sync/notifier/gcm_network_channel.cc - chromium/src.git - Git at Google

 // Copyright 2014 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 "base/base64.h"
 #include "base/i18n/time_formatting.h"
 #include "base/metrics/histogram.h"
 #include "base/sha1.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #if !defined(OS_ANDROID)
 // channel_common.proto defines ANDROID constant that conflicts with Android
 // build. At the same time TiclInvalidationService is not used on Android so it
 // is safe to exclude these protos from Android build.
 #include "google/cacheinvalidation/android_channel.pb.h"
 #include "google/cacheinvalidation/channel_common.pb.h"
 #include "google/cacheinvalidation/types.pb.h"
 #endif
 #include "google_apis/gaia/google_service_auth_error.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_status.h"
 #include "sync/notifier/gcm_network_channel.h"
 #include "sync/notifier/gcm_network_channel_delegate.h"

 namespace syncer {

 namespace {

 const char kCacheInvalidationEndpointUrl[] =
     "https://clients4.google.com/invalidation/android/request/";
 const char kCacheInvalidationPackageName[] = "com.google.chrome.invalidations";

 // Register backoff policy.
 const net::BackoffEntry::Policy kRegisterBackoffPolicy = {
   // Number of initial errors (in sequence) to ignore before applying
   // exponential back-off rules.
   0,

   // Initial delay for exponential back-off in ms.
   2000, // 2 seconds.

   // Factor by which the waiting time will be multiplied.
   2,

   // Fuzzing percentage. ex: 10% will spread requests randomly
   // between 90%-100% of the calculated time.
   0.2, // 20%.

   // Maximum amount of time we are willing to delay our request in ms.
   1000 * 3600 * 4, // 4 hours.

   // Time to keep an entry from being discarded even when it
   // has no significant state, -1 to never discard.
   -1,

   // Don't use initial delay unless the last request was an error.
   false,
 };

 // Incoming message status values for UMA_HISTOGRAM.
 enum IncomingMessageStatus {
   INCOMING_MESSAGE_SUCCESS,
   MESSAGE_EMPTY,     // GCM message's content is missing or empty.
   INVALID_ENCODING,  // Base64Decode failed.
   INVALID_PROTO,     // Parsing protobuf failed.

   // This enum is used in UMA_HISTOGRAM_ENUMERATION. Insert new values above
   // this line.
   INCOMING_MESSAGE_STATUS_COUNT
 };

 // Outgoing message status values for UMA_HISTOGRAM.
 enum OutgoingMessageStatus {
   OUTGOING_MESSAGE_SUCCESS,
   MESSAGE_DISCARDED,     // New message started before old one was sent.
   ACCESS_TOKEN_FAILURE,  // Requeting access token failed.
   POST_FAILURE,          // HTTP Post failed.

   // This enum is used in UMA_HISTOGRAM_ENUMERATION. Insert new values above
   // this line.
   OUTGOING_MESSAGE_STATUS_COUNT
 };

 const char kIncomingMessageStatusHistogram[] =
     "GCMInvalidations.IncomingMessageStatus";
 const char kOutgoingMessageStatusHistogram[] =
     "GCMInvalidations.OutgoingMessageStatus";

 void RecordIncomingMessageStatus(IncomingMessageStatus status) {
   UMA_HISTOGRAM_ENUMERATION(kIncomingMessageStatusHistogram,
                             status,
                             INCOMING_MESSAGE_STATUS_COUNT);
 }

 void RecordOutgoingMessageStatus(OutgoingMessageStatus status) {
   UMA_HISTOGRAM_ENUMERATION(kOutgoingMessageStatusHistogram,
                             status,
                             OUTGOING_MESSAGE_STATUS_COUNT);
 }

 }  // namespace

 GCMNetworkChannel::GCMNetworkChannel(
     scoped_refptr<net::URLRequestContextGetter> request_context_getter,
     scoped_ptr<GCMNetworkChannelDelegate> delegate)
     : request_context_getter_(request_context_getter),
       delegate_(delegate.Pass()),
       register_backoff_entry_(new net::BackoffEntry(&kRegisterBackoffPolicy)),
       diagnostic_info_(this),
       weak_factory_(this) {
   net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
   delegate_->Initialize();
   Register();
 }

