end;

        } else if (feof(view->pipe)) {
                report("");
                goto end;
        }

        return TRUE;

alloc_error:
        report("Allocation failure");

end:
        end_update(view);
        return FALSE;
}


/*
 * View opening
 */

static void open_help_view(struct view *view)
{
        char buf[BUFSIZ];
        int lines = ARRAY_SIZE(req_info) + 2;
        int i;

        if (view->lines > 0)
                return;

        for (i = 0; i < ARRAY_SIZE(req_info); i++)
                if (!req_info[i].request)
                        lines++;

        view->line = calloc(lines, sizeof(*view->line));
        if (!view->line) {
                report("Allocation failure");
                return;
        }

        view->ops->read(view, "Quick reference for tig keybindings:");

        for (i = 0; i < ARRAY_SIZE(req_info); i++) {
                char *key;

                if (!req_info[i].request) {
                        view->ops->read(view, "");
                        view->ops->read(view, req_info[i].help);
                        continue;
                }

                key = get_key(req_info[i].request);
                if (!string_format(buf, "%-25s %s", key, req_info[i].help))
                        continue;

                view->ops->read(view, buf);
        }
}

enum open_flags {
        OPEN_DEFAULT = 0,       /* Use default view switching. */
        OPEN_SPLIT = 1,         /* Split current view. */
        OPEN_BACKGROUNDED = 2,  /* Backgrounded. */
        OPEN_RELOAD = 4,        /* Reload view even if it is the current. */
};

static void
open_view(struct view *prev, enum request request, enum open_flags flags)
{
        bool backgrounded = !!(flags & OPEN_BACKGROUNDED);
        bool split = !!(flags & OPEN_SPLIT);
        bool reload = !!(flags & OPEN_RELOAD);
        struct view *view = VIEW(request);
        int nviews = displayed_views();
        struct view *base_view = display[0];

        if (view == prev && nviews == 1 && !reload) {
                report("Already in %s view", view->name);
                return;
        }

        if (view == VIEW(REQ_VIEW_HELP)) {
                open_help_view(view);

        } else if ((reload || strcmp(view->vid, view->id)) &&
                   !begin_update(view)) {
                report("Failed to load %s view", view->name);
                return;
        }

        if (split) {
                display[1] = view;
                if (!backgrounded)
                        current_view = 1;
        } else {
                /* Maximize the current view. */
                memset(display, 0, sizeof(display));
                current_view = 0;
                display[current_view] = view;
        }

        /* Resize the view when switching between split- and full-screen,
         * or when switching between two different full-screen views. */
        if (nviews != displayed_views() ||
            (nviews == 1 && base_view != display[0]))
                resize_display();

        if (split && prev->lineno - prev->offset >= prev->height) {
                /* Take the title line into account. */
                int lines = prev->lineno - prev->offset - prev->height + 1;

                /* Scroll the view that was split if the current line is
                 * outside the new limited view. */
                do_scroll_view(prev, lines);
        }

        if (prev && view != prev) {
                if (split && !backgrounded) {
                        /* "Blur" the previous view. */
                        update_view_title(prev);
                }

                view->parent = prev;
        }

        if (view->pipe && view->lines == 0) {
                /* Clear the old view and let the incremental updating refill
                 * the screen. */
                wclear(view->win);
                report("");
        } else {
                redraw_view(view);
                report("");
        }

        /* If the view is backgrounded the above calls to report()
         * won't redraw the view title. */
        if (backgrounded)
                update_view_title(view);
}


/*
 * User request switch noodle
 */

static int
view_driver(struct view *view, enum request request)
{
        int i;

        switch (request) {
        case REQ_MOVE_UP:
        case REQ_MOVE_DOWN:
        case REQ_MOVE_PAGE_UP:
        case REQ_MOVE_PAGE_DOWN:
        case REQ_MOVE_FIRST_LINE:
        case REQ_MOVE_LAST_LINE:
                move_view(view, request);
                break;

        case REQ_SCROLL_LINE_DOWN:
        case REQ_SCROLL_LINE_UP:
        case REQ_SCROLL_PAGE_DOWN:
        case REQ_SCROLL_PAGE_UP:
                scroll_view(view, request);
                break;

        case REQ_VIEW_BLOB:
                if (!ref_blob[0]) {
                        report("No file chosen, press 't' to open tree view");
                        break;
                }
                /* Fall-through */
        case REQ_VIEW_MAIN:
        case REQ_VIEW_DIFF:
        case REQ_VIEW_LOG:
        case REQ_VIEW_TREE:
        case REQ_VIEW_HELP:
        case REQ_VIEW_PAGER:
                open_view(view, request, OPEN_DEFAULT);
                break;

        case REQ_NEXT:
        case REQ_PREVIOUS:
                request = request == REQ_NEXT ? REQ_MOVE_DOWN : REQ_MOVE_UP;

                if ((view == VIEW(REQ_VIEW_DIFF) &&
                     view->parent == VIEW(REQ_VIEW_MAIN)) ||
                   (view == VIEW(REQ_VIEW_BLOB) &&
                     view->parent == VIEW(REQ_VIEW_TREE))) {
                        view = view->parent;
                        move_view(view, request);
                        if (view_is_displayed(view))
                                update_view_title(view);
                } else {
                        move_view(view, request);
                        break;
                }
                /* Fall-through */

        case REQ_ENTER:
                if (!view->lines) {
                        report("Nothing to enter");
                        break;
                }
                return view->ops->enter(view, &view->line[view->lineno]);

