google_apis/gaia/oauth2_token_service.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "google_apis/gaia/oauth2_token_service.h"
   6
   7 #include <vector>
   8
   9 #include "base/bind.h"
  10 #include "base/memory/weak_ptr.h"
  11 #include "base/message_loop/message_loop.h"
  12 #include "base/rand_util.h"
  13 #include "base/stl_util.h"
  14 #include "base/time/time.h"
  15 #include "base/timer/timer.h"
  16 #include "google_apis/gaia/gaia_urls.h"
  17 #include "google_apis/gaia/google_service_auth_error.h"
  18 #include "google_apis/gaia/oauth2_access_token_fetcher_impl.h"
  19 #include "net/url_request/url_request_context_getter.h"
  20
  21 int OAuth2TokenService::max_fetch_retry_num_ = 5;
  22
  23 OAuth2TokenService::RequestParameters::RequestParameters(
  24     const std::string& client_id,
  25     const std::string& account_id,
  26     const ScopeSet& scopes)
  27     : client_id(client_id),
  28       account_id(account_id),
  29       scopes(scopes) {
  30 }
  31
  32 OAuth2TokenService::RequestParameters::~RequestParameters() {
  33 }
  34
  35 bool OAuth2TokenService::RequestParameters::operator<(
  36     const RequestParameters& p) const {
  37   if (client_id < p.client_id)
  38     return true;
  39   else if (p.client_id < client_id)
  40     return false;
  41
  42   if (account_id < p.account_id)
  43     return true;
  44   else if (p.account_id < account_id)
  45     return false;
  46
  47   return scopes < p.scopes;
  48 }
  49
  50 OAuth2TokenService::RequestImpl::RequestImpl(
  51     const std::string& account_id,
  52     OAuth2TokenService::Consumer* consumer)
  53     : account_id_(account_id),
  54       consumer_(consumer) {
  55 }
  56
  57 OAuth2TokenService::RequestImpl::~RequestImpl() {
  58   DCHECK(CalledOnValidThread());
  59 }
  60
  61 std::string OAuth2TokenService::RequestImpl::GetAccountId() const {
  62   return account_id_;
  63 }
  64
  65 std::string OAuth2TokenService::RequestImpl::GetConsumerId() const {
  66   return consumer_->id();
  67 }
  68
  69 void OAuth2TokenService::RequestImpl::InformConsumer(
  70     const GoogleServiceAuthError& error,
  71     const std::string& access_token,
  72     const base::Time& expiration_date) {
  73   DCHECK(CalledOnValidThread());
  74   if (error.state() == GoogleServiceAuthError::NONE)
  75     consumer_->OnGetTokenSuccess(this, access_token, expiration_date);
  76   else
  77     consumer_->OnGetTokenFailure(this, error);
  78 }
  79
  80 OAuth2TokenService::ScopedBacthChange::ScopedBacthChange(
  81     OAuth2TokenService* token_service) : token_service_(token_service) {
  82   DCHECK(token_service_);
  83   token_service_->StartBatchChanges();
  84 }
  85
  86 OAuth2TokenService::ScopedBacthChange::~ScopedBacthChange() {
  87   token_service_->EndBatchChanges();
  88 }
  89
  90 // Class that fetches an OAuth2 access token for a given account id and set of
  91 // scopes.
  92 //
  93 // It aims to meet OAuth2TokenService's requirements on token fetching. Retry
  94 // mechanism is used to handle failures.
  95 //
  96 // To use this class, call CreateAndStart() to create and start a Fetcher.
  97 //
  98 // The Fetcher will call back the service by calling
  99 // OAuth2TokenService::OnFetchComplete() when it completes fetching, if it is
 100 // not destructed before it completes fetching; if the Fetcher is destructed
 101 // before it completes fetching, the service will never be called back. The
 102 // Fetcher destructs itself after calling back the service when finishes
 103 // fetching.
 104 //
 105 // Requests that are waiting for the fetching results of this Fetcher can be
 106 // added to the Fetcher by calling
 107 // OAuth2TokenService::Fetcher::AddWaitingRequest() before the Fetcher
 108 // completes fetching.
 109 //
 110 // The waiting requests are taken as weak pointers and they can be deleted.
