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/*
* Copyright (C) 2005 Junio C Hamano
*/
#include <sys/types.h>
#include <sys/wait.h>
#include "cache.h"
#include "diff.h"
static char *diff_cmd = "diff -L'k/%s' -L'l/%s'";
static char *diff_opts = "-pu";
static const char *external_diff(void)
{
static char *external_diff_cmd = NULL;
static int done_preparing = 0;
if (done_preparing)
return external_diff_cmd;
/*
* 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";
*/
if (getenv("GIT_EXTERNAL_DIFF"))
external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
/* In case external diff fails... */
diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
done_preparing = 1;
return external_diff_cmd;
}
/* 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;
buf = xmalloc(cnt);
bp = buf;
while ((c = *src++)) {
if (c != '\'')
*bp++ = c;
else {
bp = strcpy(bp, "'\\''");
bp += 4;
}
}
*bp = 0;
return buf;
}
static struct diff_tempfile {
const char *name;
char hex[41];
char mode[10];
char tmp_path[50];
} diff_temp[2];
static void builtin_diff(const char *name,
struct diff_tempfile *temp)
{
static char *diff_arg = "'%s' '%s'";
const char *name_1_sq = sq_expand(temp[0].name);
const char *name_2_sq = sq_expand(temp[1].name);
const char *name_sq = sq_expand(name);
/* diff_cmd and diff_arg have 4 %s in total which makes
* the sum of these strings 8 bytes larger than required.
* we use 2 spaces around diff-opts, and we need to count
* terminating NUL, so we subtract 5 here.
*/
int cmd_size = (strlen(diff_cmd) +
strlen(name_sq) * 2 +
strlen(diff_opts) +
strlen(diff_arg) +
strlen(name_1_sq) + strlen(name_2_sq)
- 5);
char *cmd = xmalloc(cmd_size);
int next_at = 0;
next_at += snprintf(cmd+next_at, cmd_size-next_at,
diff_cmd, name_sq, name_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_1_sq, name_2_sq);
execlp("/bin/sh","sh", "-c", cmd, NULL);
}
static void prepare_temp_file(const char *name,
struct diff_tempfile *temp,
struct diff_spec *one)
{
static unsigned char null_sha1[20] = { 0, };
if (!one->file_valid) {
not_a_valid_file:
temp->name = "/dev/null";
strcpy(temp->hex, ".");
strcpy(temp->mode, ".");
return;
}
if (one->sha1_valid &&
!memcmp(one->u.sha1, null_sha1, sizeof(null_sha1))) {
one->sha1_valid = 0;
one->u.name = name;
}
if (!one->sha1_valid) {
struct stat st;
temp->name = one->u.name;
if (stat(temp->name, &st) < 0) {
if (errno == ENOENT)
goto not_a_valid_file;
die("stat(%s): %s", temp->name, strerror(errno));
}
strcpy(temp->hex, ".");
sprintf(temp->mode, "%06o",
S_IFREG |ce_permissions(st.st_mode));
}
else {
int fd;
void *blob;
char type[20];
unsigned long size;
blob = read_sha1_file(one->u.sha1, type, &size);
if (!blob || strcmp(type, "blob"))
die("unable to read blob object for %s (%s)",
name, sha1_to_hex(one->u.sha1));
strcpy(temp->tmp_path, ".diff_XXXXXX");
fd = mkstemp(temp->tmp_path);
if (fd < 0)
die("unable to create temp-file");
if (write(fd, blob, size) != size)
die("unable to write temp-file");
close(fd);
free(blob);
temp->name = temp->tmp_path;
strcpy(temp->hex, sha1_to_hex(one->u.sha1));
temp->hex[40] = 0;
sprintf(temp->mode, "%06o", one->mode);
}
}
static void remove_tempfile(void)
{
int i;
for (i = 0; i < 2; i++)
if (diff_temp[i].name == diff_temp[i].tmp_path) {
unlink(diff_temp[i].name);
diff_temp[i].name = NULL;
}
}
/* An external diff command takes:
*
* diff-cmd name infile1 infile1-sha1 infile1-mode \
* infile2 infile2-sha1 infile2-mode.
*
*/
void run_external_diff(const char *name,
struct diff_spec *one,
struct diff_spec *two)
{
struct diff_tempfile *temp = diff_temp;
int pid, status;
static int atexit_asked = 0;
prepare_temp_file(name, &temp[0], one);
prepare_temp_file(name, &temp[1], two);
if (! atexit_asked &&
(temp[0].name == temp[0].tmp_path ||
temp[1].name == temp[1].tmp_path)) {
atexit_asked = 1;
atexit(remove_tempfile);
}
fflush(NULL);
pid = fork();
if (pid < 0)
die("unable to fork");
if (!pid) {
const char *pgm = external_diff();
if (pgm)
execlp(pgm, pgm,
name,
temp[0].name, temp[0].hex, temp[0].mode,
temp[1].name, temp[1].hex, temp[1].mode,
NULL);
/*
* otherwise we use the built-in one.
*/
builtin_diff(name, temp);
exit(0);
}
if (waitpid(pid, &status, 0) < 0 || !WIFEXITED(status))
die("diff program failed");
remove_tempfile();
}
void show_diff_empty(const struct cache_entry *ce, int reverse)
{
struct diff_spec spec[2], *one, *two;
memcpy(spec[0].u.sha1, ce->sha1, 20);
spec[0].mode = ntohl(ce->ce_mode);
spec[0].sha1_valid = spec[0].file_valid = 1;
spec[1].file_valid = 0;
if (reverse) {
one = spec + 1; two = spec;
} else {
one = spec; two = one + 1;
}
run_external_diff(ce->name, one, two);
}
void show_differences(const struct cache_entry *ce, int reverse)
{
struct diff_spec spec[2], *one, *two;
memcpy(spec[0].u.sha1, ce->sha1, 20);
spec[0].mode = ntohl(ce->ce_mode);
spec[0].sha1_valid = spec[0].file_valid = 1;
spec[1].u.name = ce->name; /* the name we stated */
spec[1].sha1_valid = 0;
spec[1].file_valid = 1;
if (reverse) {
one = spec + 1; two = spec;
} else {
one = spec; two = one + 1;
}
run_external_diff(ce->name, one, two);
}
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