// 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.
//
// This file contains an implementation of the ResourceLoaderBridge class.
// The class is implemented using net::URLRequest, meaning it is a "simple"
// version that directly issues requests. The more complicated one used in the
// browser uses IPC.
//
// Because net::URLRequest only provides an asynchronous resource loading API,
// this file makes use of net::URLRequest from a background IO thread. Requests
// for cookies and synchronously loaded resources result in the main thread of
// the application blocking until the IO thread completes the operation.  (See
// GetCookies and SyncLoad)
//
// Main thread                          IO thread
// -----------                          ---------
// ResourceLoaderBridge <---o---------> RequestProxy (normal case)
//                           \            -> net::URLRequest
//                            o-------> SyncRequestProxy (synchronous case)
//                                        -> net::URLRequest
// SetCookie <------------------------> CookieSetter
//                                        -> net_util::SetCookie
// GetCookies <-----------------------> CookieGetter
//                                        -> net_util::GetCookies
//
// NOTE: The implementation in this file may be used to have WebKit fetch
// resources in-process.  For example, it is handy for building a single-
// process WebKit embedding (e.g., test_shell) that can use net::URLRequest to
// perform URL loads.  See renderer/resource_dispatcher.h for details on an
// alternate implementation that defers fetching to another process.

#include "webkit/tools/test_shell/simple_resource_loader_bridge.h"

#include "base/file_path.h"
#include "base/file_util.h"
#include "base/logging.h"
#include "base/message_loop.h"
#include "base/message_loop_proxy.h"
#include "base/memory/ref_counted.h"
#include "base/time.h"
#include "base/timer.h"
#include "base/threading/thread.h"
#include "base/synchronization/waitable_event.h"
#include "net/base/cookie_store.h"
#include "net/base/file_stream.h"
#include "net/base/io_buffer.h"
#include "net/base/load_flags.h"
#include "net/base/net_errors.h"
#include "net/base/net_util.h"
#include "net/base/static_cookie_policy.h"
#include "net/base/upload_data.h"
#include "net/http/http_cache.h"
#include "net/http/http_request_headers.h"
#include "net/http/http_response_headers.h"
#include "net/proxy/proxy_service.h"
#include "net/url_request/url_request.h"
#include "net/url_request/url_request_job.h"
#include "webkit/appcache/appcache_interfaces.h"
#include "webkit/blob/blob_storage_controller.h"
#include "webkit/blob/blob_url_request_job.h"
#include "webkit/blob/deletable_file_reference.h"
#include "webkit/fileapi/file_system_context.h"
#include "webkit/fileapi/file_system_dir_url_request_job.h"
#include "webkit/fileapi/file_system_url_request_job.h"
#include "webkit/glue/resource_loader_bridge.h"
#include "webkit/tools/test_shell/simple_appcache_system.h"
#include "webkit/tools/test_shell/simple_file_writer.h"
#include "webkit/tools/test_shell/simple_socket_stream_bridge.h"
#include "webkit/tools/test_shell/test_shell_request_context.h"
#include "webkit/tools/test_shell/test_shell_webblobregistry_impl.h"

#if defined(OS_MACOSX) || defined(OS_WIN)
#include "crypto/nss_util.h"
#endif

using webkit_glue::ResourceLoaderBridge;
using webkit_glue::ResourceResponseInfo;
using net::StaticCookiePolicy;
using net::HttpResponseHeaders;
using webkit_blob::DeletableFileReference;

namespace {

struct TestShellRequestContextParams {
  TestShellRequestContextParams(
      const FilePath& in_cache_path,
      net::HttpCache::Mode in_cache_mode,
      bool in_no_proxy)
      : cache_path(in_cache_path),
        cache_mode(in_cache_mode),
        no_proxy(in_no_proxy),
        accept_all_cookies(false) {}

  FilePath cache_path;
  net::HttpCache::Mode cache_mode;
  bool no_proxy;
  bool accept_all_cookies;
};

net::URLRequestJob* BlobURLRequestJobFactory(net::URLRequest* request,
                                             const std::string& scheme) {
  webkit_blob::BlobStorageController* blob_storage_controller =
      static_cast<TestShellRequestContext*>(request->context())->
          blob_storage_controller();
  return new webkit_blob::BlobURLRequestJob(
      request,
      blob_storage_controller->GetBlobDataFromUrl(request->url()),
      SimpleResourceLoaderBridge::GetIoThread());
}


net::URLRequestJob* FileSystemURLRequestJobFactory(net::URLRequest* request,
                                                   const std::string& scheme) {
  fileapi::FileSystemContext* fs_context =
      static_cast<TestShellRequestContext*>(request->context())
          ->file_system_context();
  if (!fs_context) {
    LOG(WARNING) << "No FileSystemContext found, ignoring filesystem: URL";
    return NULL;
  }