        case REQ_VIEW_NEXT:
        {
                int nviews = displayed_views();
                int next_view = (current_view + 1) % nviews;

                if (next_view == current_view) {
                        report("Only one view is displayed");
                        break;
                }

                current_view = next_view;
                /* Blur out the title of the previous view. */
                update_view_title(view);
                report("");
                break;
        }
        case REQ_TOGGLE_LINENO:
                opt_line_number = !opt_line_number;
                redraw_display();
                break;

        case REQ_TOGGLE_REV_GRAPH:
                opt_rev_graph = !opt_rev_graph;
                redraw_display();
                break;

        case REQ_PROMPT:
                /* Always reload^Wrerun commands from the prompt. */
                open_view(view, opt_request, OPEN_RELOAD);
                break;

        case REQ_SEARCH:
        case REQ_SEARCH_BACK:
                search_view(view, request);
                break;

        case REQ_FIND_NEXT:
        case REQ_FIND_PREV:
                find_next(view, request);
                break;

        case REQ_STOP_LOADING:
                for (i = 0; i < ARRAY_SIZE(views); i++) {
                        view = &views[i];
                        if (view->pipe)
                                report("Stopped loading the %s view", view->name),
                        end_update(view);
                }
                break;

        case REQ_SHOW_VERSION:
                report("%s (built %s)", VERSION, __DATE__);
                return TRUE;

        case REQ_SCREEN_RESIZE:
                resize_display();
                /* Fall-through */
        case REQ_SCREEN_REDRAW:
                redraw_display();
                break;

        case REQ_NONE:
                doupdate();
                return TRUE;

        case REQ_VIEW_CLOSE:
                /* XXX: Mark closed views by letting view->parent point to the
                 * view itself. Parents to closed view should never be
                 * followed. */
                if (view->parent &&
                    view->parent->parent != view->parent) {
                        memset(display, 0, sizeof(display));
                        current_view = 0;
                        display[current_view] = view->parent;
                        view->parent = view;
                        resize_display();
                        redraw_display();
                        break;
                }
                /* Fall-through */
        case REQ_QUIT:
                return FALSE;

        default:
                /* An unknown key will show most commonly used commands. */
                report("Unknown key, press 'h' for help");
                return TRUE;
        }

        return TRUE;
}


/*
 * Pager backend
 */

static bool
pager_draw(struct view *view, struct line *line, unsigned int lineno, bool selected)
{
        char *text = line->data;
        enum line_type type = line->type;
        int textlen = strlen(text);
        int attr;

        wmove(view->win, lineno, 0);

        if (selected) {
                type = LINE_CURSOR;
                wchgat(view->win, -1, 0, type, NULL);
        }

        attr = get_line_attr(type);
        wattrset(view->win, attr);

        if (opt_line_number || opt_tab_size < TABSIZE) {
                static char spaces[] = "                    ";
                int col_offset = 0, col = 0;

                if (opt_line_number) {
                        unsigned long real_lineno = view->offset + lineno + 1;

                        if (real_lineno == 1 ||
                            (real_lineno % opt_num_interval) == 0) {
                                wprintw(view->win, "%.*d", view->digits, real_lineno);

                        } else {
                                waddnstr(view->win, spaces,
                                         MIN(view->digits, STRING_SIZE(spaces)));
                        }
                        waddstr(view->win, ": ");
                        col_offset = view->digits + 2;
                }

                while (text && col_offset + col < view->width) {
                        int cols_max = view->width - col_offset - col;
                        char *pos = text;
                        int cols;

                        if (*text == '\t') {
                                text++;
                                assert(sizeof(spaces) > TABSIZE);
                                pos = spaces;
                                cols = opt_tab_size - (col % opt_tab_size);

                        } else {
                                text = strchr(text, '\t');
                                cols = line ? text - pos : strlen(pos);
                        }

                        waddnstr(view->win, pos, MIN(cols, cols_max));
                        col += cols;
                }

        } else {
                int col = 0, pos = 0;

                for (; pos < textlen && col < view->width; pos++, col++)
                        if (text[pos] == '\t')
                                col += TABSIZE - (col % TABSIZE) - 1;

                waddnstr(view->win, text, pos);
        }

        return TRUE;
}

static bool
add_describe_ref(char *buf, size_t *bufpos, char *commit_id, const char *sep)
{
        char refbuf[SIZEOF_STR];
        char *ref = NULL;
        FILE *pipe;

        if (!string_format(refbuf, "git describe %s", commit_id))
                return TRUE;

        pipe = popen(refbuf, "r");
        if (!pipe)
                return TRUE;

        if ((ref = fgets(refbuf, sizeof(refbuf), pipe)))
                ref = chomp_string(ref);
        pclose(pipe);

        if (!ref || !*ref)
                return TRUE;

