hash: convert remaining direct function calls

The previous patch added a coccinelle rule to make sure callers always
use git_hash_init() rather than direct function pointers from the algo
struct.

Let's do the same for the rest of the git_hash_*() wrappers. I split
these out because they're a bit different: they implicitly use the algop
pointer in the git_hash_ctx. So when we convert:

  -algo->update_fn(&ctx, buf, len);
  +git_hash_update(&ctx, buf, len);

we drop the reference to algo entirely! But this is always going to be
the right thing. If "algo" does not match what is in ctx.algop, then
we'd already be invoking undefined behavior.

So in addition to making it possible to add more logic to the
git_hash_*() functions, we're avoiding the need to pass around the extra
algo pointer and make sure that it matches what's in "ctx".

The rest of the patch is the mechanical application of that coccinelle
patch, plus a minor cleanup in test-synthesize.c to drop a now-unused
function parameter (since we don't have to pass around the algo
separately anymore).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/submodule--helper.c

@@ -551,10 +551,10 @@ static void create_default_gitdir_config(const char *submodule_name)
 	/* Case 2.4: If all the above failed, try a hash of the name as a last resort */
 	header_len = snprintf(header, sizeof(header), "blob %zu", strlen(submodule_name));
 	git_hash_init(&ctx, the_hash_algo);
-	the_hash_algo->update_fn(&ctx, header, header_len);
-	the_hash_algo->update_fn(&ctx, "\0", 1);
-	the_hash_algo->update_fn(&ctx, submodule_name, strlen(submodule_name));
-	the_hash_algo->final_fn(raw_name_hash, &ctx);
+	git_hash_update(&ctx, header, header_len);
+	git_hash_update(&ctx, "\0", 1);
+	git_hash_update(&ctx, submodule_name, strlen(submodule_name));
+	git_hash_final(raw_name_hash, &ctx);
 	hash_to_hex_algop_r(hex_name_hash, raw_name_hash, the_hash_algo);
 	strbuf_reset(&gitdir_path);
 	repo_git_path_append(the_repository, &gitdir_path, "modules/%s", hex_name_hash);

t/helper/test-synthesize.c

@@ -25,8 +25,7 @@ static const unsigned char zeros[BLOCK_SIZE];
  * Updates the pack checksum context.
  */
 static void write_uncompressed_zlib(FILE *f, struct git_hash_ctx *pack_ctx,
-				    const void *data, size_t len,
-				    const struct git_hash_algo *algo)
+				    const void *data, size_t len)
 {
 	unsigned char zlib_header[2] = { 0x78, 0x01 }; /* CMF, FLG */
 	unsigned char block_header[5];
@@ -37,7 +36,7 @@ static void write_uncompressed_zlib(FILE *f, struct git_hash_ctx *pack_ctx,
 
 	/* Write zlib header */
 	fwrite_or_die(f, zlib_header, sizeof(zlib_header));
-	algo->update_fn(pack_ctx, zlib_header, 2);
+	git_hash_update(pack_ctx, zlib_header, 2);
 
 	/* Write uncompressed blocks (max 64KB each) */
 	do {
@@ -52,11 +51,11 @@ static void write_uncompressed_zlib(FILE *f, struct git_hash_ctx *pack_ctx,
 		block_header[4] = block_header[2] ^ 0xff;
 
 		fwrite_or_die(f, block_header, sizeof(block_header));
-		algo->update_fn(pack_ctx, block_header, 5);
+		git_hash_update(pack_ctx, block_header, 5);
 
 		if (block_len) {
 			fwrite_or_die(f, block_data, block_len);
-			algo->update_fn(pack_ctx, block_data, block_len);
+			git_hash_update(pack_ctx, block_data, block_len);
 			adler = adler32(adler, block_data, block_len);
 		}
 
@@ -68,7 +67,7 @@ static void write_uncompressed_zlib(FILE *f, struct git_hash_ctx *pack_ctx,
 	/* Write adler32 checksum */
 	put_be32(adler_buf, adler);
 	fwrite_or_die(f, adler_buf, sizeof(adler_buf));
-	algo->update_fn(pack_ctx, adler_buf, 4);
+	git_hash_update(pack_ctx, adler_buf, 4);
 }
 
