Add hash_sha1_file()

Most callers of write_sha1_file_prepare() are only interested in the
resulting hash but don't care about the returned file name or the header.
This patch adds a simple wrapper named hash_sha1_file() which does just
that, and converts potential callers.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-apply.c

@@ -1783,8 +1783,6 @@ static int apply_binary(struct buffer_desc *desc, struct patch *patch)
 {
 	const char *name = patch->old_name ? patch->old_name : patch->new_name;
 	unsigned char sha1[20];
-	unsigned char hdr[50];
-	int hdrlen;
 
 	/* For safety, we require patch index line to contain
 	 * full 40-byte textual SHA1 for old and new, at least for now.
@@ -1800,8 +1798,7 @@ static int apply_binary(struct buffer_desc *desc, struct patch *patch)
 		/* See if the old one matches what the patch
 		 * applies to.
 		 */
-		write_sha1_file_prepare(desc->buffer, desc->size,
+		hash_sha1_file(desc->buffer, desc->size, blob_type, sha1);
-					blob_type, sha1, hdr, &hdrlen);
 		if (strcmp(sha1_to_hex(sha1), patch->old_sha1_prefix))
 			return error("the patch applies to '%s' (%s), "
 				     "which does not match the "
@@ -1846,8 +1843,7 @@ static int apply_binary(struct buffer_desc *desc, struct patch *patch)
 				     name);
 
 		/* verify that the result matches */
-		write_sha1_file_prepare(desc->buffer, desc->size, blob_type,
+		hash_sha1_file(desc->buffer, desc->size, blob_type, sha1);
-					sha1, hdr, &hdrlen);
 		if (strcmp(sha1_to_hex(sha1), patch->new_sha1_prefix))
 			return error("binary patch to '%s' creates incorrect result (expecting %s, got %s)", name, patch->new_sha1_prefix, sha1_to_hex(sha1));
 	}

cache-tree.c

@@ -344,12 +344,8 @@ static int update_one(struct cache_tree *it,
 #endif
 	}
 
-	if (dryrun) {
+	if (dryrun)
-		unsigned char hdr[200];
+		hash_sha1_file(buffer, offset, tree_type, it->sha1);
-		int hdrlen;
-		write_sha1_file_prepare(buffer, offset, tree_type, it->sha1,
-					hdr, &hdrlen);
-	}
 	else
 		write_sha1_file(buffer, offset, tree_type, it->sha1);
 	free(buffer);

cache.h

@@ -245,6 +245,7 @@ char *enter_repo(char *path, int strict);
 extern int sha1_object_info(const unsigned char *, char *, unsigned long *);
 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
+extern int hash_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *sha1);
 extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 extern char *write_sha1_file_prepare(void *buf,
 				     unsigned long len,

merge-recursive.c

@@ -1235,13 +1235,10 @@ int merge(struct commit *h1,
 	if (merged_common_ancestors == NULL) {
 		/* if there is no common ancestor, make an empty tree */
 		struct tree *tree = xcalloc(1, sizeof(struct tree));
-		unsigned char hdr[40];
-		int hdrlen;
 
 		tree->object.parsed = 1;
 		tree->object.type = OBJ_TREE;
-		write_sha1_file_prepare(NULL, 0, tree_type, tree->object.sha1,
+		hash_sha1_file(NULL, 0, tree_type, tree->object.sha1);
-					hdr, &hdrlen);
 		merged_common_ancestors = make_virtual_commit(tree, "ancestor");
 	}
 

sha1_file.c

@@ -1501,6 +1501,15 @@ static void setup_object_header(z_stream *stream, const char *type, unsigned lon
 	stream->avail_out -= hdr;
 }
 
+int hash_sha1_file(void *buf, unsigned long len, const char *type,
+                   unsigned char *sha1)
+{
+	unsigned char hdr[50];
+	int hdrlen;
+	write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
+	return 0;
+}
+
 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
 	int size;
@@ -1784,8 +1793,6 @@ int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
 	unsigned long size = 4096;
 	char *buf = xmalloc(size);
 	int ret;
-	unsigned char hdr[50];
-	int hdrlen;
 
 	if (read_pipe(fd, &buf, &size)) {
 		free(buf);
@@ -1796,10 +1803,8 @@ int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
 		type = blob_type;
 	if (write_object)
 		ret = write_sha1_file(buf, size, type, sha1);
-	else {
+	else
-		write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
+		ret = hash_sha1_file(buf, size, type, sha1);
-		ret = 0;
-	}
 	free(buf);
 	return ret;
 }
@@ -1809,8 +1814,6 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, con
 	unsigned long size = st->st_size;
 	void *buf;
 	int ret;
-	unsigned char hdr[50];
-	int hdrlen;
 
 	buf = "";
 	if (size)
@@ -1823,10 +1826,8 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, con
 		type = blob_type;
 	if (write_object)
 		ret = write_sha1_file(buf, size, type, sha1);
-	else {
+	else
-		write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
+		ret = hash_sha1_file(buf, size, type, sha1);
-		ret = 0;
-	}
 	if (size)
 		munmap(buf, size);
 	return ret;
@@ -1855,12 +1856,9 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
 			return error("readlink(\"%s\"): %s", path,
 			             errstr);
 		}
-		if (!write_object) {
+		if (!write_object)
-			unsigned char hdr[50];
+			hash_sha1_file(target, st->st_size, blob_type, sha1);
-			int hdrlen;
+		else if (write_sha1_file(target, st->st_size, blob_type, sha1))
-			write_sha1_file_prepare(target, st->st_size, blob_type,
-						sha1, hdr, &hdrlen);
-		} else if (write_sha1_file(target, st->st_size, blob_type, sha1))
 			return error("%s: failed to insert into database",
 				     path);
 		free(target);