Improve performance of proxy resolver by tracing DNS dependencies.

net/proxy/sync_host_resolver_bridge_unittest.cc

-// Copyright (c) 2012 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/sync_host_resolver_bridge.h"
-
-#include "base/threading/thread.h"
-#include "base/synchronization/waitable_event.h"
-#include "net/base/address_list.h"
-#include "net/base/net_errors.h"
-#include "net/base/net_log.h"
-#include "net/proxy/multi_threaded_proxy_resolver.h"
-#include "net/base/test_completion_callback.h"
-#include "net/proxy/proxy_info.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-// TODO(eroman): This test should be moved into
-//               multi_threaded_proxy_resolver_unittest.cc.
-
-namespace net {
-
-namespace {
-
-// This implementation of HostResolver allows blocking until a resolve request
-// has been received. The resolve requests it receives will never be completed.
-class BlockableHostResolver : public HostResolver {
- public:
-  BlockableHostResolver()
-      : event_(true, false),
-        was_request_cancelled_(false) {
-  }
-
-  virtual int Resolve(const RequestInfo& info,
-                      AddressList* addresses,
-                      const CompletionCallback& callback,
-                      RequestHandle* out_req,
-                      const BoundNetLog& net_log) OVERRIDE {
-    EXPECT_FALSE(callback.is_null());
-    EXPECT_TRUE(out_req);
-    *out_req = reinterpret_cast<RequestHandle*>(1);  // Magic value.
-
-    // Indicate to the caller that a request was received.
-    event_.Signal();
-
-    // We return ERR_IO_PENDING, as this request will NEVER be completed.
-    // Expectation is for the caller to later cancel the request.
-    return ERR_IO_PENDING;
-  }
-
-  virtual int ResolveFromCache(const RequestInfo& info,
-                               AddressList* addresses,
-                               const BoundNetLog& net_log) OVERRIDE {
-    NOTIMPLEMENTED();
-    return ERR_UNEXPECTED;
-  }
-
-  virtual void CancelRequest(RequestHandle req) OVERRIDE {
-    EXPECT_EQ(reinterpret_cast<RequestHandle*>(1), req);
-    was_request_cancelled_ = true;
-  }
-
-  // Waits until Resolve() has been called.
-  void WaitUntilRequestIsReceived() {
-    event_.Wait();
-  }
-
-  bool was_request_cancelled() const {
-    return was_request_cancelled_;
-  }
-
- private:
-  // Event to notify when a resolve request was received.
-  base::WaitableEvent event_;
-  bool was_request_cancelled_;
-};
-
-// This implementation of ProxyResolver simply does a synchronous resolve
-// on |host_resolver| in response to GetProxyForURL().
-class SyncProxyResolver : public ProxyResolver {
- public:
-  explicit SyncProxyResolver(SyncHostResolverBridge* host_resolver)
-      : ProxyResolver(false), host_resolver_(host_resolver) {}
-
-  virtual int GetProxyForURL(const GURL& url,
-                             ProxyInfo* results,
-                             const CompletionCallback& callback,
-                             RequestHandle* request,
-                             const BoundNetLog& net_log) {
-    EXPECT_FALSE(!callback.is_null());
-    EXPECT_FALSE(request);
-
-    // Do a synchronous host resolve.