  // If the path ends with a /, we know it's a directory. If the path refers
  // to a directory and gets dispatched to FileSystemURLRequestJob, that class
  // redirects back here, by adding a / to the URL.
  const std::string path = request->url().path();
  if (!path.empty() && path[path.size() - 1] == '/') {
    return new fileapi::FileSystemDirURLRequestJob(
        request,
        fs_context,
        SimpleResourceLoaderBridge::GetIoThread());
  }
  return new fileapi::FileSystemURLRequestJob(
      request,
      fs_context,
      SimpleResourceLoaderBridge::GetIoThread());
}

TestShellRequestContextParams* g_request_context_params = NULL;
TestShellRequestContext* g_request_context = NULL;
base::Thread* g_cache_thread = NULL;

//-----------------------------------------------------------------------------

class IOThread : public base::Thread {
 public:
  IOThread() : base::Thread("IOThread") {
  }

  ~IOThread() {
    // We cannot rely on our base class to stop the thread since we want our
    // CleanUp function to run.
    Stop();
  }

  virtual void Init() {
    if (g_request_context_params) {
      g_request_context = new TestShellRequestContext(
          g_request_context_params->cache_path,
          g_request_context_params->cache_mode,
          g_request_context_params->no_proxy);
      SetAcceptAllCookies(g_request_context_params->accept_all_cookies);
      delete g_request_context_params;
      g_request_context_params = NULL;
    } else {
      g_request_context = new TestShellRequestContext();
      SetAcceptAllCookies(false);
    }

    g_request_context->AddRef();

    SimpleAppCacheSystem::InitializeOnIOThread(g_request_context);
    SimpleSocketStreamBridge::InitializeOnIOThread(g_request_context);
    SimpleFileWriter::InitializeOnIOThread(g_request_context);
    TestShellWebBlobRegistryImpl::InitializeOnIOThread(
        g_request_context->blob_storage_controller());

    net::URLRequest::RegisterProtocolFactory("blob", &BlobURLRequestJobFactory);
    net::URLRequest::RegisterProtocolFactory("filesystem",
                                             &FileSystemURLRequestJobFactory);
  }

  virtual void CleanUp() {
    // In reverse order of initialization.
    TestShellWebBlobRegistryImpl::Cleanup();
    SimpleFileWriter::CleanupOnIOThread();
    SimpleSocketStreamBridge::Cleanup();
    SimpleAppCacheSystem::CleanupOnIOThread();

    if (g_request_context) {
      g_request_context->Release();
      g_request_context = NULL;
    }
  }

  void SetAcceptAllCookies(bool accept_all_cookies) {
    StaticCookiePolicy::Type policy_type = accept_all_cookies ?
        StaticCookiePolicy::ALLOW_ALL_COOKIES :
        StaticCookiePolicy::BLOCK_SETTING_THIRD_PARTY_COOKIES;
    static_cast<StaticCookiePolicy*>(g_request_context->cookie_policy())->
        set_type(policy_type);
  }
};

IOThread* g_io_thread = NULL;

//-----------------------------------------------------------------------------

struct RequestParams {
  std::string method;
  GURL url;
  GURL first_party_for_cookies;
  GURL referrer;
  std::string headers;
  int load_flags;
  ResourceType::Type request_type;
  int appcache_host_id;
  bool download_to_file;
  scoped_refptr<net::UploadData> upload;
};

// The interval for calls to RequestProxy::MaybeUpdateUploadProgress
static const int kUpdateUploadProgressIntervalMsec = 100;

// The RequestProxy does most of its work on the IO thread.  The Start and
// Cancel methods are proxied over to the IO thread, where an net::URLRequest
// object is instantiated.
class RequestProxy : public net::URLRequest::Delegate,
                     public base::RefCountedThreadSafe<RequestProxy> {
 public:
  // Takes ownership of the params.
  RequestProxy()
      : download_to_file_(false),
        buf_(new net::IOBuffer(kDataSize)),
        last_upload_position_(0) {
  }

  void DropPeer() {
    peer_ = NULL;
  }

  void Start(ResourceLoaderBridge::Peer* peer, RequestParams* params) {
    peer_ = peer;
    owner_loop_ = MessageLoop::current();

    // proxy over to the io thread
    g_io_thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
        this, &RequestProxy::AsyncStart, params));
  }

  void Cancel() {
    // proxy over to the io thread
    g_io_thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
        this, &RequestProxy::AsyncCancel));
  }

 protected:
  friend class base::RefCountedThreadSafe<RequestProxy>;

  virtual ~RequestProxy() {
    // If we have a request, then we'd better be on the io thread!
    DCHECK(!request_.get() ||
           MessageLoop::current() == g_io_thread->message_loop());
  }

