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git/sh-i18n--envsubst.c

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10 KiB

/*
* sh-i18n--envsubst.c - a stripped-down version of gettext's envsubst(1)
*
* Copyright (C) 2010 Ævar Arnfjörð Bjarmason
*
* This is a modified version of
* 67d0871a8c:gettext-runtime/src/envsubst.c from the gettext.git
* repository. It has been stripped down to only implement the
* envsubst(1) features that we need in the git-sh-i18n fallbacks.
*
* The "Close standard error" part in main() is from
* 8dac033df0:gnulib-local/lib/closeout.c. The copyright notices for
* both files are reproduced immediately below.
*/
#include "git-compat-util.h"
#include "trace2.h"
/* Substitution of environment variables in shell format strings.
Copyright (C) 2003-2007 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2003.
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, 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.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>. */
/* closeout.c - close standard output and standard error
Copyright (C) 1998-2007 Free Software Foundation, Inc.
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, 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.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* If true, substitution shall be performed on all variables. */
static unsigned short int all_variables;
/* Forward declaration of local functions. */
static void print_variables (const char *string);
static void note_variables (const char *string);
static void subst_from_stdin (void);
int
add an extra level of indirection to main() There are certain startup tasks that we expect every git process to do. In some cases this is just to improve the quality of the program (e.g., setting up gettext()). In others it is a requirement for using certain functions in libgit.a (e.g., system_path() expects that you have called git_extract_argv0_path()). Most commands are builtins and are covered by the git.c version of main(). However, there are still a few external commands that use their own main(). Each of these has to remember to include the correct startup sequence, and we are not always consistent. Rather than just fix the inconsistencies, let's make this harder to get wrong by providing a common main() that can run this standard startup. We basically have two options to do this: - the compat/mingw.h file already does something like this by adding a #define that replaces the definition of main with a wrapper that calls mingw_startup(). The upside is that the code in each program doesn't need to be changed at all; it's rewritten on the fly by the preprocessor. The downside is that it may make debugging of the startup sequence a bit more confusing, as the preprocessor is quietly inserting new code. - the builtin functions are all of the form cmd_foo(), and git.c's main() calls them. This is much more explicit, which may make things more obvious to somebody reading the code. It's also more flexible (because of course we have to figure out _which_ cmd_foo() to call). The downside is that each of the builtins must define cmd_foo(), instead of just main(). This patch chooses the latter option, preferring the more explicit approach, even though it is more invasive. We introduce a new file common-main.c, with the "real" main. It expects to call cmd_main() from whatever other objects it is linked against. We link common-main.o against anything that links against libgit.a, since we know that such programs will need to do this setup. Note that common-main.o can't actually go inside libgit.a, as the linker would not pick up its main() function automatically (it has no callers). The rest of the patch is just adjusting all of the various external programs (mostly in t/helper) to use cmd_main(). I've provided a global declaration for cmd_main(), which means that all of the programs also need to match its signature. In particular, many functions need to switch to "const char **" instead of "char **" for argv. This effect ripples out to a few other variables and functions, as well. This makes the patch even more invasive, but the end result is much better. We should be treating argv strings as const anyway, and now all programs conform to the same signature (which also matches the way builtins are defined). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
6 years ago
cmd_main (int argc, const char *argv[])
{
/* Default values for command line options. */
/* unsigned short int show_variables = 0; */
trace2_cmd_name("sh-i18n--envsubst");
switch (argc)
{
case 1:
error ("we won't substitute all variables on stdin for you");
break;
/*
all_variables = 1;
subst_from_stdin ();
*/
case 2:
/* echo '$foo and $bar' | git sh-i18n--envsubst --variables '$foo and $bar' */
all_variables = 0;
note_variables (argv[1]);
subst_from_stdin ();
break;
case 3:
/* git sh-i18n--envsubst --variables '$foo and $bar' */
if (strcmp(argv[1], "--variables"))
error ("first argument must be --variables when two are given");
/* show_variables = 1; */
print_variables (argv[2]);
break;
default:
error ("too many arguments");
break;
}
/* Close standard error. This is simpler than fwriteerror_no_ebadf, because
upon failure we don't need an errno - all we can do at this point is to
set an exit status. */
errno = 0;
if (ferror (stderr) || fflush (stderr))
{
fclose (stderr);
return (EXIT_FAILURE);
}
if (fclose (stderr) && errno != EBADF)
return (EXIT_FAILURE);
return (EXIT_SUCCESS);
}
/* Parse the string and invoke the callback each time a $VARIABLE or
${VARIABLE} construct is seen, where VARIABLE is a nonempty sequence
of ASCII alphanumeric/underscore characters, starting with an ASCII
alphabetic/underscore character.
