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git/diff-no-index.c
Jeff King e4da43b1f0 prefix_filename: return newly allocated string
The prefix_filename() function returns a pointer to static
storage, which makes it easy to use dangerously. We already
fixed one buggy caller in hash-object recently, and the
calls in apply.c are suspicious (I didn't dig in enough to
confirm that there is a bug, but we call the function once
in apply_all_patches() and then again indirectly from
parse_chunk()).

Let's make it harder to get wrong by allocating the return
value. For simplicity, we'll do this even when the prefix is
empty (and we could just return the original file pointer).
That will cause us to allocate sometimes when we wouldn't
otherwise need to, but this function isn't called in
performance critical code-paths (and it already _might_
allocate on any given call, so a caller that cares about
performance is questionable anyway).

The downside is that the callers need to remember to free()
the result to avoid leaking. Most of them already used
xstrdup() on the result, so we know they are OK. The
remainder have been converted to use free() as appropriate.

I considered retaining a prefix_filename_unsafe() for cases
where we know the static lifetime is OK (and handling the
cleanup is awkward). This is only a handful of cases,
though, and it's not worth the mental energy in worrying
about whether the "unsafe" variant is OK to use in any
situation.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-21 11:18:41 -07:00

303 lines
6.8 KiB
C

/*
* "diff --no-index" support
* Copyright (c) 2007 by Johannes Schindelin
* Copyright (c) 2008 by Junio C Hamano
*/
#include "cache.h"
#include "color.h"
#include "commit.h"
#include "blob.h"
#include "tag.h"
#include "diff.h"
#include "diffcore.h"
#include "revision.h"
#include "log-tree.h"
#include "builtin.h"
#include "string-list.h"
#include "dir.h"
static int read_directory_contents(const char *path, struct string_list *list)
{
DIR *dir;
struct dirent *e;
if (!(dir = opendir(path)))
return error("Could not open directory %s", path);
while ((e = readdir(dir)))
if (!is_dot_or_dotdot(e->d_name))
string_list_insert(list, e->d_name);
closedir(dir);
return 0;
}
/*
* This should be "(standard input)" or something, but it will
* probably expose many more breakages in the way no-index code
* is bolted onto the diff callchain.
*/
static const char file_from_standard_input[] = "-";
static int get_mode(const char *path, int *mode)
{
struct stat st;
if (!path || !strcmp(path, "/dev/null"))
*mode = 0;
#ifdef GIT_WINDOWS_NATIVE
else if (!strcasecmp(path, "nul"))
*mode = 0;
#endif
else if (path == file_from_standard_input)
*mode = create_ce_mode(0666);
else if (lstat(path, &st))
return error("Could not access '%s'", path);
else
*mode = st.st_mode;
return 0;
}
static int populate_from_stdin(struct diff_filespec *s)
{
struct strbuf buf = STRBUF_INIT;
size_t size = 0;
if (strbuf_read(&buf, 0, 0) < 0)
return error_errno("error while reading from stdin");
s->should_munmap = 0;
s->data = strbuf_detach(&buf, &size);
s->size = size;
s->should_free = 1;
s->is_stdin = 1;
return 0;
}
static struct diff_filespec *noindex_filespec(const char *name, int mode)
{
struct diff_filespec *s;
if (!name)
name = "/dev/null";
s = alloc_filespec(name);
fill_filespec(s, null_sha1, 0, mode);
if (name == file_from_standard_input)
populate_from_stdin(s);
return s;
}
static int queue_diff(struct diff_options *o,
const char *name1, const char *name2)
{
int mode1 = 0, mode2 = 0;
if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
return -1;
if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2)) {
struct diff_filespec *d1, *d2;
if (S_ISDIR(mode1)) {
/* 2 is file that is created */
d1 = noindex_filespec(NULL, 0);
d2 = noindex_filespec(name2, mode2);
name2 = NULL;
mode2 = 0;
} else {
/* 1 is file that is deleted */
d1 = noindex_filespec(name1, mode1);
d2 = noindex_filespec(NULL, 0);
name1 = NULL;
mode1 = 0;
}
/* emit that file */
diff_queue(&diff_queued_diff, d1, d2);