 111 // The waiting requests will be called back with fetching results if they are
 112 // not deleted
 113 // - when the Fetcher completes fetching, if the Fetcher is not destructed
 114 //   before it completes fetching, or
 115 // - when the Fetcher is destructed if the Fetcher is destructed before it
 116 //   completes fetching (in this case, the waiting requests will be called
 117 //   back with error).
 118 class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
 119  public:
 120   // Creates a Fetcher and starts fetching an OAuth2 access token for
 121   // |account_id| and |scopes| in the request context obtained by |getter|.
 122   // The given |oauth2_token_service| will be informed when fetching is done.
 123   static Fetcher* CreateAndStart(OAuth2TokenService* oauth2_token_service,
 124                                  const std::string& account_id,
 125                                  net::URLRequestContextGetter* getter,
 126                                  const std::string& client_id,
 127                                  const std::string& client_secret,
 128                                  const ScopeSet& scopes,
 129                                  base::WeakPtr<RequestImpl> waiting_request);
 130   virtual ~Fetcher();
 131
 132   // Add a request that is waiting for the result of this Fetcher.
 133   void AddWaitingRequest(base::WeakPtr<RequestImpl> waiting_request);
 134
 135   // Returns count of waiting requests.
 136   size_t GetWaitingRequestCount() const;
 137
 138   const std::vector<base::WeakPtr<RequestImpl> >& waiting_requests() const {
 139     return waiting_requests_;
 140   }
 141
 142   void Cancel();
 143
 144   const ScopeSet& GetScopeSet() const;
 145   const std::string& GetClientId() const;
 146   const std::string& GetAccountId() const;
 147
 148   // The error result from this fetcher.
 149   const GoogleServiceAuthError& error() const { return error_; }
 150
 151  protected:
 152    // OAuth2AccessTokenConsumer
 153   virtual void OnGetTokenSuccess(const std::string& access_token,
 154                                  const base::Time& expiration_date) OVERRIDE;
 155   virtual void OnGetTokenFailure(
 156       const GoogleServiceAuthError& error) OVERRIDE;
 157
 158  private:
 159   Fetcher(OAuth2TokenService* oauth2_token_service,
 160           const std::string& account_id,
 161           net::URLRequestContextGetter* getter,
 162           const std::string& client_id,
 163           const std::string& client_secret,
 164           const OAuth2TokenService::ScopeSet& scopes,
 165           base::WeakPtr<RequestImpl> waiting_request);
 166   void Start();
 167   void InformWaitingRequests();
 168   void InformWaitingRequestsAndDelete();
 169   static bool ShouldRetry(const GoogleServiceAuthError& error);
 170   int64 ComputeExponentialBackOffMilliseconds(int retry_num);
 171
 172   // |oauth2_token_service_| remains valid for the life of this Fetcher, since
 173   // this Fetcher is destructed in the dtor of the OAuth2TokenService or is
 174   // scheduled for deletion at the end of OnGetTokenFailure/OnGetTokenSuccess
 175   // (whichever comes first).
 176   OAuth2TokenService* const oauth2_token_service_;
 177   scoped_refptr<net::URLRequestContextGetter> getter_;
 178   const std::string account_id_;
 179   const ScopeSet scopes_;
 180   std::vector<base::WeakPtr<RequestImpl> > waiting_requests_;
 181
 182   int retry_number_;
 183   base::OneShotTimer<Fetcher> retry_timer_;
 184   scoped_ptr<OAuth2AccessTokenFetcher> fetcher_;
 185
 186   // Variables that store fetch results.
 187   // Initialized to be GoogleServiceAuthError::SERVICE_UNAVAILABLE to handle
 188   // destruction.
 189   GoogleServiceAuthError error_;
 190   std::string access_token_;
 191   base::Time expiration_date_;
 192
 193   // OAuth2 client id and secret.
