[PATCH] Diff-tree-helper take two.

This reworks the diff-tree-helper and show-diff to further make external
diff command interface simpler.

These commands now honor GIT_EXTERNAL_DIFF environment variable which
can point at an arbitrary program that takes 7 parameters:

  name file1 file1-sha1 file1-mode file2 file2-sha1 file2-mode

The parameters for an external diff command are as follows:

  name        this invocation of the command is to emit diff
	      for the named cache/tree entry.

  file1       pathname that holds the contents of the first
	      file.  This can be a file inside the working
	      tree, or a temporary file created from the blob
	      object, or /dev/null.  The command should not
	      attempt to unlink it -- the temporary is
	      unlinked by the caller.

  file1-sha1  sha1 hash if file1 is a blob object, or "."
	      otherwise.

  file1-mode  mode bits for file1, or "." for a deleted file.

If GIT_EXTERNAL_DIFF environment variable is not set, the
default is to invoke diff with the set of parameters old
show-diff used to use.  This built-in implementation honors the
GIT_DIFF_CMD and GIT_DIFF_OPTS environment variables as before.

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
2005-04-26 09:25:05 -07:00
committed by Linus Torvalds
parent d1df574380
commit be3cfa85f4
4 changed files with 271 additions and 270 deletions

248
diff.c
View File

@ -1,13 +1,22 @@
/*
* 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 = "-p -u";
static char *diff_arg_forward = " - '%s'";
static char *diff_arg_reverse = " '%s' -";
static char *diff_cmd = "diff -L'k/%s' -L'l/%s'";
static char *diff_opts = "-pu";
void prepare_diff_cmd(void)
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
@ -17,8 +26,15 @@ void prepare_diff_cmd(void)
* 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.
@ -58,49 +74,195 @@ static char *sq_expand(const char *src)
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;
static struct diff_tempfile {
const char *name;
char hex[41];
char mode[10];
char tmp_path[50];
} diff_temp[2];
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);
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 = malloc(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);
}
void show_diff_empty(const unsigned char *sha1,
const char *name,
int reverse)
static void prepare_temp_file(const char *name,
struct diff_tempfile *temp,
struct diff_spec *one)
{
char *old;
unsigned long int size;
unsigned char type[20];
static unsigned char null_sha1[20] = { 0, };
old = read_sha1_file(sha1, type, &size);
if (! old) {
error("unable to read blob object for %s (%s)", name,
sha1_to_hex(sha1));
if (!one->file_valid) {
not_a_valid_file:
temp->name = "/dev/null";
strcpy(temp->hex, ".");
strcpy(temp->mode, ".");
return;
}
show_differences("/dev/null", name, old, size, reverse);
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);
}