Index: chrome/browser/device_orientation/provider_impl.cc |
diff --git a/chrome/browser/device_orientation/provider_impl.cc b/chrome/browser/device_orientation/provider_impl.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..184e5f8a029a4f05d0fb0c965d1a4e379a1cae1a |
--- /dev/null |
+++ b/chrome/browser/device_orientation/provider_impl.cc |
@@ -0,0 +1,199 @@ |
+// Copyright (c) 2010 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 <cmath> |
+#include <set> |
+#include <vector> |
+ |
+#include "base/logging.h" |
+#include "base/task.h" |
+#include "chrome/browser/chrome_thread.h" |
+#include "chrome/browser/device_orientation/orientation.h" |
+#include "chrome/browser/device_orientation/provider_impl.h" |
+ |
+namespace device_orientation { |
+ |
+ProviderImpl::ProviderImpl(MessageLoop* message_loop, |
+ const DataFetcherFactory factories[]) |
+ : creator_loop_(message_loop), |
+ ALLOW_THIS_IN_INITIALIZER_LIST(do_poll_method_factory_(this)) { |
+ for (const DataFetcherFactory* fp = factories; *fp; ++fp) |
+ factories_.push_back(*fp); |
+} |
+ |
+ProviderImpl::~ProviderImpl() { |
+} |
+ |
+void ProviderImpl::AddObserver(Observer* observer) { |
+ DCHECK(MessageLoop::current() == creator_loop_); |
+ |
+ observers_.insert(observer); |
+ if (observers_.size() == 1) |
+ Start(); |
+ else |
+ observer->OnOrientationUpdate(last_notification_); |
+} |
+ |
+void ProviderImpl::RemoveObserver(Observer* observer) { |
+ DCHECK(MessageLoop::current() == creator_loop_); |
+ |
+ observers_.erase(observer); |
+ if (observers_.empty()) |
+ Stop(); |
+} |
+ |
+void ProviderImpl::Start() { |
+ DCHECK(MessageLoop::current() == creator_loop_); |
+ DCHECK(!polling_thread_.get()); |
+ |
+ polling_thread_.reset(new base::Thread("Device orientation polling thread")); |
+ if (!polling_thread_->Start()) { |
+ LOG(ERROR) << "Failed to start device orientation polling thread"; |
+ polling_thread_.reset(); |
+ return; |
+ } |
+ ScheduleInitializePollingThread(); |
+} |
+ |
+void ProviderImpl::Stop() { |
+ DCHECK(MessageLoop::current() == creator_loop_); |
+ polling_thread_.reset(); |
+ data_fetcher_.reset(); |
+} |
+ |
+void ProviderImpl::DoInitializePollingThread( |
+ std::vector<DataFetcherFactory> factories) { |
+ DCHECK(MessageLoop::current() == polling_thread_->message_loop()); |
+ |
+ typedef std::vector<DataFetcherFactory>::const_iterator Iterator; |
+ for (Iterator i = factories_.begin(), e = factories_.end(); i != e; ++i) { |
+ DataFetcherFactory factory = *i; |
+ scoped_ptr<DataFetcher> fetcher(factory()); |
+ Orientation orientation; |
+ |
+ if (fetcher.get() && fetcher->GetOrientation(&orientation)) { |
+ // Pass ownership of fetcher to provider_. |
+ data_fetcher_.swap(fetcher); |
+ last_orientation_ = orientation; |
+ |
+ // Notify observers. |
+ ScheduleDoNotify(orientation); |
+ |
+ // Start polling. |
+ ScheduleDoPoll(); |
+ return; |
+ } |
+ } |
+ |
+ // When no orientation data can be provided. |
+ ScheduleDoNotify(Orientation::Empty()); |
+} |
+ |
+void ProviderImpl::ScheduleInitializePollingThread() { |
+ DCHECK(MessageLoop::current() == creator_loop_); |
+ |
+ Task* task = NewRunnableMethod(this, |
+ &ProviderImpl::DoInitializePollingThread, |