 194   std::string client_id_;
 195   std::string client_secret_;
 196
 197   DISALLOW_COPY_AND_ASSIGN(Fetcher);
 198 };
 199
 200 // static
 201 OAuth2TokenService::Fetcher* OAuth2TokenService::Fetcher::CreateAndStart(
 202     OAuth2TokenService* oauth2_token_service,
 203     const std::string& account_id,
 204     net::URLRequestContextGetter* getter,
 205     const std::string& client_id,
 206     const std::string& client_secret,
 207     const OAuth2TokenService::ScopeSet& scopes,
 208     base::WeakPtr<RequestImpl> waiting_request) {
 209   OAuth2TokenService::Fetcher* fetcher = new Fetcher(
 210       oauth2_token_service,
 211       account_id,
 212       getter,
 213       client_id,
 214       client_secret,
 215       scopes,
 216       waiting_request);
 217   fetcher->Start();
 218   return fetcher;
 219 }
 220
 221 OAuth2TokenService::Fetcher::Fetcher(
 222     OAuth2TokenService* oauth2_token_service,
 223     const std::string& account_id,
 224     net::URLRequestContextGetter* getter,
 225     const std::string& client_id,
 226     const std::string& client_secret,
 227     const OAuth2TokenService::ScopeSet& scopes,
 228     base::WeakPtr<RequestImpl> waiting_request)
 229     : oauth2_token_service_(oauth2_token_service),
 230       getter_(getter),
 231       account_id_(account_id),
 232       scopes_(scopes),
 233       retry_number_(0),
 234       error_(GoogleServiceAuthError::SERVICE_UNAVAILABLE),
 235       client_id_(client_id),
 236       client_secret_(client_secret) {
 237   DCHECK(oauth2_token_service_);
 238   waiting_requests_.push_back(waiting_request);
 239 }
 240
 241 OAuth2TokenService::Fetcher::~Fetcher() {
 242   // Inform the waiting requests if it has not done so.
 243   if (waiting_requests_.size())
 244     InformWaitingRequests();
 245 }
 246
 247 void OAuth2TokenService::Fetcher::Start() {
 248   fetcher_.reset(oauth2_token_service_->CreateAccessTokenFetcher(
 249       account_id_, getter_.get(), this));
 250   DCHECK(fetcher_);
 251   fetcher_->Start(client_id_,
 252                   client_secret_,
 253                   std::vector<std::string>(scopes_.begin(), scopes_.end()));
 254   retry_timer_.Stop();
 255 }
 256
 257 void OAuth2TokenService::Fetcher::OnGetTokenSuccess(
 258     const std::string& access_token,
 259     const base::Time& expiration_date) {
 260   fetcher_.reset();
 261
 262   // Fetch completes.
 263   error_ = GoogleServiceAuthError::AuthErrorNone();
 264   access_token_ = access_token;
 265   expiration_date_ = expiration_date;
 266
 267   // Subclasses may override this method to skip caching in some cases, but
 268   // we still inform all waiting Consumers of a successful token fetch below.
 269   // This is intentional -- some consumers may need the token for cleanup
 270   // tasks. https://chromiumcodereview.appspot.com/11312124/
 271   oauth2_token_service_->RegisterCacheEntry(client_id_,
 272                                             account_id_,
 273                                             scopes_,
 274                                             access_token_,
 275                                             expiration_date_);
 276   InformWaitingRequestsAndDelete();
 277 }
 278
 279 void OAuth2TokenService::Fetcher::OnGetTokenFailure(
 280     const GoogleServiceAuthError& error) {
 281   fetcher_.reset();
 282
 283   if (ShouldRetry(error) && retry_number_ < max_fetch_retry_num_) {
 284     base::TimeDelta backoff = base::TimeDelta::FromMilliseconds(
 285         ComputeExponentialBackOffMilliseconds(retry_number_));
 286     ++retry_number_;
 287     retry_timer_.Stop();
 288     retry_timer_.Start(FROM_HERE,
 289                        backoff,
 290                        this,
 291                        &OAuth2TokenService::Fetcher::Start);
 292     return;
 293   }
 294
 295   error_ = error;
 296   InformWaitingRequestsAndDelete();
 297 }
 298
 299 // Returns an exponential backoff in milliseconds including randomness less than
 300 // 1000 ms when retrying fetching an OAuth2 access token.