 GCMNetworkChannel::~GCMNetworkChannel() {
   net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
 }

 void GCMNetworkChannel::Register() {
   delegate_->Register(base::Bind(&GCMNetworkChannel::OnRegisterComplete,
                                  weak_factory_.GetWeakPtr()));
 }

 void GCMNetworkChannel::OnRegisterComplete(
     const std::string& registration_id,
     gcm::GCMClient::Result result) {
   DCHECK(CalledOnValidThread());
   if (result == gcm::GCMClient::SUCCESS) {
     DCHECK(!registration_id.empty());
     DVLOG(2) << "Got registration_id";
     register_backoff_entry_->Reset();
     registration_id_ = registration_id;
     if (!cached_message_.empty())
       RequestAccessToken();
   } else {
     DVLOG(2) << "Register failed: " << result;
     // Retry in case of transient error.
     switch (result) {
       case gcm::GCMClient::NETWORK_ERROR:
       case gcm::GCMClient::SERVER_ERROR:
       case gcm::GCMClient::TTL_EXCEEDED:
       case gcm::GCMClient::UNKNOWN_ERROR: {
         register_backoff_entry_->InformOfRequest(false);
         base::MessageLoop::current()->PostDelayedTask(
             FROM_HERE,
             base::Bind(&GCMNetworkChannel::Register,
                        weak_factory_.GetWeakPtr()),
             register_backoff_entry_->GetTimeUntilRelease());
         break;
       }
       default:
         break;
     }
   }
   diagnostic_info_.registration_id_ = registration_id_;
   diagnostic_info_.registration_result_ = result;
 }

 void GCMNetworkChannel::SendMessage(const std::string& message) {
   DCHECK(CalledOnValidThread());
   DCHECK(!message.empty());
   DVLOG(2) << "SendMessage";
   diagnostic_info_.sent_messages_count_++;
   if (!cached_message_.empty()) {
     RecordOutgoingMessageStatus(MESSAGE_DISCARDED);
   }
   cached_message_ = message;

   if (!registration_id_.empty()) {
     RequestAccessToken();
   }
 }

 void GCMNetworkChannel::RequestAccessToken() {
   DCHECK(CalledOnValidThread());
   delegate_->RequestToken(base::Bind(&GCMNetworkChannel::OnGetTokenComplete,
                                      weak_factory_.GetWeakPtr()));
 }

 void GCMNetworkChannel::OnGetTokenComplete(
     const GoogleServiceAuthError& error,
     const std::string& token) {
   DCHECK(CalledOnValidThread());
   if (cached_message_.empty()) {
     // Nothing to do.
     return;
   }

   if (error.state() != GoogleServiceAuthError::NONE) {
     // Requesting access token failed. Persistent errors will be reported by
     // token service. Just drop this request, cacheinvalidations will retry
     // sending message and at that time we'll retry requesting access token.
     DVLOG(1) << "RequestAccessToken failed: " << error.ToString();
     RecordOutgoingMessageStatus(ACCESS_TOKEN_FAILURE);
     // Message won't get sent because of connection failure. Let's retry once
     // connection is restored.
     if (error.state() == GoogleServiceAuthError::CONNECTION_FAILED)
       NotifyStateChange(TRANSIENT_INVALIDATION_ERROR);
     cached_message_.clear();
     return;
   }
   DCHECK(!token.empty());
   // Save access token in case POST fails and we need to invalidate it.
   access_token_ = token;

   DVLOG(2) << "Got access token, sending message";
   fetcher_.reset(net::URLFetcher::Create(
       BuildUrl(registration_id_), net::URLFetcher::POST, this));
   fetcher_->SetRequestContext(request_context_getter_);
   const std::string auth_header("Authorization: Bearer " + access_token_);
   fetcher_->AddExtraRequestHeader(auth_header);
   if (!echo_token_.empty()) {
     const std::string echo_header("echo-token: " + echo_token_);
     fetcher_->AddExtraRequestHeader(echo_header);
   }
   fetcher_->SetUploadData("application/x-protobuffer", cached_message_);
   fetcher_->Start();
   // Clear message to prevent accidentally resending it in the future.
   cached_message_.clear();
 }

 void GCMNetworkChannel::OnURLFetchComplete(const net::URLFetcher* source) {
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(fetcher_, source);
   // Free fetcher at the end of function.
   scoped_ptr<net::URLFetcher> fetcher = fetcher_.Pass();

   net::URLRequestStatus status = fetcher->GetStatus();
   diagnostic_info_.last_post_response_code_ =
       status.is_success() ? source->GetResponseCode() : status.error();

