transport-helper: drop read/write errno checks
[git.git] / sh-i18n--envsubst.c
blob09c6b445b9631202c69d2a1804a757148b43beb0
1 /*
2 * sh-i18n--envsubst.c - a stripped-down version of gettext's envsubst(1)
4 * Copyright (C) 2010 Ævar Arnfjörð Bjarmason
6 * This is a modified version of
7 * 67d0871a8c:gettext-runtime/src/envsubst.c from the gettext.git
8 * repository. It has been stripped down to only implement the
9 * envsubst(1) features that we need in the git-sh-i18n fallbacks.
11 * The "Close standard error" part in main() is from
12 * 8dac033df0:gnulib-local/lib/closeout.c. The copyright notices for
13 * both files are reproduced immediately below.
16 #include "git-compat-util.h"
18 /* Substitution of environment variables in shell format strings.
19 Copyright (C) 2003-2007 Free Software Foundation, Inc.
20 Written by Bruno Haible <bruno@clisp.org>, 2003.
22 This program is free software; you can redistribute it and/or modify
23 it under the terms of the GNU General Public License as published by
24 the Free Software Foundation; either version 2, or (at your option)
25 any later version.
27 This program is distributed in the hope that it will be useful,
28 but WITHOUT ANY WARRANTY; without even the implied warranty of
29 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
30 GNU General Public License for more details.
32 You should have received a copy of the GNU General Public License
33 along with this program; if not, see <http://www.gnu.org/licenses/>. */
35 /* closeout.c - close standard output and standard error
36 Copyright (C) 1998-2007 Free Software Foundation, Inc.
38 This program is free software; you can redistribute it and/or modify
39 it under the terms of the GNU General Public License as published by
40 the Free Software Foundation; either version 2, or (at your option)
41 any later version.
43 This program is distributed in the hope that it will be useful,
44 but WITHOUT ANY WARRANTY; without even the implied warranty of
45 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
46 GNU General Public License for more details.
48 You should have received a copy of the GNU General Public License
49 along with this program; if not, see <http://www.gnu.org/licenses/>. */
51 #include <errno.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
56 /* If true, substitution shall be performed on all variables. */
57 static unsigned short int all_variables;
59 /* Forward declaration of local functions. */
60 static void print_variables (const char *string);
61 static void note_variables (const char *string);
62 static void subst_from_stdin (void);
64 int
65 cmd_main (int argc, const char *argv[])
67 /* Default values for command line options. */
68 /* unsigned short int show_variables = 0; */
70 switch (argc)
72 case 1:
73 error ("we won't substitute all variables on stdin for you");
74 break;
76 all_variables = 1;
77 subst_from_stdin ();
79 case 2:
80 /* echo '$foo and $bar' | git sh-i18n--envsubst --variables '$foo and $bar' */
81 all_variables = 0;
82 note_variables (argv[1]);
83 subst_from_stdin ();
84 break;
85 case 3:
86 /* git sh-i18n--envsubst --variables '$foo and $bar' */
87 if (strcmp(argv[1], "--variables"))
88 error ("first argument must be --variables when two are given");
89 /* show_variables = 1; */
90 print_variables (argv[2]);
91 break;
92 default:
93 error ("too many arguments");
94 break;
97 /* Close standard error. This is simpler than fwriteerror_no_ebadf, because
98 upon failure we don't need an errno - all we can do at this point is to
99 set an exit status. */
100 errno = 0;
101 if (ferror (stderr) || fflush (stderr))
103 fclose (stderr);
104 exit (EXIT_FAILURE);
106 if (fclose (stderr) && errno != EBADF)
107 exit (EXIT_FAILURE);
109 exit (EXIT_SUCCESS);
112 /* Parse the string and invoke the callback each time a $VARIABLE or
113 ${VARIABLE} construct is seen, where VARIABLE is a nonempty sequence
114 of ASCII alphanumeric/underscore characters, starting with an ASCII
115 alphabetic/underscore character.
