Make HostResolver NonThreadSafe and not thread safe refcounted.

Required making SyncHostResolverBridge not use RefCountedThreadSafe.  I refactored the innards to have a thread safe refcounted Core implementation.

BUG=45298

Review URL: http://codereview.chromium.org/2122015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@48867 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 183 insertions, 121 deletions

diff --git a/net/base/host_resolver.h b/net/base/host_resolver.h
index e4bf847..d798688 100644
--- a/net/base/host_resolver.h
+++ b/net/base/host_resolver.h
@@ -32,7 +32,7 @@ class NetworkChangeNotifier;
 // request at a time is to create a SingleRequestHostResolver wrapper around
 // HostResolver (which will automatically cancel the single request when it
 // goes out of scope).
-class HostResolver : public base::RefCountedThreadSafe<HostResolver> {
+class HostResolver : public base::RefCounted<HostResolver> {
  public:
   // The parameters for doing a Resolve(). |hostname| and |port| are required,
   // the rest are optional (and have reasonable defaults).
@@ -179,7 +179,7 @@ class HostResolver : public base::RefCountedThreadSafe<HostResolver> {
   virtual HostResolverImpl* GetAsHostResolverImpl() { return NULL; }
 
  protected:
-  friend class base::RefCountedThreadSafe<HostResolver>;
+  friend class base::RefCounted<HostResolver>;
 
   HostResolver() { }
 
diff --git a/net/base/host_resolver_impl.cc b/net/base/host_resolver_impl.cc
index 1f89af4..f3bc5c1 100644
--- a/net/base/host_resolver_impl.cc
+++ b/net/base/host_resolver_impl.cc
@@ -755,6 +755,8 @@ int HostResolverImpl::Resolve(const RequestInfo& info,
                               CompletionCallback* callback,
                               RequestHandle* out_req,
                               const BoundNetLog& net_log) {
+  DCHECK(CalledOnValidThread());
+
   if (shutdown_)
     return ERR_UNEXPECTED;
 
@@ -840,6 +842,7 @@ int HostResolverImpl::Resolve(const RequestInfo& info,
 // See OnJobComplete(Job*) for why it is important not to clean out
 // cancelled requests from Job::requests_.
 void HostResolverImpl::CancelRequest(RequestHandle req_handle) {
+  DCHECK(CalledOnValidThread());
   if (shutdown_) {
     // TODO(eroman): temp hack for: http://crbug.com/18373
     // Because we destroy outstanding requests during Shutdown(),
@@ -869,10 +872,12 @@ void HostResolverImpl::CancelRequest(RequestHandle req_handle) {
 }
 
 void HostResolverImpl::AddObserver(HostResolver::Observer* observer) {
+  DCHECK(CalledOnValidThread());
   observers_.push_back(observer);
 }
 
 void HostResolverImpl::RemoveObserver(HostResolver::Observer* observer) {
+  DCHECK(CalledOnValidThread());
   ObserversList::iterator it =
       std::find(observers_.begin(), observers_.end(), observer);
 
@@ -883,18 +888,21 @@ void HostResolverImpl::RemoveObserver(HostResolver::Observer* observer) {
 }
 
 void HostResolverImpl::SetDefaultAddressFamily(AddressFamily address_family) {
+  DCHECK(CalledOnValidThread());
   ipv6_probe_monitoring_ = false;
   DiscardIPv6ProbeJob();
   default_address_family_ = address_family;
 }
 
 void HostResolverImpl::ProbeIPv6Support() {
+  DCHECK(CalledOnValidThread());
   DCHECK(!ipv6_probe_monitoring_);
   ipv6_probe_monitoring_ = true;
   OnIPAddressChanged();  // Give initial setup call.
 }
 
 void HostResolverImpl::Shutdown() {
+  DCHECK(CalledOnValidThread());
   shutdown_ = true;
 