   if (status.is_success() &&
       fetcher->GetResponseCode() == net::HTTP_UNAUTHORIZED) {
     DVLOG(1) << "URLFetcher failure: HTTP_UNAUTHORIZED";
     delegate_->InvalidateToken(access_token_);
   }

   if (!status.is_success() ||
       (fetcher->GetResponseCode() != net::HTTP_OK &&
        fetcher->GetResponseCode() != net::HTTP_NO_CONTENT)) {
     DVLOG(1) << "URLFetcher failure";
     RecordOutgoingMessageStatus(POST_FAILURE);
     NotifyStateChange(TRANSIENT_INVALIDATION_ERROR);
     return;
   }

   RecordOutgoingMessageStatus(OUTGOING_MESSAGE_SUCCESS);
   NotifyStateChange(INVALIDATIONS_ENABLED);
   DVLOG(2) << "URLFetcher success";
 }

 void GCMNetworkChannel::OnIncomingMessage(const std::string& message,
                                           const std::string& echo_token) {
 #if !defined(OS_ANDROID)
   if (!echo_token.empty())
     echo_token_ = echo_token;
   diagnostic_info_.last_message_empty_echo_token_ = echo_token.empty();
   diagnostic_info_.last_message_received_time_ = base::Time::Now();

   if (message.empty()) {
     RecordIncomingMessageStatus(MESSAGE_EMPTY);
     return;
   }
   std::string data;
   if (!Base64DecodeURLSafe(message, &data)) {
     RecordIncomingMessageStatus(INVALID_ENCODING);
     return;
   }
   ipc::invalidation::AddressedAndroidMessage android_message;
   if (!android_message.ParseFromString(data) ||
       !android_message.has_message()) {
     RecordIncomingMessageStatus(INVALID_PROTO);
     return;
   }
   DVLOG(2) << "Deliver incoming message";
   RecordIncomingMessageStatus(INCOMING_MESSAGE_SUCCESS);
   DeliverIncomingMessage(android_message.message());
 #else
   // This code shouldn't be invoked on Android.
   NOTREACHED();
 #endif
 }

 void GCMNetworkChannel::OnNetworkChanged(
     net::NetworkChangeNotifier::ConnectionType connection_type) {
   // Network connection is restored. Let's notify cacheinvalidations so it has
   // chance to retry.
   if (connection_type != net::NetworkChangeNotifier::CONNECTION_NONE)
     NotifyStateChange(INVALIDATIONS_ENABLED);
 }

 GURL GCMNetworkChannel::BuildUrl(const std::string& registration_id) {
   DCHECK(!registration_id.empty());

 #if !defined(OS_ANDROID)
   ipc::invalidation::EndpointId endpoint_id;
   endpoint_id.set_c2dm_registration_id(registration_id);
   endpoint_id.set_client_key(std::string());
   endpoint_id.set_package_name(kCacheInvalidationPackageName);
   endpoint_id.mutable_channel_version()->set_major_version(
       ipc::invalidation::INITIAL);
   std::string endpoint_id_buffer;
   endpoint_id.SerializeToString(&endpoint_id_buffer);

   ipc::invalidation::NetworkEndpointId network_endpoint_id;
   network_endpoint_id.set_network_address(
       ipc::invalidation::NetworkEndpointId_NetworkAddress_ANDROID);
   network_endpoint_id.set_client_address(endpoint_id_buffer);
   std::string network_endpoint_id_buffer;
   network_endpoint_id.SerializeToString(&network_endpoint_id_buffer);

   std::string base64URLPiece;
   Base64EncodeURLSafe(network_endpoint_id_buffer, &base64URLPiece);

   std::string url(kCacheInvalidationEndpointUrl);
   url += base64URLPiece;
   return GURL(url);
 #else
   // This code shouldn't be invoked on Android.
   NOTREACHED();
   return GURL();
 #endif
 }

 void GCMNetworkChannel::Base64EncodeURLSafe(const std::string& input,
                                             std::string* output) {
   base::Base64Encode(input, output);
   // Covert to url safe alphabet.
   base::ReplaceChars(*output, "+", "-", output);
   base::ReplaceChars(*output, "/", "_", output);
   // Trim padding.
   size_t padding_size = 0;
   for (size_t i = output->size(); i > 0 && (*output)[i - 1] == '='; --i)
     ++padding_size;
   output->resize(output->size() - padding_size);
 }