        /* This is the only fatal call, since it can "corrupt" the buffer. */
        if (!string_nformat(buf, SIZEOF_STR, bufpos, "%s%s", sep, ref))
                return FALSE;

        return TRUE;
}

static void
add_pager_refs(struct view *view, struct line *line)
{
        char buf[SIZEOF_STR];
        char *commit_id = line->data + STRING_SIZE("commit ");
        struct ref **refs;
        size_t bufpos = 0, refpos = 0;
        const char *sep = "Refs: ";
        bool is_tag = FALSE;

        assert(line->type == LINE_COMMIT);

        refs = get_refs(commit_id);
        if (!refs) {
                if (view == VIEW(REQ_VIEW_DIFF))
                        goto try_add_describe_ref;
                return;
        }

        do {
                struct ref *ref = refs[refpos];
                char *fmt = ref->tag ? "%s[%s]" : "%s%s";

                if (!string_format_from(buf, &bufpos, fmt, sep, ref->name))
                        return;
                sep = ", ";
                if (ref->tag)
                        is_tag = TRUE;
        } while (refs[refpos++]->next);

        if (!is_tag && view == VIEW(REQ_VIEW_DIFF)) {
try_add_describe_ref:
                /* Add <tag>-g<commit_id> "fake" reference. */
                if (!add_describe_ref(buf, &bufpos, commit_id, sep))
                        return;
        }

        if (bufpos == 0)
                return;

        if (!realloc_lines(view, view->line_size + 1))
                return;

        line = &view->line[view->lines];
        line->data = strdup(buf);
        if (!line->data)
                return;

        line->type = LINE_PP_REFS;
        view->lines++;
}

static bool
pager_read(struct view *view, char *data)
{
        struct line *line = &view->line[view->lines];

        line->data = strdup(data);
        if (!line->data)
                return FALSE;

        line->type = get_line_type(line->data);
        view->lines++;

        if (line->type == LINE_COMMIT &&
            (view == VIEW(REQ_VIEW_DIFF) ||
             view == VIEW(REQ_VIEW_LOG)))
                add_pager_refs(view, line);

        return TRUE;
}

static bool
pager_enter(struct view *view, struct line *line)
{
        int split = 0;

        if (line->type == LINE_COMMIT &&
           (view == VIEW(REQ_VIEW_LOG) ||
            view == VIEW(REQ_VIEW_PAGER))) {
                open_view(view, REQ_VIEW_DIFF, OPEN_SPLIT);
                split = 1;
        }

        /* Always scroll the view even if it was split. That way
         * you can use Enter to scroll through the log view and
         * split open each commit diff. */
        scroll_view(view, REQ_SCROLL_LINE_DOWN);

        /* FIXME: A minor workaround. Scrolling the view will call report("")
         * but if we are scrolling a non-current view this won't properly
         * update the view title. */
        if (split)
                update_view_title(view);

        return TRUE;
}

static bool
pager_grep(struct view *view, struct line *line)
{
        regmatch_t pmatch;
        char *text = line->data;

        if (!*text)
                return FALSE;

        if (regexec(view->regex, text, 1, &pmatch, 0) == REG_NOMATCH)
                return FALSE;

        return TRUE;
}

static void
pager_select(struct view *view, struct line *line)
{
        if (line->type == LINE_COMMIT) {
                char *text = line->data;

                string_copy(view->ref, text + STRING_SIZE("commit "));
                string_copy(ref_commit, view->ref);
        }
}

static struct view_ops pager_ops = {
        "line",
        pager_draw,
        pager_read,
        pager_enter,
        pager_grep,
        pager_select,
};


/*
 * Tree backend
 */

/* Parse output from git-ls-tree(1):
 *
 * 100644 blob fb0e31ea6cc679b7379631188190e975f5789c26 Makefile
 * 100644 blob 5304ca4260aaddaee6498f9630e7d471b8591ea6 README
 * 100644 blob f931e1d229c3e185caad4449bf5b66ed72462657 tig.c
 * 100644 blob ed09fe897f3c7c9af90bcf80cae92558ea88ae38 web.conf
 */

#define SIZEOF_TREE_ATTR \
        STRING_SIZE("100644 blob ed09fe897f3c7c9af90bcf80cae92558ea88ae38\t")

#define TREE_UP_FORMAT "040000 tree %s\t.."

static int
tree_compare_entry(enum line_type type1, char *name1,
                   enum line_type type2, char *name2)
{
        if (type1 != type2) {
                if (type1 == LINE_TREE_DIR)
                        return -1;
                return 1;
        }

        return strcmp(name1, name2);
}

static bool
tree_read(struct view *view, char *text)
{
        size_t textlen = strlen(text);
        char buf[SIZEOF_STR];
        unsigned long pos;
        enum line_type type;
        bool first_read = view->lines == 0;

        if (textlen <= SIZEOF_TREE_ATTR)
                return FALSE;

        type = text[STRING_SIZE("100644 ")] == 't'
             ? LINE_TREE_DIR : LINE_TREE_FILE;

        if (first_read) {
                /* Add path info line */
                if (string_format(buf, "Directory path /%s", opt_path) &&
                    realloc_lines(view, view->line_size + 1) &&
                    pager_read(view, buf))
                        view->line[view->lines - 1].type = LINE_DEFAULT;
                else
                        return FALSE;

                /* Insert "link" to parent directory. */
                if (*opt_path &&
                    string_format(buf, TREE_UP_FORMAT, view->ref) &&
                    realloc_lines(view, view->line_size + 1) &&
                    pager_read(view, buf))
                        view->line[view->lines - 1].type = LINE_TREE_DIR;
                else if (*opt_path)
                        return FALSE;
        }

        /* Strip the path part ... */
        if (*opt_path) {
                size_t pathlen = textlen - SIZEOF_TREE_ATTR;
                size_t striplen = strlen(opt_path);
                char *path = text + SIZEOF_TREE_ATTR;

                if (pathlen > striplen)
                        memmove(path, path + striplen,
                                pathlen - striplen + 1);
        }