   // Cancel the outstanding jobs.
@@ -907,6 +915,7 @@ void HostResolverImpl::Shutdown() {
 void HostResolverImpl::SetPoolConstraints(JobPoolIndex pool_index,
                                           size_t max_outstanding_jobs,
                                           size_t max_pending_requests) {
+  DCHECK(CalledOnValidThread());
   CHECK_GE(pool_index, 0);
   CHECK_LT(pool_index, POOL_COUNT);
   CHECK(jobs_.empty()) << "Can only set constraints during setup";
diff --git a/net/base/host_resolver_impl.h b/net/base/host_resolver_impl.h
index 417cc77..a0e34ca 100644
--- a/net/base/host_resolver_impl.h
+++ b/net/base/host_resolver_impl.h
@@ -8,6 +8,7 @@
 #include <string>
 #include <vector>
 
+#include "base/non_thread_safe.h"
 #include "base/scoped_ptr.h"
 #include "net/base/capturing_net_log.h"
 #include "net/base/host_cache.h"
@@ -49,6 +50,7 @@ namespace net {
 // Requests are ordered in the queue based on their priority.
 
 class HostResolverImpl : public HostResolver,
+                         public NonThreadSafe,
                          public NetworkChangeNotifier::Observer {
  public:
   // The index into |job_pools_| for the various job pools. Pools with a higher
diff --git a/net/proxy/sync_host_resolver_bridge.cc b/net/proxy/sync_host_resolver_bridge.cc
index 31a326d..caf4549 100644
--- a/net/proxy/sync_host_resolver_bridge.cc
+++ b/net/proxy/sync_host_resolver_bridge.cc
@@ -6,50 +6,123 @@
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
+#include "base/lock.h"
 #include "base/message_loop.h"
+#include "base/waitable_event.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
 
 namespace net {
 
-// SyncHostResolverBridge -----------------------------------------------------
+// SyncHostResolverBridge::Core ----------------------------------------------
 
-SyncHostResolverBridge::SyncHostResolverBridge(HostResolver* host_resolver,
-                                               MessageLoop* host_resolver_loop)
+class SyncHostResolverBridge::Core
+    : public base::RefCountedThreadSafe<SyncHostResolverBridge::Core> {
+ public:
+  Core(HostResolver* resolver, MessageLoop* host_resolver_loop);
+
+  int ResolveSynchronously(const HostResolver::RequestInfo& info,
+                           AddressList* addresses);
+
+  // Returns true if Shutdown() has been called.
+  bool HasShutdown() const {
+    AutoLock l(lock_);
+    return HasShutdownLocked();
+  }
+
+  // Called on |host_resolver_loop_|.
+  void Shutdown();
+
+ private:
+  friend class base::RefCountedThreadSafe<SyncHostResolverBridge::Core>;
+
+  bool HasShutdownLocked() const {
+    return has_shutdown_;
+  }
+
+  // Called on |host_resolver_loop_|.
+  void StartResolve(const HostResolver::RequestInfo& info,
+                    AddressList* addresses);
+
+  // Called on |host_resolver_loop_|.
+  void OnResolveCompletion(int result);
+
+  // Not called on |host_resolver_loop_|.
+  int WaitForResolveCompletion();
+
+  const scoped_refptr<HostResolver> host_resolver_;
+  MessageLoop* const host_resolver_loop_;
+  net::CompletionCallbackImpl<Core> callback_;
+  // The result from the current request (set on |host_resolver_loop_|).
+  int err_;
+  // The currently outstanding request to |host_resolver_|, or NULL.
+  HostResolver::RequestHandle outstanding_request_;
+
+  // Event to notify completion of resolve request.  We always Signal() on
+  // |host_resolver_loop_| and Wait() on a different thread.
+  base::WaitableEvent event_;
+
+  // True if Shutdown() has been called. Must hold |lock_| to access it.
+  bool has_shutdown_;
+
+  // Mutex to guard accesses to |has_shutdown_|.
+  mutable Lock lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(Core);
+};
+
+SyncHostResolverBridge::Core::Core(HostResolver* host_resolver,
+                                   MessageLoop* host_resolver_loop)
     : host_resolver_(host_resolver),
       host_resolver_loop_(host_resolver_loop),
-      event_(true, false),
       ALLOW_THIS_IN_INITIALIZER_LIST(
-          callback_(this, &SyncHostResolverBridge::OnResolveCompletion)),
+          callback_(this, &Core::OnResolveCompletion)),
+      err_(0),
       outstanding_request_(NULL),
-      has_shutdown_(false) {
-  DCHECK(host_resolver_loop_);
-}
-
-SyncHostResolverBridge::~SyncHostResolverBridge() {
-  DCHECK(HasShutdown());
-}
-
-int SyncHostResolverBridge::Resolve(const RequestInfo& info,
-                                    AddressList* addresses,
-                                    CompletionCallback* callback,
-                                    RequestHandle* out_req,
-                                    const BoundNetLog& net_log) {
-  DCHECK(!callback);
-  DCHECK(!out_req);
+      event_(true, false),
+      has_shutdown_(false) {}
 