We allow only ASCII characters, to avoid dependencies w.r.t. the current
encoding: While "${\xe0}" looks like a variable access in ISO-8859-1
encoding, it doesn't look like one in the BIG5, BIG5-HKSCS, GBK, GB18030,
SHIFT_JIS, JOHAB encodings, because \xe0\x7d is a single character in these
encodings. */
static void
find_variables (const char *string,
void (*callback) (const char *var_ptr, size_t var_len))
{
for (; *string != '\0';)
if (*string++ == '$')
{
const char *variable_start;
const char *variable_end;
unsigned short int valid;
char c;
if (*string == '{')
string++;
variable_start = string;
c = *string;
if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
{
do
c = *++string;
while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
|| (c >= '0' && c <= '9') || c == '_');
variable_end = string;
if (variable_start[-1] == '{')
{
if (*string == '}')
{
string++;
valid = 1;
}
else
valid = 0;
}
else
valid = 1;
if (valid)
callback (variable_start, variable_end - variable_start);
}
}
}
/* Print a variable to stdout, followed by a newline. */
static void
print_variable (const char *var_ptr, size_t var_len)
{
fwrite (var_ptr, var_len, 1, stdout);
putchar ('\n');
}
/* Print the variables contained in STRING to stdout, each one followed by a
newline. */
static void
print_variables (const char *string)
{
find_variables (string, &print_variable);
}
/* Type describing list of immutable strings,
implemented using a dynamic array. */
typedef struct string_list_ty string_list_ty;
struct string_list_ty
{
const char **item;
size_t nitems;
size_t nitems_max;
};
/* Initialize an empty list of strings. */
static inline void
string_list_init (string_list_ty *slp)
{
slp->item = NULL;
slp->nitems = 0;
slp->nitems_max = 0;
}
/* Append a single string to the end of a list of strings. */
static inline void
string_list_append (string_list_ty *slp, const char *s)
{
/* Grow the list. */
if (slp->nitems >= slp->nitems_max)
{
slp->nitems_max = slp->nitems_max * 2 + 4;
REALLOC_ARRAY(slp->item, slp->nitems_max);
}
/* Add the string to the end of the list. */
slp->item[slp->nitems++] = s;
}
/* Compare two strings given by reference. */
static int
cmp_string (const void *pstr1, const void *pstr2)
{
const char *str1 = *(const char **)pstr1;
const char *str2 = *(const char **)pstr2;
return strcmp (str1, str2);
}
/* Sort a list of strings. */
static inline void
string_list_sort (string_list_ty *slp)
{
QSORT(slp->item, slp->nitems, cmp_string);
}
/* Test whether a sorted string list contains a given string. */
static int
sorted_string_list_member (const string_list_ty *slp, const char *s)
{
size_t j1, j2;
j1 = 0;
j2 = slp->nitems;
if (j2 > 0)
{
/* Binary search. */
while (j2 - j1 > 1)
{
/* Here we know that if s is in the list, it is at an index j
with j1 <= j < j2. */
size_t j = j1 + ((j2 - j1) >> 1);
int result = strcmp (slp->item[j], s);
if (result > 0)
j2 = j;
else if (result == 0)
return 1;
else
j1 = j + 1;
}
if (j2 > j1)
if (strcmp (slp->item[j1], s) == 0)
return 1;
}
return 0;
}
/* Set of variables on which to perform substitution.
Used only if !all_variables. */
static string_list_ty variables_set;
/* Adds a variable to variables_set. */
static void
note_variable (const char *var_ptr, size_t var_len)
{
char *string = xmemdupz (var_ptr, var_len);
string_list_append (&variables_set, string);
}
/* Stores the variables occurring in the string in variables_set. */
static void
note_variables (const char *string)
{
string_list_init (&variables_set);
find_variables (string, &note_variable);
string_list_sort (&variables_set);
}
static int
do_getc (void)
{
int c = getc (stdin);
if (c == EOF)
{
if (ferror (stdin))
error ("error while reading standard input");
}
return c;
}
static inline void
do_ungetc (int c)
{
if (c != EOF)
ungetc (c, stdin);
}
/* Copies stdin to stdout, performing substitutions. */
static void
subst_from_stdin (void)
{
static char *buffer;
static size_t bufmax;
static size_t buflen;
int c;
for (;;)
{
c = do_getc ();
if (c == EOF)
break;
/* Look for $VARIABLE or ${VARIABLE}. */
if (c == '$')
{
unsigned short int opening_brace = 0;
unsigned short int closing_brace = 0;
c = do_getc ();
if (c == '{')
{
opening_brace = 1;
c = do_getc ();
}
if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
{
unsigned short int valid;
/* Accumulate the VARIABLE in buffer. */
buflen = 0;
do
{
if (buflen >= bufmax)
{
bufmax = 2 * bufmax + 10;
buffer = xrealloc (buffer, bufmax);
}
buffer[buflen++] = c;
c = do_getc ();
}
while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
|| (c >= '0' && c <= '9') || c == '_');
if (opening_brace)
{
if (c == '}')
{
closing_brace = 1;
valid = 1;
}
else
{
valid = 0;
do_ungetc (c);
}
}
else
{
valid = 1;
do_ungetc (c);
}
if (valid)
{
/* Terminate the variable in the buffer. */
if (buflen >= bufmax)
{
bufmax = 2 * bufmax + 10;
buffer = xrealloc (buffer, bufmax);
}
buffer[buflen] = '\0';
/* Test whether the variable shall be substituted. */
if (!all_variables
&& !sorted_string_list_member (&variables_set, buffer))
valid = 0;
}
if (valid)
{
/* Substitute the variable's value from the environment. */
const char *env_value = getenv (buffer);
if (env_value)
fputs (env_value, stdout);
}
else
{
/* Perform no substitution at all. Since the buffered input
contains no other '$' than at the start, we can just
output all the buffered contents. */
putchar ('$');
if (opening_brace)
putchar ('{');
fwrite (buffer, buflen, 1, stdout);
if (closing_brace)
putchar ('}');
}
}
else
{
do_ungetc (c);
putchar ('$');
if (opening_brace)
putchar ('{');
}
}
else
putchar (c);
}
}