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[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>
maint
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

242
diff-tree-helper.c
View File

@ -1,3 +1,6 @@
/*
* Copyright (C) 2005 Junio C Hamano
*/
#include "cache.h"
#include "strbuf.h"
#include "diff.h"
@ -17,15 +20,22 @@ static int matches_pathspec(const char *name, char **spec, int cnt)
return 0;
}

static int parse_oneside_change(const char *cp, unsigned char *sha1,
char *path) {
static int parse_oneside_change(const char *cp, struct diff_spec *one,
char *path)
{
int ch;
while ((ch = *cp) && '0' <= ch && ch <= '7')
cp++; /* skip mode bits */

one->file_valid = one->sha1_valid = 1;
one->mode = 0;
while ((ch = *cp) && '0' <= ch && ch <= '7') {
one->mode = (one->mode << 3) | (ch - '0');
cp++;
}

if (strncmp(cp, "\tblob\t", 6))
return -1;
cp += 6;
if (get_sha1_hex(cp, sha1))
if (get_sha1_hex(cp, one->u.sha1))
return -1;
cp += 40;
if (*cp++ != '\t')
@ -34,31 +44,20 @@ static int parse_oneside_change(const char *cp, unsigned char *sha1,
return 0;
}

#define STATUS_CACHED 0 /* cached and sha1 valid */
#define STATUS_ABSENT 1 /* diff-tree says old removed or new added */
#define STATUS_UNCACHED 2 /* diff-cache output: read from working tree */

static int parse_diff_tree_output(const char *buf,
unsigned char *old_sha1,
int *old_status,
unsigned char *new_sha1,
int *new_status,
struct diff_spec *old,
struct diff_spec *new,
char *path) {
const char *cp = buf;
int ch;
static unsigned char null_sha[20] = { 0, };

switch (*cp++) {
case '+':
*old_status = STATUS_ABSENT;
*new_status = (memcmp(new_sha1, null_sha, sizeof(null_sha)) ?
STATUS_CACHED : STATUS_UNCACHED);
return parse_oneside_change(cp, new_sha1, path);
old->file_valid = 0;
return parse_oneside_change(cp, new, path);
case '-':
*new_status = STATUS_ABSENT;
*old_status = (memcmp(old_sha1, null_sha, sizeof(null_sha)) ?
STATUS_CACHED : STATUS_UNCACHED);
return parse_oneside_change(cp, old_sha1, path);
new->file_valid = 0;
return parse_oneside_change(cp, old, path);
case '*':
break;
default:
@ -66,191 +65,36 @@ static int parse_diff_tree_output(const char *buf,
}
/* This is for '*' entries */
while ((ch = *cp) && ('0' <= ch && ch <= '7'))
cp++; /* skip mode bits */
old->file_valid = old->sha1_valid = 1;
new->file_valid = new->sha1_valid = 1;

old->mode = new->mode = 0;
while ((ch = *cp) && ('0' <= ch && ch <= '7')) {
old->mode = (old->mode << 3) | (ch - '0');
cp++;
}
if (strncmp(cp, "->", 2))
return -1;
cp += 2;
while ((ch = *cp) && ('0' <= ch && ch <= '7'))
cp++; /* skip mode bits */
while ((ch = *cp) && ('0' <= ch && ch <= '7')) {
new->mode = (new->mode << 3) | (ch - '0');
cp++;
}
if (strncmp(cp, "\tblob\t", 6))
return -1;
cp += 6;
if (get_sha1_hex(cp, old_sha1))
if (get_sha1_hex(cp, old->u.sha1))
return -1;
cp += 40;
if (strncmp(cp, "->", 2))
return -1;
cp += 2;
if (get_sha1_hex(cp, new_sha1))
if (get_sha1_hex(cp, new->u.sha1))
return -1;
cp += 40;
if (*cp++ != '\t')
return -1;
strcpy(path, cp);
*old_status = (memcmp(old_sha1, null_sha, sizeof(null_sha)) ?
STATUS_CACHED : STATUS_UNCACHED);
*new_status = (memcmp(new_sha1, null_sha, sizeof(null_sha)) ?
STATUS_CACHED : STATUS_UNCACHED);
return 0;
}

static int sha1err(const char *path, const unsigned char *sha1)
{
return error("diff-tree-helper: unable to read sha1 file of %s (%s)",
path, sha1_to_hex(sha1));
}

static int fserr(const char *path)
{
return error("diff-tree-helper: unable to read file %s", path);
}

static char *map_whole_file(const char *path, unsigned long *size) {
int fd;
struct stat st;
void *buf;

if ((fd = open(path, O_RDONLY)) < 0) {
error("diff-tree-helper: unable to read file %s", path);
return 0;
}
if (fstat(fd, &st) < 0) {
close(fd);
error("diff-tree-helper: unable to stat file %s", path);
return 0;
}
*size = st.st_size;
buf = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
return buf;
}

static int show_diff(const unsigned char *old_sha1, int old_status,
const unsigned char *new_sha1, int new_status,
const char *path, int reverse_diff)
{
char other[PATH_MAX];
unsigned long size;
char type[20];
int fd;
int reverse;
void *blob = 0;
const char *fs = 0;
int need_unmap = 0;
int need_unlink = 0;