        /* Skip "Directory ..." and ".." line. */
        for (pos = 1 + !!*opt_path; pos < view->lines; pos++) {
                struct line *line = &view->line[pos];
                char *path1 = ((char *) line->data) + SIZEOF_TREE_ATTR;
                char *path2 = text + SIZEOF_TREE_ATTR;
                int cmp = tree_compare_entry(line->type, path1, type, path2);

                if (cmp <= 0)
                        continue;

                text = strdup(text);
                if (!text)
                        return FALSE;

                if (view->lines > pos)
                        memmove(&view->line[pos + 1], &view->line[pos],
                                (view->lines - pos) * sizeof(*line));

                line = &view->line[pos];
                line->data = text;
                line->type = type;
                view->lines++;
                return TRUE;
        }

        if (!pager_read(view, text))
                return FALSE;

        /* Move the current line to the first tree entry. */
        if (first_read)
                view->lineno++;

        view->line[view->lines - 1].type = type;
        return TRUE;
}

static bool
tree_enter(struct view *view, struct line *line)
{
        enum open_flags flags = display[0] == view ? OPEN_SPLIT : OPEN_DEFAULT;
        enum request request;

        switch (line->type) {
        case LINE_TREE_DIR:
                /* Depending on whether it is a subdir or parent (updir?) link
                 * mangle the path buffer. */
                if (line == &view->line[1] && *opt_path) {
                        size_t path_len = strlen(opt_path);
                        char *dirsep = opt_path + path_len - 1;

                        while (dirsep > opt_path && dirsep[-1] != '/')
                                dirsep--;

                        dirsep[0] = 0;

                } else {
                        size_t pathlen = strlen(opt_path);
                        size_t origlen = pathlen;
                        char *data = line->data;
                        char *basename = data + SIZEOF_TREE_ATTR;

                        if (!string_format_from(opt_path, &pathlen, "%s/", basename)) {
                                opt_path[origlen] = 0;
                                return TRUE;
                        }
                }

                /* Trees and subtrees share the same ID, so they are not not
                 * unique like blobs. */
                flags |= OPEN_RELOAD;
                request = REQ_VIEW_TREE;
                break;

        case LINE_TREE_FILE:
                request = REQ_VIEW_BLOB;
                break;

        default:
                return TRUE;
        }

        open_view(view, request, flags);

        return TRUE;
}

static void
tree_select(struct view *view, struct line *line)
{
        char *text = line->data;

        text += STRING_SIZE("100644 blob ");

        if (line->type == LINE_TREE_FILE) {
                string_ncopy(ref_blob, text, 40);
                /* Also update the blob view's ref, since all there must always
                 * be in sync. */
                string_copy(VIEW(REQ_VIEW_BLOB)->ref, ref_blob);

        } else if (line->type != LINE_TREE_DIR) {
                return;
        }

        string_ncopy(view->ref, text, 40);
}

static struct view_ops tree_ops = {
        "file",
        pager_draw,
        tree_read,
        tree_enter,
        pager_grep,
        tree_select,
};

static bool
blob_read(struct view *view, char *line)
{
        bool state = pager_read(view, line);

        if (state == TRUE)
                view->line[view->lines - 1].type = LINE_DEFAULT;

        return state;
}

static struct view_ops blob_ops = {
        "line",
        pager_draw,
        blob_read,
        pager_enter,
        pager_grep,
        pager_select,
};


/*
 * Main view backend
 */

struct commit {
        char id[SIZEOF_REV];            /* SHA1 ID. */
        char title[75];                 /* First line of the commit message. */
        char author[75];                /* Author of the commit. */
        struct tm time;                 /* Date from the author ident. */
        struct ref **refs;              /* Repository references. */
        chtype graph[SIZEOF_REVGRAPH];  /* Ancestry chain graphics. */
        size_t graph_size;              /* The width of the graph array. */
};

static bool
main_draw(struct view *view, struct line *line, unsigned int lineno, bool selected)
{
        char buf[DATE_COLS + 1];
        struct commit *commit = line->data;
        enum line_type type;
        int col = 0;
        size_t timelen;
        size_t authorlen;
        int trimmed = 1;

        if (!*commit->author)
                return FALSE;

        wmove(view->win, lineno, col);

        if (selected) {
                type = LINE_CURSOR;
                wattrset(view->win, get_line_attr(type));
                wchgat(view->win, -1, 0, type, NULL);

        } else {
                type = LINE_MAIN_COMMIT;
                wattrset(view->win, get_line_attr(LINE_MAIN_DATE));
        }

        timelen = strftime(buf, sizeof(buf), DATE_FORMAT, &commit->time);
        waddnstr(view->win, buf, timelen);
        waddstr(view->win, " ");

        col += DATE_COLS;
        wmove(view->win, lineno, col);
        if (type != LINE_CURSOR)
                wattrset(view->win, get_line_attr(LINE_MAIN_AUTHOR));

        if (opt_utf8) {
                authorlen = utf8_length(commit->author, AUTHOR_COLS - 2, &col, &trimmed);
        } else {
                authorlen = strlen(commit->author);
                if (authorlen > AUTHOR_COLS - 2) {
                        authorlen = AUTHOR_COLS - 2;
                        trimmed = 1;
                }
        }

