[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 kGCMAccountMapperMessageTTL = 60 * 60;  // 1 day in seconds.
+const int kGCMUpdateIntervalHours = 24;
+const int kGCMUpdateEarlyStartHours = 6;

[jianli, 2014/08/28 18:43:51]

Please comment on this.

[fgorski, 2014/08/29 02:29:17]

Done.

+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();
+    // Sending a message triggers a status change, this is a check if a message
+    // expired and a relevant event was missed.

[jianli, 2014/08/28 18:43:51]

What do you mean by "relevant event was missed"?

Also it seems to be that this piece of logic could be moved inside the 3rd for
loop in this method.

[fgorski, 2014/08/29 02:29:17]

Done.

+    if ((iter->status == AccountMapping::ADDING ||
+         iter->status == AccountMapping::REMOVING) &&
+        IsLastStatusChangeOlderThanTTL(iter->status_change_timestamp)) {
+      if (iter->status == AccountMapping::ADDING)
+        iter->status = AccountMapping::NEW;
+      iter->last_message_type = AccountMapping::MSG_NONE;
+      iter->last_message_id.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;
+      new_mapping.last_message_type = AccountMapping::MSG_NONE;
+      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->last_message_type == AccountMapping::MSG_REMOVE) {
+        account_mapping->status = AccountMapping::MAPPED;
+        account_mapping->status_change_timestamp = base::Time();
+        account_mapping->last_message_type = AccountMapping::MSG_NONE;
+        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()) {
+      if (mappings_iter->last_message_id.empty() ||

[jianli, 2014/08/28 18:43:50]

Please add comment saying something like:
  // No need to resend removing message if it has not expired.

[fgorski, 2014/08/29 02:29:17]

Done.

+          mappings_iter->last_message_type != AccountMapping::MSG_REMOVE) {
+        SendRemoveMappingMessage(*mappings_iter);
+      }
+    } else {
+      // A message is sent for all of the mappings considered NEW, or for those
+      // mapped accounts that are due for update.
+      if (mappings_iter->status == AccountMapping::NEW ||
+          (mappings_iter->status == AccountMapping::MAPPED &&
+           IsUpdateDue(mappings_iter->status_change_timestamp))) {
+        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->last_message_type == AccountMapping::MSG_REMOVE) {
+    SendRemoveMappingMessage(*account_mapping_it);

[jianli, 2014/08/28 18:43:51]

Do you mean keeping resending remove message when send error is encountered? If
so, it seems not to be good to do with without backoff.

[fgorski, 2014/08/29 02:29:17]

Done.

+  } else {
+    DCHECK_EQ(account_mapping_it->last_message_type, AccountMapping::MSG_ADD);
+    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();
+      account_mapping_it->last_message_type = AccountMapping::MSG_NONE;
+      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->last_message_type == AccountMapping::MSG_REMOVE) {
+    DCHECK_EQ(account_mapping_it->status, AccountMapping::REMOVING);

[jianli, 2014/08/28 18:43:51]

It seems to me that the mapping status could be found in 2 places: status and
last_message_type for certain status. This results in some additional code to
set and DCHECK for consistency. Why not just maintaining the state in one place:
status. We can just remove last_message_type.

In addition, it seems that we're not changing the status to REMOVED when the
remove message is ACKed (per the doc). Do we want to remove this enum state?

[fgorski, 2014/08/29 02:29:17]

REMOVED is removed. I am seeing if I can remove the MessageType

+    // 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 {
+    DCHECK_EQ(account_mapping_it->last_message_type, AccountMapping::MSG_ADD);
+    // 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_type = AccountMapping::MSG_NONE;
+    account_mapping_it->last_message_id.clear();
+
+    gcm_driver_->UpdateAccountMapping(*account_mapping_it);
+  }
+}
+
+void GCMAccountMapper::OnConnected(const net::IPEndPoint& ip_endpoint) {
+  // Account mapper ignores connection status.
+}
+
+void GCMAccountMapper::OnDisconnected() {
+  // Account mapper ignores connection status.
+}
+
+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 = kGCMAccountMapperMessageTTL;
+  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,
+                               AccountMapping::MSG_ADD));
+}
+
+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();
+  account_mapping.last_message_type = AccountMapping::MSG_NONE;
+
+  gcm_driver_->UpdateAccountMapping(account_mapping);
+
+  GCMClient::OutgoingMessage outgoing_message;
+  outgoing_message.id = GenerateMessageID();
+  outgoing_message.time_to_live = kGCMAccountMapperMessageTTL;
+  outgoing_message.data[kRegistrationIdMessgaeKey] = registration_id_;
+  outgoing_message.data[kAccountMessageKey] = account_mapping.email;
+  outgoing_message.data[kRemoveAccountMessageKey] = kRemoveAccountMessageValue;
+
+  gcm_driver_->Send(kGCMAccountMapperAppId,
+                    kGCMAccountMapperSenderId,
+                    outgoing_message,
+                    base::Bind(&GCMAccountMapper::OnSendFinished,
+                               weak_ptr_factory_.GetWeakPtr(),
+                               account_mapping.account_id,
+                               AccountMapping::MSG_REMOVE));
+}
+
+void GCMAccountMapper::OnSendFinished(const std::string& account_id,
+                                      AccountMapping::MessageType message_type,
+                                      const std::string& message_id,
+                                      GCMClient::Result result) {
+  // TODO(fgorski): Add another attempt, in case the QUEUE is not full.

[jianli, 2014/08/28 18:43:51]

remove "not"?

[fgorski, 2014/08/29 02:29:17]

I actually mean it. If the queue is full, no need to retry, as I'll be hitting
that over and over.

If there is other error, perhaps I should try.

+  if (result != GCMClient::SUCCESS)
+    return;
+
+  AccountMapping* account_mapping_it = FindMappingByAccountId(account_id);

[jianli, 2014/08/28 18:43:51]

Remove "_it" since it is not an iterator.

[fgorski, 2014/08/29 02:29:17]

Done.

+  DCHECK(account_mapping_it);
+
+  // 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_it->status == AccountMapping::NEW) {
+    DCHECK(message_type == AccountMapping::MSG_ADD);
+    account_mapping_it->status = AccountMapping::ADDING;
+    account_mapping_it->status_change_timestamp = clock_->Now();
+  }
+
+  account_mapping_it->last_message_type = message_type;
+  account_mapping_it->last_message_id = message_id;
+
+  gcm_driver_->UpdateAccountMapping(*account_mapping_it);
+}
+
+bool GCMAccountMapper::IsUpdateDue(const base::Time& last_update_time) const {
+  return last_update_time +
+             base::TimeDelta::FromHours(kGCMUpdateIntervalHours -
+                                        kGCMUpdateEarlyStartHours) <
+         clock_->Now();
+}
+
+bool GCMAccountMapper::IsLastStatusChangeOlderThanTTL(
+    const base::Time& estimated_send_time) const {
+  return estimated_send_time +
+             base::TimeDelta::FromSeconds(kGCMAccountMapperMessageTTL) <
+         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