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// Copyright (c) 2006-2008 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/base/host_resolver.h"
#if defined(OS_WIN)
#include <ws2tcpip.h>
#include <wspiapi.h> // Needed for Win2k compat.
#elif defined(OS_POSIX)
#include <netdb.h>
#include <sys/socket.h>
#endif
#include "base/message_loop.h"
#include "base/string_util.h"
#include "base/worker_pool.h"
#include "net/base/address_list.h"
#include "net/base/net_errors.h"
#if defined(OS_WIN)
#include "net/base/winsock_init.h"
#endif
namespace net {
//-----------------------------------------------------------------------------
static HostMapper* host_mapper;
std::string HostMapper::MapUsingPrevious(const std::string& host) {
return previous_mapper_.get() ? previous_mapper_->Map(host) : host;
}
HostMapper* SetHostMapper(HostMapper* value) {
std::swap(host_mapper, value);
return value;
}
static int HostResolverProc(
const std::string& host, const std::string& port, struct addrinfo** out) {
struct addrinfo hints = {0};
hints.ai_family = PF_UNSPEC;
hints.ai_flags = AI_ADDRCONFIG;
// Restrict result set to only this socket type to avoid duplicates.
hints.ai_socktype = SOCK_STREAM;
int err = getaddrinfo(host.c_str(), port.c_str(), &hints, out);
return err ? ERR_NAME_NOT_RESOLVED : OK;
}
static int ResolveAddrInfo(HostMapper* mapper, const std::string& host,
const std::string& port, struct addrinfo** out) {
if (mapper) {
std::string mapped_host = mapper->Map(host);
if (mapped_host.empty())
return ERR_NAME_NOT_RESOLVED;
return HostResolverProc(mapped_host, port, out);
} else {
return HostResolverProc(host, port, out);
}
}
//-----------------------------------------------------------------------------
class HostResolver::Request :
public base::RefCountedThreadSafe<HostResolver::Request> {
public:
Request(HostResolver* resolver,
const std::string& host,
const std::string& port,
AddressList* addresses,
CompletionCallback* callback)
: host_(host),
port_(port),
resolver_(resolver),
addresses_(addresses),
callback_(callback),
origin_loop_(MessageLoop::current()),
host_mapper_(host_mapper),
error_(OK),
results_(NULL) {
}
~Request() {
if (results_)
freeaddrinfo(results_);
}
void DoLookup() {
// Running on the worker thread
error_ = ResolveAddrInfo(host_mapper_, host_, port_, &results_);
Task* reply = NewRunnableMethod(this, &Request::DoCallback);
// The origin loop could go away while we are trying to post to it, so we
// need to call its PostTask method inside a lock. See ~HostResolver.
{
AutoLock locked(origin_loop_lock_);
if (origin_loop_) {
origin_loop_->PostTask(FROM_HERE, reply);
reply = NULL;
}
}
// Does nothing if it got posted.
delete reply;
}
void DoCallback() {
// Running on the origin thread.
DCHECK(error_ || results_);
// We may have been cancelled!
if (!resolver_)
return;
if (!error_) {
addresses_->Adopt(results_);
results_ = NULL;
}
// Drop the resolver's reference to us. Do this before running the
// callback since the callback might result in the resolver being
// destroyed.
resolver_->request_ = NULL;
callback_->Run(error_);
}
void Cancel() {
resolver_ = NULL;
AutoLock locked(origin_loop_lock_);
origin_loop_ = NULL;
}
private:
// Set on the origin thread, read on the worker thread.
std::string host_;
std::string port_;
// Only used on the origin thread (where Resolve was called).
HostResolver* resolver_;
AddressList* addresses_;
CompletionCallback* callback_;
// Used to post ourselves onto the origin thread.
Lock origin_loop_lock_;
MessageLoop* origin_loop_;
// Hold an owning reference to the host mapper that we are going to use.
// This may not be the current host mapper by the time we call
// ResolveAddrInfo, but that's OK... we'll use it anyways, and the owning
// reference ensures that it remains valid until we are done.
scoped_refptr<HostMapper> host_mapper_;
// Assigned on the worker thread, read on the origin thread.
int error_;
struct addrinfo* results_;
};
//-----------------------------------------------------------------------------
HostResolver::HostResolver() {
#if defined(OS_WIN)
EnsureWinsockInit();
#endif
}
HostResolver::~HostResolver() {
if (request_)
request_->Cancel();
}
int HostResolver::Resolve(const std::string& hostname, int port,
AddressList* addresses,
CompletionCallback* callback) {
DCHECK(!request_) << "resolver already in use";
const std::string& port_str = IntToString(port);
// Do a synchronous resolution.
if (!callback) {
struct addrinfo* results;
int rv = ResolveAddrInfo(host_mapper, hostname, port_str, &results);
if (rv == OK)
addresses->Adopt(results);
return rv;
}
request_ = new Request(this, hostname, port_str, addresses, callback);
// Dispatch to worker thread...
if (!WorkerPool::PostTask(FROM_HERE,
NewRunnableMethod(request_.get(), &Request::DoLookup), true)) {
NOTREACHED();
request_ = NULL;
return ERR_FAILED;
}
return ERR_IO_PENDING;
}
} // namespace net
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