grep: allocate subrepos on heap

Currently, struct repository objects corresponding to submodules are
allocated on the stack in grep_submodule(). This currently works because
they will not be used once grep_submodule() exits, but a subsequent
patch will require these structs to be accessible for longer (perhaps
even in another thread). Allocate them on the heap and clear them only
at the very end.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Reviewed-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/grep.c b/builtin/grep.c
index 9e61c7c9936c8ab945e2c2016768d433eb0040d0..fa7fd081506629946f6ee0773f5f9a9fccd26f19 100644 (file)
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -65,6 +65,9 @@ static int todo_done;
 /* Has all work items been added? */
 static int all_work_added;
 
+static struct repository **repos_to_free;
+static size_t repos_to_free_nr, repos_to_free_alloc;
+
 /* This lock protects all the variables above. */
 static pthread_mutex_t grep_mutex;
 
@@ -168,6 +171,19 @@ static void work_done(struct work_item *w)
        grep_unlock();
 }
 
+static void free_repos(void)
+{
+       int i;
+
+       for (i = 0; i < repos_to_free_nr; i++) {
+               repo_clear(repos_to_free[i]);
+               free(repos_to_free[i]);
+       }
+       FREE_AND_NULL(repos_to_free);
+       repos_to_free_nr = 0;
+       repos_to_free_alloc = 0;
+}
+
 static void *run(void *arg)
 {
        int hit = 0;
@@ -415,19 +431,24 @@ static int grep_submodule(struct grep_opt *opt,
                          const struct object_id *oid,
                          const char *filename, const char *path, int cached)
 {
-       struct repository subrepo;
+       struct repository *subrepo;
        struct repository *superproject = opt->repo;
        const struct submodule *sub;
        struct grep_opt subopt;
-       int hit;
+       int hit = 0;
 
        sub = submodule_from_path(superproject, null_oid(), path);
 
        if (!is_submodule_active(superproject, path))
                return 0;
 
-       if (repo_submodule_init(&subrepo, superproject, sub))
+       subrepo = xmalloc(sizeof(*subrepo));
+       if (repo_submodule_init(subrepo, superproject, sub)) {
+               free(subrepo);
                return 0;
+       }
+       ALLOC_GROW(repos_to_free, repos_to_free_nr + 1, repos_to_free_alloc);
+       repos_to_free[repos_to_free_nr++] = subrepo;
 
        /*
         * NEEDSWORK: repo_read_gitmodules() might call
@@ -438,7 +459,7 @@ static int grep_submodule(struct grep_opt *opt,
         * subrepo's odbs to the in-memory alternates list.
         */
        obj_read_lock();
-       repo_read_gitmodules(&subrepo, 0);
+       repo_read_gitmodules(subrepo, 0);
 
        /*
         * NEEDSWORK: This adds the submodule's object directory to the list of
@@ -450,11 +471,11 @@ static int grep_submodule(struct grep_opt *opt,
         * store is no longer global and instead is a member of the repository
         * object.
         */
-       add_submodule_odb_by_path(subrepo.objects->odb->path);
+       add_submodule_odb_by_path(subrepo->objects->odb->path);
        obj_read_unlock();
 
        memcpy(&subopt, opt, sizeof(subopt));
-       subopt.repo = &subrepo;
+       subopt.repo = subrepo;
 
        if (oid) {
                enum object_type object_type;
@@ -464,9 +485,9 @@ static int grep_submodule(struct grep_opt *opt,
                struct strbuf base = STRBUF_INIT;
 
                obj_read_lock();
-               object_type = oid_object_info(&subrepo, oid, NULL);
+               object_type = oid_object_info(subrepo, oid, NULL);
                obj_read_unlock();
-               data = read_object_with_reference(&subrepo,
+               data = read_object_with_reference(subrepo,
                                                  oid, tree_type,
                                                  &size, NULL);
                if (!data)
@@ -484,7 +505,6 @@ static int grep_submodule(struct grep_opt *opt,
                hit = grep_cache(&subopt, pathspec, cached);
        }
 
-       repo_clear(&subrepo);
        return hit;
 }
 
@@ -1182,5 +1202,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
                run_pager(&opt, prefix);
        clear_pathspec(&pathspec);
        free_grep_patterns(&opt);
+       free_repos();
        return !hit;
 }