Merge branch 'ds/blame-on-bloom'

"git blame" learns to take advantage of the "changed-paths" Bloom
filter stored in the commit-graph file.

* ds/blame-on-bloom:
  test-bloom: check that we have expected arguments
  test-bloom: fix some whitespace issues
  blame: drop unused parameter from maybe_changed_path
  blame: use changed-path Bloom filters
  tests: write commit-graph with Bloom filters
  revision: complicated pathspecs disable filters

Author: gitster

blame.c

@@ -9,6 +9,8 @@
 #include "blame.h"
 #include "alloc.h"
 #include "commit-slab.h"
+#include "bloom.h"
+#include "commit-graph.h"
 
 define_commit_slab(blame_suspects, struct blame_origin *);
 static struct blame_suspects blame_suspects;
@@ -1246,13 +1248,74 @@ static int fill_blob_sha1_and_mode(struct repository *r,
 	return -1;
 }
 
+struct blame_bloom_data {
+	/*
+	 * Changed-path Bloom filter keys. These can help prevent
+	 * computing diffs against first parents, but we need to
+	 * expand the list as code is moved or files are renamed.
+	 */
+	struct bloom_filter_settings *settings;
+	struct bloom_key **keys;
+	int nr;
+	int alloc;
+};
+
+static int bloom_count_queries = 0;
+static int bloom_count_no = 0;
+static int maybe_changed_path(struct repository *r,
+			      struct blame_origin *origin,
+			      struct blame_bloom_data *bd)
+{
+	int i;
+	struct bloom_filter *filter;
+
+	if (!bd)
+		return 1;
+
+	if (origin->commit->generation == GENERATION_NUMBER_INFINITY)
+		return 1;
+
+	filter = get_bloom_filter(r, origin->commit, 0);
+
+	if (!filter)
+		return 1;
+
+	bloom_count_queries++;
+	for (i = 0; i < bd->nr; i++) {
+		if (bloom_filter_contains(filter,
+					  bd->keys[i],
+					  bd->settings))
+			return 1;
+	}
+
+	bloom_count_no++;
+	return 0;
+}
+
+static void add_bloom_key(struct blame_bloom_data *bd,
+			  const char *path)
+{
+	if (!bd)
+		return;
+
+	if (bd->nr >= bd->alloc) {
+		bd->alloc *= 2;
+		REALLOC_ARRAY(bd->keys, bd->alloc);
+	}
+
+	bd->keys[bd->nr] = xmalloc(sizeof(struct bloom_key));
+	fill_bloom_key(path, strlen(path), bd->keys[bd->nr], bd->settings);
+	bd->nr++;
+}
+
 /*
  * We have an origin -- check if the same path exists in the
  * parent and return an origin structure to represent it.
  */
 static struct blame_origin *find_origin(struct repository *r,
 					struct commit *parent,
-					struct blame_origin *origin)
+					struct blame_origin *origin,
+					struct blame_bloom_data *bd)
 {
 	struct blame_origin *porigin;
 	struct diff_options diff_opts;
@@ -1286,10 +1349,18 @@ static struct blame_origin *find_origin(struct repository *r,
 
 	if (is_null_oid(&origin->commit->object.oid))
 		do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
-	else
-		diff_tree_oid(get_commit_tree_oid(parent),
-			      get_commit_tree_oid(origin->commit),
-			      "", &diff_opts);
+	else {
+		int compute_diff = 1;
+		if (origin->commit->parents &&
+		    !oidcmp(&parent->object.oid,
+			    &origin->commit->parents->item->object.oid))
+			compute_diff = maybe_changed_path(r, origin, bd);
+
+		if (compute_diff)
+			diff_tree_oid(get_commit_tree_oid(parent),
+				      get_commit_tree_oid(origin->commit),
+				      "", &diff_opts);
+	}
 	diffcore_std(&diff_opts);
 