switch (old_status) {
case STATUS_CACHED:
blob = read_sha1_file(old_sha1, type, &size);
if (! blob)
return sha1err(path, old_sha1);
switch (new_status) {
case STATUS_CACHED:
strcpy(other, ".diff_tree_helper_XXXXXX");
fd = mkstemp(other);
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);

blob = read_sha1_file(new_sha1, type, &size);
if (! blob)
return sha1err(path, new_sha1);

need_unlink = 1;
/* new = blob, old = fs */
reverse = !reverse_diff;
fs = other;
break;

case STATUS_ABSENT:
case STATUS_UNCACHED:
fs = ((new_status == STATUS_ABSENT) ?
"/dev/null" : path);
reverse = reverse_diff;
break;

default:
reverse = reverse_diff;
}
break;

case STATUS_ABSENT:
switch (new_status) {
case STATUS_CACHED:
blob = read_sha1_file(new_sha1, type, &size);
if (! blob)
return sha1err(path, new_sha1);
/* old = fs, new = blob */
fs = "/dev/null";
reverse = !reverse_diff;
break;

case STATUS_ABSENT:
return error("diff-tree-helper: absent from both old and new?");
case STATUS_UNCACHED:
fs = path;
blob = strdup("");
size = 0;
/* old = blob, new = fs */
reverse = reverse_diff;
break;
default:
reverse = reverse_diff;
}
break;

case STATUS_UNCACHED:
fs = path; /* old = fs, new = blob */
reverse = !reverse_diff;

switch (new_status) {
case STATUS_CACHED:
blob = read_sha1_file(new_sha1, type, &size);
if (! blob)
return sha1err(path, new_sha1);
break;

case STATUS_ABSENT:
blob = strdup("");
size = 0;
break;

case STATUS_UNCACHED:
/* old = fs */
blob = map_whole_file(path, &size);
if (! blob)
return fserr(path);
need_unmap = 1;
break;
default:
reverse = reverse_diff;
}
break;

default:
reverse = reverse_diff;
}
if (fs)
show_differences(fs,
path, /* label */
blob,
size,
reverse /* 0: diff blob fs
1: diff fs blob */);

if (need_unlink)
unlink(other);
if (need_unmap && blob)
munmap(blob, size);
else
free(blob);
return 0;
}

@ -275,28 +119,20 @@ int main(int ac, char **av) {
}
/* the remaining parameters are paths patterns */

prepare_diff_cmd();

while (1) {
int old_status, new_status;
unsigned char old_sha1[20], new_sha1[20];
struct diff_spec old, new;
char path[PATH_MAX];
read_line(&sb, stdin, line_termination);
if (sb.eof)
break;
if (parse_diff_tree_output(sb.buf,
old_sha1, &old_status,
new_sha1, &new_status,
path)) {
if (parse_diff_tree_output(sb.buf, &old, &new, path)) {
fprintf(stderr, "cannot parse %s\n", sb.buf);
continue;
}
if (1 < ac && ! matches_pathspec(path, av+1, ac-1))
if (1 < ac && !matches_pathspec(path, av+1, ac-1))
continue;

show_diff(old_sha1, old_status,
new_sha1, new_status,
path, reverse_diff);
run_external_diff(path, &old, &new);
}
return 0;
}

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);
}

34
diff.h
View File

@ -1,17 +1,31 @@
/*
* Copyright (C) 2005 Junio C Hamano
*/
#ifndef DIFF_H
#define DIFF_H

extern void prepare_diff_cmd(void);
/* These two are for backward compatibility with show-diff;
* new users should not use them.
*/
extern void show_differences(const struct cache_entry *ce, int reverse);
extern void show_diff_empty(const struct cache_entry *ce, int reverse);

extern 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 */);
struct diff_spec {
union {
const char *name; /* path on the filesystem */
unsigned char sha1[20]; /* blob object ID */
} u;
unsigned short mode; /* file mode */
unsigned sha1_valid : 1; /* if true, use u.sha1 and trust mode.
* (however with a NULL SHA1, read them
* from the file!).
* if false, use u.name and read mode from
* the filesystem.
*/
unsigned file_valid : 1; /* if false the file does not even exist */
};

extern void show_diff_empty(const unsigned char *sha1,
const char *name,
int reverse);
extern void run_external_diff(const char *name,
struct diff_spec *, struct diff_spec *);

#endif /* DIFF_H */

17
show-diff.c
View File

@ -53,14 +53,11 @@ int main(int argc, char **argv)
perror("read_cache");
exit(1);
}
prepare_diff_cmd();

for (i = 0; i < entries; i++) {
struct stat st;
struct cache_entry *ce = active_cache[i];
int changed;
unsigned long size;
char type[20];
void *old;

if (1 < argc &&
! matches_pathspec(ce, argv+1, argc-1))
@ -87,8 +84,7 @@ int main(int argc, char **argv)
else {
printf("%s: %s\n", ce->name, strerror(errno));
if (errno == ENOENT)
show_diff_empty(ce->sha1, ce->name,
reverse);
show_diff_empty(ce, reverse);
}
continue;
}
@ -104,14 +100,7 @@ int main(int argc, char **argv)
if (silent)
continue;

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));
else
show_differences(ce->name, ce->name, old, size,
reverse);
free(old);
show_differences(ce, reverse);
}
return 0;
}