  // --------------------------------------------------------------------------
  // The following methods are called on the owner's thread in response to
  // various net::URLRequest callbacks.  The event hooks, defined below, trigger
  // these methods asynchronously.

  void NotifyReceivedRedirect(const GURL& new_url,
                              const ResourceResponseInfo& info) {
    bool has_new_first_party_for_cookies = false;
    GURL new_first_party_for_cookies;
    if (peer_ && peer_->OnReceivedRedirect(new_url, info,
                                           &has_new_first_party_for_cookies,
                                           &new_first_party_for_cookies)) {
      g_io_thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
          this, &RequestProxy::AsyncFollowDeferredRedirect,
          has_new_first_party_for_cookies, new_first_party_for_cookies));
    } else {
      Cancel();
    }
  }

  void NotifyReceivedResponse(const ResourceResponseInfo& info) {
    if (peer_)
      peer_->OnReceivedResponse(info);
  }

  void NotifyReceivedData(int bytes_read) {
    if (!peer_)
      return;

    // Make a local copy of buf_, since AsyncReadData reuses it.
    scoped_array<char> buf_copy(new char[bytes_read]);
    memcpy(buf_copy.get(), buf_->data(), bytes_read);

    // Continue reading more data into buf_
    // Note: Doing this before notifying our peer ensures our load events get
    // dispatched in a manner consistent with DumpRenderTree (and also avoids a
    // race condition).  If the order of the next 2 functions were reversed, the
    // peer could generate new requests in reponse to the received data, which
    // when run on the io thread, could race against this function in doing
    // another InvokeLater.  See bug 769249.
    g_io_thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
        this, &RequestProxy::AsyncReadData));

    peer_->OnReceivedData(buf_copy.get(), bytes_read, -1);
  }

  void NotifyDownloadedData(int bytes_read) {
    if (!peer_)
      return;

    // Continue reading more data, see the comment in NotifyReceivedData.
    g_io_thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
        this, &RequestProxy::AsyncReadData));

    peer_->OnDownloadedData(bytes_read);
  }

  void NotifyCompletedRequest(const net::URLRequestStatus& status,
                              const std::string& security_info,
                              const base::Time& complete_time) {
    if (peer_) {
      peer_->OnCompletedRequest(status, security_info, complete_time);
      DropPeer();  // ensure no further notifications
    }
  }

  void NotifyUploadProgress(uint64 position, uint64 size) {
    if (peer_)
      peer_->OnUploadProgress(position, size);
  }

  // --------------------------------------------------------------------------
  // The following methods are called on the io thread.  They correspond to
  // actions performed on the owner's thread.

  void AsyncStart(RequestParams* params) {
    // Might need to resolve the blob references in the upload data.
    if (params->upload) {
      static_cast<TestShellRequestContext*>(g_request_context)->
          blob_storage_controller()->ResolveBlobReferencesInUploadData(
              params->upload.get());
    }

    request_.reset(new net::URLRequest(params->url, this));
    request_->set_method(params->method);
    request_->set_first_party_for_cookies(params->first_party_for_cookies);
    request_->set_referrer(params->referrer.spec());
    net::HttpRequestHeaders headers;
    headers.AddHeadersFromString(params->headers);
    request_->SetExtraRequestHeaders(headers);
    request_->set_load_flags(params->load_flags);
    request_->set_upload(params->upload.get());
    request_->set_context(g_request_context);
    SimpleAppCacheSystem::SetExtraRequestInfo(
        request_.get(), params->appcache_host_id, params->request_type);

    download_to_file_ = params->download_to_file;
    if (download_to_file_) {
      FilePath path;
      if (file_util::CreateTemporaryFile(&path)) {
        downloaded_file_ = DeletableFileReference::GetOrCreate(
            path, base::MessageLoopProxy::CreateForCurrentThread());
        file_stream_.Open(
            path, base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_WRITE);
      }
    }

    request_->Start();

    if (request_->has_upload() &&
        params->load_flags & net::LOAD_ENABLE_UPLOAD_PROGRESS) {
      upload_progress_timer_.Start(
          base::TimeDelta::FromMilliseconds(kUpdateUploadProgressIntervalMsec),
          this, &RequestProxy::MaybeUpdateUploadProgress);
    }

    delete params;
  }

  void AsyncCancel() {
    // This can be null in cases where the request is already done.
    if (!request_.get())
      return;

