ls-tree: slightly refactor show_tree()

This is a non-functional change, we introduce an enum "ls_tree_cmdmode"
then use it to mark which columns to output.

This has the advantage of making the show_tree logic simpler and more
readable, as well as making it easier to extend new options (for example,
if we want to add a "--object-only" option, we just need to add a similar
"short-circuit logic in "show_tree()").

Helped-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Teng Long <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dyrone

builtin/ls-tree.c

@@ -16,10 +16,8 @@
 
 static int line_termination = '\n';
 #define LS_RECURSIVE 1
-#define LS_TREE_ONLY 2
-#define LS_SHOW_TREES 4
-#define LS_NAME_ONLY 8
-#define LS_SHOW_SIZE 16
+#define LS_TREE_ONLY (1 << 1)
+#define LS_SHOW_TREES (1 << 2)
 static int abbrev;
 static int ls_options;
 static struct pathspec pathspec;
@@ -31,6 +29,11 @@ static const  char * const ls_tree_usage[] = {
 	NULL
 };
 
+static enum ls_tree_cmdmode {
+	MODE_LONG = 1,
+	MODE_NAME_ONLY,
+} cmdmode;
+
 static int show_recursive(const char *base, size_t baselen, const char *pathname)
 {
 	int i;
@@ -61,6 +64,39 @@ static int show_recursive(const char *base, size_t baselen, const char *pathname
 	return 0;
 }
 
+static int show_default(const struct object_id *oid, enum object_type type,
+			const char *pathname, unsigned mode,
+			struct strbuf *base)
+{
+	size_t baselen = base->len;
+
+	if (cmdmode == MODE_LONG) {
+		char size_text[24];
+		if (type == OBJ_BLOB) {
+			unsigned long size;
+			if (oid_object_info(the_repository, oid, &size) == OBJ_BAD)
+				xsnprintf(size_text, sizeof(size_text), "BAD");
+			else
+				xsnprintf(size_text, sizeof(size_text),
+					  "%" PRIuMAX, (uintmax_t)size);
+		} else {
+			xsnprintf(size_text, sizeof(size_text), "-");
+		}
+		printf("%06o %s %s %7s\t", mode, type_name(type),
+		find_unique_abbrev(oid, abbrev), size_text);
+	} else {
+		printf("%06o %s %s\t", mode, type_name(type),
+		find_unique_abbrev(oid, abbrev));
+	}
+	baselen = base->len;
+	strbuf_addstr(base, pathname);
+	write_name_quoted_relative(base->buf,
+				   chomp_prefix ? ls_tree_prefix : NULL, stdout,
+				   line_termination);
+	strbuf_setlen(base, baselen);
+	return 1;
+}
+
 static int show_tree(const struct object_id *oid, struct strbuf *base,
 		const char *pathname, unsigned mode, void *context)
 {
@@ -78,34 +114,22 @@ static int show_tree(const struct object_id *oid, struct strbuf *base,
 			return recurse;
 	}
 
-	if (!(ls_options & LS_NAME_ONLY)) {
-		if (ls_options & LS_SHOW_SIZE) {
-			char size_text[24];
-			if (type == OBJ_BLOB) {
-				unsigned long size;
-				if (oid_object_info(the_repository, oid, &size) == OBJ_BAD)
-					xsnprintf(size_text, sizeof(size_text),
-						  "BAD");
-				else
-					xsnprintf(size_text, sizeof(size_text),
-						  "%"PRIuMAX, (uintmax_t)size);
-			} else {
-				xsnprintf(size_text, sizeof(size_text), "-");
-			}
-			printf("%06o %s %s %7s\t", mode, type_name(type),
-			       find_unique_abbrev(oid, abbrev),
-			       size_text);
-		} else {
-			printf("%06o %s %s\t", mode, type_name(type),
-			       find_unique_abbrev(oid, abbrev));
-		}
+	if (cmdmode == MODE_NAME_ONLY) {
+		baselen = base->len;
+		strbuf_addstr(base, pathname);
+		write_name_quoted_relative(base->buf,
+					   chomp_prefix ? ls_tree_prefix : NULL,
+					   stdout, line_termination);
+		strbuf_setlen(base, baselen);
+		return recurse;
 	}
-	baselen = base->len;
-	strbuf_addstr(base, pathname);
-	write_name_quoted_relative(base->buf,
-				   chomp_prefix ? ls_tree_prefix : NULL,
-				   stdout, line_termination);
-	strbuf_setlen(base, baselen);
+
+	if (cmdmode == MODE_LONG ||
+		(!ls_options || (ls_options & LS_RECURSIVE)
+		 || (ls_options & LS_SHOW_TREES)
+		 || (ls_options & LS_TREE_ONLY)))
+			 show_default(oid, type, pathname, mode, base);
+
 	return recurse;
 }
 
@@ -123,12 +147,12 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 			LS_SHOW_TREES),
 		OPT_SET_INT('z', NULL, &line_termination,
 			    N_("terminate entries with NUL byte"), 0),
-		OPT_CMDMODE('l', "long", &ls_options, N_("include object size"),
-			    LS_SHOW_SIZE),
-		OPT_CMDMODE(0, "name-only", &ls_options, N_("list only filenames"),
-			    LS_NAME_ONLY),
-		OPT_CMDMODE(0, "name-status", &ls_options, N_("list only filenames"),
-			    LS_NAME_ONLY),
+		OPT_CMDMODE('l', "long", &cmdmode, N_("include object size"),
+			    MODE_LONG),
+		OPT_CMDMODE(0, "name-only", &cmdmode, N_("list only filenames"),
+			    MODE_NAME_ONLY),
+		OPT_CMDMODE(0, "name-status", &cmdmode, N_("list only filenames"),
+			    MODE_NAME_ONLY),
 		OPT_SET_INT(0, "full-name", &chomp_prefix,
 			    N_("use full path names"), 0),
 		OPT_BOOL(0, "full-tree", &full_tree,