        if (trimmed) {
                waddnstr(view->win, commit->author, authorlen);
                if (type != LINE_CURSOR)
                        wattrset(view->win, get_line_attr(LINE_MAIN_DELIM));
                waddch(view->win, '~');
        } else {
                waddstr(view->win, commit->author);
        }

        col += AUTHOR_COLS;
        if (type != LINE_CURSOR)
                wattrset(view->win, A_NORMAL);

        if (opt_rev_graph && commit->graph_size) {
                size_t i;

                wmove(view->win, lineno, col);
                /* Using waddch() instead of waddnstr() ensures that
                 * they'll be rendered correctly for the cursor line. */
                for (i = 0; i < commit->graph_size; i++)
                        waddch(view->win, commit->graph[i]);

                col += commit->graph_size + 1;
        }

        wmove(view->win, lineno, col);

        if (commit->refs) {
                size_t i = 0;

                do {
                        if (type == LINE_CURSOR)
                                ;
                        else if (commit->refs[i]->tag)
                                wattrset(view->win, get_line_attr(LINE_MAIN_TAG));
                        else
                                wattrset(view->win, get_line_attr(LINE_MAIN_REF));
                        waddstr(view->win, "[");
                        waddstr(view->win, commit->refs[i]->name);
                        waddstr(view->win, "]");
                        if (type != LINE_CURSOR)
                                wattrset(view->win, A_NORMAL);
                        waddstr(view->win, " ");
                        col += strlen(commit->refs[i]->name) + STRING_SIZE("[] ");
                } while (commit->refs[i++]->next);
        }

        if (type != LINE_CURSOR)
                wattrset(view->win, get_line_attr(type));

        {
                int titlelen = strlen(commit->title);

                if (col + titlelen > view->width)
                        titlelen = view->width - col;

                waddnstr(view->win, commit->title, titlelen);
        }

        return TRUE;
}

/* Reads git log --pretty=raw output and parses it into the commit struct. */
static bool
main_read(struct view *view, char *line)
{
        enum line_type type = get_line_type(line);
        struct commit *commit = view->lines
                              ? view->line[view->lines - 1].data : NULL;

        switch (type) {
        case LINE_COMMIT:
                commit = calloc(1, sizeof(struct commit));
                if (!commit)
                        return FALSE;

                line += STRING_SIZE("commit ");

                view->line[view->lines++].data = commit;
                string_copy(commit->id, line);
                commit->refs = get_refs(commit->id);
                commit->graph[commit->graph_size++] = ACS_LTEE;
                break;

        case LINE_AUTHOR:
        {
                char *ident = line + STRING_SIZE("author ");
                char *end = strchr(ident, '<');

                if (!commit)
                        break;

                if (end) {
                        char *email = end + 1;

                        for (; end > ident && isspace(end[-1]); end--) ;

                        if (end == ident && *email) {
                                ident = email;
                                end = strchr(ident, '>');
                                for (; end > ident && isspace(end[-1]); end--) ;
                        }
                        *end = 0;
                }

                /* End is NULL or ident meaning there's no author. */
                if (end <= ident)
                        ident = "Unknown";

                string_copy(commit->author, ident);

                /* Parse epoch and timezone */
                if (end) {
                        char *secs = strchr(end + 1, '>');
                        char *zone;
                        time_t time;

                        if (!secs || secs[1] != ' ')
                                break;

                        secs += 2;
                        time = (time_t) atol(secs);
                        zone = strchr(secs, ' ');
                        if (zone && strlen(zone) == STRING_SIZE(" +0700")) {
                                long tz;

                                zone++;
                                tz  = ('0' - zone[1]) * 60 * 60 * 10;
                                tz += ('0' - zone[2]) * 60 * 60;
                                tz += ('0' - zone[3]) * 60;
                                tz += ('0' - zone[4]) * 60;

                                if (zone[0] == '-')
                                        tz = -tz;

                                time -= tz;
                        }
                        gmtime_r(&time, &commit->time);
                }
                break;
        }
        default:
                if (!commit)
                        break;

                /* Fill in the commit title if it has not already been set. */
                if (commit->title[0])
                        break;

                /* Require titles to start with a non-space character at the
                 * offset used by git log. */
                /* FIXME: More gracefull handling of titles; append "..." to
                 * shortened titles, etc. */
                if (strncmp(line, "    ", 4) ||
                    isspace(line[4]))
                        break;

                string_copy(commit->title, line + 4);
        }

        return TRUE;
}

static bool
main_enter(struct view *view, struct line *line)
{
        enum open_flags flags = display[0] == view ? OPEN_SPLIT : OPEN_DEFAULT;

        open_view(view, REQ_VIEW_DIFF, flags);
        return TRUE;
}

static bool
main_grep(struct view *view, struct line *line)
{
        struct commit *commit = line->data;
        enum { S_TITLE, S_AUTHOR, S_DATE, S_END } state;
        char buf[DATE_COLS + 1];
        regmatch_t pmatch;

        for (state = S_TITLE; state < S_END; state++) {
                char *text;

                switch (state) {
                case S_TITLE:   text = commit->title;   break;
                case S_AUTHOR:  text = commit->author;  break;
                case S_DATE:
                        if (!strftime(buf, sizeof(buf), DATE_FORMAT, &commit->time))
                                continue;
                        text = buf;
                        break;

                default:
                        return FALSE;
                }

                if (regexec(view->regex, text, 1, &pmatch, 0) != REG_NOMATCH)
                        return TRUE;
        }

        return FALSE;
}

static void
main_select(struct view *view, struct line *line)
{
        struct commit *commit = line->data;

        string_copy(view->ref, commit->id);
        string_copy(ref_commit, view->ref);
}

static struct view_ops main_ops = {
        "commit",
        main_draw,
        main_read,
        main_enter,
        main_grep,
        main_select,
};