 bool GCMNetworkChannel::Base64DecodeURLSafe(const std::string& input,
                                             std::string* output) {
   // Add padding.
   size_t padded_size = (input.size() + 3) - (input.size() + 3) % 4;
   std::string padded_input(input);
   padded_input.resize(padded_size, '=');
   // Convert to standard base64 alphabet.
   base::ReplaceChars(padded_input, "-", "+", &padded_input);
   base::ReplaceChars(padded_input, "_", "/", &padded_input);
   return base::Base64Decode(padded_input, output);
 }

 void GCMNetworkChannel::SetMessageReceiver(
     invalidation::MessageCallback* incoming_receiver) {
   delegate_->SetMessageReceiver(base::Bind(
       &GCMNetworkChannel::OnIncomingMessage, weak_factory_.GetWeakPtr()));
   SyncNetworkChannel::SetMessageReceiver(incoming_receiver);
 }

 void GCMNetworkChannel::RequestDetailedStatus(
     base::Callback<void(const base::DictionaryValue&)> callback) {
   callback.Run(*diagnostic_info_.CollectDebugData());
 }

 void GCMNetworkChannel::UpdateCredentials(const std::string& email,
                                           const std::string& token) {
   // Do nothing. We get access token by requesting it for every message.
 }

 int GCMNetworkChannel::GetInvalidationClientType() {
 #if defined(OS_IOS)
   return ipc::invalidation::ClientType::CHROME_SYNC_GCM_IOS;
 #else
   return ipc::invalidation::ClientType::CHROME_SYNC_GCM_DESKTOP;
 #endif
 }

 void GCMNetworkChannel::ResetRegisterBackoffEntryForTest(
     const net::BackoffEntry::Policy* policy) {
   register_backoff_entry_.reset(new net::BackoffEntry(policy));
 }

 GCMNetworkChannelDiagnostic::GCMNetworkChannelDiagnostic(
     GCMNetworkChannel* parent)
     : parent_(parent),
       last_message_empty_echo_token_(false),
       last_post_response_code_(0),
       registration_result_(gcm::GCMClient::UNKNOWN_ERROR),
       sent_messages_count_(0) {}

 scoped_ptr<base::DictionaryValue>
 GCMNetworkChannelDiagnostic::CollectDebugData() const {
   scoped_ptr<base::DictionaryValue> status(new base::DictionaryValue);
   status->SetString("GCMNetworkChannel.Channel", "GCM");
   std::string reg_id_hash = base::SHA1HashString(registration_id_);
   status->SetString("GCMNetworkChannel.HashedRegistrationID",
                     base::HexEncode(reg_id_hash.c_str(), reg_id_hash.size()));
   status->SetString("GCMNetworkChannel.RegistrationResult",
                     GCMClientResultToString(registration_result_));
   status->SetBoolean("GCMNetworkChannel.HadLastMessageEmptyEchoToken",
                      last_message_empty_echo_token_);
   status->SetString(
       "GCMNetworkChannel.LastMessageReceivedTime",
       base::TimeFormatShortDateAndTime(last_message_received_time_));
   status->SetInteger("GCMNetworkChannel.LastPostResponseCode",
                      last_post_response_code_);
   status->SetInteger("GCMNetworkChannel.SentMessages", sent_messages_count_);
   status->SetInteger("GCMNetworkChannel.ReceivedMessages",
                      parent_->GetReceivedMessagesCount());
   return status.Pass();
 }

 std::string GCMNetworkChannelDiagnostic::GCMClientResultToString(
     const gcm::GCMClient::Result result) const {
 #define ENUM_CASE(x) case x: return #x; break;
   switch (result) {
     ENUM_CASE(gcm::GCMClient::SUCCESS);
     ENUM_CASE(gcm::GCMClient::NETWORK_ERROR);
     ENUM_CASE(gcm::GCMClient::SERVER_ERROR);
     ENUM_CASE(gcm::GCMClient::TTL_EXCEEDED);
     ENUM_CASE(gcm::GCMClient::UNKNOWN_ERROR);
     ENUM_CASE(gcm::GCMClient::NOT_SIGNED_IN);
     ENUM_CASE(gcm::GCMClient::INVALID_PARAMETER);
     ENUM_CASE(gcm::GCMClient::ASYNC_OPERATION_PENDING);
   }
   NOTREACHED();
   return "";
 }