+int SyncHostResolverBridge::Core::ResolveSynchronously(
+    const HostResolver::RequestInfo& info,
+    net::AddressList* addresses) {
   // Otherwise start an async resolve on the resolver's thread.
   host_resolver_loop_->PostTask(
       FROM_HERE,
-      NewRunnableMethod(this, &SyncHostResolverBridge::StartResolve,
+      NewRunnableMethod(this, &Core::StartResolve,
                         info, addresses));
 
-  // Wait for the resolve to complete in the resolver's thread.
+  return WaitForResolveCompletion();
+}
+
+void SyncHostResolverBridge::Core::StartResolve(
+    const HostResolver::RequestInfo& info,
+    net::AddressList* addresses) {
+  DCHECK_EQ(MessageLoop::current(), host_resolver_loop_);
+  DCHECK(!outstanding_request_);
+
+  if (HasShutdown())
+    return;
+
+  int error = host_resolver_->Resolve(
+      info, addresses, &callback_, &outstanding_request_, BoundNetLog());
+  if (error != ERR_IO_PENDING)
+    OnResolveCompletion(error);  // Completed synchronously.
+}
+
+void SyncHostResolverBridge::Core::OnResolveCompletion(int result) {
+  DCHECK_EQ(MessageLoop::current(), host_resolver_loop_);
+  err_ = result;
+  outstanding_request_ = NULL;
+  event_.Signal();
+}
+
+int SyncHostResolverBridge::Core::WaitForResolveCompletion() {
+  DCHECK_NE(MessageLoop::current(), host_resolver_loop_);
   event_.Wait();
 
   {
     AutoLock l(lock_);
-    if (has_shutdown_)
+    if (HasShutdownLocked())
       return ERR_ABORTED;
     event_.Reset();
   }
@@ -57,19 +130,7 @@ int SyncHostResolverBridge::Resolve(const RequestInfo& info,
   return err_;
 }
 
-void SyncHostResolverBridge::CancelRequest(RequestHandle req) {
-  NOTREACHED();
-}
-
-void SyncHostResolverBridge::AddObserver(Observer* observer) {
-  NOTREACHED();
-}
-
-void SyncHostResolverBridge::RemoveObserver(Observer* observer) {
-  NOTREACHED();
-}
-
-void SyncHostResolverBridge::Shutdown() {
+void SyncHostResolverBridge::Core::Shutdown() {
   DCHECK_EQ(MessageLoop::current(), host_resolver_loop_);
 
   if (outstanding_request_) {
@@ -77,32 +138,54 @@ void SyncHostResolverBridge::Shutdown() {
     outstanding_request_ = NULL;
   }
 
-  AutoLock l(lock_);
-  has_shutdown_ = true;
+  {
+    AutoLock l(lock_);
+    has_shutdown_ = true;
+  }
 
   // Wake up the PAC thread in case it was waiting for resolve completion.
   event_.Signal();
 }
 
-void SyncHostResolverBridge::StartResolve(const HostResolver::RequestInfo& info,
-                                          net::AddressList* addresses) {
-  DCHECK_EQ(host_resolver_loop_, MessageLoop::current());
-  DCHECK(!outstanding_request_);
+// SyncHostResolverBridge -----------------------------------------------------
 
-  if (HasShutdown())
-    return;
+SyncHostResolverBridge::SyncHostResolverBridge(HostResolver* host_resolver,
+                                               MessageLoop* host_resolver_loop)
+    : host_resolver_loop_(host_resolver_loop),
+      core_(new Core(host_resolver, host_resolver_loop)) {
+  DCHECK(host_resolver_loop_);
+}
 