/*
 * Unicode / UTF-8 handling
 *
 * NOTE: Much of the following code for dealing with unicode is derived from
 * ELinks' UTF-8 code developed by Scrool <scroolik@gmail.com>. Origin file is
 * src/intl/charset.c from the utf8 branch commit elinks-0.11.0-g31f2c28.
 */

/* I've (over)annotated a lot of code snippets because I am not entirely
 * confident that the approach taken by this small UTF-8 interface is correct.
 * --jonas */

static inline int
unicode_width(unsigned long c)
{
        if (c >= 0x1100 &&
           (c <= 0x115f                         /* Hangul Jamo */
            || c == 0x2329
            || c == 0x232a
            || (c >= 0x2e80  && c <= 0xa4cf && c != 0x303f)
                                                /* CJK ... Yi */
            || (c >= 0xac00  && c <= 0xd7a3)    /* Hangul Syllables */
            || (c >= 0xf900  && c <= 0xfaff)    /* CJK Compatibility Ideographs */
            || (c >= 0xfe30  && c <= 0xfe6f)    /* CJK Compatibility Forms */
            || (c >= 0xff00  && c <= 0xff60)    /* Fullwidth Forms */
            || (c >= 0xffe0  && c <= 0xffe6)
            || (c >= 0x20000 && c <= 0x2fffd)
            || (c >= 0x30000 && c <= 0x3fffd)))
                return 2;

        return 1;
}

/* Number of bytes used for encoding a UTF-8 character indexed by first byte.
 * Illegal bytes are set one. */
static const unsigned char utf8_bytes[256] = {
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2,
        3,3,3,3,3,3,3,3, 3,3,3,3,3,3,3,3, 4,4,4,4,4,4,4,4, 5,5,5,5,6,6,1,1,
};

/* Decode UTF-8 multi-byte representation into a unicode character. */
static inline unsigned long
utf8_to_unicode(const char *string, size_t length)
{
        unsigned long unicode;

        switch (length) {
        case 1:
                unicode  =   string[0];
                break;
        case 2:
                unicode  =  (string[0] & 0x1f) << 6;
                unicode +=  (string[1] & 0x3f);
                break;
        case 3:
                unicode  =  (string[0] & 0x0f) << 12;
                unicode += ((string[1] & 0x3f) << 6);
                unicode +=  (string[2] & 0x3f);
                break;
        case 4:
                unicode  =  (string[0] & 0x0f) << 18;
                unicode += ((string[1] & 0x3f) << 12);
                unicode += ((string[2] & 0x3f) << 6);
                unicode +=  (string[3] & 0x3f);
                break;
        case 5:
                unicode  =  (string[0] & 0x0f) << 24;
                unicode += ((string[1] & 0x3f) << 18);
                unicode += ((string[2] & 0x3f) << 12);
                unicode += ((string[3] & 0x3f) << 6);
                unicode +=  (string[4] & 0x3f);
                break;
        case 6:
                unicode  =  (string[0] & 0x01) << 30;
                unicode += ((string[1] & 0x3f) << 24);
                unicode += ((string[2] & 0x3f) << 18);
                unicode += ((string[3] & 0x3f) << 12);
                unicode += ((string[4] & 0x3f) << 6);
                unicode +=  (string[5] & 0x3f);
                break;
        default:
                die("Invalid unicode length");
        }

        /* Invalid characters could return the special 0xfffd value but NUL
         * should be just as good. */
        return unicode > 0xffff ? 0 : unicode;
}

/* Calculates how much of string can be shown within the given maximum width
 * and sets trimmed parameter to non-zero value if all of string could not be
 * shown.
 *
 * Additionally, adds to coloffset how many many columns to move to align with
 * the expected position. Takes into account how multi-byte and double-width
 * characters will effect the cursor position.
 *
 * Returns the number of bytes to output from string to satisfy max_width. */
static size_t
utf8_length(const char *string, size_t max_width, int *coloffset, int *trimmed)
{
        const char *start = string;
        const char *end = strchr(string, '\0');
        size_t mbwidth = 0;
        size_t width = 0;

        *trimmed = 0;

        while (string < end) {
                int c = *(unsigned char *) string;
                unsigned char bytes = utf8_bytes[c];
                size_t ucwidth;
                unsigned long unicode;

                if (string + bytes > end)
                        break;

                /* Change representation to figure out whether
                 * it is a single- or double-width character. */

                unicode = utf8_to_unicode(string, bytes);
                /* FIXME: Graceful handling of invalid unicode character. */
                if (!unicode)
                        break;

                ucwidth = unicode_width(unicode);
                width  += ucwidth;
                if (width > max_width) {
                        *trimmed = 1;
                        break;
                }

                /* The column offset collects the differences between the
                 * number of bytes encoding a character and the number of
                 * columns will be used for rendering said character.
                 *
                 * So if some character A is encoded in 2 bytes, but will be
                 * represented on the screen using only 1 byte this will and up
                 * adding 1 to the multi-byte column offset.
                 *
                 * Assumes that no double-width character can be encoding in
                 * less than two bytes. */
                if (bytes > ucwidth)
                        mbwidth += bytes - ucwidth;

                string  += bytes;
        }

        *coloffset += mbwidth;

        return string - start;
}


/*
 * Status management
 */

/* Whether or not the curses interface has been initialized. */
static bool cursed = FALSE;

