Merge branch 'ab/object-file-api-updates'

Object-file API shuffling.

* ab/object-file-api-updates:
  object-file API: pass an enum to read_object_with_reference()
  object-file.c: add a literal version of write_object_file_prepare()
  object-file API: have hash_object_file() take "enum object_type"
  object API: rename hash_object_file_literally() to write_*()
  object-file API: split up and simplify check_object_signature()
  object API users + docs: check <0, not !0 with check_object_signature()
  object API docs: move check_object_signature() docs to cache.h
  object API: correct "buf" v.s. "map" mismatch in *.c and *.h
  object-file API: have write_object_file() take "enum object_type"
  object-file API: add a format_object_header() function
  object-file API: return "void", not "int" from hash_object_file()
  object-file.c: split up declaration of unrelated variables

1 files changed, 93 insertions, 52 deletions

diff --git a/object-file.c b/object-file.c
index 03bd6a3baf..bdc5cbdd38 100644
--- a/object-file.c
+++ b/object-file.c
@@ -1049,35 +1049,50 @@ void *xmmap(void *start, size_t length,
 	return ret;
 }
 
-/*
- * With an in-core object data in "map", rehash it to make sure the
- * object name actually matches "oid" to detect object corruption.
- * With "map" == NULL, try reading the object named with "oid" using
- * the streaming interface and rehash it to do the same.
- */
+static int format_object_header_literally(char *str, size_t size,
+					  const char *type, size_t objsize)
+{
+	return xsnprintf(str, size, "%s %"PRIuMAX, type, (uintmax_t)objsize) + 1;
+}
+
+int format_object_header(char *str, size_t size, enum object_type type,
+			 size_t objsize)
+{
+	const char *name = type_name(type);
+
+	if (!name)
+		BUG("could not get a type name for 'enum object_type' value %d", type);
+
+	return format_object_header_literally(str, size, name, objsize);
+}
+
 int check_object_signature(struct repository *r, const struct object_id *oid,
-			   void *map, unsigned long size, const char *type,
-			   struct object_id *real_oidp)
+			   void *buf, unsigned long size,
+			   enum object_type type)
 {
-	struct object_id tmp;
-	struct object_id *real_oid = real_oidp ? real_oidp : &tmp;
+	struct object_id real_oid;
+
+	hash_object_file(r->hash_algo, buf, size, type, &real_oid);
+
+	return !oideq(oid, &real_oid) ? -1 : 0;
+}
+
+int stream_object_signature(struct repository *r, const struct object_id *oid)
+{
+	struct object_id real_oid;
+	unsigned long size;
 	enum object_type obj_type;
 	struct git_istream *st;
 	git_hash_ctx c;
 	char hdr[MAX_HEADER_LEN];
 	int hdrlen;
 
-	if (map) {
-		hash_object_file(r->hash_algo, map, size, type, real_oid);
-		return !oideq(oid, real_oid) ? -1 : 0;
-	}
-
 	st = open_istream(r, oid, &obj_type, &size, NULL);
 	if (!st)
 		return -1;
 
 	/* Generate the header */
-	hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(obj_type), (uintmax_t)size) + 1;
+	hdrlen = format_object_header(hdr, sizeof(hdr), obj_type, size);
 
 	/* Sha1.. */
 	r->hash_algo->init_fn(&c);
@@ -1094,9 +1109,9 @@ int check_object_signature(struct repository *r, const struct object_id *oid,
 			break;
 		r->hash_algo->update_fn(&c, buf, readlen);
 	}
-	r->hash_algo->final_oid_fn(real_oid, &c);
+	r->hash_algo->final_oid_fn(&real_oid, &c);
 	close_istream(st);
-	return !oideq(oid, real_oid) ? -1 : 0;
+	return !oideq(oid, &real_oid) ? -1 : 0;
 }
 
 int git_open_cloexec(const char *name, int flags)
@@ -1662,7 +1677,7 @@ int pretend_object_file(void *buf, unsigned long len, enum object_type type,
 {
 	struct cached_object *co;
 
