Make the rev graph visualization have a one rev look-ahead
[tig] / tig.c
diff --git a/tig.c b/tig.c
index bfa8ae8..34a6358 100644 (file)
--- a/tig.c
+++ b/tig.c
@@ -59,6 +59,16 @@ static size_t utf8_length(const char *string, size_t max_width, int *coloffset,
 
 #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 */
+
+/* Revision graph */
+
+#define REVGRAPH_INIT  'I'
+#define REVGRAPH_MERGE 'M'
+#define REVGRAPH_BRANCH        '+'
+#define REVGRAPH_COMMIT        '*'
+#define REVGRAPH_LINE  '|'
+
 #define SIZEOF_REVGRAPH        19      /* Size of revision ancestry graphics. */
 
 /* This color name can be used to refer to the default term colors. */
@@ -109,7 +119,7 @@ static size_t utf8_length(const char *string, size_t max_width, int *coloffset,
 
 struct ref {
        char *name;             /* Ref name; tag or head names are shortened. */
-       char id[41];            /* Commit SHA1 ID */
+       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? */
 };
@@ -145,16 +155,22 @@ set_from_int_map(struct int_map *map, size_t map_size,
  */
 
 static inline void
-string_ncopy(char *dst, const char *src, size_t dstlen)
+string_ncopy_do(char *dst, size_t dstlen, const char *src, size_t srclen)
 {
-       strncpy(dst, src, dstlen - 1);
-       dst[dstlen - 1] = 0;
+       if (srclen > dstlen - 1)
+               srclen = dstlen - 1;
 
+       strncpy(dst, src, srclen);
+       dst[srclen] = 0;
 }
 
-/* Shorthand for safely copying into a fixed buffer. */
+/* Shorthands for safely copying into a fixed buffer. */
+
 #define string_copy(dst, src) \
-       string_ncopy(dst, src, sizeof(dst))
+       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)
@@ -559,6 +575,7 @@ 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), \
@@ -655,6 +672,10 @@ init_colors(void)
 
 struct line {
        enum line_type type;
+
+       /* State flags */
+       unsigned int selected:1;
+
        void *data;             /* User data */
 };
 
@@ -675,7 +696,7 @@ static struct keybinding default_keybindings[] = {
        { 'd',          REQ_VIEW_DIFF },
        { 'l',          REQ_VIEW_LOG },
        { 't',          REQ_VIEW_TREE },
-       { 'b',          REQ_VIEW_BLOB },
+       { 'f',          REQ_VIEW_BLOB },
        { 'p',          REQ_VIEW_PAGER },
        { 'h',          REQ_VIEW_HELP },
 
@@ -714,7 +735,7 @@ static struct keybinding default_keybindings[] = {
        { 'z',          REQ_STOP_LOADING },
        { 'v',          REQ_SHOW_VERSION },
        { 'r',          REQ_SCREEN_REDRAW },
-       { 'n',          REQ_TOGGLE_LINENO },
+       { '.',          REQ_TOGGLE_LINENO },
        { 'g',          REQ_TOGGLE_REV_GRAPH },
        { ':',          REQ_PROMPT },
 
@@ -1186,7 +1207,7 @@ struct view {
 
        /* Searching */
        char grep[SIZEOF_STR];  /* Search string */
-       regex_t regex;          /* Pre-compiled regex */
+       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. */
@@ -1207,13 +1228,15 @@ 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 (*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;
@@ -1249,12 +1272,26 @@ static struct view views[] = {
 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;
 
-       return view->ops->draw(view, &view->line[view->offset + lineno], lineno);
+       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
@@ -1406,9 +1443,9 @@ update_display_cursor(void)
 
 /* Scrolling backend */
 static void
-do_scroll_view(struct view *view, int lines, bool redraw)
+do_scroll_view(struct view *view, int lines)
 {
-       assert(view_is_displayed(view));
+       bool redraw_current_line = FALSE;
 
        /* The rendering expects the new offset. */
        view->offset += lines;
@@ -1416,6 +1453,17 @@ do_scroll_view(struct view *view, int lines, bool redraw)
        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);
@@ -1430,29 +1478,11 @@ do_scroll_view(struct view *view, int lines, bool redraw)
                        if (!draw_view_line(view, line))
                                break;
                }
-       }
-
-       /* Move current line into the view. */
-       if (view->lineno < view->offset) {
-               view->lineno = view->offset;
-               draw_view_line(view, 0);
 
