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[PATCH] Split external diff command interface to a separate file.

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With this patch, the non-core'ish part of show-diff command that
invokes an external "diff" comand to obtain patches is split
into a separate file.  The next patch will introduce a new
command, diff-tree-helper, which uses this common diff interface
to format diff-tree and diff-cache output into a patch form.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Junio C Hamano
2005-04-25 18:22:47 -07:00
committed by Linus Torvalds
parent ab7df1874d
commit 86436c2828
4 changed files with 130 additions and 98 deletions
Download Patch File Download Diff File Expand all files Collapse all files

101
show-diff.c
View File

@ -4,103 +4,7 @@
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
static char *diff_cmd = "diff -L 'a/%s' -L 'b/%s' ";
static char *diff_opts = "-p -u";
static char *diff_arg_forward = " - '%s'";
static char *diff_arg_reverse = " '%s' -";
static 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(char *src)
{
static char *buf = NULL;
int cnt, c;
char *cp;
/* 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;
cp = buf;
while ((c = *src++)) {
if (c != '\'')
*cp++ = c;
else {
cp = strcpy(cp, "'\\''");
cp += 4;
}
}
*cp = 0;
return buf;
}
static void show_differences(char *name, char *label, void *old_contents,
unsigned long long old_size, int reverse)
{
FILE *f;
char *name_sq = sq_expand(name);
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(label_sq);
free(name_sq);
free(cmd);
}
static void show_diff_empty(struct cache_entry *ce, int reverse)
{
char *old;
unsigned long int size;
unsigned char type[20];
old = read_sha1_file(ce->sha1, type, &size);
if (! old) {
error("unable to read blob object for %s (%s)", ce->name,
sha1_to_hex(ce->sha1));
return;
}
show_differences("/dev/null", ce->name, old, size, reverse);
}
#include "diff.h"
static const char *show_diff_usage = "show-diff [-q] [-s] [-z] [paths...]";
@ -183,7 +87,8 @@ int main(int argc, char **argv)
else {
printf("%s: %s\n", ce->name, strerror(errno));
if (errno == ENOENT)
show_diff_empty(ce, reverse);
show_diff_empty(ce->sha1, ce->name,
reverse);
}
continue;
}