[PATCH 11/30] tree.h API: make read_tree_fn_t take an "enum object_type"

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Most of the users of the read_tree_fn_t callback do not care about the
"mode" per-se, they just care what type it resolves to.

Amend this callback mechanism added in 3c5e8468a93 (ls-tree: major
rewrite to do pathspec, 2005-11-26) to pass the object_type, and use
it whenever possible.

In the archive.c code we could go much deeper with this refactoring,
after getting the "mode" that code will pass it around itself and into
archive-{tar,zip}.c. As far as I can tell we could drop the mode
early, and just pass "enum_object_type type, int is_executable". That
would be slightly redundant space-wise, but would assure us that we're
not writing out raw modes found in trees, but are normalizing them.

But that particular refactoring would be larger than what I'm trying
to accomplish here, so let's leave it for now.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 archive.c          |  8 ++++----
 builtin/checkout.c |  4 ++--
 builtin/log.c      |  4 ++--
 builtin/ls-files.c |  6 ++++--
 builtin/ls-tree.c  | 12 +++++-------
 merge-recursive.c  |  6 ++++--
 tree.c             | 19 ++++++++++++-------
 tree.h             |  2 +-
 8 files changed, 34 insertions(+), 27 deletions(-)

diff --git a/archive.c b/archive.c
index 26534a30d3b..64abe736f93 100644
--- a/archive.c
+++ b/archive.c
@@ -232,7 +232,7 @@ static int write_directory(struct archiver_context *c)
 
 static int queue_or_write_archive_entry(const struct object_id *oid,
 					struct strbuf *base, const char *filename,
-					unsigned mode,
+					enum object_type object_type, unsigned mode,
 					void *context)
 {
 	struct archiver_context *c = context;
@@ -245,7 +245,7 @@ static int queue_or_write_archive_entry(const struct object_id *oid,
 		c->bottom = next;
 	}
 
-	if (S_ISDIR(mode)) {
+	if (object_type == OBJ_TREE) {
 		size_t baselen = base->len;
 		const struct attr_check *check;
 
@@ -382,13 +382,13 @@ struct path_exists_context {
 
 static int reject_entry(const struct object_id *oid, struct strbuf *base,
 			const char *filename,
-			unsigned mode,
+			enum object_type object_type, unsigned mode,
 			void *context)
 {
 	int ret = -1;
 	struct path_exists_context *ctx = context;
 
-	if (S_ISDIR(mode)) {
+	if (object_type == OBJ_TREE) {
 		struct strbuf sb = STRBUF_INIT;
 		strbuf_addbuf(&sb, base);
 		strbuf_addstr(&sb, filename);
diff --git a/builtin/checkout.c b/builtin/checkout.c
index a78b54624b0..d4adfdb5046 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -115,14 +115,14 @@ static int post_checkout_hook(struct commit *old_commit, struct commit *new_comm
 
 static int update_some(const struct object_id *oid, struct strbuf *base,
 		       const char *pathname,
-		       unsigned mode,
+		       enum object_type object_type, unsigned mode,
 		       void *context)
 {
 	int len;
 	struct cache_entry *ce;
 	int pos;
 
-	if (S_ISDIR(mode))
+	if (object_type == OBJ_TREE)
 		return READ_TREE_RECURSIVE;
 
 	len = base->len + strlen(pathname);
diff --git a/builtin/log.c b/builtin/log.c
index 3766f553971..19a916221d5 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -599,11 +599,11 @@ static int show_tag_object(const struct object_id *oid, struct rev_info *rev)
 
 static int show_tree_object(const struct object_id *oid,
 			    struct strbuf *base, const char *pathname,
-			    unsigned mode,
+			    enum object_type object_type, unsigned mode,
 			    void *context)
 {
 	FILE *file = context;
-	fprintf(file, "%s%s\n", pathname, S_ISDIR(mode) ? "/" : "");
+	fprintf(file, "%s%s\n", pathname, object_type == OBJ_TREE ? "/" : "");
 	return 0;
 }
 
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index fa9b01b6cc7..f38df439410 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -446,7 +446,8 @@ static int read_one_entry_opt(struct index_state *istate,
 }
 
 static int read_one_entry(const struct object_id *oid, struct strbuf *base,
-			  const char *pathname, unsigned mode,
+			  const char *pathname,
+			  enum object_type object_type, unsigned mode,
 			  void *context)
 {
 	struct index_state *istate = context;
@@ -460,7 +461,8 @@ static int read_one_entry(const struct object_id *oid, struct strbuf *base,
  * the stage that will conflict with the entry being added.
  */
 static int read_one_entry_quick(const struct object_id *oid, struct strbuf *base,
-				const char *pathname, unsigned mode,
+				const char *pathname,
+				enum object_type object_type, unsigned mode,
 				void *context)
 {
 	struct index_state *istate = context;
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index aaa41e66234..c6ec3ca751e 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -63,14 +63,13 @@ static int show_recursive(const char *base, int baselen, const char *pathname)
 
 static int show_tree(const struct object_id *oid, struct strbuf *base,
 		     const char *pathname,
-		     unsigned mode,
+		     enum object_type object_type, unsigned mode,
 		     void *context)
 {
 	int retval = 0;
 	int baselen;
-	const char *type = blob_type;
 
