Client|Plugin: Thread-safety for calling plugin hooks

Keep track of the active plugin ID per thread.
skyjake · Apr 7, 2014 · 4e1f63f · 4e1f63f
1 parent c40ae6b
commit 4e1f63f
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Showing 2 changed files with 13 additions and 8 deletions.
diff --git a/doomsday/client/include/dd_main.h b/doomsday/client/include/dd_main.h
@@ -94,17 +94,15 @@ de::LibraryFile const &Plug_FileForPlugin(pluginid_t id);
 int DD_CallHooks(int hook_type, int parm, void* data);
 
 /**
- * Sets the ID of the currently active plugin. Note that plugin hooks are
- * executed in a single-threaded manner; only one can be active at a time.
+ * Sets the ID of the currently active plugin in the current thread.
  *
  * @param id  Plugin id.
  */
 void DD_SetActivePluginId(pluginid_t id);
 
 /**
- * @return Unique identifier of the currently active plugin. Note that plugin
- * hooks are executed in a single-threaded manner; only one is active at a
- * time.
+ * @return Unique identifier of the currently active plugin. The currently
+ * active plugin is tracked separately for each thread.
  */
 pluginid_t DD_ActivePluginId(void);
 

diff --git a/doomsday/client/src/dd_plugin.cpp b/doomsday/client/src/dd_plugin.cpp
@@ -37,6 +37,7 @@
 #endif
 
 #include <de/findfile.h>
+#include <QThreadStorage>
 
 #define HOOKMASK(x)         ((x) & 0xffffff)
 
@@ -52,7 +53,13 @@ typedef Library* PluginHandle;
 
 static Library* hInstPlug[MAX_PLUGS]; /// @todo Remove arbitrary MAX_PLUGS.
 static hookreg_t hooks[NUM_HOOK_TYPES];
-static pluginid_t currentPlugin = 0; // none
+
+struct ThreadState
+{
+    pluginid_t currentPlugin;
+    ThreadState() : currentPlugin(0) {}
+};
+static QThreadStorage<ThreadState> pluginState; ///< Thread-local plugin state.
 
 static PluginHandle* findFirstUnusedPluginHandle(void)
 {
@@ -236,7 +243,7 @@ DENG_EXTERN_C int Plug_CheckForHook(int hookType)
 
 void DD_SetActivePluginId(pluginid_t id)
 {
-    currentPlugin = id;
+    pluginState.localData().currentPlugin = id;
 }
 
 int DD_CallHooks(int hookType, int parm, void *data)
@@ -274,7 +281,7 @@ int DD_CallHooks(int hookType, int parm, void *data)
 
 pluginid_t DD_ActivePluginId(void)
 {
-    return currentPlugin;
+    return pluginState.localData().currentPlugin;
 }
 
 void* DD_FindEntryPoint(pluginid_t pluginId, const char* fn)