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// Copyright (c) 2010 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/compiler_specific.h"
#include "base/logging.h"
#include "base/message_loop.h"
#include "base/synchronization/lock.h"
#include "base/synchronization/waitable_event.h"
#include "net/base/net_errors.h"
#include "net/base/net_log.h"
namespace net {
// SyncHostResolverBridge::Core ----------------------------------------------
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 {
base::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();
HostResolver* const 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 base::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),
ALLOW_THIS_IN_INITIALIZER_LIST(
callback_(this, &Core::OnResolveCompletion)),
err_(0),
outstanding_request_(NULL),
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, &Core::StartResolve,
info, addresses));
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();
{
base::AutoLock l(lock_);
if (HasShutdownLocked())
return ERR_ABORTED;
event_.Reset();
}
return err_;
}
void SyncHostResolverBridge::Core::Shutdown() {
DCHECK_EQ(MessageLoop::current(), host_resolver_loop_);
if (outstanding_request_) {
host_resolver_->CancelRequest(outstanding_request_);
outstanding_request_ = NULL;
}
{
base::AutoLock l(lock_);
has_shutdown_ = true;
}
// Wake up the PAC thread in case it was waiting for resolve completion.
event_.Signal();
}
// SyncHostResolverBridge -----------------------------------------------------
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_);
}
SyncHostResolverBridge::~SyncHostResolverBridge() {
DCHECK(core_->HasShutdown());
}
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();
}
} // namespace net
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