[PATCH 2/2] ls-files: allow relative pathspec

[Clemens Buchacher <drizzd@aon.at>]

git ls-files used to error out if given paths which point outside the current
working directory, such as '../'. We now allow such paths and the output is
analogous to git grep -l.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
---

There are two changes with respect to the previous version of this
patch.

- write_name() now uses the new write_name_quoted_relative()
- prefix_offset is renamed to prefix_len, which is much more
  intuitive

Clemens

 builtin/ls-files.c |   75 ++++++++++++++++++++++++++++-----------------------
 t/t7010-setup.sh   |   12 +++-----
 2 files changed, 45 insertions(+), 42 deletions(-)

diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index c0fbcdc..0804047 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -26,8 +26,9 @@ static int show_killed;
 static int show_valid_bit;
 static int line_terminator = '\n';
 
+static const char *prefix;
+static int max_prefix_len;
 static int prefix_len;
-static int prefix_offset;
 static const char **pathspec;
 static int error_unmatch;
 static char *ps_matched;
@@ -43,10 +44,15 @@ static const char *tag_modified = "";
 static const char *tag_skip_worktree = "";
 static const char *tag_resolve_undo = "";
 
+static void write_name(const char* name, size_t len)
+{
+	write_name_quoted_relative(name, len, prefix, prefix_len, stdout,
+			line_terminator);
+}
+
 static void show_dir_entry(const char *tag, struct dir_entry *ent)
 {
-	int len = prefix_len;
-	int offset = prefix_offset;
+	int len = max_prefix_len;
 
 	if (len >= ent->len)
 		die("git ls-files: internal error - directory entry not superset of prefix");
@@ -55,7 +61,7 @@ static void show_dir_entry(const char *tag, struct dir_entry *ent)
 		return;
 
 	fputs(tag, stdout);
-	write_name_quoted(ent->name + offset, stdout, line_terminator);
+	write_name(ent->name, ent->len);
 }
 
 static void show_other_files(struct dir_struct *dir)
@@ -121,8 +127,7 @@ static void show_killed_files(struct dir_struct *dir)
 
 static void show_ce_entry(const char *tag, struct cache_entry *ce)
 {
-	int len = prefix_len;
-	int offset = prefix_offset;
+	int len = max_prefix_len;
 
 	if (len >= ce_namelen(ce))
 		die("git ls-files: internal error - cache entry not superset of prefix");
@@ -156,20 +161,19 @@ static void show_ce_entry(const char *tag, struct cache_entry *ce)
 		       find_unique_abbrev(ce->sha1,abbrev),
 		       ce_stage(ce));
 	}
-	write_name_quoted(ce->name + offset, stdout, line_terminator);
+	write_name(ce->name, ce_namelen(ce));
 }
 
 static int show_one_ru(struct string_list_item *item, void *cbdata)
 {
-	int offset = prefix_offset;
 	const char *path = item->string;
 	struct resolve_undo_info *ui = item->util;
 	int i, len;
 
 	len = strlen(path);
-	if (len < prefix_len)
+	if (len < max_prefix_len)
 		return 0; /* outside of the prefix */
-	if (!match_pathspec(pathspec, path, len, prefix_len, ps_matched))
+	if (!match_pathspec(pathspec, path, len, max_prefix_len, ps_matched))
 		return 0; /* uninterested */
 	for (i = 0; i < 3; i++) {
 		if (!ui->mode[i])
@@ -177,19 +181,19 @@ static int show_one_ru(struct string_list_item *item, void *cbdata)
 		printf("%s%06o %s %d\t", tag_resolve_undo, ui->mode[i],
 		       find_unique_abbrev(ui->sha1[i], abbrev),
 		       i + 1);
-		write_name_quoted(path + offset, stdout, line_terminator);
+		write_name(path, len);
 	}
 	return 0;
 }
 
-static void show_ru_info(const char *prefix)
+static void show_ru_info(void)
 {
 	if (!the_index.resolve_undo)
 		return;
 	for_each_string_list(show_one_ru, the_index.resolve_undo, NULL);
 }
 
-static void show_files(struct dir_struct *dir, const char *prefix)
+static void show_files(struct dir_struct *dir)
 {
 	int i;
 
@@ -243,7 +247,7 @@ static void show_files(struct dir_struct *dir, const char *prefix)
  */
 static void prune_cache(const char *prefix)
 {
-	int pos = cache_name_pos(prefix, prefix_len);
+	int pos = cache_name_pos(prefix, max_prefix_len);
 	unsigned int first, last;
 
 	if (pos < 0)
@@ -256,7 +260,7 @@ static void prune_cache(const char *prefix)
 	while (last > first) {
 		int next = (last + first) >> 1;
 		struct cache_entry *ce = active_cache[next];
-		if (!strncmp(ce->name, prefix, prefix_len)) {
+		if (!strncmp(ce->name, prefix, max_prefix_len)) {
 			first = next+1;
 			continue;
 		}
@@ -265,11 +269,16 @@ static void prune_cache(const char *prefix)
 	active_nr = last;
 }
 
