Allow ProxyConfigService to report "no configuration set"

net/proxy/polling_proxy_config_service.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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 "net/proxy/polling_proxy_config_service.h"
 
 #include "base/message_loop_proxy.h"
 #include "base/observer_list.h"
 #include "base/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/worker_pool.h"
 #include "net/proxy/proxy_config.h"
 
 namespace net {
 
 // Reference-counted wrapper that does all the work (needs to be
 // reference-counted since we post tasks between threads; may outlive
 // the parent PollingProxyConfigService).
 class PollingProxyConfigService::Core
     : public base::RefCountedThreadSafe<PollingProxyConfigService::Core> {
  public:
   Core(base::TimeDelta poll_interval,
        GetConfigFunction get_config_func)
       : get_config_func_(get_config_func),
         poll_interval_(poll_interval),
         have_initialized_origin_loop_(false),
-        has_config_(false),
+        config_availability_(ProxyConfigService::CONFIG_PENDING),
         poll_task_outstanding_(false),
         poll_task_queued_(false) {
   }
 
   // Called when the parent PollingProxyConfigService is destroyed
   // (observers should not be called past this point).
   void Orphan() {
     base::AutoLock l(lock_);
     origin_loop_proxy_ = NULL;
   }
 
-  bool GetLatestProxyConfig(ProxyConfig* config) {
+  ProxyConfigService::ConfigAvailability GetLatestProxyConfig(
+      ProxyConfig* config) {
     LazyInitializeOriginLoop();
     DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
 
     OnLazyPoll();
 
     // If we have already retrieved the proxy settings (on worker thread)
     // then return what we last saw.
-    if (has_config_) {
+    if (config_availability_ == ProxyConfigService::CONFIG_VALID)
       *config = last_config_;
-      return true;
-    }
-    return false;
+
+    return config_availability_;
   }
 
   void AddObserver(Observer* observer) {
     LazyInitializeOriginLoop();
     DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
     observers_.AddObserver(observer);
   }
 
   void RemoveObserver(Observer* observer) {
     DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
@@ skipping 28 matching lines @@
     poll_task_queued_ = false;
     base::WorkerPool::PostTask(
         FROM_HERE,
         NewRunnableMethod(this, &Core::PollOnWorkerThread, get_config_func_),
         true);
   }
 
  private:
   void PollOnWorkerThread(GetConfigFunction func) {
     ProxyConfig config;
-    func(&config);
+    ProxyConfigService::ConfigAvailability available = func(&config);

[eroman, 2011/03/16 01:30:00]

Please add a DCHECK/CHECK that |available| != CONFIG_PENDING.

[Mattias Nissler (ping if slow), 2011/03/16 17:40:00]

Done.

 
     base::AutoLock l(lock_);
     if (origin_loop_proxy_) {
       origin_loop_proxy_->PostTask(
           FROM_HERE,
-          NewRunnableMethod(this, &Core::GetConfigCompleted, config));
+          NewRunnableMethod(this, &Core::GetConfigCompleted,
+                            config, available));
     }
   }
 
   // Called after the worker thread has finished retrieving a configuration.
-  void GetConfigCompleted(const ProxyConfig& config) {
+  void GetConfigCompleted(
+      const ProxyConfig& config,
+      ProxyConfigService::ConfigAvailability available) {
     DCHECK(poll_task_outstanding_);
     poll_task_outstanding_ = false;
 
     if (!origin_loop_proxy_)
       return;  // Was orphaned (parent has already been destroyed).
 
     DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
 
-    if (!has_config_ || !last_config_.Equals(config)) {
+    if (config_availability_ != available ||
+        (available == ProxyConfigService::CONFIG_VALID &&
+            !last_config_.Equals(config))) {
       // If the configuration has changed, notify the observers.
-      has_config_ = true;
+      config_availability_ = available;
       last_config_ = config;
-      FOR_EACH_OBSERVER(Observer, observers_, OnProxyConfigChanged(config));
+      FOR_EACH_OBSERVER(Observer, observers_,
+                        OnProxyConfigChanged(last_config_,
+                                             config_availability_));
     }
 
     if (poll_task_queued_)
       CheckForChangesNow();
   }
 
   void LazyInitializeOriginLoop() {
     // TODO(eroman): Really this should be done in the constructor, but right
     //               now chrome is constructing the ProxyConfigService on the
     //               UI thread so we can't cache the IO thread for the purpose
     //               of DCHECKs until the first call is made.
     if (!have_initialized_origin_loop_) {
       origin_loop_proxy_ = base::MessageLoopProxy::CreateForCurrentThread();
       have_initialized_origin_loop_ = true;
     }
   }
 
   GetConfigFunction get_config_func_;
   ObserverList<Observer> observers_;
   ProxyConfig last_config_;
   base::TimeTicks last_poll_time_;
   base::TimeDelta poll_interval_;
 
   base::Lock lock_;
   scoped_refptr<base::MessageLoopProxy> origin_loop_proxy_;
 
   bool have_initialized_origin_loop_;
-  bool has_config_;
+  ProxyConfigService::ConfigAvailability config_availability_;
   bool poll_task_outstanding_;
   bool poll_task_queued_;
 };
 
 void PollingProxyConfigService::AddObserver(Observer* observer) {
   core_->AddObserver(observer);
 }
 
 void PollingProxyConfigService::RemoveObserver(Observer* observer) {
   core_->RemoveObserver(observer);
 }
 
-bool PollingProxyConfigService::GetLatestProxyConfig(ProxyConfig* config) {
+ProxyConfigService::ConfigAvailability
+    PollingProxyConfigService::GetLatestProxyConfig(ProxyConfig* config) {
   return core_->GetLatestProxyConfig(config);
 }
 
 void PollingProxyConfigService::OnLazyPoll() {
   core_->OnLazyPoll();
 }
 
 PollingProxyConfigService::PollingProxyConfigService(
     base::TimeDelta poll_interval,
     GetConfigFunction get_config_func)
     : core_(new Core(poll_interval, get_config_func)) {
 }
 
 PollingProxyConfigService::~PollingProxyConfigService() {
   core_->Orphan();
 }
 
 void PollingProxyConfigService::CheckForChangesNow() {
   core_->CheckForChangesNow();
 }
 
 }  // namespace net