/* The status window is used for polling keystrokes. */
static WINDOW *status_win;

/* Update status and title window. */
static void
report(const char *msg, ...)
{
        static bool empty = TRUE;
        struct view *view = display[current_view];

        if (!empty || *msg) {
                va_list args;

                va_start(args, msg);

                werase(status_win);
                wmove(status_win, 0, 0);
                if (*msg) {
                        vwprintw(status_win, msg, args);
                        empty = FALSE;
                } else {
                        empty = TRUE;
                }
                wrefresh(status_win);

                va_end(args);
        }

        update_view_title(view);
        update_display_cursor(view);
}

/* Controls when nodelay should be in effect when polling user input. */
static void
set_nonblocking_input(bool loading)
{
        static unsigned int loading_views;

        if ((loading == FALSE && loading_views-- == 1) ||
            (loading == TRUE  && loading_views++ == 0))
                nodelay(status_win, loading);
}

static void
init_display(void)
{
        int x, y;

        /* Initialize the curses library */
        if (isatty(STDIN_FILENO)) {
                cursed = !!initscr();
        } else {
                /* Leave stdin and stdout alone when acting as a pager. */
                FILE *io = fopen("/dev/tty", "r+");

                if (!io)
                        die("Failed to open /dev/tty");
                cursed = !!newterm(NULL, io, io);
        }

        if (!cursed)
                die("Failed to initialize curses");

        nonl();         /* Tell curses not to do NL->CR/NL on output */
        cbreak();       /* Take input chars one at a time, no wait for \n */
        noecho();       /* Don't echo input */
        leaveok(stdscr, TRUE);

        if (has_colors())
                init_colors();

        getmaxyx(stdscr, y, x);
        status_win = newwin(1, 0, y - 1, 0);
        if (!status_win)
                die("Failed to create status window");

        /* Enable keyboard mapping */
        keypad(status_win, TRUE);
        wbkgdset(status_win, get_line_attr(LINE_STATUS));
}

static char *
read_prompt(const char *prompt)
{
        enum { READING, STOP, CANCEL } status = READING;
        static char buf[sizeof(opt_cmd) - STRING_SIZE("git \0")];
        int pos = 0;

        while (status == READING) {
                struct view *view;
                int i, key;

                foreach_view (view, i)
                        update_view(view);

                report("%s%.*s", prompt, pos, buf);
                /* Refresh, accept single keystroke of input */
                key = wgetch(status_win);
                switch (key) {
                case KEY_RETURN:
                case KEY_ENTER:
                case '\n':
                        status = pos ? STOP : CANCEL;
                        break;

                case KEY_BACKSPACE:
                        if (pos > 0)
                                pos--;
                        else
                                status = CANCEL;
                        break;

                case KEY_ESC:
                        status = CANCEL;
                        break;

                case ERR:
                        break;

                default:
                        if (pos >= sizeof(buf)) {
                                report("Input string too long");
                                return NULL;
                        }

                        if (isprint(key))
                                buf[pos++] = (char) key;
                }
        }

        if (status == CANCEL) {
                /* Clear the status window */
                report("");
                return NULL;
        }

        buf[pos++] = 0;

        return buf;
}

/*
 * Repository references
 */

static struct ref *refs;
static size_t refs_size;

/* Id <-> ref store */
static struct ref ***id_refs;
static size_t id_refs_size;

static struct ref **
get_refs(char *id)
{
        struct ref ***tmp_id_refs;
        struct ref **ref_list = NULL;
        size_t ref_list_size = 0;
        size_t i;

        for (i = 0; i < id_refs_size; i++)
                if (!strcmp(id, id_refs[i][0]->id))
                        return id_refs[i];

        tmp_id_refs = realloc(id_refs, (id_refs_size + 1) * sizeof(*id_refs));
        if (!tmp_id_refs)
                return NULL;

        id_refs = tmp_id_refs;

        for (i = 0; i < refs_size; i++) {
                struct ref **tmp;

                if (strcmp(id, refs[i].id))
                        continue;

                tmp = realloc(ref_list, (ref_list_size + 1) * sizeof(*ref_list));
                if (!tmp) {
                        if (ref_list)
                                free(ref_list);
                        return NULL;
                }

                ref_list = tmp;
                if (ref_list_size > 0)
                        ref_list[ref_list_size - 1]->next = 1;
                ref_list[ref_list_size] = &refs[i];

                /* XXX: The properties of the commit chains ensures that we can
                 * safely modify the shared ref. The repo references will
                 * always be similar for the same id. */
                ref_list[ref_list_size]->next = 0;
                ref_list_size++;
        }

        if (ref_list)
                id_refs[id_refs_size++] = ref_list;

        return ref_list;
}

static int
read_ref(char *id, int idlen, char *name, int namelen)
{
        struct ref *ref;
        bool tag = FALSE;

        if (!strncmp(name, "refs/tags/", STRING_SIZE("refs/tags/"))) {
                /* Commits referenced by tags has "^{}" appended. */
                if (name[namelen - 1] != '}')
                        return OK;

                while (namelen > 0 && name[namelen] != '^')
                        namelen--;

                tag = TRUE;
                namelen -= STRING_SIZE("refs/tags/");
                name    += STRING_SIZE("refs/tags/");