-       } else if (view->lineno >= view->offset + view->height) {
-               if (view->lineno == view->offset + view->height) {
-                       /* Clear the hidden line so it doesn't show if the view
-                        * is scrolled up. */
-                       wmove(view->win, view->height, 0);
-                       wclrtoeol(view->win);
-               }
-               view->lineno = view->offset + view->height - 1;
-               draw_view_line(view, view->lineno - view->offset);
+               if (redraw_current_line)
+                       draw_view_line(view, view->lineno - view->offset);
        }
 
-       assert(view->offset <= view->lineno && view->lineno < view->lines);
-
-       if (!redraw)
-               return;
-
        redrawwin(view->win);
        wrefresh(view->win);
        report("");
@@ -1464,6 +1494,8 @@ 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;
@@ -1495,13 +1527,14 @@ scroll_view(struct view *view, enum request request)
                die("request %d not handled in switch", request);
        }
 
-       do_scroll_view(view, lines, TRUE);
+       do_scroll_view(view, lines);
 }
 
 /* Cursor moving */
 static void
-move_view(struct view *view, enum request request, bool redraw)
+move_view(struct view *view, enum request request)
 {
+       int scroll_steps = 0;
        int steps;
 
        switch (request) {
@@ -1548,39 +1581,40 @@ move_view(struct view *view, enum request request, bool redraw)
        view->lineno += steps;
        assert(0 <= view->lineno && view->lineno < view->lines);
 
-       /* Repaint the old "current" line if we be scrolling */
-       if (ABS(steps) < view->height) {
-               int prev_lineno = view->lineno - steps - view->offset;
-
-               wmove(view->win, prev_lineno, 0);
-               wclrtoeol(view->win);
-               draw_view_line(view,  prev_lineno);
-       }
-
        /* 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) {
-                       steps = -view->offset;
+                       scroll_steps = -view->offset;
 
                } else if (steps > 0) {
                        if (view->lineno == view->lines - 1 &&
                            view->lines > view->height) {
-                               steps = view->lines - view->offset - 1;
-                               if (steps >= view->height)
-                                       steps -= view->height - 1;
+                               scroll_steps = view->lines - view->offset - 1;
+                               if (scroll_steps >= view->height)
+                                       scroll_steps -= view->height - 1;
                        }
                }
+       }
 
-               do_scroll_view(view, steps, redraw);
+       if (!view_is_displayed(view)) {
+               view->offset += steps;
+               view->ops->select(view, &view->line[view->lineno]);
                return;
        }
 
-       /* Draw the current line */
-       draw_view_line(view, view->lineno - view->offset);
+       /* Repaint the old "current" line if we be scrolling */
+       if (ABS(steps) < view->height)
+               draw_view_line(view, view->lineno - steps - view->offset);
 
-       if (!redraw)
+       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);
@@ -1592,7 +1626,7 @@ move_view(struct view *view, enum request request, bool redraw)
  * Searching
  */
 
-static void search_view(struct view *view, enum request request, const char *search);
+static void search_view(struct view *view, enum request request);
 
 static bool
 find_next_line(struct view *view, unsigned long lineno, struct line *line)
@@ -1611,9 +1645,6 @@ find_next_line(struct view *view, unsigned long lineno, struct line *line)
                unsigned long old_lineno = view->lineno - view->offset;
 
                view->lineno = lineno;
-
-               wmove(view->win, old_lineno, 0);
-               wclrtoeol(view->win);
                draw_view_line(view, old_lineno);
 
                draw_view_line(view, view->lineno - view->offset);
@@ -1635,7 +1666,7 @@ find_next(struct view *view, enum request request)
                if (!*opt_search)
                        report("No previous search");
                else
-                       search_view(view, request, opt_search);
+                       search_view(view, request);
                return;
        }
 
@@ -1670,25 +1701,29 @@ find_next(struct view *view, enum request request)
 }
 
 static void
-search_view(struct view *view, enum request request, const char *search)
+search_view(struct view *view, enum request request)
 {
        int regex_err;
 
-       if (*view->grep) {
-               regfree(&view->regex);
+       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, search, REG_EXTENDED);
+       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);;
+               regerror(regex_err, view->regex, buf, sizeof(buf));
+               report("Search failed: %s", buf);
                return;
        }
 
-       string_copy(view->grep, search);
+       string_copy(view->grep, opt_search);
 
        find_next(view, request);
 }
@@ -1731,8 +1766,7 @@ begin_update(struct view *view)
                if (strcmp(view->vid, view->id))
                        opt_path[0] = 0;
 
