[GCM] Adding GCMAccountMapper to link signed in profile to accounts.

components/gcm_driver/gcm_account_mapper.cc

+// 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 "components/gcm_driver/gcm_account_mapper.h"
+
+#include "base/bind.h"
+#include "base/guid.h"
+#include "base/time/clock.h"
+#include "base/time/default_clock.h"
+#include "components/gcm_driver/gcm_driver_desktop.h"
+#include "google_apis/gcm/engine/gcm_store.h"
+
+namespace gcm {
+
+namespace {
+
+const char kGCMAccountMapperSenderId[] = "745476177629";
+const char kGCMAccountMapperAppId[] = "com.google.android.gms";
+const int kGCMAddMappingMessageTTL = 30 * 60;  // 0.5 hours in seconds.
+const int kGCMRemoveMappingMessageTTL = 24 * 60 * 60;  // 1 day in seconds.
+const int kGCMUpdateIntervalHours = 24;
+// Because adding an account mapping is dependent on a fresh OAuth2 token, we

[jianli, 2014/09/02 18:00:10]

is dependent => depends

[fgorski, 2014/09/03 21:37:02]

Done.

+// allow the update to happen earlier then update interval, if it is within

[jianli, 2014/09/02 18:00:09]

then update interval => than update due time

[fgorski, 2014/09/03 21:37:02]

Done.

+// the early start time to take advantage of that token.
+const int kGCMUpdateEarlyStartHours = 6;
+const char kRegistrationIdMessgaeKey[] = "id";
+const char kTokenMessageKey[] = "t";
+const char kAccountMessageKey[] = "a";
+const char kRemoveAccountMessageKey[] = "r";
+const char kRemoveAccountMessageValue[] = "1";
+
+std::string GenerateMessageID() {
+  return base::GenerateGUID();
+}
+
+}  // namespace
+
+GCMAccountMapper::GCMAccountMapper(GCMDriver* gcm_driver)
+    : gcm_driver_(gcm_driver),
+      clock_(new base::DefaultClock),
+      initialized_(false),
+      weak_ptr_factory_(this) {
+}
+
+GCMAccountMapper::~GCMAccountMapper() {
+}
+
+void GCMAccountMapper::Initialize(
+    const std::vector<AccountMapping>& account_mappings,
+    const std::string& registration_id) {
+  DCHECK(!initialized_);
+  initialized_ = true;
+  registration_id_ = registration_id;
+
+  accounts_ = account_mappings;
+
+  gcm_driver_->AddAppHandler(kGCMAccountMapperAppId, this);
+
+  // TODO(fgorski): if no registration ID, get registration ID.
+}
+
+void GCMAccountMapper::SetAccountTokens(
+    const std::vector<GCMClient::AccountTokenInfo> account_tokens) {
+  DCHECK(initialized_);
+
+  // Start from removing the old tokens, from all of the known accounts.
+  for (AccountMappings::iterator iter = accounts_.begin();
+       iter != accounts_.end();
+       ++iter) {
+    iter->access_token.clear();
+  }
+
+  // Update the internal collection of mappings with the new tokens.
+  for (std::vector<GCMClient::AccountTokenInfo>::const_iterator token_iter =
+           account_tokens.begin();
+       token_iter != account_tokens.end();
+       ++token_iter) {
+    AccountMapping* account_mapping =
+        FindMappingByAccountId(token_iter->account_id);
+    if (!account_mapping) {
+      AccountMapping new_mapping;
+      new_mapping.status = AccountMapping::NEW;
+      new_mapping.account_id = token_iter->account_id;
+      new_mapping.access_token = token_iter->access_token;
+      new_mapping.email = token_iter->email;
+      accounts_.push_back(new_mapping);
+    } else {
+      // Since we got a token for an account, drop the remove message and treat
+      // it as mapped.
+      if (account_mapping->status == AccountMapping::REMOVING) {
+        account_mapping->status = AccountMapping::MAPPED;
+        account_mapping->status_change_timestamp = base::Time();
+        account_mapping->last_message_id.clear();
+      }
+
+      account_mapping->email = token_iter->email;
+      account_mapping->access_token = token_iter->access_token;
+    }
+  }
+
+  // Decide what to do with each account (either start mapping, or start
+  // removing).
+  for (AccountMappings::iterator mappings_iter = accounts_.begin();
+       mappings_iter != accounts_.end();
+       ++mappings_iter) {
+    if (mappings_iter->access_token.empty()) {
+      // Send a remove message if the account was not previously removing,

[jianli, 2014/09/02 18:00:10]

removing => being removed

[fgorski, 2014/09/03 21:37:02]

Done.