 /*
@@ -92,24 +91,24 @@ static void write_pack_object(FILE *f, struct git_hash_ctx *pack_ctx,
 						       sizeof(pack_header),
 						       type, len);
 	fwrite_or_die(f, pack_header, pack_header_len);
-	algo->update_fn(pack_ctx, pack_header, pack_header_len);
+	git_hash_update(pack_ctx, pack_header, pack_header_len);
 
 	/* Write the data as uncompressed zlib */
-	write_uncompressed_zlib(f, pack_ctx, data, len, algo);
+	write_uncompressed_zlib(f, pack_ctx, data, len);
 
 	git_hash_init(&ctx, algo);
 	object_header_len = format_object_header(object_header,
 						 sizeof(object_header),
 						 type, len);
-	algo->update_fn(&ctx, object_header, object_header_len);
+	git_hash_update(&ctx, object_header, object_header_len);
 	if (data)
-		algo->update_fn(&ctx, data, len);
+		git_hash_update(&ctx, data, len);
 	else {
 		for (size_t i = len / BLOCK_SIZE; i; i--)
-			algo->update_fn(&ctx, zeros, BLOCK_SIZE);
-		algo->update_fn(&ctx, zeros, len % BLOCK_SIZE);
+			git_hash_update(&ctx, zeros, BLOCK_SIZE);
+		git_hash_update(&ctx, zeros, len % BLOCK_SIZE);
 	}
-	algo->final_oid_fn(oid, &ctx);
+	git_hash_final_oid(oid, &ctx);
 }
 
 /*
@@ -434,7 +433,7 @@ static int generate_pack_with_large_object(const char *path, size_t blob_size,
 
 	/* Write pack header */
 	fwrite_or_die(f, &pack_header, sizeof(pack_header));
-	algo->update_fn(&pack_ctx, &pack_header, sizeof(pack_header));
+	git_hash_update(&pack_ctx, &pack_header, sizeof(pack_header));
 
 	/* 1. Write the large blob */
 	write_pack_object(f, &pack_ctx, OBJ_BLOB, NULL, blob_size, &blob_oid, algo);
@@ -472,7 +471,7 @@ static int generate_pack_with_large_object(const char *path, size_t blob_size,
 	write_pack_object(f, &pack_ctx, OBJ_COMMIT, buf.buf, buf.len, &final_commit_oid, algo);
 
 	/* Write pack trailer (checksum) */
-	algo->final_fn(pack_hash, &pack_ctx);
+	git_hash_final(pack_hash, &pack_ctx);
 	fwrite_or_die(f, pack_hash, algo->rawsz);
 	if (fclose(f))
 		die_errno(_("could not close '%s'"), path);

tools/coccinelle/hash.cocci

@@ -7,3 +7,57 @@ struct git_hash_ctx *CTX;
 - ALGO->init_fn(CTX);
 + git_hash_init(CTX, ALGO);
   ...>}
+
+@@
+identifier f != git_hash_clone;
+expression ALGO;
+struct git_hash_ctx *SRC;
+struct git_hash_ctx *DST;
+@@
+  f(...) {<...
+- ALGO->clone_fn(DST, SRC);
++ git_hash_clone(DST, SRC);
+  ...>}
+
+@@
+identifier f != git_hash_update;
+expression ALGO;
+struct git_hash_ctx *CTX;
+expression list ARGS;
+@@
+  f(...) {<...
+- ALGO->update_fn(CTX, ARGS);
++ git_hash_update(CTX, ARGS);
+  ...>}
+
+@@
+identifier f != git_hash_final;
+expression ALGO;
+struct git_hash_ctx *CTX;
+expression list ARGS;
+@@
+  f(...) {<...
+- ALGO->final_fn(ARGS, CTX);
++ git_hash_final(ARGS, CTX);
+  ...>}
+
+@@
+identifier f != git_hash_final_oid;
+expression ALGO;
+struct git_hash_ctx *CTX;
+expression list ARGS;
+@@
+  f(...) {<...
+- ALGO->final_oid_fn(ARGS, CTX);
++ git_hash_final_oid(ARGS, CTX);
+  ...>}
+
+@@
+identifier f != git_hash_discard;
+expression ALGO;
+struct git_hash_ctx *CTX;
+@@
+  f(...) {<...
+- ALGO->discard_fn(CTX);
++ git_hash_discard(CTX);
+  ...>}