Merge branch 'jk/diff-submodule-diff-inline'

The "git diff --submodule={short,log}" mechanism has been enhanced
to allow "--submodule=diff" to show the patch between the submodule
commits bound to the superproject.

* jk/diff-submodule-diff-inline:
  diff: teach diff to display submodule difference with an inline diff
  submodule: refactor show_submodule_summary with helper function
  submodule: convert show_submodule_summary to use struct object_id *
  allow do_submodule_path to work even if submodule isn't checked out
  diff: prepare for additional submodule formats
  graph: add support for --line-prefix on all graph-aware output
  diff.c: remove output_prefix_length field
  cache: add empty_tree_oid object and helper function

1 files changed, 23 insertions, 6 deletions

diff --git a/cache.h b/cache.h
index 673805013..aac38a6b9 100644
--- a/cache.h
+++ b/cache.h
@@ -819,8 +819,8 @@ extern void strbuf_git_common_path(struct strbuf *sb, const char *fmt, ...)
 	__attribute__((format (printf, 2, 3)));
 extern char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
 	__attribute__((format (printf, 2, 3)));
-extern void strbuf_git_path_submodule(struct strbuf *sb, const char *path,
-				      const char *fmt, ...)
+extern int strbuf_git_path_submodule(struct strbuf *sb, const char *path,
+				     const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
 extern char *git_pathdup(const char *fmt, ...)
 	__attribute__((format (printf, 1, 2)));
@@ -953,22 +953,39 @@ static inline void oidclr(struct object_id *oid)
 #define EMPTY_TREE_SHA1_BIN_LITERAL \
 	 "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
 	 "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
-#define EMPTY_TREE_SHA1_BIN \
-	 ((const unsigned char *) EMPTY_TREE_SHA1_BIN_LITERAL)
+extern const struct object_id empty_tree_oid;
+#define EMPTY_TREE_SHA1_BIN (empty_tree_oid.hash)
 
 #define EMPTY_BLOB_SHA1_HEX \
 	"e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"
 #define EMPTY_BLOB_SHA1_BIN_LITERAL \
 	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
 	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
-#define EMPTY_BLOB_SHA1_BIN \
-	((const unsigned char *) EMPTY_BLOB_SHA1_BIN_LITERAL)
+extern const struct object_id empty_blob_oid;
+#define EMPTY_BLOB_SHA1_BIN (empty_blob_oid.hash)
+
 
 static inline int is_empty_blob_sha1(const unsigned char *sha1)
 {
 	return !hashcmp(sha1, EMPTY_BLOB_SHA1_BIN);
 }
 
+static inline int is_empty_blob_oid(const struct object_id *oid)
+{
+	return !hashcmp(oid->hash, EMPTY_BLOB_SHA1_BIN);
+}
+
+static inline int is_empty_tree_sha1(const unsigned char *sha1)
+{
+	return !hashcmp(sha1, EMPTY_TREE_SHA1_BIN);
+}
+
+static inline int is_empty_tree_oid(const struct object_id *oid)
+{
+	return !hashcmp(oid->hash, EMPTY_TREE_SHA1_BIN);
+}
+
+
 int git_mkstemp(char *path, size_t n, const char *template);
 
 /* set default permissions by passing mode arguments to open(2) */