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-rw-r--r--builtin/difftool.c89
1 files changed, 66 insertions, 23 deletions
diff --git a/builtin/difftool.c b/builtin/difftool.c
index d13350ce83..1354d0e462 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -254,6 +254,62 @@ static int ensure_leading_directories(char *path)
}
}
+/*
+ * Unconditional writing of a plain regular file is what
+ * "git difftool --dir-diff" wants to do for symlinks. We are preparing two
+ * temporary directories to be fed to a Git-unaware tool that knows how to
+ * show a diff of two directories (e.g. "diff -r A B").
+ *
+ * Because the tool is Git-unaware, if a symbolic link appears in either of
+ * these temporary directories, it will try to dereference and show the
+ * difference of the target of the symbolic link, which is not what we want,
+ * as the goal of the dir-diff mode is to produce an output that is logically
+ * equivalent to what "git diff" produces.
+ *
+ * Most importantly, we want to get textual comparison of the result of the
+ * readlink(2). get_symlink() provides that---it returns the contents of
+ * the symlink that gets written to a regular file to force the external tool
+ * to compare the readlink(2) result as text, even on a filesystem that is
+ * capable of doing a symbolic link.
+ */
+static char *get_symlink(const struct object_id *oid, const char *path)
+{
+ char *data;
+ if (is_null_oid(oid)) {
+ /* The symlink is unknown to Git so read from the filesystem */
+ struct strbuf link = STRBUF_INIT;
+ if (has_symlinks) {
+ if (strbuf_readlink(&link, path, strlen(path)))
+ die(_("could not read symlink %s"), path);
+ } else if (strbuf_read_file(&link, path, 128))
+ die(_("could not read symlink file %s"), path);
+
+ data = strbuf_detach(&link, NULL);
+ } else {
+ enum object_type type;
+ unsigned long size;
+ data = read_sha1_file(oid->hash, &type, &size);
+ if (!data)
+ die(_("could not read object %s for symlink %s"),
+ oid_to_hex(oid), path);
+ }
+
+ return data;
+}
+
+static int checkout_path(unsigned mode, struct object_id *oid,
+ const char *path, const struct checkout *state)
+{
+ struct cache_entry *ce;
+ int ret;
+
+ ce = make_cache_entry(mode, oid->hash, path, 0, 0);
+ ret = checkout_entry(ce, state, NULL);
+
+ free(ce);
+ return ret;
+}
+
static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
int argc, const char **argv)
{
@@ -262,16 +318,14 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
struct strbuf wtdir = STRBUF_INIT;
+ char *lbase_dir, *rbase_dir;
size_t ldir_len, rdir_len, wtdir_len;
- struct cache_entry *ce = xcalloc(1, sizeof(ce) + PATH_MAX + 1);
const char *workdir, *tmp;
int ret = 0, i;
FILE *fp;
struct hashmap working_tree_dups, submodules, symlinks2;
struct hashmap_iter iter;
struct pair_entry *entry;
- enum object_type type;
- unsigned long size;
struct index_state wtindex;
struct checkout lstate, rstate;
int rc, flags = RUN_GIT_CMD, err = 0;
@@ -298,11 +352,11 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
memset(&wtindex, 0, sizeof(wtindex));
memset(&lstate, 0, sizeof(lstate));
- lstate.base_dir = ldir.buf;
+ lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
lstate.base_dir_len = ldir.len;
lstate.force = 1;
memset(&rstate, 0, sizeof(rstate));
- rstate.base_dir = rdir.buf;
+ rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
rstate.base_dir_len = rdir.len;
rstate.force = 1;
@@ -336,7 +390,6 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
struct object_id loid, roid;
char status;
const char *src_path, *dst_path;
- size_t src_path_len, dst_path_len;
if (starts_with(info.buf, "::"))
die(N_("combined diff formats('-c' and '--cc') are "
@@ -349,17 +402,14 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
if (strbuf_getline_nul(&lpath, fp))
break;
src_path = lpath.buf;
- src_path_len = lpath.len;
i++;
if (status != 'C' && status != 'R') {
dst_path = src_path;
- dst_path_len = src_path_len;
} else {
if (strbuf_getline_nul(&rpath, fp))
break;
dst_path = rpath.buf;
- dst_path_len = rpath.len;
}
if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
@@ -377,27 +427,23 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
}
if (S_ISLNK(lmode)) {
- char *content = read_sha1_file(loid.hash, &type, &size);
+ char *content = get_symlink(&loid, src_path);
add_left_or_right(&symlinks2, src_path, content, 0);
free(content);
}
if (S_ISLNK(rmode)) {
- char *content = read_sha1_file(roid.hash, &type, &size);
+ char *content = get_symlink(&roid, dst_path);
add_left_or_right(&symlinks2, dst_path, content, 1);
free(content);
}
if (lmode && status != 'C') {
- ce->ce_mode = lmode;
- oidcpy(&ce->oid, &loid);
- strcpy(ce->name, src_path);
- ce->ce_namelen = src_path_len;
- if (checkout_entry(ce, &lstate, NULL))
+ if (checkout_path(lmode, &loid, src_path, &lstate))
return error("could not write '%s'", src_path);
}
- if (rmode) {
+ if (rmode && !S_ISLNK(rmode)) {
struct working_tree_entry *entry;
/* Avoid duplicate working_tree entries */
@@ -410,11 +456,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
hashmap_add(&working_tree_dups, entry);
if (!use_wt_file(workdir, dst_path, &roid)) {
- ce->ce_mode = rmode;
- oidcpy(&ce->oid, &roid);
- strcpy(ce->name, dst_path);
- ce->ce_namelen = dst_path_len;
- if (checkout_entry(ce, &rstate, NULL))
+ if (checkout_path(rmode, &roid, dst_path, &rstate))
return error("could not write '%s'",
dst_path);
} else if (!is_null_oid(&roid)) {
@@ -584,7 +626,8 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
exit_cleanup(tmpdir, rc);
finish:
- free(ce);
+ free(lbase_dir);
+ free(rbase_dir);
strbuf_release(&ldir);
strbuf_release(&rdir);
strbuf_release(&wtdir);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-02 08:51:56 +0000