 }  // namespace syncer
	// Copyright 2014 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 "base/base64.h"
	#include "base/i18n/time_formatting.h"
	#include "base/metrics/histogram.h"
	#include "base/sha1.h"
	#include "base/strings/string_number_conversions.h"
	#include "base/strings/string_util.h"
	#if !defined(OS_ANDROID)
	// channel_common.proto defines ANDROID constant that conflicts with Android
	// build. At the same time TiclInvalidationService is not used on Android so it
	// is safe to exclude these protos from Android build.
	#include "google/cacheinvalidation/android_channel.pb.h"
	#include "google/cacheinvalidation/channel_common.pb.h"
	#include "google/cacheinvalidation/types.pb.h"
	#endif
	#include "google_apis/gaia/google_service_auth_error.h"
	#include "net/http/http_status_code.h"
	#include "net/url_request/url_fetcher.h"
	#include "net/url_request/url_request_status.h"
	#include "sync/notifier/gcm_network_channel.h"
	#include "sync/notifier/gcm_network_channel_delegate.h"

	namespace syncer {

	namespace {

	const char kCacheInvalidationEndpointUrl[] =
	"https://clients4.google.com/invalidation/android/request/";
	const char kCacheInvalidationPackageName[] = "com.google.chrome.invalidations";

	// Register backoff policy.
	const net::BackoffEntry::Policy kRegisterBackoffPolicy = {
	// Number of initial errors (in sequence) to ignore before applying
	// exponential back-off rules.
	0,

	// Initial delay for exponential back-off in ms.
	2000, // 2 seconds.

	// Factor by which the waiting time will be multiplied.
	2,

	// Fuzzing percentage. ex: 10% will spread requests randomly
	// between 90%-100% of the calculated time.
	0.2, // 20%.

	// Maximum amount of time we are willing to delay our request in ms.
	1000 * 3600 * 4, // 4 hours.

	// Time to keep an entry from being discarded even when it
	// has no significant state, -1 to never discard.
	-1,

	// Don't use initial delay unless the last request was an error.
	false,
	};

	// Incoming message status values for UMA_HISTOGRAM.
	enum IncomingMessageStatus {
	INCOMING_MESSAGE_SUCCESS,
	MESSAGE_EMPTY, // GCM message's content is missing or empty.
	INVALID_ENCODING, // Base64Decode failed.
	INVALID_PROTO, // Parsing protobuf failed.

	// This enum is used in UMA_HISTOGRAM_ENUMERATION. Insert new values above
	// this line.
	INCOMING_MESSAGE_STATUS_COUNT
	};

	// Outgoing message status values for UMA_HISTOGRAM.
	enum OutgoingMessageStatus {
	OUTGOING_MESSAGE_SUCCESS,
	MESSAGE_DISCARDED, // New message started before old one was sent.
	ACCESS_TOKEN_FAILURE, // Requeting access token failed.
	POST_FAILURE, // HTTP Post failed.

	// This enum is used in UMA_HISTOGRAM_ENUMERATION. Insert new values above
	// this line.
	OUTGOING_MESSAGE_STATUS_COUNT
	};

	const char kIncomingMessageStatusHistogram[] =
	"GCMInvalidations.IncomingMessageStatus";
	const char kOutgoingMessageStatusHistogram[] =
	"GCMInvalidations.OutgoingMessageStatus";

	void RecordIncomingMessageStatus(IncomingMessageStatus status) {
	UMA_HISTOGRAM_ENUMERATION(kIncomingMessageStatusHistogram,
	status,
	INCOMING_MESSAGE_STATUS_COUNT);
	}

	void RecordOutgoingMessageStatus(OutgoingMessageStatus status) {
	UMA_HISTOGRAM_ENUMERATION(kOutgoingMessageStatusHistogram,
	status,
	OUTGOING_MESSAGE_STATUS_COUNT);
	}

	} // namespace

	GCMNetworkChannel::GCMNetworkChannel(
	scoped_refptr<net::URLRequestContextGetter> request_context_getter,
	scoped_ptr<GCMNetworkChannelDelegate> delegate)
	: request_context_getter_(request_context_getter),
	delegate_(delegate.Pass()),
	register_backoff_entry_(new net::BackoffEntry(&kRegisterBackoffPolicy)),
	diagnostic_info_(this),
	weak_factory_(this) {
	net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
	delegate_->Initialize();
	Register();
	}