/* and then let the entire directory be created or deleted */
}
if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
struct strbuf buffer1 = STRBUF_INIT;
struct strbuf buffer2 = STRBUF_INIT;
struct string_list p1 = STRING_LIST_INIT_DUP;
struct string_list p2 = STRING_LIST_INIT_DUP;
int i1, i2, ret = 0;
size_t len1 = 0, len2 = 0;
if (name1 && read_directory_contents(name1, &p1))
return -1;
if (name2 && read_directory_contents(name2, &p2)) {
string_list_clear(&p1, 0);
return -1;
}
if (name1) {
strbuf_addstr(&buffer1, name1);
strbuf_complete(&buffer1, '/');
len1 = buffer1.len;
}
if (name2) {
strbuf_addstr(&buffer2, name2);
strbuf_complete(&buffer2, '/');
len2 = buffer2.len;
}
for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
const char *n1, *n2;
int comp;
strbuf_setlen(&buffer1, len1);
strbuf_setlen(&buffer2, len2);
if (i1 == p1.nr)
comp = 1;
else if (i2 == p2.nr)
comp = -1;
else
comp = strcmp(p1.items[i1].string, p2.items[i2].string);
if (comp > 0)
n1 = NULL;
else {
strbuf_addstr(&buffer1, p1.items[i1++].string);
n1 = buffer1.buf;
}
if (comp < 0)
n2 = NULL;
else {
strbuf_addstr(&buffer2, p2.items[i2++].string);
n2 = buffer2.buf;
}
ret = queue_diff(o, n1, n2);
}
string_list_clear(&p1, 0);
string_list_clear(&p2, 0);
strbuf_release(&buffer1);
strbuf_release(&buffer2);
return ret;
} else {
struct diff_filespec *d1, *d2;
if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
SWAP(mode1, mode2);
SWAP(name1, name2);
}
d1 = noindex_filespec(name1, mode1);
d2 = noindex_filespec(name2, mode2);
diff_queue(&diff_queued_diff, d1, d2);
return 0;
}
}
/* append basename of F to D */
static void append_basename(struct strbuf *path, const char *dir, const char *file)
{
const char *tail = strrchr(file, '/');
strbuf_addstr(path, dir);
while (path->len && path->buf[path->len - 1] == '/')
path->len--;
strbuf_addch(path, '/');
strbuf_addstr(path, tail ? tail + 1 : file);
}
/*
* DWIM "diff D F" into "diff D/F F" and "diff F D" into "diff F D/F"
* Note that we append the basename of F to D/, so "diff a/b/file D"
* becomes "diff a/b/file D/file", not "diff a/b/file D/a/b/file".
*/
static void fixup_paths(const char **path, struct strbuf *replacement)
{
unsigned int isdir0, isdir1;
if (path[0] == file_from_standard_input ||
path[1] == file_from_standard_input)
return;
isdir0 = is_directory(path[0]);
isdir1 = is_directory(path[1]);
if (isdir0 == isdir1)
return;
if (isdir0) {
append_basename(replacement, path[0], path[1]);
path[0] = replacement->buf;
} else {
append_basename(replacement, path[1], path[0]);
path[1] = replacement->buf;
}
}
void diff_no_index(struct rev_info *revs,
int argc, const char **argv)
{
int i;
const char *paths[2];
struct strbuf replacement = STRBUF_INIT;
const char *prefix = revs->prefix;
diff_setup(&revs->diffopt);
for (i = 1; i < argc - 2; ) {
int j;
if (!strcmp(argv[i], "--no-index"))
i++;
else if (!strcmp(argv[i], "--"))
i++;
else {
j = diff_opt_parse(&revs->diffopt, argv + i, argc - i,
revs->prefix);
if (j <= 0)
die("invalid diff option/value: %s", argv[i]);
i += j;
}
}
for (i = 0; i < 2; i++) {
const char *p = argv[argc - 2 + i];
if (!strcmp(p, "-"))
/*
* stdin should be spelled as "-"; if you have
* path that is "-", spell it as "./-".
*/
p = file_from_standard_input;
else if (prefix)
p = prefix_filename(prefix, p);
paths[i] = p;
}
fixup_paths(paths, &replacement);
revs->diffopt.skip_stat_unmatch = 1;
if (!revs->diffopt.output_format)
revs->diffopt.output_format = DIFF_FORMAT_PATCH;
DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
DIFF_OPT_SET(&revs->diffopt, RELATIVE_NAME);
revs->diffopt.prefix = prefix;
revs->max_count = -2;
diff_setup_done(&revs->diffopt);
setup_diff_pager(&revs->diffopt);
DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
if (queue_diff(&revs->diffopt, paths[0], paths[1]))
exit(1);
diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
diffcore_std(&revs->diffopt);
diff_flush(&revs->diffopt);
strbuf_release(&replacement);
/*
* The return code for --no-index imitates diff(1):
* 0 = no changes, 1 = changes, else error
*/
exit(diff_result_code(&revs->diffopt, 0));
}