116 We allow only ASCII characters, to avoid dependencies w.r.t. the current
117 encoding: While "${\xe0}" looks like a variable access in ISO-8859-1
118 encoding, it doesn't look like one in the BIG5, BIG5-HKSCS, GBK, GB18030,
119 SHIFT_JIS, JOHAB encodings, because \xe0\x7d is a single character in these
120 encodings. */
121 static void
122 find_variables (const char *string,
123 void (*callback) (const char *var_ptr, size_t var_len))
125 for (; *string != '\0';)
126 if (*string++ == '$')
128 const char *variable_start;
129 const char *variable_end;
130 unsigned short int valid;
131 char c;
133 if (*string == '{')
134 string++;
136 variable_start = string;
137 c = *string;
138 if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
141 c = *++string;
142 while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
143 || (c >= '0' && c <= '9') || c == '_');
144 variable_end = string;
146 if (variable_start[-1] == '{')
148 if (*string == '}')
150 string++;
151 valid = 1;
153 else
154 valid = 0;
156 else
157 valid = 1;
159 if (valid)
160 callback (variable_start, variable_end - variable_start);
166 /* Print a variable to stdout, followed by a newline. */
167 static void
168 print_variable (const char *var_ptr, size_t var_len)
170 fwrite (var_ptr, var_len, 1, stdout);
171 putchar ('\n');
174 /* Print the variables contained in STRING to stdout, each one followed by a
175 newline. */
176 static void
177 print_variables (const char *string)
179 find_variables (string, &print_variable);
183 /* Type describing list of immutable strings,
184 implemented using a dynamic array. */
185 typedef struct string_list_ty string_list_ty;
186 struct string_list_ty
188 const char **item;
189 size_t nitems;
190 size_t nitems_max;
193 /* Initialize an empty list of strings. */
194 static inline void
195 string_list_init (string_list_ty *slp)
197 slp->item = NULL;
198 slp->nitems = 0;
199 slp->nitems_max = 0;
202 /* Append a single string to the end of a list of strings. */
203 static inline void
204 string_list_append (string_list_ty *slp, const char *s)
206 /* Grow the list. */
207 if (slp->nitems >= slp->nitems_max)
209 slp->nitems_max = slp->nitems_max * 2 + 4;
210 REALLOC_ARRAY(slp->item, slp->nitems_max);
213 /* Add the string to the end of the list. */
214 slp->item[slp->nitems++] = s;
217 /* Compare two strings given by reference. */
218 static int
219 cmp_string (const void *pstr1, const void *pstr2)
221 const char *str1 = *(const char **)pstr1;
222 const char *str2 = *(const char **)pstr2;
224 return strcmp (str1, str2);
227 /* Sort a list of strings. */
228 static inline void
229 string_list_sort (string_list_ty *slp)
231 QSORT(slp->item, slp->nitems, cmp_string);
234 /* Test whether a sorted string list contains a given string. */
235 static int
236 sorted_string_list_member (const string_list_ty *slp, const char *s)
238 size_t j1, j2;
240 j1 = 0;
241 j2 = slp->nitems;
242 if (j2 > 0)
244 /* Binary search. */
245 while (j2 - j1 > 1)
247 /* Here we know that if s is in the list, it is at an index j
248 with j1 <= j < j2. */
249 size_t j = (j1 + j2) >> 1;
250 int result = strcmp (slp->item[j], s);
252 if (result > 0)
253 j2 = j;
254 else if (result == 0)
255 return 1;
256 else
257 j1 = j + 1;
259 if (j2 > j1)
260 if (strcmp (slp->item[j1], s) == 0)
261 return 1;
263 return 0;
267 /* Set of variables on which to perform substitution.
268 Used only if !all_variables. */
269 static string_list_ty variables_set;
271 /* Adds a variable to variables_set. */
272 static void
273 note_variable (const char *var_ptr, size_t var_len)
275 char *string = xmemdupz (var_ptr, var_len);
277 string_list_append (&variables_set, string);
280 /* Stores the variables occurring in the string in variables_set. */
281 static void
282 note_variables (const char *string)
284 string_list_init (&variables_set);
285 find_variables (string, &note_variable);
286 string_list_sort (&variables_set);
290 static int
291 do_getc (void)
293 int c = getc (stdin);
295 if (c == EOF)
297 if (ferror (stdin))
298 error ("error while reading standard input");
301 return c;
304 static inline void
305 do_ungetc (int c)
307 if (c != EOF)
308 ungetc (c, stdin);
311 /* Copies stdin to stdout, performing substitutions. */
312 static void
313 subst_from_stdin (void)
315 static char *buffer;
316 static size_t bufmax;
317 static size_t buflen;
318 int c;
320 for (;;)
322 c = do_getc ();
323 if (c == EOF)
324 break;
325 /* Look for $VARIABLE or ${VARIABLE}. */
326 if (c == '$')
328 unsigned short int opening_brace = 0;
329 unsigned short int closing_brace = 0;
331 c = do_getc ();
332 if (c == '{')
334 opening_brace = 1;
335 c = do_getc ();
337 if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
339 unsigned short int valid;
341 /* Accumulate the VARIABLE in buffer. */
342 buflen = 0;
345 if (buflen >= bufmax)
347 bufmax = 2 * bufmax + 10;
348 buffer = xrealloc (buffer, bufmax);
350 buffer[buflen++] = c;
352 c = do_getc ();
354 while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
355 || (c >= '0' && c <= '9') || c == '_');
357 if (opening_brace)
359 if (c == '}')
361 closing_brace = 1;
362 valid = 1;
364 else
366 valid = 0;
367 do_ungetc (c);
370 else
372 valid = 1;
373 do_ungetc (c);
376 if (valid)
378 /* Terminate the variable in the buffer. */
379 if (buflen >= bufmax)
381 bufmax = 2 * bufmax + 10;
382 buffer = xrealloc (buffer, bufmax);
384 buffer[buflen] = '\0';
386 /* Test whether the variable shall be substituted. */
387 if (!all_variables
388 && !sorted_string_list_member (&variables_set, buffer))
389 valid = 0;
392 if (valid)
394 /* Substitute the variable's value from the environment. */
395 const char *env_value = getenv (buffer);
397 if (env_value != NULL)
398 fputs (env_value, stdout);
400 else
402 /* Perform no substitution at all. Since the buffered input
403 contains no other '$' than at the start, we can just
404 output all the buffered contents. */
405 putchar ('$');
406 if (opening_brace)
407 putchar ('{');
408 fwrite (buffer, buflen, 1, stdout);
409 if (closing_brace)
410 putchar ('}');
413 else
415 do_ungetc (c);
416 putchar ('$');
417 if (opening_brace)
418 putchar ('{');
421 else
422 putchar (c);