 301 int64 OAuth2TokenService::Fetcher::ComputeExponentialBackOffMilliseconds(
 302     int retry_num) {
 303   DCHECK(retry_num < max_fetch_retry_num_);
 304   int64 exponential_backoff_in_seconds = 1 << retry_num;
 305   // Returns a backoff with randomness < 1000ms
 306   return (exponential_backoff_in_seconds + base::RandDouble()) * 1000;
 307 }
 308
 309 // static
 310 bool OAuth2TokenService::Fetcher::ShouldRetry(
 311     const GoogleServiceAuthError& error) {
 312   GoogleServiceAuthError::State error_state = error.state();
 313   return error_state == GoogleServiceAuthError::CONNECTION_FAILED ||
 314          error_state == GoogleServiceAuthError::REQUEST_CANCELED ||
 315          error_state == GoogleServiceAuthError::SERVICE_UNAVAILABLE;
 316 }
 317
 318 void OAuth2TokenService::Fetcher::InformWaitingRequests() {
 319   std::vector<base::WeakPtr<RequestImpl> >::const_iterator iter =
 320       waiting_requests_.begin();
 321   for (; iter != waiting_requests_.end(); ++iter) {
 322     base::WeakPtr<RequestImpl> waiting_request = *iter;
 323     if (waiting_request.get())
 324       waiting_request->InformConsumer(error_, access_token_, expiration_date_);
 325   }
 326   waiting_requests_.clear();
 327 }
 328
 329 void OAuth2TokenService::Fetcher::InformWaitingRequestsAndDelete() {
 330   // Deregisters itself from the service to prevent more waiting requests to
 331   // be added when it calls back the waiting requests.
 332   oauth2_token_service_->OnFetchComplete(this);
 333   InformWaitingRequests();
 334   base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 335 }
 336
 337 void OAuth2TokenService::Fetcher::AddWaitingRequest(
 338     base::WeakPtr<OAuth2TokenService::RequestImpl> waiting_request) {
 339   waiting_requests_.push_back(waiting_request);
 340 }
 341
 342 size_t OAuth2TokenService::Fetcher::GetWaitingRequestCount() const {
 343   return waiting_requests_.size();
 344 }
 345
 346 void OAuth2TokenService::Fetcher::Cancel() {
 347   if (fetcher_)
 348     fetcher_->CancelRequest();
 349   fetcher_.reset();
 350   retry_timer_.Stop();
 351   error_ = GoogleServiceAuthError(GoogleServiceAuthError::REQUEST_CANCELED);
 352   InformWaitingRequestsAndDelete();
 353 }
 354
 355 const OAuth2TokenService::ScopeSet& OAuth2TokenService::Fetcher::GetScopeSet()
 356     const {
 357   return scopes_;
 358 }
 359
 360 const std::string& OAuth2TokenService::Fetcher::GetClientId() const {
 361   return client_id_;
 362 }
 363
 364 const std::string& OAuth2TokenService::Fetcher::GetAccountId() const {
 365   return account_id_;
 366 }
 367
 368 OAuth2TokenService::Request::Request() {
 369 }
 370
 371 OAuth2TokenService::Request::~Request() {
 372 }
 373
 374 OAuth2TokenService::Consumer::Consumer(const std::string& id)
 375     : id_(id) {}
 376
 377 OAuth2TokenService::Consumer::~Consumer() {
 378 }
 379
 380 OAuth2TokenService::OAuth2TokenService() : batch_change_depth_(0) {
 381 }
 382
 383 OAuth2TokenService::~OAuth2TokenService() {
 384   // Release all the pending fetchers.