-    HostResolver::RequestInfo info(HostPortPair::FromURL(url));
-    AddressList addresses;
-    int rv = host_resolver_->Resolve(info, &addresses, net_log);
-
-    EXPECT_EQ(ERR_ABORTED, rv);
-
-    return rv;
-  }
-
-  virtual void CancelRequest(RequestHandle request) OVERRIDE {
-    NOTREACHED();
-  }
-
-  virtual LoadState GetLoadState(RequestHandle request) const OVERRIDE {
-    NOTREACHED();
-    return LOAD_STATE_IDLE;
-  }
-
-  virtual LoadState GetLoadStateThreadSafe(
-      RequestHandle request) const OVERRIDE {
-    NOTREACHED();
-    return LOAD_STATE_IDLE;
-  }
-
-  virtual void Shutdown() OVERRIDE {
-    host_resolver_->Shutdown();
-  }
-
-  virtual void CancelSetPacScript() OVERRIDE {
-    NOTREACHED();
-  }
-
-  virtual int SetPacScript(
-      const scoped_refptr<ProxyResolverScriptData>& script_data,
-      const CompletionCallback& callback) OVERRIDE {
-    return OK;
-  }
-
- private:
-  SyncHostResolverBridge* const host_resolver_;
-};
-
-class SyncProxyResolverFactory : public ProxyResolverFactory {
- public:
-  // Takes ownership of |sync_host_resolver|.
-  explicit SyncProxyResolverFactory(SyncHostResolverBridge* sync_host_resolver)
-      : ProxyResolverFactory(false),
-        sync_host_resolver_(sync_host_resolver) {
-  }
-
-  virtual ProxyResolver* CreateProxyResolver() OVERRIDE {
-    return new SyncProxyResolver(sync_host_resolver_.get());
-  }
-
- private:
-  const scoped_ptr<SyncHostResolverBridge> sync_host_resolver_;
-};
-
-// This helper thread is used to create the circumstances for the deadlock.
-// It is analagous to the "IO thread" which would be main thread running the
-// network stack.
-class IOThread : public base::Thread {
- public:
-  IOThread() : base::Thread("IO-thread") {}
-
-  virtual ~IOThread() {
-    Stop();
-  }
-
-  BlockableHostResolver* async_resolver() {
-    return async_resolver_.get();
-  }
-
- protected:
-  virtual void Init() OVERRIDE {
-    async_resolver_.reset(new BlockableHostResolver());
-
-    // Create a synchronous host resolver that operates the async host
-    // resolver on THIS thread.
-    SyncHostResolverBridge* sync_resolver =
-        new SyncHostResolverBridge(async_resolver_.get(), message_loop());
-
-    proxy_resolver_.reset(
-        new MultiThreadedProxyResolver(
-            new SyncProxyResolverFactory(sync_resolver),
-            1u));
-
-    // Initialize the resolver.
-    TestCompletionCallback callback;
-    proxy_resolver_->SetPacScript(ProxyResolverScriptData::FromURL(GURL()),
-                                  callback.callback());
-    EXPECT_EQ(OK, callback.WaitForResult());
-
-    // Start an asynchronous request to the proxy resolver
-    // (note that it will never complete).
-    proxy_resolver_->GetProxyForURL(
-        GURL("http://test/"), &results_, callback_.callback(), &request_,
-        BoundNetLog());
-  }
-
-  virtual void CleanUp() OVERRIDE {
-    // Cancel the outstanding request (note however that this will not
-    // unblock the PAC thread though).
-    proxy_resolver_->CancelRequest(request_);
-
-    // Delete the single threaded proxy resolver.
-    proxy_resolver_.reset();
-
-    // (There may have been a completion posted back to origin thread, avoid
-    // leaking it by running).
-    MessageLoop::current()->RunUntilIdle();
-
-    // 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());
-  }
-
- private:
-  // This (async) host resolver will outlive the thread that is operating it
-  // synchronously.
-  scoped_ptr<BlockableHostResolver> async_resolver_;
-
-  scoped_ptr<ProxyResolver> proxy_resolver_;
-
-  // Data for the outstanding request to the single threaded proxy resolver.
-  TestCompletionCallback callback_;
-  ProxyInfo results_;
-  ProxyResolver::RequestHandle request_;
-};
-
-// Test that a deadlock does not happen during shutdown when a host resolve
-// is outstanding on the SyncHostResolverBridge.
-// This is a regression test for http://crbug.com/41244.
-TEST(MultiThreadedProxyResolverTest, ShutdownIsCalledBeforeThreadJoin) {
-  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