-	hash_object_file(the_hash_algo, buf, len, type_name(type), oid);
+	hash_object_file(the_hash_algo, buf, len, type, oid);
 	if (has_object_file_with_flags(oid, OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT) ||
 	    find_cached_object(oid))
 		return 0;
@@ -1722,16 +1737,15 @@ void *read_object_file_extended(struct repository *r,
 
 void *read_object_with_reference(struct repository *r,
 				 const struct object_id *oid,
-				 const char *required_type_name,
+				 enum object_type required_type,
 				 unsigned long *size,
 				 struct object_id *actual_oid_return)
 {
-	enum object_type type, required_type;
+	enum object_type type;
 	void *buffer;
 	unsigned long isize;
 	struct object_id actual_oid;
 
-	required_type = type_from_string(required_type_name);
 	oidcpy(&actual_oid, oid);
 	while (1) {
 		int ref_length = -1;
@@ -1769,21 +1783,40 @@ void *read_object_with_reference(struct repository *r,
 	}
 }
 
+static void hash_object_body(const struct git_hash_algo *algo, git_hash_ctx *c,
+			     const void *buf, unsigned long len,
+			     struct object_id *oid,
+			     char *hdr, int *hdrlen)
+{
+	algo->init_fn(c);
+	algo->update_fn(c, hdr, *hdrlen);
+	algo->update_fn(c, buf, len);
+	algo->final_oid_fn(oid, c);
+}
+
 static void write_object_file_prepare(const struct git_hash_algo *algo,
 				      const void *buf, unsigned long len,
-				      const char *type, struct object_id *oid,
+				      enum object_type type, struct object_id *oid,
 				      char *hdr, int *hdrlen)
 {
 	git_hash_ctx c;
 
 	/* Generate the header */
-	*hdrlen = xsnprintf(hdr, *hdrlen, "%s %"PRIuMAX , type, (uintmax_t)len)+1;
+	*hdrlen = format_object_header(hdr, *hdrlen, type, len);
 
 	/* Sha1.. */
-	algo->init_fn(&c);
-	algo->update_fn(&c, hdr, *hdrlen);
-	algo->update_fn(&c, buf, len);
-	algo->final_oid_fn(oid, &c);
+	hash_object_body(algo, &c, buf, len, oid, hdr, hdrlen);
+}
+
+static void write_object_file_prepare_literally(const struct git_hash_algo *algo,
+				      const void *buf, unsigned long len,
+				      const char *type, struct object_id *oid,
+				      char *hdr, int *hdrlen)
+{
+	git_hash_ctx c;
+
+	*hdrlen = format_object_header_literally(hdr, *hdrlen, type, len);
+	hash_object_body(algo, &c, buf, len, oid, hdr, hdrlen);
 }
 
 /*
@@ -1836,14 +1869,21 @@ static int write_buffer(int fd, const void *buf, size_t len)
 	return 0;
 }
 
-int hash_object_file(const struct git_hash_algo *algo, const void *buf,
-		     unsigned long len, const char *type,
-		     struct object_id *oid)
+static void hash_object_file_literally(const struct git_hash_algo *algo,
+				       const void *buf, unsigned long len,
+				       const char *type, struct object_id *oid)
 {
 	char hdr[MAX_HEADER_LEN];
 	int hdrlen = sizeof(hdr);
-	write_object_file_prepare(algo, buf, len, type, oid, hdr, &hdrlen);
-	return 0;
+
+	write_object_file_prepare_literally(algo, buf, len, type, oid, hdr, &hdrlen);
+}
+
+void hash_object_file(const struct git_hash_algo *algo, const void *buf,
+		      unsigned long len, enum object_type type,
+		      struct object_id *oid)
+{
+	hash_object_file_literally(algo, buf, len, type_name(type), oid);
 }
 
 /* Finalize a file on disk, and close it. */
@@ -1998,7 +2038,7 @@ static int freshen_packed_object(const struct object_id *oid)
 }
 
 int write_object_file_flags(const void *buf, unsigned long len,
-			    const char *type, struct object_id *oid,
+			    enum object_type type, struct object_id *oid,
 			    unsigned flags)
 {
 	char hdr[MAX_HEADER_LEN];
@@ -2014,9 +2054,9 @@ int write_object_file_flags(const void *buf, unsigned long len,
 	return write_loose_object(oid, hdr, hdrlen, buf, len, 0, flags);
 }
 
