mdw@git.distorted.org.uk Git - sw-tools/blob - src/sw_env.h

   1 /* -*-c-*-
   2  *
   3  * $Id: sw_env.h,v 1.1 1999/06/02 16:53:35 mdw Exp $
   4  *
   5  * Mangling of environment variables
   6  *
   7  * (c) 1999 EBI
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of sw-tools.
  13  *
  14  * sw-tools is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * sw-tools is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with sw-tools; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: sw_env.h,v $
  32  * Revision 1.1  1999/06/02 16:53:35  mdw
  33  * Initial revision
  34  *
  35  */
  36
  37 #ifndef SW_ENV_H
  38 #define SW_ENV_H
  39
  40 #ifdef __cplusplus
  41   extern "C" {
  42 #endif
  43
  44 /*----- Header files ------------------------------------------------------*/
  45
  46 #include <stdio.h>
  47
  48 #include <mLib/dstr.h>
  49 #include <mLib/sym.h>
  50
  51 /*----- Important constants -----------------------------------------------*/
  52
  53 enum {
  54   ENV_OK = 0,                           /* Parsed OK */
  55   ENV_EOF,                              /* End-of-file encountered */
  56   ENV_VCHAR,                            /* Bad character in variable name */
  57   ENV_SUBST,                            /* Bad parameter substitution */
  58   ENV_QUOTE,                            /* Mismatched quote */
  59   ENV_BRACE,                            /* Missing brace character */
  60   ENV_SYSTEM,                           /* System error (see @errno@) */
  61   ENV_INTERNAL                          /* Internal error */
  62 };
  63
  64 enum {
  65   EVF_INCSPC = 1,                       /* Allow spaces in values */
  66   EVF_BACKTICK = 2,                     /* Make backtick self-delimiting */
  67   EVF_SKIP = 4,                         /* Skipping this section of text */
  68   EVF_INITSPC = 8                       /* Allow and ignore leading space */
  69 };
  70
  71 /*----- Functions provided ------------------------------------------------*/
  72
  73 /* --- @env_get@ --- *
  74  *
  75  * Arguments:   @sym_table *t@ = pointer to a symbol table
  76  *              @const char *name@ = pointer to variable name to look up
  77  *
  78  * Returns:     Pointer to corresponding value string, or null.
  79  *
  80  * Use:         Looks up an environment variable in the table and returns its
  81  *              value.  If the variable can't be found, a null pointer is
  82  *              returned.
  83  */
  84
  85 extern char *env_get(sym_table */*t*/, const char */*name*/);
  86
  87 /* --- @env_put@ --- *
  88  *
  89  * Arguments:   @sym_table *t@ = pointer to a symbol table
  90  *              @const char *name@ = pointer to variable name to set
  91  *              @const char *value@ = pointer to value string to assign
  92  *
  93  * Returns:     ---
  94  *
  95  * Use:         Assigns a value to a variable.  If the @name@ contains an
  96  *              equals character, then it's assumed to be of the form
  97  *              `VAR=VALUE' and @value@ argument is ignored.  Otherwise, if
  98  *              @value@ is null, the variable is deleted.  Finally, the
  99  *              normal case: @name@ is a plain name, and @value@ is a normal
 100  *              string causes the variable to be assigned the value in the
 101  *              way you'd expect.
 102  */
 103
 104 extern void env_put(sym_table */*t*/,
 105                     const char */*name*/, const char */*value*/);
 106
 107 /* --- @env_import@ --- *
 108  *
 109  * Arguments:   @sym_table *t@ = pointer to a symbol table
 110  *              @char **env@ = pointer to an environment list
 111  *
 112  * Returns:     ---
 113  *
 114  * Use:         Inserts all of the environment variables listed into a symbol
 115  *              table for rapid access.  Equivalent to a lot of calls to
 116  *              @env_put@.
 117  */
 118
 119 extern void env_import(sym_table */*t*/, char **/*env*/);
 120
 121 /* --- @env_export@ --- *
 122  *
 123  * Arguments:   @sym_table *t@ = pointer to a symbol table
 124  *
 125  * Returns:     A big environment list.
 126  *
 127  * Use:         Extracts an environment table from a symbol table
 128  *              representation of an environment.  The table and all of the
 129  *              strings are in one big block allocated from the heap.
 130  */
 131
 132 extern char **env_export(sym_table */*t*/);
 133
 134 /* --- @env_destroy@ --- *
 135  *
 136  * Arguments:   @sym_table *t@ = pointer to symbol table
 137  *
 138  * Returns:     ---
 139  *
 140  * Use:         Destroys all the variables in the symbol table.
 141  */
 142
 143 extern void env_destroy(sym_table */*t*/);
 144
 145 /* --- @env_error@ --- *
 146  *
 147  * Arguments:   @int e@ = error code
 148  *
 149  * Returns:     String representation of error.
 150  *
 151  * Use:         Transforms an error into something a user can understand.
 152  */
 153
 154 extern const char *env_error(int /*e*/);
 155
 156 /* --- @env_var@ --- *
 157  *
 158  * Arguments:   @sym_table *t@ = pointer to symbol table
 159  *              @FILE *fp@ = pointer to stream to read from
 160  *              @dstr *d@ = pointer to output variable
 161  *
 162  * Returns:     One of the @ENV_@ constants.
 163  *
 164  * Use:         Scans a variable name from the input stream.
 165  */
 166
 167 extern int env_var(sym_table */*t*/, FILE */*fp*/, dstr */*d*/);
 168
 169 /* --- @env_value@ --- *
 170  *
 171  * Arguments:   @sym_table *t@ = pointer to symbol table
 172  *              @FILE *fp@ = pointer to stream to read from
 173  *              @dstr *d@ = pointer to output variable
 174  *              @unsigned f@ = various interesting flags
 175  *
 176  * Returns:     0 if OK, @EOF@ if end-of-file encountered, or >0 on error.
 177  *
 178  * Use:         Scans a value from the input stream.  The value read may be
 179  *              quoted in a Bourne-shell sort of a way, and contain Bourne-
 180  *              shell-like parameter substitutions.  Some substitutions
 181  *              aren't available because they're too awkward to implement.
 182  */
 183
 184 extern int env_value(sym_table */*t*/, FILE */*fp*/,
 185                      dstr */*d*/, unsigned /*f*/);
 186
 187 /* --- @env_read@ --- *
 188  *
 189  * Arguments:   @sym_table *t@ = pointer to symbol table
 190  *              @FILE *fp@ = file handle to read
 191  *              @unsigned f@ = various flags
 192  *
 193  * Returns:     Zero if OK, @EOF@ for end-of-file, or error code.
 194  *
 195  * Use:         Reads the environment assignment statements in the file.
 196  */
 197
 198 extern int env_read(sym_table */*t*/, FILE */*fp*/, unsigned /*f*/);
 199
 200 /* --- @env_file@ --- *
 201  *
 202  * Arguments:   @sym_table *t@ = pointer to symbol table
 203  *              @const char *name@ = pointer to filename
 204  *
 205  * Returns:     Zero if OK, or an error code.
 206  *
 207  * Use:         Reads a named file of environment assignments.
 208  */
 209
 210 extern int env_file(sym_table */*t*/, const char */*name*/);
 211
 212 /*----- That's all, folks -------------------------------------------------*/
 213
 214 #ifdef __cplusplus
 215   }
 216 #endif
 217
 218 #endif