xdiff-interface: stop using the_repository

Use the algorithm-agnostic is_null_oid() and push the dependency of
read_mmblob() on the_repository->objects to its callers.  This allows it
to be used with arbitrary object databases.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: rscharfe

apply.c

@@ -3568,9 +3568,9 @@ static int three_way_merge(struct apply_state *state,
 	else if (oideq(base, theirs) || oideq(ours, theirs))
 		return resolve_to(image, ours);
 
-	read_mmblob(&base_file, base);
-	read_mmblob(&our_file, ours);
-	read_mmblob(&their_file, theirs);
+	read_mmblob(&base_file, the_repository->objects, base);
+	read_mmblob(&our_file, the_repository->objects, ours);
+	read_mmblob(&their_file, the_repository->objects, theirs);
 	merge_opts.variant = state->merge_variant;
 	status = ll_merge(&result, path,
 			  &base_file, "base",

builtin/checkout.c

@@ -294,9 +294,9 @@ static int checkout_merged(int pos, const struct checkout *state,
 	if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
 		return error(_("path '%s' does not have necessary versions"), path);
 
-	read_mmblob(&ancestor, &threeway[0]);
-	read_mmblob(&ours, &threeway[1]);
-	read_mmblob(&theirs, &threeway[2]);
+	read_mmblob(&ancestor, the_repository->objects, &threeway[0]);
+	read_mmblob(&ours, the_repository->objects, &threeway[1]);
+	read_mmblob(&theirs, the_repository->objects, &threeway[2]);
 
 	repo_config_get_bool(the_repository, "merge.renormalize", &renormalize);
 	ll_opts.renormalize = renormalize;

builtin/merge-file.c

@@ -128,7 +128,7 @@ int cmd_merge_file(int argc,
 				ret = error(_("object '%s' does not exist"),
 					      argv[i]);
 			else if (!oideq(&oid, the_hash_algo->empty_blob))
-				read_mmblob(mmf, &oid);
+				read_mmblob(mmf, the_repository->objects, &oid);
 			else
 				read_mmfile(mmf, "/dev/null");
 		} else if (read_mmfile(mmf, fname)) {

merge-ort.c

@@ -2136,9 +2136,9 @@ static int merge_3way(struct merge_options *opt,
 		name2 = mkpathdup("%s:%s", opt->branch2,  pathnames[2]);
 	}
 
-	read_mmblob(&orig, o);
-	read_mmblob(&src1, a);
-	read_mmblob(&src2, b);
+	read_mmblob(&orig, the_repository->objects, o);
+	read_mmblob(&src1, the_repository->objects, a);
+	read_mmblob(&src2, the_repository->objects, b);
 
 	merge_status = ll_merge(result_buf, path, &orig, base,
 				&src1, name1, &src2, name2,

notes-merge.c

@@ -359,9 +359,9 @@ static int ll_merge_in_worktree(struct notes_merge_options *o,
 	mmfile_t base, local, remote;
 	enum ll_merge_result status;
 
-	read_mmblob(&base, &p->base);
-	read_mmblob(&local, &p->local);
-	read_mmblob(&remote, &p->remote);
+	read_mmblob(&base, the_repository->objects, &p->base);
+	read_mmblob(&local, the_repository->objects, &p->local);
+	read_mmblob(&remote, the_repository->objects, &p->remote);
 
 	status = ll_merge(&result_buf, oid_to_hex(&p->obj), &base, NULL,
 			  &local, o->local_ref, &remote, o->remote_ref,

xdiff-interface.c

@@ -1,4 +1,3 @@
-#define USE_THE_REPOSITORY_VARIABLE
 #define DISABLE_SIGN_COMPARE_WARNINGS
 
 #include "git-compat-util.h"
@@ -177,18 +176,19 @@ int read_mmfile(mmfile_t *ptr, const char *filename)
 	return 0;
 }
 
-void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
+void read_mmblob(mmfile_t *ptr, struct object_database *odb,
+		 const struct object_id *oid)
 {
 	unsigned long size;
 	enum object_type type;
 
-	if (oideq(oid, null_oid(the_hash_algo))) {
+	if (is_null_oid(oid)) {
 		ptr->ptr = xstrdup("");
 		ptr->size = 0;
 		return;
 	}
 
-	ptr->ptr = odb_read_object(the_repository->objects, oid, &type, &size);
+	ptr->ptr = odb_read_object(odb, oid, &type, &size);
 	if (!ptr->ptr || type != OBJ_BLOB)
 		die("unable to read blob object %s", oid_to_hex(oid));
 	ptr->size = size;

xdiff-interface.h

@@ -4,6 +4,8 @@
 #include "hash.h"
 #include "xdiff/xdiff.h"
 
+struct object_database;
+
 /*
  * xdiff isn't equipped to handle content over a gigabyte;
  * we make the cutoff 1GB - 1MB to give some breathing
@@ -45,7 +47,8 @@ int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
 		  void *consume_callback_data,
 		  xpparam_t const *xpp, xdemitconf_t const *xecfg);
 int read_mmfile(mmfile_t *ptr, const char *filename);
-void read_mmblob(mmfile_t *ptr, const struct object_id *oid);
+void read_mmblob(mmfile_t *ptr, struct object_database *odb,
+		 const struct object_id *oid);
 int buffer_is_binary(const char *ptr, unsigned long size);
 
 void xdiff_set_find_func(xdemitconf_t *xecfg, const char *line, int cflags);