        } else if (!strncmp(name, "refs/heads/", STRING_SIZE("refs/heads/"))) {
                namelen -= STRING_SIZE("refs/heads/");
                name    += STRING_SIZE("refs/heads/");

        } else if (!strcmp(name, "HEAD")) {
                return OK;
        }

        refs = realloc(refs, sizeof(*refs) * (refs_size + 1));
        if (!refs)
                return ERR;

        ref = &refs[refs_size++];
        ref->name = malloc(namelen + 1);
        if (!ref->name)
                return ERR;

        strncpy(ref->name, name, namelen);
        ref->name[namelen] = 0;
        ref->tag = tag;
        string_copy(ref->id, id);

        return OK;
}

static int
load_refs(void)
{
        const char *cmd_env = getenv("TIG_LS_REMOTE");
        const char *cmd = cmd_env && *cmd_env ? cmd_env : TIG_LS_REMOTE;

        return read_properties(popen(cmd, "r"), "\t", read_ref);
}

static int
read_repo_config_option(char *name, int namelen, char *value, int valuelen)
{
        if (!strcmp(name, "i18n.commitencoding"))
                string_copy(opt_encoding, value);

        return OK;
}

static int
load_repo_config(void)
{
        return read_properties(popen("git repo-config --list", "r"),
                               "=", read_repo_config_option);
}

static int
read_properties(FILE *pipe, const char *separators,
                int (*read_property)(char *, int, char *, int))
{
        char buffer[BUFSIZ];
        char *name;
        int state = OK;

        if (!pipe)
                return ERR;

        while (state == OK && (name = fgets(buffer, sizeof(buffer), pipe))) {
                char *value;
                size_t namelen;
                size_t valuelen;

                name = chomp_string(name);
                namelen = strcspn(name, separators);

                if (name[namelen]) {
                        name[namelen] = 0;
                        value = chomp_string(name + namelen + 1);
                        valuelen = strlen(value);

                } else {
                        value = "";
                        valuelen = 0;
                }

                state = read_property(name, namelen, value, valuelen);
        }

        if (state != ERR && ferror(pipe))
                state = ERR;

        pclose(pipe);

        return state;
}


/*
 * Main
 */

static void __NORETURN
quit(int sig)
{
        /* XXX: Restore tty modes and let the OS cleanup the rest! */
        if (cursed)
                endwin();
        exit(0);
}

static void __NORETURN
die(const char *err, ...)
{
        va_list args;

        endwin();

        va_start(args, err);
        fputs("tig: ", stderr);
        vfprintf(stderr, err, args);
        fputs("\n", stderr);
        va_end(args);

        exit(1);
}

int
main(int argc, char *argv[])
{
        struct view *view;
        enum request request;
        size_t i;

        signal(SIGINT, quit);

        if (setlocale(LC_ALL, "")) {
                string_copy(opt_codeset, nl_langinfo(CODESET));
        }

        if (load_options() == ERR)
                die("Failed to load user config.");

        /* Load the repo config file so options can be overwritten from
         * the command line.  */
        if (load_repo_config() == ERR)
                die("Failed to load repo config.");

        if (!parse_options(argc, argv))
                return 0;

        if (*opt_codeset && strcmp(opt_codeset, opt_encoding)) {
                opt_iconv = iconv_open(opt_codeset, opt_encoding);
                if (opt_iconv == ICONV_NONE)
                        die("Failed to initialize character set conversion");
        }

        if (load_refs() == ERR)
                die("Failed to load refs.");

        /* Require a git repository unless when running in pager mode. */
        if (refs_size == 0 && opt_request != REQ_VIEW_PAGER)
                die("Not a git repository");

        for (i = 0; i < ARRAY_SIZE(views) && (view = &views[i]); i++)
                view->cmd_env = getenv(view->cmd_env);

        request = opt_request;

        init_display();

        while (view_driver(display[current_view], request)) {
                int key;
                int i;

                foreach_view (view, i)
                        update_view(view);

                /* Refresh, accept single keystroke of input */
                key = wgetch(status_win);

                request = get_keybinding(display[current_view]->keymap, key);

                /* Some low-level request handling. This keeps access to
                 * status_win restricted. */
                switch (request) {
                case REQ_PROMPT:
                {
                        char *cmd = read_prompt(":");

                        if (cmd && string_format(opt_cmd, "git %s", cmd)) {
                                if (strncmp(cmd, "show", 4) && isspace(cmd[4])) {
                                        opt_request = REQ_VIEW_DIFF;
                                } else {
                                        opt_request = REQ_VIEW_PAGER;
                                }
                                break;
                        }

                        request = REQ_NONE;
                        break;
                }
                case REQ_SEARCH:
                case REQ_SEARCH_BACK:
                {
                        const char *prompt = request == REQ_SEARCH
                                           ? "/" : "?";
                        char *search = read_prompt(prompt);

                        if (search)
                                string_copy(opt_search, search);
                        else
                                request = REQ_NONE;
                        break;
                }
                case REQ_SCREEN_RESIZE:
                {
                        int height, width;

                        getmaxyx(stdscr, height, width);

                        /* Resize the status view and let the view driver take
                         * care of resizing the displayed views. */
                        wresize(status_win, 1, width);
                        mvwin(status_win, height - 1, 0);
                        wrefresh(status_win);
                        break;
                }
                default:
                        break;
                }
        }

        quit(0);

        return 0;
}