-  int error = host_resolver_->Resolve(
-      info, addresses, &callback_, &outstanding_request_, BoundNetLog());
-  if (error != ERR_IO_PENDING)
-    OnResolveCompletion(error);  // Completed synchronously.
+SyncHostResolverBridge::~SyncHostResolverBridge() {
+  DCHECK(core_->HasShutdown());
 }
 
-void SyncHostResolverBridge::OnResolveCompletion(int result) {
-  DCHECK_EQ(host_resolver_loop_, MessageLoop::current());
-  err_ = result;
-  outstanding_request_ = NULL;
-  event_.Signal();
+int SyncHostResolverBridge::Resolve(const RequestInfo& info,
+                                    AddressList* addresses,
+                                    CompletionCallback* callback,
+                                    RequestHandle* out_req,
+                                    const BoundNetLog& net_log) {
+  DCHECK(!callback);
+  DCHECK(!out_req);
+
+  return core_->ResolveSynchronously(info, addresses);
+}
+
+void SyncHostResolverBridge::CancelRequest(RequestHandle req) {
+  NOTREACHED();
+}
+
+void SyncHostResolverBridge::AddObserver(Observer* observer) {
+  NOTREACHED();
+}
+
+void SyncHostResolverBridge::RemoveObserver(Observer* observer) {
+  NOTREACHED();
+}
+
+void SyncHostResolverBridge::Shutdown() {
+  DCHECK_EQ(MessageLoop::current(), host_resolver_loop_);
+  core_->Shutdown();
 }
 
 // SingleThreadedProxyResolverUsingBridgedHostResolver -----------------------
diff --git a/net/proxy/sync_host_resolver_bridge.h b/net/proxy/sync_host_resolver_bridge.h
index d082043..4d25b4d 100644
--- a/net/proxy/sync_host_resolver_bridge.h
+++ b/net/proxy/sync_host_resolver_bridge.h
@@ -5,9 +5,7 @@
 #ifndef NET_PROXY_SYNC_HOST_RESOLVER_BRIDGE_H_
 #define NET_PROXY_SYNC_HOST_RESOLVER_BRIDGE_H_
 
-#include "base/lock.h"
 #include "base/scoped_ptr.h"
-#include "base/waitable_event.h"
 #include "net/base/host_resolver.h"
 #include "net/proxy/single_threaded_proxy_resolver.h"
 
@@ -40,39 +38,10 @@ class SyncHostResolverBridge : public HostResolver {
   void Shutdown();
 
  private:
-  // Called on |host_resolver_loop_|.
-  void StartResolve(const HostResolver::RequestInfo& info,
-                    net::AddressList* addresses);
+  class Core;
 
-  // Called on |host_resolver_loop_|.
-  void OnResolveCompletion(int result);
-
-  // Returns true if Shutdown() has been called.
-  bool HasShutdown() const {
-    AutoLock l(lock_);
-    return has_shutdown_;
-  }
-
-  scoped_refptr<HostResolver> host_resolver_;
-  MessageLoop* host_resolver_loop_;
-
-  // Event to notify completion of resolve request.
-  base::WaitableEvent event_;
-
-  // Callback for when the resolve completes on host_resolver_loop_.
-  net::CompletionCallbackImpl<SyncHostResolverBridge> callback_;
-
-  // The result from the current request (set on |host_resolver_loop_|).
-  int err_;
-
-  // The currently outstanding request to |host_resolver_|, or NULL.
-  HostResolver::RequestHandle outstanding_request_;
-
-  // True if Shutdown() has been called. Must hold |lock_| to access it.
-  bool has_shutdown_;
-
-  // Mutex to guard accesses to |has_shutdown_|.
-  mutable Lock lock_;
+  MessageLoop* const host_resolver_loop_;
+  scoped_refptr<Core> core_;
 };
 
 // Subclass of SingleThreadedProxyResolver that additionally calls
@@ -94,4 +63,3 @@ class SingleThreadedProxyResolverUsingBridgedHostResolver
 }  // namespace net
 