-               if (snprintf(view->cmd, sizeof(view->cmd), format, id, opt_path)
-                   >= sizeof(view->cmd))
+               if (!string_format(view->cmd, format, id, opt_path))
                        return FALSE;
 
        } else {
@@ -1894,6 +1928,7 @@ alloc_error:
        report("Allocation failure");
 
 end:
+       view->ops->read(view, NULL);
        end_update(view);
        return FALSE;
 }
@@ -1995,7 +2030,7 @@ open_view(struct view *prev, enum request request, enum open_flags flags)
 
                /* Scroll the view that was split if the current line is
                 * outside the new limited view. */
-               do_scroll_view(prev, lines, TRUE);
+               do_scroll_view(prev, lines);
        }
 
        if (prev && view != prev) {
@@ -2040,7 +2075,7 @@ view_driver(struct view *view, enum request request)
        case REQ_MOVE_PAGE_DOWN:
        case REQ_MOVE_FIRST_LINE:
        case REQ_MOVE_LAST_LINE:
-               move_view(view, request, TRUE);
+               move_view(view, request);
                break;
 
        case REQ_SCROLL_LINE_DOWN:
@@ -2073,14 +2108,12 @@ view_driver(struct view *view, enum request request)
                     view->parent == VIEW(REQ_VIEW_MAIN)) ||
                   (view == VIEW(REQ_VIEW_BLOB) &&
                     view->parent == VIEW(REQ_VIEW_TREE))) {
-                       bool redraw = display[1] == view;
-
                        view = view->parent;
-                       move_view(view, request, redraw);
-                       if (redraw)
+                       move_view(view, request);
+                       if (view_is_displayed(view))
                                update_view_title(view);
                } else {
-                       move_view(view, request, TRUE);
+                       move_view(view, request);
                        break;
                }
                /* Fall-through */
@@ -2125,7 +2158,7 @@ view_driver(struct view *view, enum request request)
 
        case REQ_SEARCH:
        case REQ_SEARCH_BACK:
-               search_view(view, request, opt_search);
+               search_view(view, request);
                break;
 
        case REQ_FIND_NEXT:
@@ -2190,7 +2223,7 @@ view_driver(struct view *view, enum request request)
  */
 
 static bool
-pager_draw(struct view *view, struct line *line, unsigned int lineno)
+pager_draw(struct view *view, struct line *line, unsigned int lineno, bool selected)
 {
        char *text = line->data;
        enum line_type type = line->type;
@@ -2199,17 +2232,7 @@ pager_draw(struct view *view, struct line *line, unsigned int lineno)
 
        wmove(view->win, lineno, 0);
 
-       if (view->offset + lineno == view->lineno) {
-               if (type == LINE_COMMIT) {
-                       string_copy(view->ref, text + 7);
-                       string_copy(ref_commit, view->ref);
-
-               } else if (type == LINE_TREE_DIR || type == LINE_TREE_FILE) {
-                       strncpy(view->ref, text + STRING_SIZE("100644 blob "), 41);
-                       view->ref[40] = 0;
-                       string_copy(ref_blob, view->ref);
-               }
-
+       if (selected) {
                type = LINE_CURSOR;
                wchgat(view->win, -1, 0, type, NULL);
        }
@@ -2329,10 +2352,14 @@ add_pager_refs(struct view *view, struct line *line)
 
        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;
 
@@ -2350,6 +2377,9 @@ pager_read(struct view *view, char *data)
 {
        struct line *line = &view->line[view->lines];
 
+       if (!data)
+               return TRUE;
+
        line->data = strdup(data);
        if (!line->data)
                return FALSE;
@@ -2400,18 +2430,30 @@ pager_grep(struct view *view, struct line *line)
        if (!*text)
                return FALSE;
 
-       if (regexec(&view->regex, text, 1, &pmatch, 0) == REG_NOMATCH)
+       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,
 };
 