	GCMNetworkChannel::~GCMNetworkChannel() {
	net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
	}

	void GCMNetworkChannel::Register() {
	delegate_->Register(base::Bind(&GCMNetworkChannel::OnRegisterComplete,
	weak_factory_.GetWeakPtr()));
	}

	void GCMNetworkChannel::OnRegisterComplete(
	const std::string& registration_id,
	gcm::GCMClient::Result result) {
	DCHECK(CalledOnValidThread());
	if (result == gcm::GCMClient::SUCCESS) {
	DCHECK(!registration_id.empty());
	DVLOG(2) << "Got registration_id";
	register_backoff_entry_->Reset();
	registration_id_ = registration_id;
	if (!cached_message_.empty())
	RequestAccessToken();
	} else {
	DVLOG(2) << "Register failed: " << result;
	// Retry in case of transient error.
	switch (result) {
	case gcm::GCMClient::NETWORK_ERROR:
	case gcm::GCMClient::SERVER_ERROR:
	case gcm::GCMClient::TTL_EXCEEDED:
	case gcm::GCMClient::UNKNOWN_ERROR: {
	register_backoff_entry_->InformOfRequest(false);
	base::MessageLoop::current()->PostDelayedTask(
	FROM_HERE,
	base::Bind(&GCMNetworkChannel::Register,
	weak_factory_.GetWeakPtr()),
	register_backoff_entry_->GetTimeUntilRelease());
	break;
	}
	default:
	break;
	}
	}
	diagnostic_info_.registration_id_ = registration_id_;
	diagnostic_info_.registration_result_ = result;
	}

	void GCMNetworkChannel::SendMessage(const std::string& message) {
	DCHECK(CalledOnValidThread());
	DCHECK(!message.empty());
	DVLOG(2) << "SendMessage";
	diagnostic_info_.sent_messages_count_++;
	if (!cached_message_.empty()) {
	RecordOutgoingMessageStatus(MESSAGE_DISCARDED);
	}
	cached_message_ = message;

	if (!registration_id_.empty()) {
	RequestAccessToken();
	}
	}

	void GCMNetworkChannel::RequestAccessToken() {
	DCHECK(CalledOnValidThread());
	delegate_->RequestToken(base::Bind(&GCMNetworkChannel::OnGetTokenComplete,
	weak_factory_.GetWeakPtr()));
	}

	void GCMNetworkChannel::OnGetTokenComplete(
	const GoogleServiceAuthError& error,
	const std::string& token) {
	DCHECK(CalledOnValidThread());
	if (cached_message_.empty()) {
	// Nothing to do.
	return;
	}

	if (error.state() != GoogleServiceAuthError::NONE) {
	// Requesting access token failed. Persistent errors will be reported by
	// token service. Just drop this request, cacheinvalidations will retry
	// sending message and at that time we'll retry requesting access token.
	DVLOG(1) << "RequestAccessToken failed: " << error.ToString();
	RecordOutgoingMessageStatus(ACCESS_TOKEN_FAILURE);
	// Message won't get sent because of connection failure. Let's retry once
	// connection is restored.
	if (error.state() == GoogleServiceAuthError::CONNECTION_FAILED)
	NotifyStateChange(TRANSIENT_INVALIDATION_ERROR);
	cached_message_.clear();
	return;
	}
	DCHECK(!token.empty());
	// Save access token in case POST fails and we need to invalidate it.
	access_token_ = token;

	DVLOG(2) << "Got access token, sending message";
	fetcher_.reset(net::URLFetcher::Create(
	BuildUrl(registration_id_), net::URLFetcher::POST, this));
	fetcher_->SetRequestContext(request_context_getter_);
	const std::string auth_header("Authorization: Bearer " + access_token_);
	fetcher_->AddExtraRequestHeader(auth_header);
	if (!echo_token_.empty()) {
	const std::string echo_header("echo-token: " + echo_token_);
	fetcher_->AddExtraRequestHeader(echo_header);
	}
	fetcher_->SetUploadData("application/x-protobuffer", cached_message_);
	fetcher_->Start();
	// Clear message to prevent accidentally resending it in the future.
	cached_message_.clear();
	}

	void GCMNetworkChannel::OnURLFetchComplete(const net::URLFetcher* source) {
	DCHECK(CalledOnValidThread());
	DCHECK_EQ(fetcher_, source);
	// Free fetcher at the end of function.
	scoped_ptr<net::URLFetcher> fetcher = fetcher_.Pass();