 #endif  // NET_PROXY_SYNC_HOST_RESOLVER_BRIDGE_H_
-
diff --git a/net/proxy/sync_host_resolver_bridge_unittest.cc b/net/proxy/sync_host_resolver_bridge_unittest.cc
index 916252b..42dbacc 100644
--- a/net/proxy/sync_host_resolver_bridge_unittest.cc
+++ b/net/proxy/sync_host_resolver_bridge_unittest.cc
@@ -5,6 +5,7 @@
 #include "net/proxy/sync_host_resolver_bridge.h"
 
 #include "base/thread.h"
+#include "base/waitable_event.h"
 #include "net/base/address_list.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
@@ -116,16 +117,20 @@ class SyncProxyResolver : public ProxyResolver {
 // network stack.
 class IOThread : public base::Thread {
  public:
-  explicit IOThread(HostResolver* async_resolver)
-      : base::Thread("IO-thread"), async_resolver_(async_resolver) {
-  }
+  IOThread() : base::Thread("IO-thread") {}
 
   virtual ~IOThread() {
     Stop();
   }
 
+  const scoped_refptr<BlockableHostResolver>& async_resolver() {
+    return async_resolver_;
+  }
+
  protected:
   virtual void Init() {
+    async_resolver_ = new BlockableHostResolver();
+
     // Create a synchronous host resolver that operates the async host
     // resolver on THIS thread.
     scoped_refptr<SyncHostResolverBridge> sync_resolver =
@@ -149,10 +154,19 @@ class IOThread : public base::Thread {
 
     // Delete the single threaded proxy resolver.
     proxy_resolver_.reset();
+
+    // During the teardown sequence of the single threaded proxy resolver,
+    // the outstanding host resolve should have been cancelled.
+    EXPECT_TRUE(async_resolver_->was_request_cancelled());
+
+    async_resolver_ = NULL;
   }
 
  private:
-  HostResolver* async_resolver_;
+  // This (async) host resolver will outlive the thread that is operating it
+  // synchronously.
+  scoped_refptr<BlockableHostResolver> async_resolver_;
+
   scoped_ptr<ProxyResolver> proxy_resolver_;
 
   // Data for the outstanding request to the single threaded proxy resolver.
@@ -165,35 +179,21 @@ class IOThread : public base::Thread {
 // is outstanding on the SyncHostResolverBridge.
 // This is a regression test for http://crbug.com/41244.
 TEST(SingleThreadedProxyResolverWithBridgedHostResolverTest, ShutdownDeadlock) {
-  // This (async) host resolver will outlive the thread that is operating it
-  // synchronously.
-  scoped_refptr<BlockableHostResolver> host_resolver =
-      new BlockableHostResolver();
-
-  {
-    IOThread io_thread(host_resolver.get());
-    base::Thread::Options options;
-    options.message_loop_type = MessageLoop::TYPE_IO;
-    ASSERT_TRUE(io_thread.StartWithOptions(options));
-
-    // Wait until the host resolver receives a request (this means that the
-    // PAC thread is now blocked, waiting for the async response from the
-    // host resolver.
-    host_resolver->WaitUntilRequestIsReceived();
-
-    // Now upon exitting this scope, the IOThread is destroyed -- this will
-    // stop the IOThread, which will in turn delete the
-    // SingleThreadedProxyResolver, which in turn will stop its internal
-    // PAC thread (which is currently blocked waiting on the host resolve which
-    // is running on IOThread).
-  }
-
-  // During the teardown sequence of the single threaded proxy resolver,
-  // the outstanding host resolve should have been cancelled.
-  EXPECT_TRUE(host_resolver->was_request_cancelled());
+  IOThread io_thread;
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_IO;
+  ASSERT_TRUE(io_thread.StartWithOptions(options));
+
+  io_thread.async_resolver()->WaitUntilRequestIsReceived();
+
+  // Now upon exitting this scope, the IOThread is destroyed -- this will
+  // stop the IOThread, which will in turn delete the
+  // SingleThreadedProxyResolver, which in turn will stop its internal
+  // PAC thread (which is currently blocked waiting on the host resolve which
+  // is running on IOThread).  The IOThread::Cleanup() will verify that after
+  // the PAC thread is stopped, it cancels the request on the HostResolver.
 }
 
 }  // namespace
 
 }  // namespace net
-