 
@@ -2419,7 +2461,7 @@ static struct view_ops pager_ops = {
  * Tree backend
  */
 
-/* Parse output from git ls-tree:
+/* Parse output from git-ls-tree(1):
  *
  * 100644 blob fb0e31ea6cc679b7379631188190e975f5789c26        Makefile
  * 100644 blob 5304ca4260aaddaee6498f9630e7d471b8591ea6        README
@@ -2448,10 +2490,11 @@ tree_compare_entry(enum line_type type1, char *name1,
 static bool
 tree_read(struct view *view, char *text)
 {
-       size_t textlen = strlen(text);
+       size_t textlen = text ? strlen(text) : 0;
        char buf[SIZEOF_STR];
        unsigned long pos;
        enum line_type type;
+       bool first_read = view->lines == 0;
 
        if (textlen <= SIZEOF_TREE_ATTR)
                return FALSE;
@@ -2459,10 +2502,9 @@ tree_read(struct view *view, char *text)
        type = text[STRING_SIZE("100644 ")] == 't'
             ? LINE_TREE_DIR : LINE_TREE_FILE;
 
-       /* The first time around ... */
-       if (!view->lines) {
+       if (first_read) {
                /* Add path info line */
-               if (snprintf(buf, sizeof(buf), "Directory path /%s", opt_path) < sizeof(buf) &&
+               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;
@@ -2471,7 +2513,7 @@ tree_read(struct view *view, char *text)
 
                /* Insert "link" to parent directory. */
                if (*opt_path &&
-                   snprintf(buf, sizeof(buf), TREE_UP_FORMAT, view->ref) < sizeof(buf) &&
+                   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;
@@ -2518,6 +2560,10 @@ tree_read(struct view *view, char *text)
        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;
 }
@@ -2525,8 +2571,7 @@ tree_read(struct view *view, char *text)
 static bool
 tree_enter(struct view *view, struct line *line)
 {
-       enum open_flags flags = OPEN_DEFAULT;
-       char *data = line->data;
+       enum open_flags flags = display[0] == view ? OPEN_SPLIT : OPEN_DEFAULT;
        enum request request;
 
        switch (line->type) {
@@ -2544,9 +2589,14 @@ tree_enter(struct view *view, struct line *line)
 
                } else {
                        size_t pathlen = strlen(opt_path);
+                       size_t origlen = pathlen;
+                       char *data = line->data;
                        char *basename = data + SIZEOF_TREE_ATTR;
 
-                       string_format_from(opt_path, &pathlen, "%s/", basename);
+                       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
@@ -2556,10 +2606,6 @@ tree_enter(struct view *view, struct line *line)
                break;
 
        case LINE_TREE_FILE:
-               /* This causes the blob view to become split, and not having it
-                * in the tree dir case will make the blob view automatically
-                * disappear when moving to a different directory. */
-               flags |= OPEN_SPLIT;
                request = REQ_VIEW_BLOB;
                break;
 
@@ -2569,18 +2615,27 @@ tree_enter(struct view *view, struct line *line)
 
        open_view(view, request, flags);
 
-       if (!VIEW(request)->pipe)
-               return TRUE;
+       return TRUE;
+}
+
+static void
+tree_select(struct view *view, struct line *line)
+{
+       char *text = line->data;
+
+       text += STRING_SIZE("100644 blob ");
 
-       /* For tree views insert the path to the parent as the first line. */
-       if (request == REQ_VIEW_BLOB) {
-               /* Mirror what is showed in the title bar. */
-               string_ncopy(ref_blob, data + STRING_SIZE("100644 blob "), 40);
+       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);
-               return TRUE;
+
+       } else if (line->type != LINE_TREE_DIR) {
+               return;
        }
 
-       return TRUE;
+       string_ncopy(view->ref, text, 40);
 }
 
 static struct view_ops tree_ops = {
@@ -2589,6 +2644,7 @@ static struct view_ops tree_ops = {
        tree_read,
        tree_enter,
        pager_grep,
+       tree_select,
 };
 
 static bool
@@ -2608,15 +2664,16 @@ static struct view_ops blob_ops = {
        blob_read,
        pager_enter,
        pager_grep,
+       pager_select,
 };
 
 
 /*
- * Main view backend
+ * Revision graph
  */
 
 struct commit {
-       char id[41];                    /* SHA1 ID. */
+       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. */
@@ -2625,8 +2682,195 @@ struct commit {
        size_t graph_size;              /* The width of the graph array. */
 };
 
