1 files changed, 231 insertions, 0 deletions
diff --git a/dom/events/JSEventHandler.h b/dom/events/JSEventHandler.h
new file mode 100644
index 0000000000..60a3a259e3
--- /dev/null
+++ b/dom/events/JSEventHandler.h
@@ -0,0 +1,231 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_JSEventHandler_h_
+#define mozilla_JSEventHandler_h_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/dom/EventHandlerBinding.h"
+#include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsAtom.h"
+#include "nsIDOMEventListener.h"
+#include "nsIScriptContext.h"
+
+namespace mozilla {
+namespace dom {
+class EventTarget;
+}  // namespace dom
+
+class TypedEventHandler {
+ public:
+  enum HandlerType {
+    eUnset = 0,
+    eNormal = 0x1,
+    eOnError = 0x2,
+    eOnBeforeUnload = 0x3,
+    eTypeBits = 0x3
+  };
+
+  TypedEventHandler() : mBits(0) {}
+
+  explicit TypedEventHandler(dom::EventHandlerNonNull* aHandler) : mBits(0) {
+    Assign(aHandler, eNormal);
+  }
+
+  explicit TypedEventHandler(dom::OnErrorEventHandlerNonNull* aHandler)
+      : mBits(0) {
+    Assign(aHandler, eOnError);
+  }
+
+  explicit TypedEventHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler)
+      : mBits(0) {
+    Assign(aHandler, eOnBeforeUnload);
+  }
+
+  TypedEventHandler(const TypedEventHandler& aOther) {
+    if (aOther.HasEventHandler()) {
+      // Have to make sure we take our own ref
+      Assign(aOther.Ptr(), aOther.Type());
+    } else {
+      mBits = 0;
+    }
+  }
+
+  ~TypedEventHandler() { ReleaseHandler(); }
+
+  HandlerType Type() const { return HandlerType(mBits & eTypeBits); }
+
+  bool HasEventHandler() const { return !!Ptr(); }
+
+  void SetHandler(const TypedEventHandler& aHandler) {
+    if (aHandler.HasEventHandler()) {
+      ReleaseHandler();
+      Assign(aHandler.Ptr(), aHandler.Type());
+    } else {
+      ForgetHandler();
+    }
+  }
+
+  dom::EventHandlerNonNull* NormalEventHandler() const {
+    MOZ_ASSERT(Type() == eNormal && Ptr());
+    return reinterpret_cast<dom::EventHandlerNonNull*>(Ptr());
+  }
+
+  void SetHandler(dom::EventHandlerNonNull* aHandler) {
+    ReleaseHandler();
+    Assign(aHandler, eNormal);
+  }
+
+  dom::OnBeforeUnloadEventHandlerNonNull* OnBeforeUnloadEventHandler() const {
+    MOZ_ASSERT(Type() == eOnBeforeUnload);
+    return reinterpret_cast<dom::OnBeforeUnloadEventHandlerNonNull*>(Ptr());
+  }
+
+  void SetHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler) {
+    ReleaseHandler();
+    Assign(aHandler, eOnBeforeUnload);
+  }
+
+  dom::OnErrorEventHandlerNonNull* OnErrorEventHandler() const {
+    MOZ_ASSERT(Type() == eOnError);
+    return reinterpret_cast<dom::OnErrorEventHandlerNonNull*>(Ptr());
+  }
+
+  void SetHandler(dom::OnErrorEventHandlerNonNull* aHandler) {
+    ReleaseHandler();
+    Assign(aHandler, eOnError);
+  }
+
+  dom::CallbackFunction* Ptr() const {
+    // Have to cast eTypeBits so we don't have to worry about
+    // promotion issues after the bitflip.
+    return reinterpret_cast<dom::CallbackFunction*>(mBits &
+                                                    ~uintptr_t(eTypeBits));
+  }
+
+  void ForgetHandler() {
+    ReleaseHandler();
+    mBits = 0;
+  }
+
+  bool operator==(const TypedEventHandler& aOther) const {
+    return Ptr() && aOther.Ptr() &&
+           Ptr()->CallbackPreserveColor() ==
+               aOther.Ptr()->CallbackPreserveColor();
+  }
+
+ private:
+  void operator=(const TypedEventHandler&) = delete;
+
+  void ReleaseHandler() {
+    nsISupports* ptr = Ptr();
+    NS_IF_RELEASE(ptr);
+  }
+
+  void Assign(nsISupports* aHandler, HandlerType aType) {
+    MOZ_ASSERT(aHandler, "Must have handler");
+    NS_ADDREF(aHandler);
+    mBits = uintptr_t(aHandler) | uintptr_t(aType);
+  }
+
+  uintptr_t mBits;
+};
+
+/**
+ * Implemented by script event listeners. Used to retrieve the script object
+ * corresponding to the event target and the handler itself.
+ *
+ * Note, mTarget is a raw pointer and the owner of the JSEventHandler object
+ * is expected to call Disconnect()!
+ */
+
+#define NS_JSEVENTHANDLER_IID                        \
+  {                                                  \
+    0x4f486881, 0x1956, 0x4079, {                    \
+      0x8c, 0xa0, 0xf3, 0xbd, 0x60, 0x5c, 0xc2, 0x79 \
+    }                                                \
+  }
+
+class JSEventHandler : public nsIDOMEventListener {
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_JSEVENTHANDLER_IID)
+
+  JSEventHandler(dom::EventTarget* aTarget, nsAtom* aType,
+                 const TypedEventHandler& aTypedHandler);
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+
+  // nsIDOMEventListener interface
+  NS_DECL_NSIDOMEVENTLISTENER
+
+  void Disconnect() { mTarget = nullptr; }
+
+  const TypedEventHandler& GetTypedEventHandler() const {
+    return mTypedHandler;
+  }
+
+  void ForgetHandler() { mTypedHandler.ForgetHandler(); }
+
+  nsAtom* EventName() const { return mEventName; }
+
+  // Set a handler for this event listener.  The handler must already
+  // be bound to the right target.
+  void SetHandler(const TypedEventHandler& aTypedHandler) {
+    mTypedHandler.SetHandler(aTypedHandler);
+  }
+  void SetHandler(dom::EventHandlerNonNull* aHandler) {
+    mTypedHandler.SetHandler(aHandler);
+  }
+  void SetHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler) {
+    mTypedHandler.SetHandler(aHandler);
+  }
+  void SetHandler(dom::OnErrorEventHandlerNonNull* aHandler) {
+    mTypedHandler.SetHandler(aHandler);
+  }
+
+  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+    return 0;
+
+    // Measurement of the following members may be added later if DMD finds it
+    // is worthwhile:
+    // - mTarget
+    //
+    // The following members are not measured:
+    // - mTypedHandler: may be shared with others
+    // - mEventName: shared with others
+  }
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_CLASS(JSEventHandler)
+
+  bool IsBlackForCC();
+
+ protected:
+  virtual ~JSEventHandler();
+
+  dom::EventTarget* mTarget;
+  RefPtr<nsAtom> mEventName;
+  TypedEventHandler mTypedHandler;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(JSEventHandler, NS_JSEVENTHANDLER_IID)
+
+}  // namespace mozilla
+
+/**
+ * Factory function.  aHandler must already be bound to aTarget.
+ * aContext is allowed to be null if aHandler is already set up.
+ */
+nsresult NS_NewJSEventHandler(mozilla::dom::EventTarget* aTarget, nsAtom* aType,
+                              const mozilla::TypedEventHandler& aTypedHandler,
+                              mozilla::JSEventHandler** aReturn);
+
+#endif  // mozilla_JSEventHandler_h_