[WIP] BufferedInputRouter

content/renderer/gpu/renderer_event_packet.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/gpu/renderer_event_packet.h"
+
+#include "content/common/input/event_packet.h"
+#include "content/common/input/input_event.h"
+#include "content/common/input/ipc_input_event_payload.h"
+#include "content/common/input/web_input_event_payload.h"
+#include "content/common/input_messages.h"
+
+namespace content {
+namespace {
+
+class RendererInputEvent {
+ public:
+  // |event| should outlive the created RendererInputEvent.
+  explicit RendererInputEvent(const InputEvent* event) : event_(event) {
+    DCHECK(event_);
+  }
+
+  InputEventDisposition Dispatch(RendererEventPacket::Dispatcher* dispatcher,
+                                 int routing_id) {
+    DCHECK(dispatcher);
+    const InputEvent::Payload* payload = event_->payload();
+
+    if (payload->GetType() == InputEvent::Payload::IPC_MESSAGE) {
+      return dispatcher->Dispatch(
+          *IPCInputEventPayload::Cast(payload)->message);
+    }
+
+    if (payload->GetType() == InputEvent::Payload::WEB_INPUT_EVENT) {
+      const WebInputEventPayload* web_payload =
+          WebInputEventPayload::Cast(payload);
+      return dispatcher->Dispatch(routing_id,
+                                  web_payload->web_event(),
+                                  web_payload->latency_info(),
+                                  web_payload->is_keyboard_shortcut());
+    }
+
+    NOTREACHED() << "Invalid InputEvent type.";
+    return INPUT_EVENT_UNHANDLED;
+  }
+
+  bool CanCreateFollowupEvents() const {
+    const InputEvent::Payload* payload = event_->payload();
+    return payload->GetType() == InputEvent::Payload::WEB_INPUT_EVENT &&
+        WebInputEventPayload::Cast(payload)->CanCreateFollowupEvents();
+  }
+
+  bool CanDeliverOnThread(RendererEventPacket::DispatchThreadType thread_type) {
+    switch (thread_type) {
+      case RendererEventPacket::THREAD_MAIN:
+        return true;
+      case RendererEventPacket::THREAD_IMPL:
+        return event_->payload()->GetType() ==
+               InputEvent::Payload::WEB_INPUT_EVENT;
+    }
+    NOTREACHED() << "Invalid dispatch thread type.";
+    return false;
+  }
+
+private:
+  const InputEvent* event_;
+
+  DISALLOW_COPY_AND_ASSIGN(RendererInputEvent);
+};
+
+}  // namespace
+
+RendererEventPacket::RendererEventPacket(
+    const EventPacket* packet,
+    const InputEventDispositions& dispositions)
+    : packet_(packet),
+      dispositions_(dispositions) {
+  DCHECK(packet_);
+  DCHECK_LE(dispositions_.size(), packet_->size());
+  dispositions_.resize(packet_->size(), INPUT_EVENT_UNHANDLED);
+}
+
+RendererEventPacket::~RendererEventPacket() {}
+
+scoped_ptr<IPC::Message> RendererEventPacket::DispatchWith(
+    Dispatcher* dispatcher,
+    DispatchThreadType thread_type,
+    int routing_id) {
+  DCHECK(dispatcher);
+  DCHECK_EQ(dispositions_.size(), packet_->size());
+  const EventPacket::InputEvents& events = packet_->events();
+  for (size_t i = 0; i < events.size(); ++i) {
+    RendererInputEvent event(events[i]);
+
+    // Ignore previously handled events.
+    InputEventDisposition old_disposition = dispositions_[i];
+    if (old_disposition != INPUT_EVENT_UNHANDLED &&
+        (thread_type == THREAD_IMPL ||
+         old_disposition != INPUT_EVENT_IMPL_THREAD_BOUNCE_TO_MAIN))
+      continue;
+
+    InputEventDisposition disposition = event.Dispatch(dispatcher, routing_id);
+    dispositions_[i] = disposition;
+
+    if (disposition == INPUT_EVENT_IMPL_THREAD_BOUNCE_TO_MAIN) {
+      DCHECK_EQ(THREAD_IMPL, thread_type);
+      // Bounce subsequent events to main. Events that should be offered to the
+      // impl thread will prevent further delivery.
+      bool can_continue_delivery = true;
+      while (++i < events.size()) {
+        RendererInputEvent current_event(events[i]);
+        if (current_event.CanDeliverOnThread(thread_type))
+          can_continue_delivery = false;
+        dispositions_[i] = can_continue_delivery
+                               ? INPUT_EVENT_IMPL_THREAD_BOUNCE_TO_MAIN
+                               : INPUT_EVENT_COULD_NOT_DELIVER;
+      }
+      return scoped_ptr<IPC::Message>(
+          new InputMsg_HandleEventPacket(routing_id, *packet_, dispositions_));
+    }
+
+    // Unconsumed events that create followup will prevent further delivery.
+    bool event_consumed =
+        disposition == INPUT_EVENT_IMPL_THREAD_CONSUMED ||
+        disposition == INPUT_EVENT_MAIN_THREAD_CONSUMED ||
+        disposition == INPUT_EVENT_MAIN_THREAD_PREVENT_DEFAULTED;
+    if (!event_consumed && event.CanCreateFollowupEvents()) {
+      while (++i < events.size())
+        dispositions_[i] = INPUT_EVENT_COULD_NOT_DELIVER;
+    }
+  }
+
+  return scoped_ptr<IPC::Message>(new InputHostMsg_HandleEventPacket_ACK(
+      routing_id, packet_->id(), dispositions_));
+}
+
+}  // namespace content