sha1_name.c: add support for disambiguating other types

This teaches the revision parser that in "$name:$path" (used for a
blob object name), "$name" must be a tree-ish.

There are many more places where we know what types of objects are
called for.  This patch adds support for "commit", "treeish", "tree",
and "blob", which could be used in the following contexts:

 - "git apply --build-fake-ancestor" reads the "index" lines from
   the patch; they must name blob objects (not even "blob-ish");

 - "git commit-tree" reads a tree object name (not "tree-ish"), and
   zero or more commit object names (not "committish");

 - "git reset $rev" wants a committish; "git reset $rev -- $path"
   wants a treeish.

They will come in later patches in the series.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 65 insertions, 1 deletions

diff --git a/sha1_name.c b/sha1_name.c
index 9e13d60bf..18fac921d 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -242,6 +242,36 @@ static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data
 	return 0;
 }
 
+static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	int kind = sha1_object_info(sha1, NULL);
+	return kind == OBJ_TREE;
+}
+
+static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	struct object *obj;
+	int kind;
+
+	kind = sha1_object_info(sha1, NULL);
+	if (kind == OBJ_TREE || kind == OBJ_COMMIT)
+		return 1;
+	if (kind != OBJ_TAG)
+		return 0;
+
+	/* We need to do this the hard way... */
+	obj = deref_tag(lookup_object(sha1), NULL, 0);
+	if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
+		return 1;
+	return 0;
+}
+
+static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
+{
+	int kind = sha1_object_info(sha1, NULL);
+	return kind == OBJ_BLOB;
+}
+
 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 			  unsigned flags)
 {
@@ -281,6 +311,12 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 		ds.fn = disambiguate_commit_only;
 	else if (flags & GET_SHA1_COMMITTISH)
 		ds.fn = disambiguate_committish_only;
+	else if (flags & GET_SHA1_TREE)
+		ds.fn = disambiguate_tree_only;
+	else if (flags & GET_SHA1_TREEISH)
+		ds.fn = disambiguate_treeish_only;
+	else if (flags & GET_SHA1_BLOB)
+		ds.fn = disambiguate_blob_only;
 
 	find_short_object_filename(len, hex_pfx, &ds);
 	find_short_packed_object(len, bin_pfx, &ds);
@@ -1016,6 +1052,34 @@ int get_sha1_committish(const char *name, unsigned char *sha1)
 				     sha1, &unused);
 }
 
+int get_sha1_treeish(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_TREEISH,
+				     sha1, &unused);
+}
+
+int get_sha1_commit(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_COMMIT,
+				     sha1, &unused);
+}
+
+int get_sha1_tree(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_TREE,
+				     sha1, &unused);
+}
+
+int get_sha1_blob(const char *name, unsigned char *sha1)
+{
+	struct object_context unused;
+	return get_sha1_with_context(name, GET_SHA1_BLOB,
+				     sha1, &unused);
+}
+
 /* Must be called only when object_name:filename doesn't exist. */
 static void diagnose_invalid_sha1_path(const char *prefix,
 				       const char *filename,
@@ -1221,7 +1285,7 @@ static int get_sha1_with_context_1(const char *name,
 			strncpy(object_name, name, cp-name);
 			object_name[cp-name] = '\0';
 		}
-		if (!get_sha1_1(name, cp-name, tree_sha1, 0)) {
+		if (!get_sha1_1(name, cp-name, tree_sha1, GET_SHA1_TREEISH)) {
 			const char *filename = cp+1;
 			char *new_filename = NULL;