+      // or it doesn't have a pending message, or the pending message is
+      // already expired, but OnSendError event was lost.
+      if (mappings_iter->status != AccountMapping::REMOVING ||
+          mappings_iter->last_message_id.empty() ||
+          IsLastStatusChangeOlderThanTTL(*mappings_iter)) {
+        SendRemoveMappingMessage(*mappings_iter);
+      }
+    } else {
+      // A message is sent for all of the mappings considered NEW, or mappings
+      // that are ADDING, but have expired message (OnSendError event lost), or
+      // for those mapped accounts that can be refreshed.
+      if (mappings_iter->status == AccountMapping::NEW ||
+          (mappings_iter->status == AccountMapping::ADDING &&
+           IsLastStatusChangeOlderThanTTL(*mappings_iter)) ||
+          (mappings_iter->status == AccountMapping::MAPPED &&
+           CanTriggerUpdate(mappings_iter->status_change_timestamp))) {
+        mappings_iter->last_message_id.clear();
+        SendAddMappingMessage(*mappings_iter);
+      }
+    }
+  }
+}
+
+void GCMAccountMapper::ShutdownHandler() {
+  gcm_driver_->RemoveAppHandler(kGCMAccountMapperAppId);
+}
+
+void GCMAccountMapper::OnMessage(const std::string& app_id,
+                                 const GCMClient::IncomingMessage& message) {
+  // Account message does not expect messages right now.
+}
+
+void GCMAccountMapper::OnMessagesDeleted(const std::string& app_id) {
+  // Account message does not expect messages right now.
+}
+
+void GCMAccountMapper::OnSendError(
+    const std::string& app_id,
+    const GCMClient::SendErrorDetails& send_error_details) {
+  DCHECK_EQ(app_id, kGCMAccountMapperAppId);
+
+  AccountMappings::iterator account_mapping_it =
+      FindMappingByMessageId(send_error_details.message_id);
+
+  if (account_mapping_it == accounts_.end())
+    return;
+
+  // TODO(fgorski): What other status can we get here if any? What should we do
+  // about that. (likely TTL_EXCEEDED is the only one)
+  DCHECK_EQ(send_error_details.result, GCMClient::TTL_EXCEEDED);
+
+  if (account_mapping_it->status == AccountMapping::REMOVING) {

[jianli, 2014/09/02 18:00:10]

It would be better to add the check for TTL_EXCEEDED in the if condition in case
that a different error is returned in a short time and we keep retrying.

[fgorski, 2014/09/03 21:37:02]

Done.

+    // Another message to remove mapping can be sent immediately, because TTL
+    // for those is one day. No need to back off.
+    SendRemoveMappingMessage(*account_mapping_it);
+  } else {
+    if (account_mapping_it->status == AccountMapping::ADDING) {
+      // There is no mapping established, so we can remove the entry.
+      // Getting a fresh token will trigger a new attempt.
+      gcm_driver_->RemoveAccountMapping(account_mapping_it->account_id);
+      accounts_.erase(account_mapping_it);
+    } else {
+      // Account is already MAPPED, we have to wait for another token.
+      account_mapping_it->last_message_id.clear();
+      gcm_driver_->UpdateAccountMapping(*account_mapping_it);
+    }
+  }
+}
+
+void GCMAccountMapper::OnSendAcknowledged(const std::string& app_id,
+                                          const std::string& message_id) {
+  DCHECK_EQ(app_id, kGCMAccountMapperAppId);
+  AccountMappings::iterator account_mapping_it =
+      FindMappingByMessageId(message_id);
+
+  DVLOG(1) << "OnSendAcknowledged with message ID: " << message_id;
+
+  if (account_mapping_it == accounts_.end())
+    return;
+
+  // Here is where we advance a status of a mapping and persist or remove.
+  if (account_mapping_it->status == AccountMapping::REMOVING) {
+    // Message removing the account has been confirmed by the GCM, we can remove
+    // all the information related to the account (from memory and store).
+    gcm_driver_->RemoveAccountMapping(account_mapping_it->account_id);
+    accounts_.erase(account_mapping_it);
+  } else {
+    // Mapping status is ADDING only when it is a first time mapping.
+    DCHECK(account_mapping_it->status == AccountMapping::ADDING ||
+           account_mapping_it->status == AccountMapping::MAPPED);
+
+    // Account is marked as mapped with the current time.
+    account_mapping_it->status = AccountMapping::MAPPED;
+    account_mapping_it->status_change_timestamp = clock_->Now();
+    // There is no pending message for the account.
+    account_mapping_it->last_message_id.clear();
+
+    gcm_driver_->UpdateAccountMapping(*account_mapping_it);
+  }
+}
+
+bool GCMAccountMapper::CanHandle(const std::string& app_id) const {
+  return app_id.compare(kGCMAccountMapperAppId) == 0;
+}
+
+void GCMAccountMapper::SendAddMappingMessage(AccountMapping& account_mapping) {
+  GCMClient::OutgoingMessage outgoing_message;
+  outgoing_message.id = GenerateMessageID();
+  outgoing_message.time_to_live = kGCMAddMappingMessageTTL;
+  outgoing_message.data[kRegistrationIdMessgaeKey] = registration_id_;
+  outgoing_message.data[kTokenMessageKey] = account_mapping.access_token;
+  outgoing_message.data[kAccountMessageKey] = account_mapping.email;
+
+  gcm_driver_->Send(kGCMAccountMapperAppId,
+                    kGCMAccountMapperSenderId,
+                    outgoing_message,
+                    base::Bind(&GCMAccountMapper::OnSendFinished,
+                               weak_ptr_factory_.GetWeakPtr(),
+                               account_mapping.account_id));
+}
+
+void GCMAccountMapper::SendRemoveMappingMessage(
+    AccountMapping& account_mapping) {
+  // We want to persist an account that is being removed as quickly as possible
+  // as well as clean up the last message information.
+  if (account_mapping.status != AccountMapping::REMOVING) {
+    account_mapping.status = AccountMapping::REMOVING;
+    account_mapping.status_change_timestamp = clock_->Now();
+  }
+
+  account_mapping.last_message_id.clear();
+
+  gcm_driver_->UpdateAccountMapping(account_mapping);
+
+  GCMClient::OutgoingMessage outgoing_message;
+  outgoing_message.id = GenerateMessageID();
+  outgoing_message.time_to_live = kGCMRemoveMappingMessageTTL;
+  outgoing_message.data[kRegistrationIdMessgaeKey] = registration_id_;
+  outgoing_message.data[kAccountMessageKey] = account_mapping.email;
+  outgoing_message.data[kRemoveAccountMessageKey] = kRemoveAccountMessageValue;

