From 92ef2cd56bb859e7fa266145e9eea2bcc9819e11 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Fri, 14 Jan 2022 20:01:21 +0100
Subject: [PATCH] Revert "context: implement faster id collision check"

This reverts commit 8ca037683ef5585a6d8501c8a34d7ceea797f088.
---
 src/pipewire/context.c | 43 +++++++++++++++---------------------------
 src/pipewire/core.h    |  3 ---
 src/pipewire/private.h |  2 --
 3 files changed, 15 insertions(+), 33 deletions(-)

diff --git a/src/pipewire/context.c b/src/pipewire/context.c
index 040e23184..f473177f7 100644
--- a/src/pipewire/context.c
+++ b/src/pipewire/context.c
@@ -221,7 +221,6 @@ struct pw_context *pw_context_new(struct pw_loop *main_loop,
 	spa_list_init(&this->core_list);
 	spa_list_init(&this->registry_resource_list);
 	spa_list_init(&this->global_list);
-	spa_list_init(&this->sorted_globals);
 	spa_list_init(&this->module_list);
 	spa_list_init(&this->device_list);
 	spa_list_init(&this->client_list);
@@ -592,34 +591,23 @@ static struct pw_global *find_global(struct pw_context *context, uint32_t id)
 	return NULL;
 }
 
+static uint32_t next_global_id(struct pw_context *context)
+{
+	uint32_t id, start = context->serial;
+	while (true) {
+		id = context->serial;
+		context->serial = (context->serial+1) & 0xffffff;
+		if (find_global(context, id) == NULL)
+			return id;
+		if (context->serial == start)
+			break;
+	}
+	return SPA_ID_INVALID;
+}
+
 uint32_t pw_context_add_global(struct pw_context *context, struct pw_global *global)
 {
-	uint32_t count = 0;
-
-	while (true) {
-		struct pw_global *g;
-
-		if (spa_list_is_empty(&context->sorted_globals))
-			break;
-
-		g = spa_list_first(&context->sorted_globals, struct pw_global, sorted_link);
-		if (g->id != context->serial)
-			break;
-		context->serial = (context->serial+1) & PW_ID_MASK;
-
-		/* we have found a global with the next serial, move it to the back
-		 * of the sorted list */
-		spa_list_remove(&g->sorted_link);
-		spa_list_append(&context->sorted_globals, &g->sorted_link);
-
-		/* if we tried PW_ID_MASK times, we're out of ids */
-		if (++count == PW_ID_MASK)
-			return SPA_ID_INVALID;
-	}
-	global->id = context->serial;
-	context->serial = (context->serial+1) & PW_ID_MASK;
-
-	spa_list_append(&context->sorted_globals, &global->sorted_link);
+	global->id = next_global_id(context);
 	spa_list_append(&context->global_list, &global->link);
 	return global->id;
 }
@@ -627,7 +615,6 @@ uint32_t pw_context_add_global(struct pw_context *context, struct pw_global *glo
 void pw_context_remove_global(struct pw_context *context, struct pw_global *global)
 {
 	spa_list_remove(&global->link);
-	spa_list_remove(&global->sorted_link);
 }
 
 SPA_EXPORT
diff --git a/src/pipewire/core.h b/src/pipewire/core.h
index f6cc0884e..5995b36dd 100644
--- a/src/pipewire/core.h
+++ b/src/pipewire/core.h
@@ -68,9 +68,6 @@ struct pw_registry;
 /* invalid ID that matches any object when used for permissions */
 #define PW_ID_ANY		(uint32_t)(0xffffffff)
 
-/* ID will only use these bits */
-#define PW_ID_MASK		(uint32_t)(0xffffff)
-
 /**  The core information. Extra information may be added in later versions,
  * clients must not assume a constant struct size */
 struct pw_core_info {
diff --git a/src/pipewire/private.h b/src/pipewire/private.h
index 6f706e4f6..1c5751e44 100644
--- a/src/pipewire/private.h
+++ b/src/pipewire/private.h
@@ -320,7 +320,6 @@ struct pw_global {
 	struct pw_context *context;		/**< the context */
 
 	struct spa_list link;		/**< link in context list of globals */
-	struct spa_list sorted_link;	/**< link in context list of sorted_globals */
 	uint32_t id;			/**< server id of the object */
 
 	struct pw_properties *properties;	/**< properties of the global */
@@ -452,7 +451,6 @@ struct pw_context {
 	struct pw_array factory_lib;	/**< mapping of factory_name regexp to library */
 
 	uint32_t serial;
-	struct spa_list sorted_globals;
 	struct pw_array objects;	/**< objects */
 
 	struct pw_impl_client *current_client;	/**< client currently executing code in mainloop */