 	if (!diff_queued_diff.nr) {
@@ -1341,7 +1412,8 @@ static struct blame_origin *find_origin(struct repository *r,
  */
 static struct blame_origin *find_rename(struct repository *r,
 					struct commit *parent,
-					struct blame_origin *origin)
+					struct blame_origin *origin,
+					struct blame_bloom_data *bd)
 {
 	struct blame_origin *porigin = NULL;
 	struct diff_options diff_opts;
@@ -1366,6 +1438,7 @@ static struct blame_origin *find_rename(struct repository *r,
 		struct diff_filepair *p = diff_queued_diff.queue[i];
 		if ((p->status == 'R' || p->status == 'C') &&
 		    !strcmp(p->two->path, origin->path)) {
+			add_bloom_key(bd, p->one->path);
 			porigin = get_origin(parent, p->one->path);
 			oidcpy(&porigin->blob_oid, &p->one->oid);
 			porigin->mode = p->one->mode;
@@ -2332,6 +2405,11 @@ static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *bl
 
 #define MAXSG 16
 
+typedef struct blame_origin *(*blame_find_alg)(struct repository *,
+					       struct commit *,
+					       struct blame_origin *,
+					       struct blame_bloom_data *);
+
 static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin, int opt)
 {
 	struct rev_info *revs = sb->revs;
@@ -2356,8 +2434,7 @@ static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin,
 	 * common cases, then we look for renames in the second pass.
 	 */
 	for (pass = 0; pass < 2 - sb->no_whole_file_rename; pass++) {
-		struct blame_origin *(*find)(struct repository *, struct commit *, struct blame_origin *);
-		find = pass ? find_rename : find_origin;
+		blame_find_alg find = pass ? find_rename : find_origin;
 
 		for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
 		     i < num_sg && sg;
@@ -2369,7 +2446,7 @@ static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin,
 				continue;
 			if (parse_commit(p))
 				continue;
-			porigin = find(sb->repo, p, origin);
+			porigin = find(sb->repo, p, origin, sb->bloom_data);
 			if (!porigin)
 				continue;
 			if (oideq(&porigin->blob_oid, &origin->blob_oid)) {
@@ -2809,3 +2886,45 @@ struct blame_entry *blame_entry_prepend(struct blame_entry *head,
 	blame_origin_incref(o);
 	return new_head;
 }
+
+void setup_blame_bloom_data(struct blame_scoreboard *sb,
+			    const char *path)
+{
+	struct blame_bloom_data *bd;
+
+	if (!sb->repo->objects->commit_graph)
+		return;
+
+	if (!sb->repo->objects->commit_graph->bloom_filter_settings)
+		return;
+
+	bd = xmalloc(sizeof(struct blame_bloom_data));
+
+	bd->settings = sb->repo->objects->commit_graph->bloom_filter_settings;
+
+	bd->alloc = 4;
+	bd->nr = 0;
+	ALLOC_ARRAY(bd->keys, bd->alloc);
+
+	add_bloom_key(bd, path);
+
+	sb->bloom_data = bd;
+}
+
+void cleanup_scoreboard(struct blame_scoreboard *sb)
+{
+	if (sb->bloom_data) {
+		int i;
+		for (i = 0; i < sb->bloom_data->nr; i++) {
+			free(sb->bloom_data->keys[i]->hashes);
+			free(sb->bloom_data->keys[i]);
+		}
+		free(sb->bloom_data->keys);
+		FREE_AND_NULL(sb->bloom_data);
+
+		trace2_data_intmax("blame", sb->repo,
+				   "bloom/queries", bloom_count_queries);
+		trace2_data_intmax("blame", sb->repo,
+				   "bloom/response-no", bloom_count_no);
+	}
+}

blame.h

@@ -100,6 +100,8 @@ struct blame_entry {
 	int unblamable;
 };
 
+struct blame_bloom_data;
+
 /*
  * The current state of the blame assignment.
  */
@@ -156,6 +158,7 @@ struct blame_scoreboard {
 	void(*found_guilty_entry)(struct blame_entry *, void *);
 
 	void *found_guilty_entry_data;
+	struct blame_bloom_data *bloom_data;
 };
 