 385   STLDeleteContainerPairSecondPointers(
 386       pending_fetchers_.begin(), pending_fetchers_.end());
 387 }
 388
 389 void OAuth2TokenService::AddObserver(Observer* observer) {
 390   observer_list_.AddObserver(observer);
 391 }
 392
 393 void OAuth2TokenService::RemoveObserver(Observer* observer) {
 394   observer_list_.RemoveObserver(observer);
 395 }
 396
 397 void OAuth2TokenService::AddDiagnosticsObserver(DiagnosticsObserver* observer) {
 398   diagnostics_observer_list_.AddObserver(observer);
 399 }
 400
 401 void OAuth2TokenService::RemoveDiagnosticsObserver(
 402     DiagnosticsObserver* observer) {
 403   diagnostics_observer_list_.RemoveObserver(observer);
 404 }
 405
 406 std::vector<std::string> OAuth2TokenService::GetAccounts() {
 407   return std::vector<std::string>();
 408 }
 409
 410 scoped_ptr<OAuth2TokenService::Request> OAuth2TokenService::StartRequest(
 411     const std::string& account_id,
 412     const OAuth2TokenService::ScopeSet& scopes,
 413     OAuth2TokenService::Consumer* consumer) {
 414   return StartRequestForClientWithContext(
 415       account_id,
 416       GetRequestContext(),
 417       GaiaUrls::GetInstance()->oauth2_chrome_client_id(),
 418       GaiaUrls::GetInstance()->oauth2_chrome_client_secret(),
 419       scopes,
 420       consumer);
 421 }
 422
 423 scoped_ptr<OAuth2TokenService::Request>
 424 OAuth2TokenService::StartRequestForClient(
 425     const std::string& account_id,
 426     const std::string& client_id,
 427     const std::string& client_secret,
 428     const OAuth2TokenService::ScopeSet& scopes,
 429     OAuth2TokenService::Consumer* consumer) {
 430   return StartRequestForClientWithContext(
 431       account_id,
 432       GetRequestContext(),
 433       client_id,
 434       client_secret,
 435       scopes,
 436       consumer);
 437 }
 438
 439 scoped_ptr<OAuth2TokenService::Request>
 440 OAuth2TokenService::StartRequestWithContext(
 441     const std::string& account_id,
 442     net::URLRequestContextGetter* getter,
 443     const ScopeSet& scopes,
 444     Consumer* consumer) {
 445   return StartRequestForClientWithContext(
 446       account_id,
 447       getter,
 448       GaiaUrls::GetInstance()->oauth2_chrome_client_id(),
 449       GaiaUrls::GetInstance()->oauth2_chrome_client_secret(),
 450       scopes,
 451       consumer);
 452 }
 453
 454 scoped_ptr<OAuth2TokenService::Request>
 455 OAuth2TokenService::StartRequestForClientWithContext(
 456     const std::string& account_id,
 457     net::URLRequestContextGetter* getter,
 458     const std::string& client_id,
 459     const std::string& client_secret,
 460     const ScopeSet& scopes,
 461     Consumer* consumer) {
 462   DCHECK(CalledOnValidThread());
 463
 464   scoped_ptr<RequestImpl> request(new RequestImpl(account_id, consumer));
 465   FOR_EACH_OBSERVER(DiagnosticsObserver, diagnostics_observer_list_,
 466                     OnAccessTokenRequested(account_id,
 467                                            consumer->id(),
 468                                            scopes));
 469
 470   if (!RefreshTokenIsAvailable(account_id)) {
 471     GoogleServiceAuthError error(GoogleServiceAuthError::USER_NOT_SIGNED_UP);
 472
 473     FOR_EACH_OBSERVER(DiagnosticsObserver, diagnostics_observer_list_,
 474                       OnFetchAccessTokenComplete(
 475                           account_id, consumer->id(), scopes, error,
 476                           base::Time()));
 477
 478     base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
 479         &RequestImpl::InformConsumer,
 480         request->AsWeakPtr(),
 481         error,
 482         std::string(),
 483         base::Time()));
 484     return request.PassAs<Request>();
 485   }
 486
 487   RequestParameters request_parameters(client_id,
 488                                        account_id,
 489                                        scopes);
 490   if (HasCacheEntry(request_parameters)) {
 491     StartCacheLookupRequest(request.get(), request_parameters, consumer);
 492   } else {
 493     FetchOAuth2Token(request.get(),
 494                      account_id,
 495                      getter,
 496                      client_id,
 497                      client_secret,
 498                      scopes);
 499   }
 500   return request.PassAs<Request>();
 501 }
 502
 503 void OAuth2TokenService::FetchOAuth2Token(RequestImpl* request,
 504                                           const std::string& account_id,
 505                                           net::URLRequestContextGetter* getter,
 506                                           const std::string& client_id,
 507                                           const std::string& client_secret,
 508                                           const ScopeSet& scopes) {
 509   // If there is already a pending fetcher for |scopes| and |account_id|,
 510   // simply register this |request| for those results rather than starting
 511   // a new fetcher.
