Vibration API: plumbing from Blink to Java.

content/browser/vibration/vibration_message_filter.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/browser/vibration/vibration_message_filter.h"
+
+#include <algorithm>
+
+#include "content/common/view_messages.h"
+
+namespace content {
+
+// Minimum duration of a vibration is 1 millisecond.
+const int64 kMinimumVibrationDurationMs = 1;
+
+// Maximum duration of a vibration is 10 seconds.
+const int64 kMaximumVibrationDurationMs = 10000;
+
+VibrationMessageFilter::VibrationMessageFilter() {
+}
+
+VibrationMessageFilter::~VibrationMessageFilter() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (vibration_service_.get())
+    vibration_service_->CancelVibration();
+}
+
+bool VibrationMessageFilter::OnMessageReceived(
+    const IPC::Message& message,
+    bool* message_was_ok) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(VibrationMessageFilter,
+                           message,
+                           *message_was_ok)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_Vibrate, OnVibrate)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_CancelVibration, OnCancelVibration)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP_EX()
+  return handled;
+}
+
+void VibrationMessageFilter::OnVibrate(int64 milliseconds) {
+  if (!vibration_service_.get()) {
+    vibration_service_.reset(VibrationService::Create().release());
+  }
+  if (vibration_service_.get()) {
+    // Though the Blink implementation already sanitizes vibration times, don't
+    // trust any values passed from the renderer.

[jam, 2013/07/01 18:14:40]

hmm, where is the sanitization happening there? seems that the constants need to
be exported so that they're shared instead of duplicated

[Michael van Ouwerkerk, 2013/07/02 17:52:39]

It's in third_party/WebKit/Source/modules/vibration/NavigatorVibration.cpp . Is
there an elegant way of sharing these constants without ending up with incorrect
dependencies or layering violations?

[jam, 2013/07/02 22:11:15]

you can put them in a public file in the WebKit API. jamesr can tell you exactly
which one

+    milliseconds = std::max(kMinimumVibrationDurationMs,
+        std::min(milliseconds, kMaximumVibrationDurationMs));
+    vibration_service_->Vibrate(milliseconds);
+  }
+}
+
+void VibrationMessageFilter::OnCancelVibration() {
+  if (!vibration_service_.get()) {
+    vibration_service_.reset(VibrationService::Create().release());

[jam, 2013/07/01 18:14:40]

when would this condition occur? i.e. that a vibration is being cancelled but
there's no vibration service?

[Michael van Ouwerkerk, 2013/07/02 17:52:39]

I've changed this. The implementation was such that non-Android builds always
had an empty pointer.

+  }
+  if (vibration_service_.get())

[jam, 2013/07/01 18:14:40]

what's the point of this line, since you're creating it above?

[Michael van Ouwerkerk, 2013/07/02 17:52:39]

I've changed this. The implementation was such that non-Android builds always
had an empty pointer.

+    vibration_service_->CancelVibration();
+}
+
+}  // namespace content