 /*
@@ -180,6 +183,9 @@ void init_scoreboard(struct blame_scoreboard *sb);
 void setup_scoreboard(struct blame_scoreboard *sb,
 		      const char *path,
 		      struct blame_origin **orig);
+void setup_blame_bloom_data(struct blame_scoreboard *sb,
+			    const char *path);
+void cleanup_scoreboard(struct blame_scoreboard *sb);
 
 struct blame_entry *blame_entry_prepend(struct blame_entry *head,
 					long start, long end,

builtin/blame.c

@@ -1061,6 +1061,14 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 	string_list_clear(&ignore_revs_file_list, 0);
 	string_list_clear(&ignore_rev_list, 0);
 	setup_scoreboard(&sb, path, &o);
+
+	/*
+	 * Changed-path Bloom filters are disabled when looking
+	 * for copies.
+	 */
+	if (!(opt & PICKAXE_BLAME_COPY))
+		setup_blame_bloom_data(&sb, path);
+
 	lno = sb.num_lines;
 
 	if (lno && !range_list.nr)
@@ -1164,5 +1172,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 		printf("num get patch: %d\n", sb.num_get_patch);
 		printf("num commits: %d\n", sb.num_commits);
 	}
+
+	cleanup_scoreboard(&sb);
 	return 0;
 }

builtin/commit.c

@@ -1700,9 +1700,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		      "new_index file. Check that disk is not full and quota is\n"
 		      "not exceeded, and then \"git restore --staged :/\" to recover."));
 
-	if (git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
-	    write_commit_graph_reachable(the_repository->objects->odb, 0, NULL))
-		return 1;
+	git_test_write_commit_graph_or_die();
 
 	repo_rerere(the_repository, 0);
 	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);

builtin/merge.c

@@ -40,6 +40,7 @@
 #include "branch.h"
 #include "commit-reach.h"
 #include "wt-status.h"
+#include "commit-graph.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -1700,9 +1701,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 				   head_commit);
 	}
 
-	if (squash)
+	if (squash) {
 		finish(head_commit, remoteheads, NULL, NULL);
-	else
+
+		git_test_write_commit_graph_or_die();
+	} else
 		write_merge_state(remoteheads);
 
 	if (merge_was_ok)

commit-graph.c

@@ -19,6 +19,20 @@
 #include "bloom.h"
 #include "commit-slab.h"
 
+void git_test_write_commit_graph_or_die(void)
+{
+	int flags = 0;
+	if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0))
+		return;
+
+	if (git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0))
+		flags = COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
+
+	if (write_commit_graph_reachable(the_repository->objects->odb,
+					 flags, NULL))
+		die("failed to write commit-graph under GIT_TEST_COMMIT_GRAPH");
+}
+
 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */

commit-graph.h

@@ -12,6 +12,15 @@
 #define GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD "GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD"
 #define GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS "GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS"
 
+/*
+ * This method is only used to enhance coverage of the commit-graph
+ * feature in the test suite with the GIT_TEST_COMMIT_GRAPH and
+ * GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS environment variables. Do not
+ * call this method oustide of a builtin, and only if you know what
+ * you are doing!
+ */
+void git_test_write_commit_graph_or_die(void);
+
 struct commit;
 struct bloom_filter_settings;
 

revision.c

@@ -650,6 +650,20 @@ static void trace2_bloom_filter_statistics_atexit(void)
 	jw_release(&jw);
 }
 
+static int forbid_bloom_filters(struct pathspec *spec)
+{
+	if (spec->has_wildcard)
+		return 1;
+	if (spec->nr > 1)
+		return 1;
+	if (spec->magic & ~PATHSPEC_LITERAL)
+		return 1;
+	if (spec->nr && (spec->items[0].magic & ~PATHSPEC_LITERAL))
+		return 1;
+
+	return 0;
+}
+
 static void prepare_to_use_bloom_filter(struct rev_info *revs)
 {
 	struct pathspec_item *pi;
@@ -659,7 +673,10 @@ static void prepare_to_use_bloom_filter(struct rev_info *revs)
 	int len;
 
 	if (!revs->commits)
-	    return;
+		return;
+
+	if (forbid_bloom_filters(&revs->prune_data))
+		return;
 
 	repo_parse_commit(revs->repo, revs->commits->item);