refs: store submodule ref stores in a hashmap

Aside from scaling better, this means that the submodule name needn't be
stored in the ref_store instance anymore (which will be changed in a
moment). This, in turn, will help loosen the strict 1:1 relationship
between ref_stores and submodules.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index d7158b628999182c10396c43005c7a58769e3016..5121c57b7821d215da073aa6342e12c0337c555d 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -3,6 +3,7 @@
  */
 
 #include "cache.h"
  */
 
 #include "cache.h"

+#include "hashmap.h"

 #include "lockfile.h"
 #include "refs.h"
 #include "refs/refs-internal.h"
 #include "lockfile.h"
 #include "refs.h"
 #include "refs/refs-internal.h"


@@ -1352,11 +1353,41 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
        return 0;
 }
 
        return 0;
 }
 

+struct submodule_hash_entry
+{
+       struct hashmap_entry ent; /* must be the first member! */
+
+       struct ref_store *refs;
+
+       /* NUL-terminated name of submodule: */
+       char submodule[FLEX_ARRAY];
+};
+
+static int submodule_hash_cmp(const void *entry, const void *entry_or_key,
+                             const void *keydata)
+{
+       const struct submodule_hash_entry *e1 = entry, *e2 = entry_or_key;
+       const char *submodule = keydata ? keydata : e2->submodule;
+
+       return strcmp(e1->submodule, submodule);
+}
+
+static struct submodule_hash_entry *alloc_submodule_hash_entry(
+               const char *submodule, struct ref_store *refs)
+{
+       struct submodule_hash_entry *entry;
+
+       FLEX_ALLOC_STR(entry, submodule, submodule);
+       hashmap_entry_init(entry, strhash(submodule));
+       entry->refs = refs;
+       return entry;
+}
+

 /* A pointer to the ref_store for the main repository: */
 static struct ref_store *main_ref_store;
 
 /* A pointer to the ref_store for the main repository: */
 static struct ref_store *main_ref_store;
 

-/* A linked list of ref_stores for submodules: */
-static struct ref_store *submodule_ref_stores;
+/* A hashmap of ref_stores, stored by submodule name: */
+static struct hashmap submodule_ref_stores;

 
 /*
  * Return the ref_store instance for the specified submodule (or the
 
 /*
  * Return the ref_store instance for the specified submodule (or the


@@ -1365,17 +1396,18 @@ static struct ref_store *submodule_ref_stores;
  */
 static struct ref_store *lookup_ref_store(const char *submodule)
 {
  */
 static struct ref_store *lookup_ref_store(const char *submodule)
 {

-       struct ref_store *refs;
+       struct submodule_hash_entry *entry;

 
        if (!submodule)
                return main_ref_store;
 
 
        if (!submodule)
                return main_ref_store;
 

-       for (refs = submodule_ref_stores; refs; refs = refs->next) {
-               if (!strcmp(submodule, refs->submodule))
-                       return refs;
-       }
+       if (!submodule_ref_stores.tablesize)
+               /* It's initialized on demand in register_ref_store(). */
+               return NULL;

 
 

-       return NULL;
+       entry = hashmap_get_from_hash(&submodule_ref_stores,
+                                     strhash(submodule), submodule);
+       return entry ? entry->refs : NULL;

 }
 
 /*
 }
 
 /*


@@ -1389,15 +1421,15 @@ static void register_ref_store(struct ref_store *refs, const char *submodule)
                if (main_ref_store)
                        die("BUG: main_ref_store initialized twice");
 
                if (main_ref_store)
                        die("BUG: main_ref_store initialized twice");
 

-               refs->next = NULL;

                main_ref_store = refs;
        } else {
                main_ref_store = refs;
        } else {

-               if (lookup_ref_store(submodule))
+               if (!submodule_ref_stores.tablesize)
+                       hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
+
+               if (hashmap_put(&submodule_ref_stores,
+                               alloc_submodule_hash_entry(submodule, refs)))

                        die("BUG: ref_store for submodule '%s' initialized twice",
                            submodule);
                        die("BUG: ref_store for submodule '%s' initialized twice",
                            submodule);

-
-               refs->next = submodule_ref_stores;
-               submodule_ref_stores = refs;

        }
 }
 
        }
 }
 

diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index d8a7eb1841768c1ce399d2fa46e3614fe03162f8..07fd208f2c172ef567cf064660d649e35d69b25b 100644 (file)
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -636,12 +636,6 @@ struct ref_store {
         * reference store:
         */
        const char *submodule;
         * reference store:
         */
        const char *submodule;

-
-       /*
-        * Submodule reference store instances are stored in a linked
-        * list using this pointer.
-        */
-       struct ref_store *next;

 };
 
 /*
 };
 
 /*