+ factories_); |
+ MessageLoop* polling_loop = polling_thread_->message_loop(); |
+ polling_loop->PostTask(FROM_HERE, task); |
+} |
+ |
+void ProviderImpl::DoNotify(Orientation orientation) { |
+ DCHECK(MessageLoop::current() == creator_loop_); |
+ |
+ last_notification_ = orientation; |
+ |
+ typedef std::set<Observer*>::const_iterator Iterator; |
+ for (Iterator i = observers_.begin(), e = observers_.end(); i != e; ++i) |
+ (*i)->OnOrientationUpdate(orientation); |
+ |
+ if (orientation.IsEmpty()) { |
+ // Notify observers about failure to provide data exactly once. |
+ observers_.clear(); |
+ Stop(); |
+ } |
+} |
+ |
+void ProviderImpl::ScheduleDoNotify(Orientation orientation) { |
+ DCHECK(MessageLoop::current() == polling_thread_->message_loop()); |
+ |
+ Task* task = NewRunnableMethod(this, &ProviderImpl::DoNotify, orientation); |
+ creator_loop_->PostTask(FROM_HERE, task); |
+} |
+ |
+void ProviderImpl::DoPoll() { |
+ DCHECK(MessageLoop::current() == polling_thread_->message_loop()); |
+ |
+ Orientation orientation; |
+ if (!data_fetcher_->GetOrientation(&orientation)) { |
+ LOG(ERROR) << "Failed to poll device orientation data fetcher."; |
+ |
+ ScheduleDoNotify(Orientation::Empty()); |
+ return; |
+ } |
+ |
+ if (SignificantlyDifferent(orientation, last_orientation_)) { |
+ last_orientation_ = orientation; |
+ ScheduleDoNotify(orientation); |
+ } |
+ |
+ ScheduleDoPoll(); |
+} |
+ |
+void ProviderImpl::ScheduleDoPoll() { |
+ DCHECK(MessageLoop::current() == polling_thread_->message_loop()); |
+ |
+ Task* task = do_poll_method_factory_.NewRunnableMethod(&ProviderImpl::DoPoll); |
+ MessageLoop* polling_loop = polling_thread_->message_loop(); |
+ polling_loop->PostDelayedTask(FROM_HERE, task, SamplingIntervalMs()); |
+} |
+ |
+namespace { |
+bool IsElementSignificantlyDifferent(bool can_provide_element1, |
+ bool can_provide_element2, |
+ double element1, |
+ double element2) { |
+ const double kThreshold = 0.1; |
+ |
+ if (can_provide_element1 != can_provide_element2) |
+ return true; |
+ if (can_provide_element1 && |
+ std::fabs(element1 - element2) >= kThreshold) |
+ return true; |
+ return false; |
+} |
+} // namespace |
+ |
+// Returns true if two orientations are considered different enough that |
+// observers should be notified of the new orientation. |
+bool ProviderImpl::SignificantlyDifferent(const Orientation& o1, |
+ const Orientation& o2) { |
+ return IsElementSignificantlyDifferent(o1.can_provide_alpha_, |
+ o2.can_provide_alpha_, |
+ o1.alpha_, |
+ o2.alpha_) || |
+ IsElementSignificantlyDifferent(o1.can_provide_beta_, |
+ o2.can_provide_beta_, |
+ o1.beta_, |
+ o2.beta_) || |
+ IsElementSignificantlyDifferent(o1.can_provide_gamma_, |
+ o2.can_provide_gamma_, |
+ o1.gamma_, |
+ o2.gamma_); |
+} |
+ |
+int ProviderImpl::SamplingIntervalMs() const { |
+ DCHECK(MessageLoop::current() == polling_thread_->message_loop()); |
+ DCHECK(data_fetcher_.get()); |
+ |
+ int fetcher_interval = data_fetcher_->MinSamplingIntervalMs(); |
+ |
+ if (fetcher_interval > kDesiredSamplingIntervalMs) |
+ return fetcher_interval; |
+ else |
+ return kDesiredSamplingIntervalMs; |
+} |
+ |
+} // namespace device_orientation |