-	if (S_ISGITLINK(mode)) {
+	if (object_type == OBJ_COMMIT) {
 		/*
 		 * Maybe we want to have some recursive version here?
 		 *
@@ -80,22 +79,21 @@ static int show_tree(const struct object_id *oid, struct strbuf *base,
 			retval = READ_TREE_RECURSIVE;
 		 *
 		 */
-		type = commit_type;
-	} else if (S_ISDIR(mode)) {
+	} else if (object_type == OBJ_TREE) {
 		if (show_recursive(base->buf, base->len, pathname)) {
 			retval = READ_TREE_RECURSIVE;
 			if (!(ls_options & LS_SHOW_TREES))
 				return retval;
 		}
-		type = tree_type;
 	}
 	else if (ls_options & LS_TREE_ONLY)
 		return 0;
 
 	if (!(ls_options & LS_NAME_ONLY)) {
+		const char *type = type_name(object_type);
 		if (ls_options & LS_SHOW_SIZE) {
 			char size_text[24];
-			if (!strcmp(type, blob_type)) {
+			if (object_type == OBJ_BLOB) {
 				unsigned long size;
 				if (oid_object_info(the_repository, oid, &size) == OBJ_BAD)
 					xsnprintf(size_text, sizeof(size_text),
diff --git a/merge-recursive.c b/merge-recursive.c
index aa12543ecc9..31c080538ef 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -453,7 +453,7 @@ static void unpack_trees_finish(struct merge_options *opt)
 
 static int save_files_dirs(const struct object_id *oid,
 			   struct strbuf *base, const char *path,
-			   unsigned int mode,
+			   enum object_type object_type, unsigned int mode,
 			   void *context)
 {
 	struct path_hashmap_entry *entry;
@@ -467,7 +467,9 @@ static int save_files_dirs(const struct object_id *oid,
 	hashmap_add(&opt->priv->current_file_dir_set, &entry->e);
 
 	strbuf_setlen(base, baselen);
-	return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
+	if (object_type != OBJ_TREE)
+		return 0;
+	return READ_TREE_RECURSIVE;
 }
 
 static void get_files_dirs(struct merge_options *opt, struct tree *tree)
diff --git a/tree.c b/tree.c
index fb4985f22ca..e4402fad69b 100644
--- a/tree.c
+++ b/tree.c
@@ -28,6 +28,8 @@ static int read_tree_1(struct repository *r,
 	init_tree_desc(&desc, tree->buffer, tree->size);
 
 	while (tree_entry(&desc, &entry)) {
+		struct commit *commit;
+
 		if (retval != all_entries_interesting) {
 			retval = tree_entry_interesting(r->index, &entry,
 							base, 0, pathspec);
@@ -38,7 +40,7 @@ static int read_tree_1(struct repository *r,
 		}
 
 		switch (fn(&entry.oid, base,
-			   entry.path, entry.mode, context)) {
+			   entry.path, entry.object_type, entry.mode, context)) {
 		case 0:
 			continue;
 		case READ_TREE_RECURSIVE:
@@ -47,11 +49,11 @@ static int read_tree_1(struct repository *r,
 			return -1;
 		}
 
-		if (S_ISDIR(entry.mode))
+		switch (entry.object_type) {
+		case OBJ_TREE:
 			oidcpy(&oid, &entry.oid);
-		else if (S_ISGITLINK(entry.mode)) {
-			struct commit *commit;
-
+			break;
+		case OBJ_COMMIT:
 			commit = lookup_commit(r, &entry.oid);
 			if (!commit)
 				die("Commit %s in submodule path %s%s not found",
@@ -64,9 +66,12 @@ static int read_tree_1(struct repository *r,
 				    base->buf, entry.path);
 
 			oidcpy(&oid, get_commit_tree_oid(commit));
-		}
-		else
+			break;
+		case OBJ_BLOB:
 			continue;
+		default:
+			BUG("unreachable");
+		}
 
 		len = tree_entry_len(&entry);
 		strbuf_add(base, entry.path, len);
diff --git a/tree.h b/tree.h
index a7030e52679..eba51417d26 100644
--- a/tree.h
+++ b/tree.h
@@ -33,7 +33,7 @@ int cmp_cache_name_compare(const void *a_, const void *b_);
 #define READ_TREE_RECURSIVE 1
 typedef int (*read_tree_fn_t)(const struct object_id *, struct strbuf *,
 			      const char *,
-			      unsigned int,
+			      enum object_type, unsigned int,
 			      void *);
 
 int read_tree_recursive(struct repository *r,
-- 
2.31.0.rc0.126.g04f22c5b82