 512   RequestParameters request_parameters = RequestParameters(client_id,
 513                                                            account_id,
 514                                                            scopes);
 515   std::map<RequestParameters, Fetcher*>::iterator iter =
 516       pending_fetchers_.find(request_parameters);
 517   if (iter != pending_fetchers_.end()) {
 518     iter->second->AddWaitingRequest(request->AsWeakPtr());
 519     return;
 520   }
 521
 522   pending_fetchers_[request_parameters] =
 523       Fetcher::CreateAndStart(this,
 524                               account_id,
 525                               getter,
 526                               client_id,
 527                               client_secret,
 528                               scopes,
 529                               request->AsWeakPtr());
 530 }
 531
 532 void OAuth2TokenService::StartCacheLookupRequest(
 533     RequestImpl* request,
 534     const OAuth2TokenService::RequestParameters& request_parameters,
 535     OAuth2TokenService::Consumer* consumer) {
 536   CHECK(HasCacheEntry(request_parameters));
 537   const CacheEntry* cache_entry = GetCacheEntry(request_parameters);
 538   FOR_EACH_OBSERVER(DiagnosticsObserver, diagnostics_observer_list_,
 539                     OnFetchAccessTokenComplete(
 540                         request_parameters.account_id,
 541                         consumer->id(),
 542                         request_parameters.scopes,
 543                         GoogleServiceAuthError::AuthErrorNone(),
 544                         cache_entry->expiration_date));
 545   base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
 546       &RequestImpl::InformConsumer,
 547       request->AsWeakPtr(),
 548       GoogleServiceAuthError(GoogleServiceAuthError::NONE),
 549       cache_entry->access_token,
 550       cache_entry->expiration_date));
 551 }
 552
 553 void OAuth2TokenService::InvalidateToken(const std::string& account_id,
 554                                          const ScopeSet& scopes,
 555                                          const std::string& access_token) {
 556   InvalidateOAuth2Token(account_id,
 557                         GaiaUrls::GetInstance()->oauth2_chrome_client_id(),
 558                         scopes,
 559                         access_token);
 560 }
 561
 562 void OAuth2TokenService::InvalidateTokenForClient(
 563     const std::string& account_id,
 564     const std::string& client_id,
 565     const ScopeSet& scopes,
 566     const std::string& access_token) {
 567   InvalidateOAuth2Token(account_id, client_id, scopes, access_token);
 568 }
 569
 570 void OAuth2TokenService::InvalidateOAuth2Token(
 571     const std::string& account_id,
 572     const std::string& client_id,
 573     const ScopeSet& scopes,
 574     const std::string& access_token) {
 575   DCHECK(CalledOnValidThread());
 576   RemoveCacheEntry(
 577       RequestParameters(client_id,
 578                         account_id,
 579                         scopes),
 580       access_token);
 581 }
 582
 583 void OAuth2TokenService::OnFetchComplete(Fetcher* fetcher) {
 584   DCHECK(CalledOnValidThread());
 585
 586   // Update the auth error state so auth errors are appropriately communicated
 587   // to the user.
 588   UpdateAuthError(fetcher->GetAccountId(), fetcher->error());
 589
 590   // Note |fetcher| is recorded in |pending_fetcher_| mapped to its refresh
 591   // token and scope set. This is guaranteed as follows; here a Fetcher is said
 592   // to be uncompleted if it has not finished calling back
 593   // OAuth2TokenService::OnFetchComplete().
 594   //
 595   // (1) All the live Fetchers are created by this service.
 596   //     This is because (1) all the live Fetchers are created by a live
 597   //     service, as all the fetchers created by a service are destructed in the
 598   //     service's dtor.
 599   //
 600   // (2) All the uncompleted Fetchers created by this service are recorded in
 601   //     |pending_fetchers_|.
 602   //     This is because (1) all the created Fetchers are added to
 603   //     |pending_fetchers_| (in method StartRequest()) and (2) method
 604   //     OnFetchComplete() is the only place where a Fetcher is erased from
 605   //     |pending_fetchers_|. Note no Fetcher is erased in method
 606   //     StartRequest().
 607   //
 608   // (3) Each of the Fetchers recorded in |pending_fetchers_| is mapped to its
 609   //     refresh token and ScopeSet. This is guaranteed by Fetcher creation in
 610   //     method StartRequest().
 611   //
 612   // When this method is called, |fetcher| is alive and uncompleted.
 613   // By (1), |fetcher| is created by this service.