+/* Size of rev graph with no  "padding" columns */
+#define SIZEOF_REVITEMS        (SIZEOF_REVGRAPH - (SIZEOF_REVGRAPH / 2))
+
+struct rev_graph {
+       struct rev_graph *prev, *next, *parents;
+       char rev[SIZEOF_REVITEMS][SIZEOF_REV];
+       size_t size;
+       struct commit *commit;
+       size_t pos;
+};
+
+/* Parents of the commit being visualized. */
+static struct rev_graph graph_parents[4];
+
+/* The current stack of revisions on the graph. */
+static struct rev_graph graph_stacks[4] = {
+       { &graph_stacks[3], &graph_stacks[1], &graph_parents[0] },
+       { &graph_stacks[0], &graph_stacks[2], &graph_parents[1] },
+       { &graph_stacks[1], &graph_stacks[3], &graph_parents[2] },
+       { &graph_stacks[2], &graph_stacks[0], &graph_parents[3] },
+};
+
+static inline bool
+graph_parent_is_merge(struct rev_graph *graph)
+{
+       return graph->parents->size > 1;
+}
+
+static inline void
+append_to_rev_graph(struct rev_graph *graph, chtype symbol)
+{
+       struct commit *commit = graph->commit;
+
+       if (commit->graph_size < ARRAY_SIZE(commit->graph) - 1)
+               commit->graph[commit->graph_size++] = symbol;
+}
+
+static void
+done_rev_graph(struct rev_graph *graph)
+{
+       if (graph_parent_is_merge(graph) &&
+           graph->pos < graph->size - 1 &&
+           graph->next->size == graph->size + graph->parents->size - 1) {
+               size_t i = graph->pos + graph->parents->size - 1;
+
+               graph->commit->graph_size = i * 2;
+               while (i < graph->next->size - 1) {
+                       append_to_rev_graph(graph, ' ');
+                       append_to_rev_graph(graph, '\\');
+                       i++;
+               }
+       }
+
+       graph->size = graph->pos = 0;
+       graph->commit = NULL;
+       memset(graph->parents, 0, sizeof(*graph->parents));
+}
+
+static void
+push_rev_graph(struct rev_graph *graph, char *parent)
+{
+       /* Combine duplicate parents lines. */
+       if (graph->size > 0 &&
+           !strncmp(graph->rev[graph->size - 1], parent, SIZEOF_REV))
+               return;
+
+       if (graph->size < SIZEOF_REVITEMS) {
+               string_ncopy(graph->rev[graph->size++], parent, SIZEOF_REV);
+       }
+}
+
+static chtype
+get_rev_graph_symbol(struct rev_graph *graph)
+{
+       chtype symbol;
+
+       if (graph->parents->size == 0)
+               symbol = REVGRAPH_INIT;
+       else if (graph_parent_is_merge(graph))
+               symbol = REVGRAPH_MERGE;
+       else if (graph->pos >= graph->size)
+               symbol = REVGRAPH_BRANCH;
+       else
+               symbol = REVGRAPH_COMMIT;
+
+       return symbol;
+}
+
+static void
+draw_rev_graph(struct rev_graph *graph)
+{
+       struct rev_filler {
+               chtype separator, line;
+       };
+       enum { DEFAULT, RSHARP, RDIAG, LDIAG };
+       static struct rev_filler fillers[] = {
+               { ' ',  REVGRAPH_LINE },
+               { '`',  '.' },
+               { '\'', ' ' },
+               { '/',  ' ' },
+       };
+       chtype symbol = get_rev_graph_symbol(graph);
+       struct rev_filler *filler;
+       size_t i;
+
+       filler = &fillers[DEFAULT];
+
+       for (i = 0; i < graph->pos; i++) {
+               append_to_rev_graph(graph, filler->line);
+               if (graph_parent_is_merge(graph->prev) &&
+                   graph->prev->pos == i)
+                       filler = &fillers[RSHARP];
+
+               append_to_rev_graph(graph, filler->separator);
+       }
+
+       /* Place the symbol for this revision. */
+       append_to_rev_graph(graph, symbol);
+
+       if (graph->prev->size > graph->size)
+               filler = &fillers[RDIAG];
+       else
+               filler = &fillers[DEFAULT];
+
+       i++;
+
+       for (; i < graph->size; i++) {
+               append_to_rev_graph(graph, filler->separator);
+               append_to_rev_graph(graph, filler->line);
+               if (graph_parent_is_merge(graph->prev) &&
+                   i < graph->prev->pos + graph->parents->size)
+                       filler = &fillers[RSHARP];
+               if (graph->prev->size > graph->size)
+                       filler = &fillers[LDIAG];
+       }
+
+       if (graph->prev->size > graph->size) {
+               append_to_rev_graph(graph, filler->separator);
+               if (filler->line != ' ')
+                       append_to_rev_graph(graph, filler->line);
+       }
+}
+
+/* Prepare the next rev graph */
+static void
+prepare_rev_graph(struct rev_graph *graph)
+{
+       size_t i;
+
+       /* First, traverse all lines of revisions up to the active one. */
+       for (graph->pos = 0; graph->pos < graph->size; graph->pos++) {
+               if (!strcmp(graph->rev[graph->pos], graph->commit->id))
+                       break;
+
+               push_rev_graph(graph->next, graph->rev[graph->pos]);
+       }
+
+       /* Interleave the new revision parent(s). */
+       for (i = 0; i < graph->parents->size; i++)
+               push_rev_graph(graph->next, graph->parents->rev[i]);
+
+       /* Lastly, put any remaining revisions. */
+       for (i = graph->pos + 1; i < graph->size; i++)
+               push_rev_graph(graph->next, graph->rev[i]);
+}
+
+static void
+update_rev_graph(struct rev_graph *graph)
+{
+       /* If this is the finalizing update ... */
+       if (graph->commit)
+               prepare_rev_graph(graph);
+
+       /* Graph visualization needs a one rev look-ahead,
+        * so the first update doesn't visualize anything. */
+       if (!graph->prev->commit)
+               return;
+
+       draw_rev_graph(graph->prev);
+       done_rev_graph(graph->prev->prev);
+}
+
+
+/*
+ * Main view backend
+ */
+
 static bool
-main_draw(struct view *view, struct line *line, unsigned int lineno)
+main_draw(struct view *view, struct line *line, unsigned int lineno, bool selected)
 {
        char buf[DATE_COLS + 1];
        struct commit *commit = line->data;
@@ -2641,9 +2885,7 @@ main_draw(struct view *view, struct line *line, unsigned int lineno)
 
