1 files changed, 83 insertions, 18 deletions

diff --git a/diffcore-rename.c b/diffcore-rename.c
index 8affa6130e..5ab513e78c 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -87,13 +87,13 @@ struct diff_score {
 	short name_score;
 };
 
-struct prefetch_options {
+struct inexact_prefetch_options {
 	struct repository *repo;
 	int skip_unmodified;
 };
-static void prefetch(void *prefetch_options)
+static void inexact_prefetch(void *prefetch_options)
 {
-	struct prefetch_options *options = prefetch_options;
+	struct inexact_prefetch_options *options = prefetch_options;
 	int i;
 	struct oid_array to_fetch = OID_ARRAY_INIT;
 
@@ -816,6 +816,78 @@ static int idx_possible_rename(char *filename, struct dir_rename_info *info)
 	return idx;
 }
 
+struct basename_prefetch_options {
+	struct repository *repo;
+	struct strintmap *relevant_sources;
+	struct strintmap *sources;
+	struct strintmap *dests;
+	struct dir_rename_info *info;
+};
+static void basename_prefetch(void *prefetch_options)
+{
+	struct basename_prefetch_options *options = prefetch_options;
+	struct strintmap *relevant_sources = options->relevant_sources;
+	struct strintmap *sources = options->sources;
+	struct strintmap *dests = options->dests;
+	struct dir_rename_info *info = options->info;
+	int i;
+	struct oid_array to_fetch = OID_ARRAY_INIT;
+
+	/*
+	 * TODO: The following loops mirror the code/logic from
+	 * find_basename_matches(), though not quite exactly.  Maybe
+	 * abstract the iteration logic out somehow?
+	 */
+	for (i = 0; i < rename_src_nr; ++i) {
+		char *filename = rename_src[i].p->one->path;
+		const char *base = NULL;
+		intptr_t src_index;
+		intptr_t dst_index;
+
+		/* Skip irrelevant sources */
+		if (relevant_sources &&
+		    !strintmap_contains(relevant_sources, filename))
+			continue;
+
+		/*
+		 * If the basename is unique among remaining sources, then
+		 * src_index will equal 'i' and we can attempt to match it
+		 * to a unique basename in the destinations.  Otherwise,
+		 * use directory rename heuristics, if possible.
+		 */
+		base = get_basename(filename);
+		src_index = strintmap_get(sources, base);
+		assert(src_index == -1 || src_index == i);
+
+		if (strintmap_contains(dests, base)) {
+			struct diff_filespec *one, *two;
+
+			/* Find a matching destination, if possible */
+			dst_index = strintmap_get(dests, base);
+			if (src_index == -1 || dst_index == -1) {
+				src_index = i;
+				dst_index = idx_possible_rename(filename, info);
+			}
+			if (dst_index == -1)
+				continue;
+
+			/* Ignore this dest if already used in a rename */
+			if (rename_dst[dst_index].is_rename)
+				continue; /* already used previously */
+
+			one = rename_src[src_index].p->one;
+			two = rename_dst[dst_index].p->two;
+
+			/* Add the pairs */
+			diff_add_if_missing(options->repo, &to_fetch, two);
+			diff_add_if_missing(options->repo, &to_fetch, one);
+		}
+	}
+
+	promisor_remote_get_direct(options->repo, to_fetch.oid, to_fetch.nr);
+	oid_array_clear(&to_fetch);
+}
+
 static int find_basename_matches(struct diff_options *options,
 				 int minimum_score,
 				 struct dir_rename_info *info,
@@ -860,19 +932,12 @@ static int find_basename_matches(struct diff_options *options,
 		.missing_object_cb = NULL,
 		.missing_object_data = NULL
 	};
-	/*
-	 * The prefeteching stuff wants to know if it can skip prefetching
-	 * blobs that are unmodified...and will then do a little extra work
-	 * to verify that the oids are indeed different before prefetching.
-	 * Unmodified blobs are only relevant when doing copy detection;
-	 * when limiting to rename detection, diffcore_rename[_extended]()
-	 * will never be called with unmodified source paths fed to us, so
-	 * the extra work necessary to check if rename_src entries are
-	 * unmodified would be a small waste.
-	 */
-	struct prefetch_options prefetch_options = {
+	struct basename_prefetch_options prefetch_options = {
 		.repo = options->repo,
-		.skip_unmodified = 0
+		.relevant_sources = relevant_sources,
+		.sources = &sources,
+		.dests = &dests,
+		.info = info
 	};
 
 	/*
@@ -911,7 +976,7 @@ static int find_basename_matches(struct diff_options *options,
 	}
 
 	if (options->repo == the_repository && has_promisor_remote()) {
-		dpf_options.missing_object_cb = prefetch;
+		dpf_options.missing_object_cb = basename_prefetch;
 		dpf_options.missing_object_data = &prefetch_options;
 	}
 
@@ -1282,7 +1347,7 @@ void diffcore_rename_extended(struct diff_options *options,
 		.missing_object_cb = NULL,
 		.missing_object_data = NULL
 	};
-	struct prefetch_options prefetch_options = {
+	struct inexact_prefetch_options prefetch_options = {
 		.repo = options->repo
 	};
 
@@ -1449,7 +1514,7 @@ void diffcore_rename_extended(struct diff_options *options,
 	/* Finish setting up dpf_options */
 	prefetch_options.skip_unmodified = skip_unmodified;
 	if (options->repo == the_repository && has_promisor_remote()) {
-		dpf_options.missing_object_cb = prefetch;
+		dpf_options.missing_object_cb = inexact_prefetch;
 		dpf_options.missing_object_data = &prefetch_options;
 	}