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#include "cache.h"
#include "diff.h"
static char *diff_cmd = "diff -L 'k/%s' -L 'l/%s' ";
static char *diff_opts = "-p -u";
static char *diff_arg_forward = " - '%s'";
static char *diff_arg_reverse = " '%s' -";
void prepare_diff_cmd(void)
{
/*
* Default values above are meant to match the
* Linux kernel development style. Examples of
* alternative styles you can specify via environment
* variables are:
*
* GIT_DIFF_CMD="diff -L '%s' -L '%s'"
* GIT_DIFF_OPTS="-c";
*/
diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
}
/* Help to copy the thing properly quoted for the shell safety.
* any single quote is replaced with '\'', and the caller is
* expected to enclose the result within a single quote pair.
*
* E.g.
* original sq_expand result
* name ==> name ==> 'name'
* a b ==> a b ==> 'a b'
* a'b ==> a'\''b ==> 'a'\''b'
*/
static char *sq_expand(const char *src)
{
static char *buf = NULL;
int cnt, c;
const char *cp;
char *bp;
/* count bytes needed to store the quoted string. */
for (cnt = 1, cp = src; *cp; cnt++, cp++)
if (*cp == '\'')
cnt += 3;
if (! (buf = malloc(cnt)))
return buf;
bp = buf;
while ((c = *src++)) {
if (c != '\'')
*bp++ = c;
else {
bp = strcpy(bp, "'\\''");
bp += 4;
}
}
*bp = 0;
return buf;
}
void show_differences(const char *name, /* filename on the filesystem */
const char *label, /* diff label to use */
void *old_contents, /* contents in core */
unsigned long long old_size, /* size in core */
int reverse /* 0: diff core file
1: diff file core */)
{
FILE *f;
char *name_sq = sq_expand(name);
const char *label_sq = (name != label) ? sq_expand(label) : name_sq;
char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
char *cmd = malloc(cmd_size);
int next_at;
fflush(stdout);
next_at = snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq);
next_at += snprintf(cmd+next_at, cmd_size-next_at, "%s", diff_opts);
next_at += snprintf(cmd+next_at, cmd_size-next_at, diff_arg, name_sq);
f = popen(cmd, "w");
if (old_size)
fwrite(old_contents, old_size, 1, f);
pclose(f);
if (label_sq != name_sq)
free((void*)label_sq); /* constness */
free(name_sq);
free(cmd);
}
void show_diff_empty(const unsigned char *sha1,
const char *name,
int reverse)
{
char *old;
unsigned long int size;
unsigned char type[20];
old = read_sha1_file(sha1, type, &size);
if (! old) {
error("unable to read blob object for %s (%s)", name,
sha1_to_hex(sha1));
return;
}
show_differences("/dev/null", name, old, size, reverse);
}
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