[GCM] Fetching OAuth2 tokens periodically in account tracker

chrome/browser/services/gcm/gcm_account_tracker.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 "chrome/browser/services/gcm/gcm_account_tracker.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/time/time.h"
 #include "components/gcm_driver/gcm_driver.h"
 #include "google_apis/gaia/google_service_auth_error.h"
 #include "net/base/ip_endpoint.h"
 
 namespace gcm {
 
 namespace {
+
+// Scopes needed by the OAuth2 access tokens.
 const char kGCMGroupServerScope[] = "https://www.googleapis.com/auth/gcm";
 const char kGCMCheckinServerScope[] =
     "https://www.googleapis.com/auth/android_checkin";
+// Name of the GCM account tracker for the OAuth2TokenService.
 const char kGCMAccountTrackerName[] = "gcm_account_tracker";
+// Minimum token validity when sending to GCM groups server.
 const int64 kMinimumTokenValidityMs = 500;
+// Token fetching interval, when no account changes are detected.
+const int64 kTokenFetchingIntervalMs = 12 * 60 * 60 * 1000;  // 12 hours in ms.
+
 }  // namespace
 
 GCMAccountTracker::AccountInfo::AccountInfo(const std::string& email,
                                             AccountState state)
     : email(email), state(state) {
 }
 
 GCMAccountTracker::AccountInfo::~AccountInfo() {
 }
 
 GCMAccountTracker::GCMAccountTracker(
     scoped_ptr<gaia::AccountTracker> account_tracker,
     GCMDriver* driver)
     : OAuth2TokenService::Consumer(kGCMAccountTrackerName),
       account_tracker_(account_tracker.release()),
       driver_(driver),
-      shutdown_called_(false) {
+      shutdown_called_(false),
+      weak_ptr_factory_(this) {
 }
 
 GCMAccountTracker::~GCMAccountTracker() {
   DCHECK(shutdown_called_);
 }
 
 void GCMAccountTracker::Shutdown() {
   shutdown_called_ = true;
   driver_->RemoveConnectionObserver(this);
   account_tracker_->RemoveObserver(this);
   account_tracker_->Shutdown();
 }
 
 void GCMAccountTracker::Start() {
   DCHECK(!shutdown_called_);
   account_tracker_->AddObserver(this);
   driver_->AddConnectionObserver(this);
 
   std::vector<gaia::AccountIds> accounts = account_tracker_->GetAccounts();
-  if (accounts.empty()) {
-    CompleteCollectingTokens();
-    return;
-  }
-
   for (std::vector<gaia::AccountIds>::const_iterator iter = accounts.begin();
        iter != accounts.end();
        ++iter) {
     if (!iter->email.empty()) {
       account_infos_.insert(std::make_pair(
           iter->account_key, AccountInfo(iter->email, TOKEN_NEEDED)));
     }
   }
 
-  GetAllNeededTokens();
+  ScheduleFetchingTokens();
+}
+
+void GCMAccountTracker::ScheduleFetchingTokens() {
+  if (!IsTokenReportingRequired()) {
+    DVLOG(1) << "Deferring the token fetching for: "
+             << GetTimeToNextTokenFetching().InSeconds() << " seconds.";
+    base::MessageLoop::current()->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&GCMAccountTracker::ReportTokens,
+                   weak_ptr_factory_.GetWeakPtr()),
+        GetTimeToNextTokenFetching());
+    return;
+  }
+
+  DVLOG(1) << "Token fetching is due calling Complete immediately.";
+  ReportTokens();
 }
 
 void GCMAccountTracker::OnAccountAdded(const gaia::AccountIds& ids) {
   DVLOG(1) << "Account added: " << ids.email;
   // We listen for the account signing in, which happens after account is added.
 }
 
 void GCMAccountTracker::OnAccountRemoved(const gaia::AccountIds& ids) {
   DVLOG(1) << "Account removed: " << ids.email;
   // We listen for the account signing out, which happens before account is
@@ skipping 24 matching lines @@
     // If OnAccountSignedOut(..) was called most recently, account is kept in
     // ACCOUNT_REMOVED state.
     if (iter->second.state == GETTING_TOKEN) {
       iter->second.state = TOKEN_PRESENT;
       iter->second.access_token = access_token;
       iter->second.expiration_time = expiration_time;
     }
   }
 
   DeleteTokenRequest(request);
-  CompleteCollectingTokens();
+  ReportTokens();
 }
 
 void GCMAccountTracker::OnGetTokenFailure(
     const OAuth2TokenService::Request* request,
     const GoogleServiceAuthError& error) {
   DCHECK(request);
   DCHECK(!request->GetAccountId().empty());
   DVLOG(1) << "Get token failure: " << request->GetAccountId();
 
   AccountInfos::iterator iter = account_infos_.find(request->GetAccountId());
   DCHECK(iter != account_infos_.end());
   if (iter != account_infos_.end()) {
     DCHECK(iter->second.state == GETTING_TOKEN ||
            iter->second.state == ACCOUNT_REMOVED);
     // If OnAccountSignedOut(..) was called most recently, account is kept in
     // ACCOUNT_REMOVED state.
     if (iter->second.state == GETTING_TOKEN)
       iter->second.state = TOKEN_NEEDED;
   }
 
   DeleteTokenRequest(request);
-  CompleteCollectingTokens();
+  ReportTokens();
 }
 
 void GCMAccountTracker::OnConnected(const net::IPEndPoint& ip_endpoint) {
-  if (SanitizeTokens())
-    GetAllNeededTokens();
+  if (IsTokenReportingRequired())
+    ReportTokens();
 }
 
 void GCMAccountTracker::OnDisconnected() {
   // We are disconnected, so no point in trying to work with tokens.
 }
 
-void GCMAccountTracker::CompleteCollectingTokens() {
+void GCMAccountTracker::ReportTokens() {
+  SanitizeTokens();

[Nicolas Zea, 2014/11/06 21:43:17]

Why do we ignore the return value now and use IsTokenFetchingRequired instead?
Isn't that what SanitizeTokens returns?

