1 files changed, 148 insertions, 0 deletions
diff --git a/xbmc/interfaces/legacy/CallbackHandler.cpp b/xbmc/interfaces/legacy/CallbackHandler.cpp
new file mode 100644
index 0000000..f567168
--- /dev/null
+++ b/xbmc/interfaces/legacy/CallbackHandler.cpp
@@ -0,0 +1,148 @@
+/*
+ *  Copyright (C) 2005-2018 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#include "CallbackHandler.h"
+
+#include "AddonUtils.h"
+#include "commons/Exception.h"
+#include "utils/log.h"
+
+#include <mutex>
+#include <vector>
+
+namespace XBMCAddon
+{
+  class AsyncCallbackMessage : public AddonClass
+  {
+  public:
+    AddonClass::Ref<Callback> cb;
+    AddonClass::Ref<RetardedAsyncCallbackHandler> handler;
+    AsyncCallbackMessage(Callback* _cb, RetardedAsyncCallbackHandler* _handler) :
+      cb(_cb), handler(_handler) { XBMC_TRACE; }
+  };
+
+  //********************************************************************
+  // This holds the callback messages which will be executed. It doesn't
+  //  seem to work correctly with the Ref object so we'll go with Ref*'s
+  typedef std::vector<AddonClass::Ref<AsyncCallbackMessage> > CallbackQueue;
+  //********************************************************************
+
+  static CCriticalSection critSection;
+  static CallbackQueue g_callQueue;
+
+  void RetardedAsyncCallbackHandler::invokeCallback(Callback* cb)
+  {
+    XBMC_TRACE;
+    std::unique_lock<CCriticalSection> lock(critSection);
+    g_callQueue.push_back(new AsyncCallbackMessage(cb,this));
+  }
+
+  RetardedAsyncCallbackHandler::~RetardedAsyncCallbackHandler()
+  {
+    XBMC_TRACE;
+    std::unique_lock<CCriticalSection> lock(critSection);
+
+    // find any messages that might be there because of me ... and remove them
+    CallbackQueue::iterator iter = g_callQueue.begin();
+    while (iter != g_callQueue.end())
+    {
+      if ((*iter)->handler.get() == this) // then this message is because of me
+      {
+        g_callQueue.erase(iter);
+        iter = g_callQueue.begin();
+      }
+      else
+        ++iter;
+    }
+  }
+
+  void RetardedAsyncCallbackHandler::makePendingCalls()
+  {
+    XBMC_TRACE;
+    std::unique_lock<CCriticalSection> lock(critSection);
+    CallbackQueue::iterator iter = g_callQueue.begin();
+    while (iter != g_callQueue.end())
+    {
+      AddonClass::Ref<AsyncCallbackMessage> p(*iter);
+
+      // only call when we are in the right thread state
+      if(p->handler->isStateOk(p->cb->getObject()))
+      {
+        // remove it from the queue. No matter what we're done with
+        //  this. Even if it doesn't execute for some reason.
+        g_callQueue.erase(iter);
+
+        // we need to release the critSection lock prior to grabbing the
+        //  lock on the object. Not doing so results in deadlocks. We no
+        //  longer are accessing the g_callQueue so it's fine to do this now
+        {
+          XBMCAddonUtils::InvertSingleLockGuard unlock(lock);
+
+          // make sure the object is not deallocating
+
+          // we need to grab the object lock to see if the object of the call
+          //  is deallocating. holding this lock should prevent it from
+          //  deallocating during the execution of this call.
+#ifdef ENABLE_XBMC_TRACE_API
+          CLog::Log(LOGDEBUG, "{}NEWADDON executing callback 0x{:x}", _tg.getSpaces(),
+                    (long)(p->cb.get()));
+#endif
+          AddonClass* obj = (p->cb->getObject());
+          AddonClass::Ref<AddonClass> ref(obj);
+          std::unique_lock<CCriticalSection> lock2(*obj);
+          if (!p->cb->getObject()->isDeallocating())
+          {
+            try
+            {
+              // need to make the call
+              p->cb->executeCallback();
+            }
+            catch (XbmcCommons::Exception& e) { e.LogThrowMessage(); }
+            catch (...)
+            {
+              CLog::Log(LOGERROR, "Unknown exception while executing callback {:#x}",
+                        reinterpret_cast<int64_t>(p->cb.get()));
+            }
+          }
+        }
+
+        // since the state of the iterator may have been corrupted by
+        //  the changing state of the list from another thread during
+        //  the releasing fo the lock in the immediately preceeding
+        //  codeblock, we need to reset it before continuing the loop
+        iter = g_callQueue.begin();
+      }
+      else // if we're not in the right thread for this callback...
+        ++iter;
+    }
+  }
+
+  void RetardedAsyncCallbackHandler::clearPendingCalls(void* userData)
+  {
+    XBMC_TRACE;
+    std::unique_lock<CCriticalSection> lock(critSection);
+    CallbackQueue::iterator iter = g_callQueue.begin();
+    while (iter != g_callQueue.end())
+    {
+      AddonClass::Ref<AsyncCallbackMessage> p(*iter);
+
+      if(p->handler->shouldRemoveCallback(p->cb->getObject(),userData))
+      {
+#ifdef ENABLE_XBMC_TRACE_API
+        CLog::Log(LOGDEBUG,
+                  "{}NEWADDON removing callback 0x{:x} for PyThreadState 0x{:x} from queue",
+                  _tg.getSpaces(), (long)(p->cb.get()), (long)userData);
+#endif
+        iter = g_callQueue.erase(iter);
+      }
+      else
+        ++iter;
+    }
+  }
+}
+