1 files changed, 90 insertions, 15 deletions

diff --git a/diff-lib.c b/diff-lib.c
index 2edea41a23..b48f155736 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -14,6 +14,7 @@
 #include "dir.h"
 #include "fsmonitor.h"
 #include "commit-reach.h"
+#include "config.h"
 
 /*
  * diff-files
@@ -53,7 +54,7 @@ static int check_removed(const struct index_state *istate, const struct cache_en
 		 * a directory --- the blob was removed!
 		 */
 		if (!S_ISGITLINK(ce->ce_mode) &&
-		    resolve_gitlink_ref(ce->name, "HEAD", &sub))
+		    resolve_gitlink_ref(ce->name, "HEAD", &sub, NULL))
 			return 1;
 	}
 	return 0;
@@ -65,26 +66,46 @@ static int check_removed(const struct index_state *istate, const struct cache_en
  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
  * option is set, the caller does not only want to know if a submodule is
  * modified at all but wants to know all the conditions that are met (new
- * commits, untracked content and/or modified content).
+ * commits, untracked content and/or modified content). If
+ * defer_submodule_status bit is set, dirty_submodule will be left to the
+ * caller to set. defer_submodule_status can also be set to 0 in this
+ * function if there is no need to check if the submodule is modified.
  */
 static int match_stat_with_submodule(struct diff_options *diffopt,
 				     const struct cache_entry *ce,
 				     struct stat *st, unsigned ce_option,
-				     unsigned *dirty_submodule)
+				     unsigned *dirty_submodule, int *defer_submodule_status,
+				     unsigned *ignore_untracked)
 {
 	int changed = ie_match_stat(diffopt->repo->index, ce, st, ce_option);
-	if (S_ISGITLINK(ce->ce_mode)) {
-		struct diff_flags orig_flags = diffopt->flags;
-		if (!diffopt->flags.override_submodule_config)
-			set_diffopt_flags_from_submodule_config(diffopt, ce->name);
-		if (diffopt->flags.ignore_submodules)
-			changed = 0;
-		else if (!diffopt->flags.ignore_dirty_submodules &&
-			 (!changed || diffopt->flags.dirty_submodules))
+	struct diff_flags orig_flags;
+	int defer = 0;
+
+	if (!S_ISGITLINK(ce->ce_mode))
+		goto ret;
+
+	orig_flags = diffopt->flags;
+	if (!diffopt->flags.override_submodule_config)
+		set_diffopt_flags_from_submodule_config(diffopt, ce->name);
+	if (diffopt->flags.ignore_submodules) {
+		changed = 0;
+		goto cleanup;
+	}
+	if (!diffopt->flags.ignore_dirty_submodules &&
+	    (!changed || diffopt->flags.dirty_submodules)) {
+		if (defer_submodule_status && *defer_submodule_status) {
+			defer = 1;
+			*ignore_untracked = diffopt->flags.ignore_untracked_in_submodules;
+		} else {
 			*dirty_submodule = is_submodule_modified(ce->name,
-								 diffopt->flags.ignore_untracked_in_submodules);
-		diffopt->flags = orig_flags;
+					 diffopt->flags.ignore_untracked_in_submodules);
+		}
 	}
+cleanup:
+	diffopt->flags = orig_flags;
+ret:
+	if (defer_submodule_status)
+		*defer_submodule_status = defer;
 	return changed;
 }
 
@@ -96,6 +117,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 			      ? CE_MATCH_RACY_IS_DIRTY : 0);
 	uint64_t start = getnanotime();
 	struct index_state *istate = revs->diffopt.repo->index;
+	struct string_list submodules = STRING_LIST_INIT_NODUP;
 
 	diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 
@@ -220,6 +242,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 			newmode = ce->ce_mode;
 		} else {
 			struct stat st;
+			unsigned ignore_untracked = 0;
+			int defer_submodule_status = !!revs->repo;
 
 			changed = check_removed(istate, ce, &st);
 			if (changed) {
@@ -241,8 +265,25 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 			}
 
 			changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
-							    ce_option, &dirty_submodule);
+							    ce_option, &dirty_submodule,
+							    &defer_submodule_status,
+							    &ignore_untracked);
 			newmode = ce_mode_from_stat(ce, st.st_mode);
+			if (defer_submodule_status) {
+				struct submodule_status_util tmp = {
+					.changed = changed,
+					.dirty_submodule = 0,
+					.ignore_untracked = ignore_untracked,
+					.newmode = newmode,
+					.ce = ce,
+				};
+				struct string_list_item *item;
+
+				item = string_list_append(&submodules, ce->name);
+				item->util = xmalloc(sizeof(tmp));
+				memcpy(item->util, &tmp, sizeof(tmp));
+				continue;
+			}
 		}
 
 		if (!changed && !dirty_submodule) {
@@ -261,6 +302,40 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 			    ce->name, 0, dirty_submodule);
 
 	}
+	if (submodules.nr > 0) {
+		int parallel_jobs;
+		if (git_config_get_int("submodule.diffjobs", &parallel_jobs))
+			parallel_jobs = 1;
+		else if (!parallel_jobs)
+			parallel_jobs = online_cpus();
+		else if (parallel_jobs < 0)
+			die(_("submodule.diffjobs cannot be negative"));
+
+		if (get_submodules_status(revs->repo, &submodules, parallel_jobs))
+			die(_("submodule status failed"));
+		for (size_t i = 0; i < submodules.nr; i++) {
+			struct submodule_status_util *util = submodules.items[i].util;
+			struct cache_entry *ce = util->ce;
+			unsigned int oldmode;
+			const struct object_id *old_oid, *new_oid;
+
+			if (!util->changed && !util->dirty_submodule) {
+				ce_mark_uptodate(ce);
+				mark_fsmonitor_valid(istate, ce);
+				if (!revs->diffopt.flags.find_copies_harder)
+					continue;
+			}
+			oldmode = ce->ce_mode;
+			old_oid = &ce->oid;
+			new_oid = util->changed ? null_oid() : &ce->oid;
+			diff_change(&revs->diffopt, oldmode, util->newmode,
+				    old_oid, new_oid,
+				    !is_null_oid(old_oid),
+				    !is_null_oid(new_oid),
+				    ce->name, 0, util->dirty_submodule);
+		}
+	}
+	string_list_clear(&submodules, 1);
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
 	trace_performance_since(start, "diff-files");
@@ -308,7 +383,7 @@ static int get_stat_data(const struct index_state *istate,
 			return -1;
 		}
 		changed = match_stat_with_submodule(diffopt, ce, &st,
-						    0, dirty_submodule);
+						    0, dirty_submodule, NULL, NULL);
 		if (changed) {
 			mode = ce_mode_from_stat(ce, st.st_mode);
 			oid = null_oid();