-int hash_object_file_literally(const void *buf, unsigned long len,
-			       const char *type, struct object_id *oid,
-			       unsigned flags)
+int write_object_file_literally(const void *buf, unsigned long len,
+				const char *type, struct object_id *oid,
+				unsigned flags)
 {
 	char *header;
 	int hdrlen, status = 0;
@@ -2024,8 +2064,8 @@ int hash_object_file_literally(const void *buf, unsigned long len,
 	/* type string, SP, %lu of the length plus NUL must fit this */
 	hdrlen = strlen(type) + MAX_HEADER_LEN;
 	header = xmalloc(hdrlen);
-	write_object_file_prepare(the_hash_algo, buf, len, type, oid, header,
-				  &hdrlen);
+	write_object_file_prepare_literally(the_hash_algo, buf, len, type,
+					    oid, header, &hdrlen);
 
 	if (!(flags & HASH_WRITE_OBJECT))
 		goto cleanup;
@@ -2052,7 +2092,7 @@ int force_object_loose(const struct object_id *oid, time_t mtime)
 	buf = read_object(the_repository, oid, &type, &len);
 	if (!buf)
 		return error(_("cannot read object for %s"), oid_to_hex(oid));
-	hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(type), (uintmax_t)len) + 1;
+	hdrlen = format_object_header(hdr, sizeof(hdr), type, len);
 	ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime, 0);
 	free(buf);
 
@@ -2118,7 +2158,8 @@ static int index_mem(struct index_state *istate,
 		     enum object_type type,
 		     const char *path, unsigned flags)
 {
-	int ret, re_allocated = 0;
+	int ret = 0;
+	int re_allocated = 0;
 	int write_object = flags & HASH_WRITE_OBJECT;
 
 	if (!type)
@@ -2145,10 +2186,9 @@ static int index_mem(struct index_state *istate,
 	}
 
 	if (write_object)
-		ret = write_object_file(buf, size, type_name(type), oid);
+		ret = write_object_file(buf, size, type, oid);
 	else
-		ret = hash_object_file(the_hash_algo, buf, size,
-				       type_name(type), oid);
+		hash_object_file(the_hash_algo, buf, size, type, oid);
 	if (re_allocated)
 		free(buf);
 	return ret;
@@ -2160,7 +2200,7 @@ static int index_stream_convert_blob(struct index_state *istate,
 				     const char *path,
 				     unsigned flags)
 {
-	int ret;
+	int ret = 0;
 	const int write_object = flags & HASH_WRITE_OBJECT;
 	struct strbuf sbuf = STRBUF_INIT;
 
@@ -2171,11 +2211,11 @@ static int index_stream_convert_blob(struct index_state *istate,
 				 get_conv_flags(flags));
 
 	if (write_object)
-		ret = write_object_file(sbuf.buf, sbuf.len, type_name(OBJ_BLOB),
+		ret = write_object_file(sbuf.buf, sbuf.len, OBJ_BLOB,
 					oid);
 	else
-		ret = hash_object_file(the_hash_algo, sbuf.buf, sbuf.len,
-				       type_name(OBJ_BLOB), oid);
+		hash_object_file(the_hash_algo, sbuf.buf, sbuf.len, OBJ_BLOB,
+				 oid);
 	strbuf_release(&sbuf);
 	return ret;
 }
@@ -2294,8 +2334,8 @@ int index_path(struct index_state *istate, struct object_id *oid,
 			return error_errno("readlink(\"%s\")", path);
 		if (!(flags & HASH_WRITE_OBJECT))
 			hash_object_file(the_hash_algo, sb.buf, sb.len,
-					 blob_type, oid);
-		else if (write_object_file(sb.buf, sb.len, blob_type, oid))
+					 OBJ_BLOB, oid);
+		else if (write_object_file(sb.buf, sb.len, OBJ_BLOB, oid))
 			rc = error(_("%s: failed to insert into database"), path);
 		strbuf_release(&sb);
 		break;
@@ -2599,9 +2639,10 @@ int read_loose_object(const char *path,
 			git_inflate_end(&stream);
 			goto out;
 		}
-		if (check_object_signature(the_repository, expected_oid,
+		hash_object_file_literally(the_repository->hash_algo,
 					   *contents, *size,
-					   oi->type_name->buf, real_oid))
+					   oi->type_name->buf, real_oid);
+		if (!oideq(expected_oid, real_oid))
 			goto out;
 	}