-static const char *verify_pathspec(const char *prefix)
+static const char *pathspec_prefix(const char *prefix)
 {
 	const char **p, *n, *prev;
 	unsigned long max;
 
+	if (!pathspec) {
+		max_prefix_len = prefix ? strlen(prefix) : 0;
+		return prefix;
+	}
+
 	prev = NULL;
 	max = PATH_MAX;
 	for (p = pathspec; (n = *p) != NULL; p++) {
@@ -291,10 +300,7 @@ static const char *verify_pathspec(const char *prefix)
 		}
 	}
 
-	if (prefix_offset > max || memcmp(prev, prefix, prefix_offset))
-		die("git ls-files: cannot generate relative filenames containing '..'");
-
-	prefix_len = max;
+	max_prefix_len = max;
 	return max ? xmemdupz(prev, max) : NULL;
 }
 
@@ -374,7 +380,7 @@ void overlay_tree_on_cache(const char *tree_name, const char *prefix)
 	}
 }
 
-int report_path_error(const char *ps_matched, const char **pathspec, int prefix_offset)
+int report_path_error(const char *ps_matched, const char **pathspec, int prefix_len)
 {
 	/*
 	 * Make sure all pathspec matched; otherwise it is an error.
@@ -404,7 +410,7 @@ int report_path_error(const char *ps_matched, const char **pathspec, int prefix_
 			continue;
 
 		error("pathspec '%s' did not match any file(s) known to git.",
-		      pathspec[num] + prefix_offset);
+		      pathspec[num] + prefix_len);
 		errors++;
 	}
 	return errors;
@@ -456,9 +462,10 @@ static int option_parse_exclude_standard(const struct option *opt,
 	return 0;
 }
 
-int cmd_ls_files(int argc, const char **argv, const char *prefix)
+int cmd_ls_files(int argc, const char **argv, const char *cmd_prefix)
 {
 	int require_work_tree = 0, show_tag = 0;
+	const char *max_prefix;
 	struct dir_struct dir;
 	struct option builtin_ls_files_options[] = {
 		{ OPTION_CALLBACK, 'z', NULL, NULL, NULL,
@@ -504,7 +511,7 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 		{ OPTION_CALLBACK, 0, "exclude-standard", &dir, NULL,
 			"add the standard git exclusions",
 			PARSE_OPT_NOARG, option_parse_exclude_standard },
-		{ OPTION_SET_INT, 0, "full-name", &prefix_offset, NULL,
+		{ OPTION_SET_INT, 0, "full-name", &prefix_len, NULL,
 			"make the output relative to the project top directory",
 			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL },
 		OPT_BOOLEAN(0, "error-unmatch", &error_unmatch,
@@ -516,8 +523,9 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 	};
 
 	memset(&dir, 0, sizeof(dir));
+	prefix = cmd_prefix;
 	if (prefix)
-		prefix_offset = strlen(prefix);
+		prefix_len = strlen(prefix);
 	git_config(git_default_config, NULL);
 
 	if (read_cache() < 0)
@@ -555,9 +563,8 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 	if (pathspec)
 		strip_trailing_slash_from_submodules();
 
-	/* Verify that the pathspec matches the prefix */
-	if (pathspec)
-		prefix = verify_pathspec(prefix);
+	/* Find common prefix for all pathspec's */
+	max_prefix = pathspec_prefix(prefix);
 
 	/* Treat unmatching pathspec elements as errors */
 	if (pathspec && error_unmatch) {
@@ -575,8 +582,8 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 	      show_killed | show_modified | show_resolve_undo))
 		show_cached = 1;
 
-	if (prefix)
-		prune_cache(prefix);
+	if (max_prefix)
+		prune_cache(max_prefix);
 	if (with_tree) {
 		/*
 		 * Basic sanity check; show-stages and show-unmerged
@@ -584,15 +591,15 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 		 */
 		if (show_stage || show_unmerged)
 			die("ls-files --with-tree is incompatible with -s or -u");
-		overlay_tree_on_cache(with_tree, prefix);
+		overlay_tree_on_cache(with_tree, max_prefix);
 	}
-	show_files(&dir, prefix);
+	show_files(&dir);
 	if (show_resolve_undo)
-		show_ru_info(prefix);
+		show_ru_info();
 
 	if (ps_matched) {
 		int bad;
-		bad = report_path_error(ps_matched, pathspec, prefix_offset);
+		bad = report_path_error(ps_matched, pathspec, prefix_len);
 		if (bad)
 			fprintf(stderr, "Did you forget to 'git add'?\n");
 
diff --git a/t/t7010-setup.sh b/t/t7010-setup.sh
index d8a7c79..0335a9a 100755
--- a/t/t7010-setup.sh
+++ b/t/t7010-setup.sh
@@ -103,14 +103,10 @@ test_expect_success 'git ls-files (relative #3)' '
 	git add a &&
 	(
 		cd a/b &&
-		if git ls-files "../e/f"
-		then
-			echo Gaah, should have failed
-			exit 1
-		else
-			: happy
-		fi
-	)
+		git ls-files "../e/f"
+	)  >current &&
+	echo ../e/f >expect &&
+	test_cmp expect current
 
 '
 
-- 
1.7.1.2.g2a651