Maybe we should just make SanitizeTokens a void method and update the comments?

[fgorski, 2014/11/07 01:42:12]

I think that was the comment we discussed with one of the previous patches. I
was meant to fix it. Thanks for the catch.

   // Make sure all tokens are valid.
-  if (SanitizeTokens()) {
+  if (IsTokenFetchingRequired()) {
     GetAllNeededTokens();
     return;
   }
 
   // Wait for gaia::AccountTracker to be done with fetching the user info, as
   // well as all of the pending token requests from GCMAccountTracker to be done
   // before you report the results.
   if (!account_tracker_->IsAllUserInfoFetched() ||
       !pending_token_requests_.empty()) {
     return;
@@ skipping 26 matching lines @@
       // pending requests above, stopping tracking of removed accounts, or start
       // fetching tokens.
       NOTREACHED();
     }
   }
 
   // Make sure that there is something to report, otherwise bail out.
   if (!account_tokens.empty() || account_removed) {
     DVLOG(1) << "Reporting the tokens to driver: " << account_tokens.size();
     driver_->SetAccountTokens(account_tokens);
+    driver_->SetLastTokenFetchTime(base::Time::Now());
+    weak_ptr_factory_.InvalidateWeakPtrs();
+    base::MessageLoop::current()->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&GCMAccountTracker::ReportTokens,
+                   weak_ptr_factory_.GetWeakPtr()),
+        GetTimeToNextTokenFetching());
   } else {
     DVLOG(1) << "No tokens and nothing removed. Skipping callback.";
   }
 }
 
 bool GCMAccountTracker::SanitizeTokens() {
   bool tokens_needed = false;
   for (AccountInfos::iterator iter = account_infos_.begin();
        iter != account_infos_.end();
        ++iter) {
     if (iter->second.state == TOKEN_PRESENT &&
         iter->second.expiration_time <
             base::Time::Now() +
                 base::TimeDelta::FromMilliseconds(kMinimumTokenValidityMs)) {
       iter->second.access_token.clear();
       iter->second.state = TOKEN_NEEDED;
       iter->second.expiration_time = base::Time();
     }
 
     if (iter->second.state == TOKEN_NEEDED)
       tokens_needed = true;
   }
 
   return tokens_needed;
 }
 
+bool GCMAccountTracker::IsTokenReportingRequired() const {
+  if (GetTimeToNextTokenFetching() == base::TimeDelta())
+    return true;
+
+  bool reporting_required = false;
+  for (AccountInfos::const_iterator iter = account_infos_.begin();
+       iter != account_infos_.end();
+       ++iter) {
+    if (iter->second.state == ACCOUNT_REMOVED)
+      reporting_required = true;
+  }
+
+  return reporting_required;
+}
+
+bool GCMAccountTracker::IsTokenFetchingRequired() const {
+  bool token_needed = false;
+  for (AccountInfos::const_iterator iter = account_infos_.begin();
+       iter != account_infos_.end();
+       ++iter) {
+    if (iter->second.state == TOKEN_NEEDED)
+      token_needed = true;
+  }
+
+  return token_needed;
+}
+
+base::TimeDelta GCMAccountTracker::GetTimeToNextTokenFetching() const {
+  base::TimeDelta time_till_next_fetching =
+      driver_->GetLastTokenFetchTime() +
+      base::TimeDelta::FromMilliseconds(kTokenFetchingIntervalMs) -
+      base::Time::Now();
+  return time_till_next_fetching < base::TimeDelta() ? base::TimeDelta()
+                                                     : time_till_next_fetching;
+}
+
 void GCMAccountTracker::DeleteTokenRequest(
     const OAuth2TokenService::Request* request) {
   ScopedVector<OAuth2TokenService::Request>::iterator iter = std::find(
       pending_token_requests_.begin(), pending_token_requests_.end(), request);
   if (iter != pending_token_requests_.end())
     pending_token_requests_.erase(iter);
 }
 
 void GCMAccountTracker::GetAllNeededTokens() {
   // Only start fetching tokens if driver is running, they have a limited
   // validity time and GCM connection is a good indication of network running.
+  // If the GetAllNeededTokens was called as part of periodic schedule, it may
+  // not have network. In that case the next network change will trigger token
+  // fetching.

[Nicolas Zea, 2014/11/06 21:43:17]

What code is listening to the network change?

[fgorski, 2014/11/07 01:42:12]

Lines 162:169 above.

   if (!driver_->IsConnected())
     return;
 
   for (AccountInfos::iterator iter = account_infos_.begin();
        iter != account_infos_.end();
        ++iter) {
     if (iter->second.state == TOKEN_NEEDED)
       GetToken(iter);
   }
 }
@@ skipping 27 matching lines @@
 }
 
 void GCMAccountTracker::OnAccountSignedOut(const gaia::AccountIds& ids) {
   DVLOG(1) << "Account signed out: " << ids.email;
   AccountInfos::iterator iter = account_infos_.find(ids.account_key);
   if (iter == account_infos_.end())
     return;
 
   iter->second.access_token.clear();
   iter->second.state = ACCOUNT_REMOVED;
-  CompleteCollectingTokens();
+  ReportTokens();
 }
 
 OAuth2TokenService* GCMAccountTracker::GetTokenService() {
   DCHECK(account_tracker_->identity_provider());
   return account_tracker_->identity_provider()->GetTokenService();
 }
 
 }  // namespace gcm