[PATCH] ls-tree: simplify prefix handling

[PATCH] ls-tree: simplify prefix handling

[René Scharfe]

git ls-tree has two prefixes: The one handed to cmd_ls_tree(), i.e. the
current subdirectory in the repository (if any) and the "display" prefix
used by the show_tree_*() functions.  The option --full-name clears the
last one, i.e. it shows full paths, and --full-tree clears both, i.e. it
acts as if the command was started in the root of the repository.

The show_tree_*() functions use the ls_tree_options members chomp_prefix
and ls_tree_prefix to determine their prefix values.  Calculate it once
in cmd_ls_tree() instead, once the main prefix value is finalized.

This allows chomp_prefix to become a local variable.  Stop using
strlen(3) to determine its initial value -- we only care whether we got
a non-empty string, not precisely how long it is.

Rename ls_tree_prefix to prefix to demonstrate that we converted all
users and because the ls_tree_ part is no longer necessary since
030a3d5d9e (ls-tree: use a "struct options", 2023-01-12) turned it from
a global variable to a struct member.

Signed-off-by: René Scharfe <l.s.r@web.de>
---
 builtin/ls-tree.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index 7a062e2b67..53073d64cb 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -50,8 +50,7 @@ struct ls_tree_options {
 		LS_SHOW_TREES = 1 << 2,
 	} ls_options;
 	struct pathspec pathspec;
-	int chomp_prefix;
-	const char *ls_tree_prefix;
+	const char *prefix;
 	const char *format;
 };

@@ -128,8 +127,7 @@ static int show_tree_fmt(const struct object_id *oid, struct strbuf *base,
 			strbuf_add_unique_abbrev(&sb, oid, options->abbrev);
 		else if (skip_prefix(format, "(path)", &format)) {
 			const char *name;
-			const char *prefix = options->chomp_prefix ?
-					     options->ls_tree_prefix : NULL;
+			const char *prefix = options->prefix;
 			struct strbuf sbuf = STRBUF_INIT;
 			size_t baselen = base->len;

@@ -173,7 +171,7 @@ static void show_tree_common_default_long(struct ls_tree_options *options,
 					  const char *pathname,
 					  const size_t baselen)
 {
-	const char *prefix = options->chomp_prefix ? options->ls_tree_prefix : NULL;
+	const char *prefix = options->prefix;

 	strbuf_addstr(base, pathname);

@@ -258,7 +256,7 @@ static int show_tree_name_only(const struct object_id *oid, struct strbuf *base,
 	if (early >= 0)
 		return early;

-	prefix = options->chomp_prefix ? options->ls_tree_prefix : NULL;
+	prefix = options->prefix;
 	strbuf_addstr(base, pathname);
 	if (options->null_termination) {
 		struct strbuf sb = STRBUF_INIT;
@@ -345,6 +343,7 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 	struct object_id oid;
 	struct tree *tree;
 	int i, full_tree = 0;
+	int chomp_prefix = prefix && *prefix;
 	read_tree_fn_t fn = NULL;
 	enum ls_tree_cmdmode cmdmode = MODE_DEFAULT;
 	int null_termination = 0;
@@ -366,7 +365,7 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 			    MODE_NAME_STATUS),
 		OPT_CMDMODE(0, "object-only", &cmdmode, N_("list only objects"),
 			    MODE_OBJECT_ONLY),
-		OPT_SET_INT(0, "full-name", &options.chomp_prefix,
+		OPT_SET_INT(0, "full-name", &chomp_prefix,
 			    N_("use full path names"), 0),
 		OPT_BOOL(0, "full-tree", &full_tree,
 			 N_("list entire tree; not just current directory "
@@ -381,18 +380,15 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 	int ret;

 	git_config(git_default_config, NULL);
-	options.ls_tree_prefix = prefix;
-	if (prefix)
-		options.chomp_prefix = strlen(prefix);

 	argc = parse_options(argc, argv, prefix, ls_tree_options,
 			     ls_tree_usage, 0);
 	options.null_termination = null_termination;

-	if (full_tree) {
-		options.ls_tree_prefix = prefix = NULL;
-		options.chomp_prefix = 0;
-	}
+	if (full_tree)
+		prefix = NULL;
+	options.prefix = chomp_prefix ? prefix : NULL;
+
 	/*
 	 * We wanted to detect conflicts between --name-only and
 	 * --name-status, but once we're done with that subsequent
--
2.41.0

Re: [PATCH] ls-tree: simplify prefix handling

[Junio C Hamano]

René Scharfe <l.s.r@web.de> writes:

> git ls-tree has two prefixes: The one handed to cmd_ls_tree(), i.e. the
> current subdirectory in the repository (if any) and the "display" prefix
> used by the show_tree_*() functions.  The option --full-name clears the
> last one, i.e. it shows full paths, and --full-tree clears both, i.e. it
> acts as if the command was started in the root of the repository.

Seeing "there are two" and then "the last one" made me come back to
the beginning to see if I missed the third option, as I am not used
to see the second one among two called "the last", even though it is
logically correct.  "clears the latter", perhaps, as "former vs
latter" is sensible only when there are two, may have avoided my
confusion, but that is minor.

> The show_tree_*() functions use the ls_tree_options members chomp_prefix
> and ls_tree_prefix to determine their prefix values.  Calculate it once
> in cmd_ls_tree() instead, once the main prefix value is finalized.

Very nice observation and simplification.

Thanks.