wmem: Add a wmem_map_foreach_remove function

Like wmem_map_remove(), this frees the key/value pair item
in the map but not the key or the value itself (which may
in fact be the same object.) Not generally a problem, as
they'll get freed by the pool. (If someone wants to manage
memory themselves, they should probably be using a GHashTable.)

packaging/debian/libwsutil0.symbols

@@ -283,6 +283,7 @@ libwsutil.so.0 libwsutil0 #MINVER#
  wmem_list_tail@Base 3.5.0
  wmem_map_contains@Base 3.5.0
  wmem_map_foreach@Base 3.5.0
+ wmem_map_foreach_remove@Base 4.1.0
  wmem_map_get_keys@Base 3.5.0
  wmem_map_insert@Base 3.5.0
  wmem_map_lookup@Base 3.5.0

wsutil/wmem/wmem_map.c

@@ -408,6 +408,34 @@ wmem_map_foreach(wmem_map_t *map, GHFunc foreach_func, gpointer user_data)
     }
 }
 
+guint
+wmem_map_foreach_remove(wmem_map_t *map, GHRFunc foreach_func, gpointer user_data)
+{
+    wmem_map_item_t **item, *tmp;
+    unsigned i, deleted = 0;
+
+    /* Make sure we have a table */
+    if (map->table == NULL) {
+        return 0;
+    }
+
+    for (i = 0; i < CAPACITY(map); i++) {
+        item = &(map->table[i]);
+        while (*item) {
+            if (foreach_func((gpointer)(*item)->key, (gpointer)(*item)->value, user_data)) {
+                tmp   = *item;
+                *item = tmp->next;
+                wmem_free(map->data_allocator, tmp);
+                map->count--;
+                deleted++;
+            } else {
+                item = &((*item)->next);
+            }
+        }
+    }
+    return deleted;
+}
+
 guint
 wmem_map_size(wmem_map_t *map)
 {

wsutil/wmem/wmem_map.h

@@ -164,6 +164,20 @@ WS_DLL_PUBLIC
 void
 wmem_map_foreach(wmem_map_t *map, GHFunc foreach_func, gpointer user_data);
 
+/** Run a function against all key/value pairs in the map. If the
+ * function returns TRUE, then the key/value pair is removed from
+ * the map. The order of the calls is unpredictable, since it is
+ * based on the internal storage of data.
+ *
+ * @param map The map to use
+ * @param foreach_func the function to call for each key/value pair
+ * @param user_data user data to pass to the function
+ * @return The number of items removed
+ */
+WS_DLL_PUBLIC
+guint
+wmem_map_foreach_remove(wmem_map_t *map, GHRFunc foreach_func, gpointer user_data);
+
 /** Return the number of elements of the map.
  *
  * @param map The map to use

wsutil/wmem/wmem_test.c

@@ -894,6 +894,12 @@ check_val_map(gpointer key _U_, gpointer val, gpointer user_data)
     g_assert_true(val == user_data);
 }
 
+static gboolean
+equal_val_map(gpointer key _U_, gpointer val, gpointer user_data)
+{
+    return val == user_data;
+}
+
 static void
 wmem_test_map(void)
 {
@@ -990,6 +996,9 @@ wmem_test_map(void)
     }
     wmem_map_foreach(map, check_val_map, GINT_TO_POINTER(2));
 
+    wmem_map_foreach_remove(map, equal_val_map, GINT_TO_POINTER(2));
+    g_assert_true(wmem_map_size(map) == 0);
+
     /* test size */
     map = wmem_map_new(allocator, g_direct_hash, g_direct_equal);
     g_assert_true(map);
@@ -998,6 +1007,11 @@ wmem_test_map(void)
     }
     g_assert_true(wmem_map_size(map) == CONTAINER_ITERS);
 
+    for (i=0; i<CONTAINER_ITERS; i+=2) {
+        wmem_map_foreach_remove(map, equal_val_map, GINT_TO_POINTER(i));
+    }
+    g_assert_true(wmem_map_size(map) == CONTAINER_ITERS/2);
+
     wmem_destroy_allocator(extra_allocator);
     wmem_destroy_allocator(allocator);
 }