Git 2.15
[git/git.git] / sh-i18n--envsubst.c
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1/*
2 * sh-i18n--envsubst.c - a stripped-down version of gettext's envsubst(1)
3 *
4 * Copyright (C) 2010 Ævar Arnfjörð Bjarmason
5 *
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.
10 *
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.
14 */
15
16#include "git-compat-util.h"
17
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.
21
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.
26
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.
31
32 You should have received a copy of the GNU General Public License
33 along with this program; if not, write to the Free Software Foundation,
34 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
35
36/* closeout.c - close standard output and standard error
37 Copyright (C) 1998-2007 Free Software Foundation, Inc.
38
39 This program is free software; you can redistribute it and/or modify
40 it under the terms of the GNU General Public License as published by
41 the Free Software Foundation; either version 2, or (at your option)
42 any later version.
43
44 This program is distributed in the hope that it will be useful,
45 but WITHOUT ANY WARRANTY; without even the implied warranty of
46 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
47 GNU General Public License for more details.
48
49 You should have received a copy of the GNU General Public License
50 along with this program; if not, write to the Free Software Foundation,
51 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
52
53#include <errno.h>
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54#include <stdio.h>
55#include <stdlib.h>
56#include <string.h>
57
58/* If true, substitution shall be performed on all variables. */
59static unsigned short int all_variables;
60
61/* Forward declaration of local functions. */
62static void print_variables (const char *string);
63static void note_variables (const char *string);
64static void subst_from_stdin (void);
65
66int
3f2e2297 67cmd_main (int argc, const char *argv[])
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68{
69 /* Default values for command line options. */
600a6a68 70 /* unsigned short int show_variables = 0; */
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71
72 switch (argc)
73 {
74 case 1:
75 error ("we won't substitute all variables on stdin for you");
8c92516f 76 break;
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77 /*
78 all_variables = 1;
79 subst_from_stdin ();
80 */
81 case 2:
82 /* echo '$foo and $bar' | git sh-i18n--envsubst --variables '$foo and $bar' */
83 all_variables = 0;
84 note_variables (argv[1]);
85 subst_from_stdin ();
86 break;
87 case 3:
88 /* git sh-i18n--envsubst --variables '$foo and $bar' */
89 if (strcmp(argv[1], "--variables"))
90 error ("first argument must be --variables when two are given");
600a6a68 91 /* show_variables = 1; */
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92 print_variables (argv[2]);
93 break;
94 default:
95 error ("too many arguments");
96 break;
97 }
98
99 /* Close standard error. This is simpler than fwriteerror_no_ebadf, because
100 upon failure we don't need an errno - all we can do at this point is to
101 set an exit status. */
102 errno = 0;
103 if (ferror (stderr) || fflush (stderr))
104 {
105 fclose (stderr);
106 exit (EXIT_FAILURE);
107 }
108 if (fclose (stderr) && errno != EBADF)
109 exit (EXIT_FAILURE);
110
111 exit (EXIT_SUCCESS);
112}
113
114/* Parse the string and invoke the callback each time a $VARIABLE or
115 ${VARIABLE} construct is seen, where VARIABLE is a nonempty sequence
116 of ASCII alphanumeric/underscore characters, starting with an ASCII
117 alphabetic/underscore character.
118 We allow only ASCII characters, to avoid dependencies w.r.t. the current
119 encoding: While "${\xe0}" looks like a variable access in ISO-8859-1
120 encoding, it doesn't look like one in the BIG5, BIG5-HKSCS, GBK, GB18030,
121 SHIFT_JIS, JOHAB encodings, because \xe0\x7d is a single character in these
122 encodings. */
123static void
124find_variables (const char *string,
125 void (*callback) (const char *var_ptr, size_t var_len))
126{
127 for (; *string != '\0';)
128 if (*string++ == '$')
129 {
130 const char *variable_start;
131 const char *variable_end;
132 unsigned short int valid;
133 char c;
134
135 if (*string == '{')
136 string++;
137
138 variable_start = string;
139 c = *string;
140 if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
141 {
142 do
143 c = *++string;
144 while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
145 || (c >= '0' && c <= '9') || c == '_');
146 variable_end = string;
147
148 if (variable_start[-1] == '{')
149 {
150 if (*string == '}')
151 {
152 string++;
153 valid = 1;
154 }
155 else
156 valid = 0;
157 }
158 else
159 valid = 1;
160
161 if (valid)
162 callback (variable_start, variable_end - variable_start);
163 }
164 }
165}
166
167
168/* Print a variable to stdout, followed by a newline. */
169static void
170print_variable (const char *var_ptr, size_t var_len)
171{
172 fwrite (var_ptr, var_len, 1, stdout);
173 putchar ('\n');
174}
175
176/* Print the variables contained in STRING to stdout, each one followed by a
177 newline. */
178static void
179print_variables (const char *string)
180{
181 find_variables (string, &print_variable);
182}
183
