lib: Maintain a representative event category inside internal state

More than one category can be represented by the internal state.  To give
consumers a unique but consistent category pointer, we allocate a category
structure (technically part of the internal state) and use it as the
representative for all the registrations.

Note: This commit only allocates and maintains the representatives.  It does
not make use of them.

diff --git a/src/lib/lib-event.c b/src/lib/lib-event.c
index a6e01de768e8ca5849803d3acad40dd1b998c69c..4296b9c9d16b666fcb9d286550ac1511d3ae401a 100644 (file)
--- a/src/lib/lib-event.c
+++ b/src/lib/lib-event.c
@@ -42,6 +42,13 @@ enum event_code {
    "internal" member).  As a result, all category structs for the same
    category point to the same internal state. */
 struct event_internal_category {
+       /* More than one category can be represented by the internal state.
+          To give consumers a unique but consistent category pointer, we
+          return a pointer to this 'represetative' category structure.
+          Because we allocated it, we know that it will live exactly as
+          long as we need it to. */
+       struct event_category representative;
+
        struct event_internal_category *parent;
        char *name;
        int refcount;
@@ -55,6 +62,7 @@ static struct event_passthrough *event_last_passthrough = NULL;
 static ARRAY(event_callback_t *) event_handlers;
 static ARRAY(event_category_callback_t *) event_category_callbacks;
 static ARRAY(struct event_internal_category *) event_registered_categories_internal;
+static ARRAY(struct event_category *) event_registered_categories_representative;
 static ARRAY(struct event_category *) event_registered_categories;
 static ARRAY(struct event *) global_event_stack;
 static uint64_t event_id_counter = 0;
@@ -613,6 +621,14 @@ event_get_registered_categories(unsigned int *count_r)
        return array_get(&event_registered_categories, count_r);
 }
 
+static void event_category_add_to_array(struct event_internal_category *internal)
+{
+       struct event_category *representative = &internal->representative;
+
+       array_push_back(&event_registered_categories_internal, &internal);
+       array_push_back(&event_registered_categories_representative, &representative);
+}
+
 static void event_category_register(struct event_category *category)
 {
        event_category_callback_t *const *callbackp;
@@ -643,8 +659,11 @@ static void event_category_register(struct event_category *category)
                        internal->parent = category->parent->internal;
                internal->name = i_strdup(category->name);
                internal->refcount = 1;
+               internal->representative.name = internal->name;
+               internal->representative.parent = category->parent;
+               internal->representative.internal = internal;
 
-               array_push_back(&event_registered_categories_internal, &internal);
+               event_category_add_to_array(internal);
 
                allocated = TRUE;
        } else {
@@ -1298,6 +1317,7 @@ void lib_event_init(void)
        i_array_init(&event_handlers, 4);
        i_array_init(&event_category_callbacks, 4);
        i_array_init(&event_registered_categories_internal, 16);
+       i_array_init(&event_registered_categories_representative, 16);
        i_array_init(&event_registered_categories, 16);
 }
 
@@ -1314,6 +1334,7 @@ void lib_event_deinit(void)
        array_free(&event_handlers);
        array_free(&event_category_callbacks);
        array_free(&event_registered_categories_internal);
+       array_free(&event_registered_categories_representative);
        array_free(&event_registered_categories);
        array_free(&global_event_stack);
 }