 614   // Then by (2), |fetcher| is recorded in |pending_fetchers_|.
 615   // Then by (3), |fetcher_| is mapped to its refresh token and ScopeSet.
 616   RequestParameters request_param(fetcher->GetClientId(),
 617                                   fetcher->GetAccountId(),
 618                                   fetcher->GetScopeSet());
 619
 620   const OAuth2TokenService::CacheEntry* entry = GetCacheEntry(request_param);
 621   const std::vector<base::WeakPtr<RequestImpl> >& requests =
 622       fetcher->waiting_requests();
 623   for (size_t i = 0; i < requests.size(); ++i) {
 624     const RequestImpl* req = requests[i].get();
 625     if (req) {
 626       FOR_EACH_OBSERVER(DiagnosticsObserver, diagnostics_observer_list_,
 627                         OnFetchAccessTokenComplete(
 628                             req->GetAccountId(), req->GetConsumerId(),
 629                             fetcher->GetScopeSet(), fetcher->error(),
 630                             entry ? entry->expiration_date : base::Time()));
 631     }
 632   }
 633
 634   std::map<RequestParameters, Fetcher*>::iterator iter =
 635     pending_fetchers_.find(request_param);
 636   DCHECK(iter != pending_fetchers_.end());
 637   DCHECK_EQ(fetcher, iter->second);
 638   pending_fetchers_.erase(iter);
 639 }
 640
 641 bool OAuth2TokenService::HasCacheEntry(
 642     const RequestParameters& request_parameters) {
 643   const CacheEntry* cache_entry = GetCacheEntry(request_parameters);
 644   return cache_entry && cache_entry->access_token.length();
 645 }
 646
 647 const OAuth2TokenService::CacheEntry* OAuth2TokenService::GetCacheEntry(
 648     const RequestParameters& request_parameters) {
 649   DCHECK(CalledOnValidThread());
 650   TokenCache::iterator token_iterator = token_cache_.find(request_parameters);
 651   if (token_iterator == token_cache_.end())
 652     return NULL;
 653   if (token_iterator->second.expiration_date <= base::Time::Now()) {
 654     token_cache_.erase(token_iterator);
 655     return NULL;
 656   }
 657   return &token_iterator->second;
 658 }
 659
 660 bool OAuth2TokenService::RemoveCacheEntry(
 661     const RequestParameters& request_parameters,
 662     const std::string& token_to_remove) {
 663   DCHECK(CalledOnValidThread());
 664   TokenCache::iterator token_iterator = token_cache_.find(request_parameters);
 665   if (token_iterator != token_cache_.end() &&
 666       token_iterator->second.access_token == token_to_remove) {
 667     FOR_EACH_OBSERVER(DiagnosticsObserver, diagnostics_observer_list_,
 668                       OnTokenRemoved(request_parameters.account_id,
 669                                      request_parameters.scopes));
 670     token_cache_.erase(token_iterator);
 671     return true;
 672   }
 673   return false;
 674 }
 675
 676 void OAuth2TokenService::RegisterCacheEntry(
 677     const std::string& client_id,
 678     const std::string& account_id,
 679     const OAuth2TokenService::ScopeSet& scopes,
 680     const std::string& access_token,
 681     const base::Time& expiration_date) {
 682   DCHECK(CalledOnValidThread());
 683
 684   CacheEntry& token = token_cache_[RequestParameters(client_id,
 685                                                      account_id,
 686                                                      scopes)];
 687   token.access_token = access_token;
 688   token.expiration_date = expiration_date;
 689 }
 690
 691 void OAuth2TokenService::UpdateAuthError(
 692     const std::string& account_id,
 693     const GoogleServiceAuthError& error) {
 694   // Default implementation does nothing.