	net::URLRequestStatus status = fetcher->GetStatus();
	diagnostic_info_.last_post_response_code_ =
	status.is_success() ? source->GetResponseCode() : status.error();

	if (status.is_success() &&
	fetcher->GetResponseCode() == net::HTTP_UNAUTHORIZED) {
	DVLOG(1) << "URLFetcher failure: HTTP_UNAUTHORIZED";
	delegate_->InvalidateToken(access_token_);
	}

	if (!status.is_success() \|\|
	(fetcher->GetResponseCode() != net::HTTP_OK &&
	fetcher->GetResponseCode() != net::HTTP_NO_CONTENT)) {
	DVLOG(1) << "URLFetcher failure";
	RecordOutgoingMessageStatus(POST_FAILURE);
	NotifyStateChange(TRANSIENT_INVALIDATION_ERROR);
	return;
	}

	RecordOutgoingMessageStatus(OUTGOING_MESSAGE_SUCCESS);
	NotifyStateChange(INVALIDATIONS_ENABLED);
	DVLOG(2) << "URLFetcher success";
	}

	void GCMNetworkChannel::OnIncomingMessage(const std::string& message,
	const std::string& echo_token) {
	#if !defined(OS_ANDROID)
	if (!echo_token.empty())
	echo_token_ = echo_token;
	diagnostic_info_.last_message_empty_echo_token_ = echo_token.empty();
	diagnostic_info_.last_message_received_time_ = base::Time::Now();

	if (message.empty()) {
	RecordIncomingMessageStatus(MESSAGE_EMPTY);
	return;
	}
	std::string data;
	if (!Base64DecodeURLSafe(message, &data)) {
	RecordIncomingMessageStatus(INVALID_ENCODING);
	return;
	}
	ipc::invalidation::AddressedAndroidMessage android_message;
	if (!android_message.ParseFromString(data) \|\|
	!android_message.has_message()) {
	RecordIncomingMessageStatus(INVALID_PROTO);
	return;
	}
	DVLOG(2) << "Deliver incoming message";
	RecordIncomingMessageStatus(INCOMING_MESSAGE_SUCCESS);
	DeliverIncomingMessage(android_message.message());
	#else
	// This code shouldn't be invoked on Android.
	NOTREACHED();
	#endif
	}

	void GCMNetworkChannel::OnNetworkChanged(
	net::NetworkChangeNotifier::ConnectionType connection_type) {
	// Network connection is restored. Let's notify cacheinvalidations so it has
	// chance to retry.
	if (connection_type != net::NetworkChangeNotifier::CONNECTION_NONE)
	NotifyStateChange(INVALIDATIONS_ENABLED);
	}

	GURL GCMNetworkChannel::BuildUrl(const std::string& registration_id) {
	DCHECK(!registration_id.empty());

	#if !defined(OS_ANDROID)
	ipc::invalidation::EndpointId endpoint_id;
	endpoint_id.set_c2dm_registration_id(registration_id);
	endpoint_id.set_client_key(std::string());
	endpoint_id.set_package_name(kCacheInvalidationPackageName);
	endpoint_id.mutable_channel_version()->set_major_version(
	ipc::invalidation::INITIAL);
	std::string endpoint_id_buffer;
	endpoint_id.SerializeToString(&endpoint_id_buffer);

	ipc::invalidation::NetworkEndpointId network_endpoint_id;
	network_endpoint_id.set_network_address(
	ipc::invalidation::NetworkEndpointId_NetworkAddress_ANDROID);
	network_endpoint_id.set_client_address(endpoint_id_buffer);
	std::string network_endpoint_id_buffer;
	network_endpoint_id.SerializeToString(&network_endpoint_id_buffer);

	std::string base64URLPiece;
	Base64EncodeURLSafe(network_endpoint_id_buffer, &base64URLPiece);

	std::string url(kCacheInvalidationEndpointUrl);
	url += base64URLPiece;
	return GURL(url);
	#else
	// This code shouldn't be invoked on Android.
	NOTREACHED();
	return GURL();
	#endif
	}

	void GCMNetworkChannel::Base64EncodeURLSafe(const std::string& input,
	std::string* output) {
	base::Base64Encode(input, output);
	// Covert to url safe alphabet.
	base::ReplaceChars(*output, "+", "-", output);
	base::ReplaceChars(*output, "/", "_", output);
	// Trim padding.
	size_t padding_size = 0;
	for (size_t i = output->size(); i > 0 && (*output)[i - 1] == '='; --i)
	++padding_size;
	output->resize(output->size() - padding_size);
	}