        wmove(view->win, lineno, col);
 
-       if (view->offset + lineno == view->lineno) {
-               string_copy(view->ref, commit->id);
-               string_copy(ref_commit, view->ref);
+       if (selected) {
                type = LINE_CURSOR;
                wattrset(view->win, get_line_attr(type));
                wchgat(view->win, -1, 0, type, NULL);
@@ -2694,6 +2936,7 @@ main_draw(struct view *view, struct line *line, unsigned int lineno)
                for (i = 0; i < commit->graph_size; i++)
                        waddch(view->win, commit->graph[i]);
 
+               waddch(view->win, ' ');
                col += commit->graph_size + 1;
        }
 
@@ -2738,10 +2981,18 @@ main_draw(struct view *view, struct line *line, unsigned int lineno)
 static bool
 main_read(struct view *view, char *line)
 {
-       enum line_type type = get_line_type(line);
+       static struct rev_graph *graph = graph_stacks;
+       enum line_type type;
        struct commit *commit = view->lines
                              ? view->line[view->lines - 1].data : NULL;
 
+       if (!line) {
+               update_rev_graph(graph);
+               return TRUE;
+       }
+
+       type = get_line_type(line);
+
        switch (type) {
        case LINE_COMMIT:
                commit = calloc(1, sizeof(struct commit));
@@ -2753,7 +3004,14 @@ main_read(struct view *view, char *line)
                view->line[view->lines++].data = commit;
                string_copy(commit->id, line);
                commit->refs = get_refs(commit->id);
-               commit->graph[commit->graph_size++] = ACS_LTEE;
+               graph->commit = commit;
+               break;
+
+       case LINE_PARENT:
+               if (commit) {
+                       line += STRING_SIZE("parent ");
+                       push_rev_graph(graph->parents, line);
+               }
                break;
 
        case LINE_AUTHOR:
@@ -2764,6 +3022,9 @@ main_read(struct view *view, char *line)
                if (!commit)
                        break;
 
+               update_rev_graph(graph);
+               graph = graph->next;
+
                if (end) {
                        char *email = end + 1;
 
@@ -2868,19 +3129,29 @@ main_grep(struct view *view, struct line *line)
                        return FALSE;
                }
 
-               if (regexec(&view->regex, text, 1, &pmatch, 0) != REG_NOMATCH)
+               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,
 };
 
 
@@ -3416,7 +3687,7 @@ main(int argc, char *argv[])
 
        if (*opt_codeset && strcmp(opt_codeset, opt_encoding)) {
                opt_iconv = iconv_open(opt_codeset, opt_encoding);
-               if (opt_iconv == (iconv_t) -1)
+               if (opt_iconv == ICONV_NONE)
                        die("Failed to initialize character set conversion");
        }