 695 }
 696
 697 void OAuth2TokenService::ClearCache() {
 698   DCHECK(CalledOnValidThread());
 699   for (TokenCache::iterator iter = token_cache_.begin();
 700        iter != token_cache_.end(); ++iter) {
 701     FOR_EACH_OBSERVER(DiagnosticsObserver, diagnostics_observer_list_,
 702                       OnTokenRemoved(iter->first.account_id,
 703                                      iter->first.scopes));
 704   }
 705
 706   token_cache_.clear();
 707 }
 708
 709 void OAuth2TokenService::ClearCacheForAccount(const std::string& account_id) {
 710   DCHECK(CalledOnValidThread());
 711   for (TokenCache::iterator iter = token_cache_.begin();
 712        iter != token_cache_.end();
 713        /* iter incremented in body */) {
 714     if (iter->first.account_id == account_id) {
 715       FOR_EACH_OBSERVER(DiagnosticsObserver, diagnostics_observer_list_,
 716                         OnTokenRemoved(account_id, iter->first.scopes));
 717       token_cache_.erase(iter++);
 718     } else {
 719       ++iter;
 720     }
 721   }
 722 }
 723
 724 void OAuth2TokenService::CancelAllRequests() {
 725   std::vector<Fetcher*> fetchers_to_cancel;
 726   for (std::map<RequestParameters, Fetcher*>::iterator iter =
 727            pending_fetchers_.begin();
 728        iter != pending_fetchers_.end();
 729        ++iter) {
 730     fetchers_to_cancel.push_back(iter->second);
 731   }
 732   CancelFetchers(fetchers_to_cancel);
 733 }
 734
 735 void OAuth2TokenService::CancelRequestsForAccount(
 736     const std::string& account_id) {
 737   std::vector<Fetcher*> fetchers_to_cancel;
 738   for (std::map<RequestParameters, Fetcher*>::iterator iter =
 739            pending_fetchers_.begin();
 740        iter != pending_fetchers_.end();
 741        ++iter) {
 742     if (iter->first.account_id == account_id)
 743       fetchers_to_cancel.push_back(iter->second);
 744   }
 745   CancelFetchers(fetchers_to_cancel);
 746 }
 747
 748 void OAuth2TokenService::CancelFetchers(
 749     std::vector<Fetcher*> fetchers_to_cancel) {
 750   for (std::vector<OAuth2TokenService::Fetcher*>::iterator iter =
 751            fetchers_to_cancel.begin();
 752        iter != fetchers_to_cancel.end();
 753        ++iter) {
 754     (*iter)->Cancel();
 755   }
 756 }
 757
 758 void OAuth2TokenService::FireRefreshTokenAvailable(
 759     const std::string& account_id) {
 760   FOR_EACH_OBSERVER(Observer, observer_list_,
 761                     OnRefreshTokenAvailable(account_id));
 762 }
 763
 764 void OAuth2TokenService::FireRefreshTokenRevoked(
 765     const std::string& account_id) {
 766   FOR_EACH_OBSERVER(Observer, observer_list_,
 767                     OnRefreshTokenRevoked(account_id));
 768 }
 769
 770 void OAuth2TokenService::FireRefreshTokensLoaded() {
 771   FOR_EACH_OBSERVER(Observer, observer_list_, OnRefreshTokensLoaded());
 772 }
 773
 774 void OAuth2TokenService::StartBatchChanges() {
 775   ++batch_change_depth_;
 776   if (batch_change_depth_ == 1)
 777     FOR_EACH_OBSERVER(Observer, observer_list_, OnStartBatchChanges());
 778 }
 779
 780 void OAuth2TokenService::EndBatchChanges() {
 781   --batch_change_depth_;
 782   DCHECK_LE(0, batch_change_depth_);
 783   if (batch_change_depth_ == 0)
 784     FOR_EACH_OBSERVER(Observer, observer_list_, OnEndBatchChanges());
 785 }
 786
 787 int OAuth2TokenService::cache_size_for_testing() const {
 788   return token_cache_.size();
 789 }
 790
 791 void OAuth2TokenService::set_max_authorization_token_fetch_retries_for_testing(
 792     int max_retries) {
 793   DCHECK(CalledOnValidThread());
 794   max_fetch_retry_num_ = max_retries;
 795 }
 796
 797 size_t OAuth2TokenService::GetNumPendingRequestsForTesting(
 798     const std::string& client_id,
 799     const std::string& account_id,
 800     const ScopeSet& scopes) const {
 801   PendingFetcherMap::const_iterator iter = pending_fetchers_.find(
 802       OAuth2TokenService::RequestParameters(
 803           client_id,
 804           account_id,
 805           scopes));
 806   return iter == pending_fetchers_.end() ?
 807              0 : iter->second->GetWaitingRequestCount();
 808 }