184
185/* Type describing list of immutable strings,
186 implemented using a dynamic array. */
187typedef struct string_list_ty string_list_ty;
188struct string_list_ty
189{
190 const char **item;
191 size_t nitems;
192 size_t nitems_max;
193};
194
195/* Initialize an empty list of strings. */
196static inline void
197string_list_init (string_list_ty *slp)
198{
199 slp->item = NULL;
200 slp->nitems = 0;
201 slp->nitems_max = 0;
202}
203
204/* Append a single string to the end of a list of strings. */
205static inline void
206string_list_append (string_list_ty *slp, const char *s)
207{
208 /* Grow the list. */
209 if (slp->nitems >= slp->nitems_max)
210 {
ba67aaf2 211 slp->nitems_max = slp->nitems_max * 2 + 4;
2756ca43 212 REALLOC_ARRAY(slp->item, slp->nitems_max);
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213 }
214
215 /* Add the string to the end of the list. */
216 slp->item[slp->nitems++] = s;
217}
218
219/* Compare two strings given by reference. */
220static int
221cmp_string (const void *pstr1, const void *pstr2)
222{
223 const char *str1 = *(const char **)pstr1;
224 const char *str2 = *(const char **)pstr2;
225
226 return strcmp (str1, str2);
227}
228
229/* Sort a list of strings. */
230static inline void
231string_list_sort (string_list_ty *slp)
232{
76dd98c1 233 QSORT(slp->item, slp->nitems, cmp_string);
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234}
235
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236/* Test whether a sorted string list contains a given string. */
237static int
238sorted_string_list_member (const string_list_ty *slp, const char *s)
239{
240 size_t j1, j2;
241
242 j1 = 0;
243 j2 = slp->nitems;
244 if (j2 > 0)
245 {
246 /* Binary search. */
247 while (j2 - j1 > 1)
248 {
249 /* Here we know that if s is in the list, it is at an index j
250 with j1 <= j < j2. */
251 size_t j = (j1 + j2) >> 1;
252 int result = strcmp (slp->item[j], s);
253
254 if (result > 0)
255 j2 = j;
256 else if (result == 0)
257 return 1;
258 else
259 j1 = j + 1;
260 }
261 if (j2 > j1)
262 if (strcmp (slp->item[j1], s) == 0)
263 return 1;
264 }
265 return 0;
266}
267
268
269/* Set of variables on which to perform substitution.
270 Used only if !all_variables. */
271static string_list_ty variables_set;
272
273/* Adds a variable to variables_set. */
274static void
275note_variable (const char *var_ptr, size_t var_len)
276{
5c0b13f8 277 char *string = xmemdupz (var_ptr, var_len);
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278
279 string_list_append (&variables_set, string);
280}
281
282/* Stores the variables occurring in the string in variables_set. */
283static void
284note_variables (const char *string)
285{
286 string_list_init (&variables_set);
287 find_variables (string, &note_variable);
288 string_list_sort (&variables_set);
289}
290
291
292static int
293do_getc (void)
294{
295 int c = getc (stdin);
296
297 if (c == EOF)
298 {
299 if (ferror (stdin))
300 error ("error while reading standard input");
301 }
302
303 return c;
304}
305
306static inline void
307do_ungetc (int c)
308{
309 if (c != EOF)
310 ungetc (c, stdin);
311}
312
313/* Copies stdin to stdout, performing substitutions. */
314static void
315subst_from_stdin (void)
316{
317 static char *buffer;
318 static size_t bufmax;
319 static size_t buflen;
320 int c;
321
322 for (;;)
323 {
324 c = do_getc ();
325 if (c == EOF)
326 break;
327 /* Look for $VARIABLE or ${VARIABLE}. */
328 if (c == '$')
329 {
330 unsigned short int opening_brace = 0;
331 unsigned short int closing_brace = 0;
332
333 c = do_getc ();
334 if (c == '{')
335 {
336 opening_brace = 1;
337 c = do_getc ();
338 }
339 if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
340 {
341 unsigned short int valid;
342
343 /* Accumulate the VARIABLE in buffer. */
344 buflen = 0;
345 do
346 {
347 if (buflen >= bufmax)
348 {
349 bufmax = 2 * bufmax + 10;
350 buffer = xrealloc (buffer, bufmax);
351 }
352 buffer[buflen++] = c;
353
354 c = do_getc ();
355 }
356 while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
357 || (c >= '0' && c <= '9') || c == '_');
358
359 if (opening_brace)
360 {
361 if (c == '}')
362 {
363 closing_brace = 1;
364 valid = 1;
365 }
366 else
367 {
368 valid = 0;
369 do_ungetc (c);
370 }
371 }
372 else
373 {
374 valid = 1;
375 do_ungetc (c);
376 }
377
378 if (valid)
379 {
380 /* Terminate the variable in the buffer. */
381 if (buflen >= bufmax)
382 {
383 bufmax = 2 * bufmax + 10;
384 buffer = xrealloc (buffer, bufmax);
385 }
386 buffer[buflen] = '\0';
387
388 /* Test whether the variable shall be substituted. */
389 if (!all_variables
390 && !sorted_string_list_member (&variables_set, buffer))
391 valid = 0;
392 }
393
394 if (valid)
395 {
396 /* Substitute the variable's value from the environment. */
397 const char *env_value = getenv (buffer);
398
399 if (env_value != NULL)
400 fputs (env_value, stdout);
401 }
402 else
403 {
404 /* Perform no substitution at all. Since the buffered input
405 contains no other '$' than at the start, we can just
406 output all the buffered contents. */
407 putchar ('$');
408 if (opening_brace)
409 putchar ('{');
410 fwrite (buffer, buflen, 1, stdout);
411 if (closing_brace)
412 putchar ('}');
413 }
414 }
415 else
416 {
417 do_ungetc (c);
418 putchar ('$');
419 if (opening_brace)
420 putchar ('{');
421 }
422 }
423 else
424 putchar (c);
425 }
426}