[jianli, 2014/09/02 18:00:10]

The code in line 241-254 is very similar to the code in line 215-227. Can we
merge the code into a function?

[fgorski, 2014/09/03 21:37:02]

Done.

+
+  gcm_driver_->Send(kGCMAccountMapperAppId,
+                    kGCMAccountMapperSenderId,
+                    outgoing_message,
+                    base::Bind(&GCMAccountMapper::OnSendFinished,
+                               weak_ptr_factory_.GetWeakPtr(),
+                               account_mapping.account_id));
+}
+
+void GCMAccountMapper::OnSendFinished(const std::string& account_id,
+                                      const std::string& message_id,
+                                      GCMClient::Result result) {
+  // TODO(fgorski): Add another attempt, in case the QUEUE is not full.
+  if (result != GCMClient::SUCCESS)
+    return;
+
+  AccountMapping* account_mapping = FindMappingByAccountId(account_id);
+  DCHECK(account_mapping);
+
+  // If we are dealing with account with status NEW, it is the first time
+  // mapping, and we should mark it as ADDING.
+  if (account_mapping->status == AccountMapping::NEW) {
+    account_mapping->status = AccountMapping::ADDING;
+    account_mapping->status_change_timestamp = clock_->Now();
+  }
+
+  account_mapping->last_message_id = message_id;
+
+  gcm_driver_->UpdateAccountMapping(*account_mapping);
+}
+
+bool GCMAccountMapper::CanTriggerUpdate(
+    const base::Time& last_update_time) const {
+  return last_update_time +
+             base::TimeDelta::FromHours(kGCMUpdateIntervalHours -
+                                        kGCMUpdateEarlyStartHours) <
+         clock_->Now();
+}
+
+bool GCMAccountMapper::IsLastStatusChangeOlderThanTTL(
+    const AccountMapping& account_mapping) const {
+  base::TimeDelta time_to_live;

[jianli, 2014/09/02 18:00:10]

Probably more efficient to say:
  int ttl_seconds = account_mapping.status == AccountMapping::REMOVING ?
kGCMRemoveMappingMessageTTL : kGCMAddMappingMessageTTL;
  return account_mapping.status_change_timestamp +
base::TimeDelta::FromSeconds(ttl_seconds) < clock_->Now();

If you decide to introduce a function for my comment above, you can also
consider adding a helper function like:
  int GetMessageTTL(... status) {
    return status == AccountMapping::REMOVING ? kGCMRemoveMappingMessageTTL :
kGCMAddMappingMessageTTL;
  }
Then you don't need the temporary variable here.

[fgorski, 2014/09/03 21:37:02]

Done.

+  if (account_mapping.status == AccountMapping::REMOVING)
+    time_to_live = base::TimeDelta::FromSeconds(kGCMRemoveMappingMessageTTL);
+  else
+    time_to_live = base::TimeDelta::FromSeconds(kGCMAddMappingMessageTTL);
+  return account_mapping.status_change_timestamp + time_to_live < clock_->Now();
+}
+
+AccountMapping* GCMAccountMapper::FindMappingByAccountId(
+    const std::string& account_id) {
+  for (AccountMappings::iterator iter = accounts_.begin();
+       iter != accounts_.end();
+       ++iter) {
+    if (iter->account_id == account_id)
+      return &*iter;
+  }
+
+  return NULL;
+}
+
+GCMAccountMapper::AccountMappings::iterator
+GCMAccountMapper::FindMappingByMessageId(const std::string& message_id) {
+  for (std::vector<AccountMapping>::iterator iter = accounts_.begin();
+       iter != accounts_.end();
+       ++iter) {
+    if (iter->last_message_id == message_id)
+      return iter;
+  }
+
+  return accounts_.end();
+}
+
+void GCMAccountMapper::SetClockForTesting(scoped_ptr<base::Clock> clock) {
+  clock_ = clock.Pass();
+}
+
+}  // namespace gcm