	bool GCMNetworkChannel::Base64DecodeURLSafe(const std::string& input,
	std::string* output) {
	// Add padding.
	size_t padded_size = (input.size() + 3) - (input.size() + 3) % 4;
	std::string padded_input(input);
	padded_input.resize(padded_size, '=');
	// Convert to standard base64 alphabet.
	base::ReplaceChars(padded_input, "-", "+", &padded_input);
	base::ReplaceChars(padded_input, "_", "/", &padded_input);
	return base::Base64Decode(padded_input, output);
	}

	void GCMNetworkChannel::SetMessageReceiver(
	invalidation::MessageCallback* incoming_receiver) {
	delegate_->SetMessageReceiver(base::Bind(
	&GCMNetworkChannel::OnIncomingMessage, weak_factory_.GetWeakPtr()));
	SyncNetworkChannel::SetMessageReceiver(incoming_receiver);
	}

	void GCMNetworkChannel::RequestDetailedStatus(
	base::Callback<void(const base::DictionaryValue&)> callback) {
	callback.Run(*diagnostic_info_.CollectDebugData());
	}

	void GCMNetworkChannel::UpdateCredentials(const std::string& email,
	const std::string& token) {
	// Do nothing. We get access token by requesting it for every message.
	}

	int GCMNetworkChannel::GetInvalidationClientType() {
	#if defined(OS_IOS)
	return ipc::invalidation::ClientType::CHROME_SYNC_GCM_IOS;
	#else
	return ipc::invalidation::ClientType::CHROME_SYNC_GCM_DESKTOP;
	#endif
	}

	void GCMNetworkChannel::ResetRegisterBackoffEntryForTest(
	const net::BackoffEntry::Policy* policy) {
	register_backoff_entry_.reset(new net::BackoffEntry(policy));
	}

	GCMNetworkChannelDiagnostic::GCMNetworkChannelDiagnostic(
	GCMNetworkChannel* parent)
	: parent_(parent),
	last_message_empty_echo_token_(false),
	last_post_response_code_(0),
	registration_result_(gcm::GCMClient::UNKNOWN_ERROR),
	sent_messages_count_(0) {}

	scoped_ptr<base::DictionaryValue>
	GCMNetworkChannelDiagnostic::CollectDebugData() const {
	scoped_ptr<base::DictionaryValue> status(new base::DictionaryValue);
	status->SetString("GCMNetworkChannel.Channel", "GCM");
	std::string reg_id_hash = base::SHA1HashString(registration_id_);
	status->SetString("GCMNetworkChannel.HashedRegistrationID",
	base::HexEncode(reg_id_hash.c_str(), reg_id_hash.size()));
	status->SetString("GCMNetworkChannel.RegistrationResult",
	GCMClientResultToString(registration_result_));
	status->SetBoolean("GCMNetworkChannel.HadLastMessageEmptyEchoToken",
	last_message_empty_echo_token_);
	status->SetString(
	"GCMNetworkChannel.LastMessageReceivedTime",
	base::TimeFormatShortDateAndTime(last_message_received_time_));
	status->SetInteger("GCMNetworkChannel.LastPostResponseCode",
	last_post_response_code_);
	status->SetInteger("GCMNetworkChannel.SentMessages", sent_messages_count_);
	status->SetInteger("GCMNetworkChannel.ReceivedMessages",
	parent_->GetReceivedMessagesCount());
	return status.Pass();
	}

	std::string GCMNetworkChannelDiagnostic::GCMClientResultToString(
	const gcm::GCMClient::Result result) const {
	#define ENUM_CASE(x) case x: return #x; break;
	switch (result) {
	ENUM_CASE(gcm::GCMClient::SUCCESS);
	ENUM_CASE(gcm::GCMClient::NETWORK_ERROR);
	ENUM_CASE(gcm::GCMClient::SERVER_ERROR);
	ENUM_CASE(gcm::GCMClient::TTL_EXCEEDED);
	ENUM_CASE(gcm::GCMClient::UNKNOWN_ERROR);
	ENUM_CASE(gcm::GCMClient::NOT_SIGNED_IN);
	ENUM_CASE(gcm::GCMClient::INVALID_PARAMETER);
	ENUM_CASE(gcm::GCMClient::ASYNC_OPERATION_PENDING);
	}
	NOTREACHED();
	return "";
	}

	} // namespace syncer