mus: Introduce AcceleratorRegistrar and AcceleratorHandler.

mash/wm/accelerator_registrar_impl.cc

+// Copyright 2015 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 "mash/wm/accelerator_registrar_impl.h"
+
+#include "components/mus/public/interfaces/window_tree_host.mojom.h"
+
+namespace mash {
+namespace wm {
+
+namespace {
+const int kAcceleratorIdMask = 0xffff;
+}
+
+AcceleratorRegistrarImpl::AcceleratorRegistrarImpl(
+    mus::mojom::WindowTreeHost* host,
+    uint32_t accelerator_namespace,
+    mojo::InterfaceRequest<AcceleratorRegistrar> request,
+    const DestroyCallback& destroy_callback)
+    : host_(host),
+      accelerator_namespace_(accelerator_namespace & 0xffff),
+      binding_(this, request.Pass()),
+      destroy_callback_(destroy_callback) {}
+
+AcceleratorRegistrarImpl::~AcceleratorRegistrarImpl() {
+  for (const auto& pair : accelerator_handlers_)
+    host_->RemoveAccelerator(pair.first);
+  destroy_callback_.Run(this);
+}
+
+bool AcceleratorRegistrarImpl::OwnsAccelerator(uint32_t accelerator_id) const {
+  return !!accelerator_handlers_.count(accelerator_id);
+}
+
+void AcceleratorRegistrarImpl::ProcessAccelerator(uint32_t accelerator_id,
+                                                  mus::mojom::EventPtr event) {
+  DCHECK(OwnsAccelerator(accelerator_id));
+  accelerator_handlers_[accelerator_id]->OnAccelerator(
+      accelerator_id & kAcceleratorIdMask, event.Pass());
+}
+
+uint32_t AcceleratorRegistrarImpl::ComputeAcceleratorId(
+    uint32_t accelerator_id) const {
+  return (accelerator_namespace_ << 16) | (accelerator_id & kAcceleratorIdMask);
+}
+
+// mus::mojom::AcceleratorRegistrar:
+void AcceleratorRegistrarImpl::AddAccelerator(
+    uint32_t accelerator_id,
+    mus::mojom::EventMatcherPtr matcher,
+    mus::mojom::AcceleratorHandlerPtr handler,
+    const AddAcceleratorCallback& callback) {
+  if ((accelerator_id & kAcceleratorIdMask) != accelerator_id) {
+    // The |accelerator_id| is too large, and it can't be handled correctly.
+    callback.Run(false);
+    return;
+  }
+  uint32_t namespaced_accelerator_id = ComputeAcceleratorId(accelerator_id);
+  accelerator_handlers_.insert(
+      std::make_pair(namespaced_accelerator_id, handler.Pass()));
+  host_->AddAccelerator(namespaced_accelerator_id, matcher.Pass());
+  callback.Run(true);
+}
+
+void AcceleratorRegistrarImpl::RemoveAccelerator(uint32_t accelerator_id) {
+  uint32_t namespaced_accelerator_id = ComputeAcceleratorId(accelerator_id);
+  if (!accelerator_handlers_.count(namespaced_accelerator_id))
+    return;
+  host_->RemoveAccelerator(namespaced_accelerator_id);
+}
+
+}  // namespace wm
+}  // namespace mash