    request_->Cancel();
    Done();
  }

  void AsyncFollowDeferredRedirect(bool has_new_first_party_for_cookies,
                                   const GURL& new_first_party_for_cookies) {
    // This can be null in cases where the request is already done.
    if (!request_.get())
      return;

    if (has_new_first_party_for_cookies)
      request_->set_first_party_for_cookies(new_first_party_for_cookies);
    request_->FollowDeferredRedirect();
  }

  void AsyncReadData() {
    // This can be null in cases where the request is already done.
    if (!request_.get())
      return;

    if (request_->status().is_success()) {
      int bytes_read;
      if (request_->Read(buf_, kDataSize, &bytes_read) && bytes_read) {
        OnReceivedData(bytes_read);
      } else if (!request_->status().is_io_pending()) {
        Done();
      }  // else wait for OnReadCompleted
    } else {
      Done();
    }
  }

  // --------------------------------------------------------------------------
  // The following methods are event hooks (corresponding to net::URLRequest
  // callbacks) that run on the IO thread.  They are designed to be overridden
  // by the SyncRequestProxy subclass.

  virtual void OnReceivedRedirect(
      const GURL& new_url,
      const ResourceResponseInfo& info,
      bool* defer_redirect) {
    *defer_redirect = true;  // See AsyncFollowDeferredRedirect
    owner_loop_->PostTask(FROM_HERE, NewRunnableMethod(
        this, &RequestProxy::NotifyReceivedRedirect, new_url, info));
  }

  virtual void OnReceivedResponse(
      const ResourceResponseInfo& info) {
    owner_loop_->PostTask(FROM_HERE, NewRunnableMethod(
        this, &RequestProxy::NotifyReceivedResponse, info));
  }

  virtual void OnReceivedData(int bytes_read) {
    if (download_to_file_) {
      file_stream_.Write(buf_->data(), bytes_read, NULL);
      owner_loop_->PostTask(FROM_HERE, NewRunnableMethod(
          this, &RequestProxy::NotifyDownloadedData, bytes_read));
      return;
    }

    owner_loop_->PostTask(FROM_HERE, NewRunnableMethod(
        this, &RequestProxy::NotifyReceivedData, bytes_read));
  }

  virtual void OnCompletedRequest(const net::URLRequestStatus& status,
                                  const std::string& security_info,
                                  const base::Time& complete_time) {
    if (download_to_file_)
      file_stream_.Close();
    owner_loop_->PostTask(FROM_HERE, NewRunnableMethod(
        this,
        &RequestProxy::NotifyCompletedRequest,
        status,
        security_info,
        complete_time));
  }

  // --------------------------------------------------------------------------
  // net::URLRequest::Delegate implementation:

  virtual void OnReceivedRedirect(net::URLRequest* request,
                                  const GURL& new_url,
                                  bool* defer_redirect) {
    DCHECK(request->status().is_success());
    ResourceResponseInfo info;
    PopulateResponseInfo(request, &info);
    OnReceivedRedirect(new_url, info, defer_redirect);
  }

  virtual void OnResponseStarted(net::URLRequest* request) {
    if (request->status().is_success()) {
      ResourceResponseInfo info;
      PopulateResponseInfo(request, &info);
      OnReceivedResponse(info);
      AsyncReadData();  // start reading
    } else {
      Done();
    }
  }

  virtual void OnSSLCertificateError(net::URLRequest* request,
                                     int cert_error,
                                     net::X509Certificate* cert) {
    // Allow all certificate errors.
    request->ContinueDespiteLastError();
  }

  virtual void OnReadCompleted(net::URLRequest* request, int bytes_read) {
    if (request->status().is_success() && bytes_read > 0) {
      OnReceivedData(bytes_read);
    } else {
      Done();
    }
  }

  // --------------------------------------------------------------------------
  // Helpers and data:

  void Done() {
    if (upload_progress_timer_.IsRunning()) {
      MaybeUpdateUploadProgress();
      upload_progress_timer_.Stop();
    }
    DCHECK(request_.get());
    OnCompletedRequest(request_->status(), std::string(), base::Time());
    request_.reset();  // destroy on the io thread
  }

  // Called on the IO thread.
  void MaybeUpdateUploadProgress() {
    // If a redirect is received upload is cancelled in net::URLRequest, we
    // should try to stop the |upload_progress_timer_| timer and return.
    if (!request_->has_upload()) {
      if (upload_progress_timer_.IsRunning())
        upload_progress_timer_.Stop();
      return;
    }

    uint64 size = request_->get_upload()->GetContentLength();
    uint64 position = request_->GetUploadProgress();
    if (position == last_upload_position_)
      return;  // no progress made since last time

    const uint64 kHalfPercentIncrements = 200;
    const base::TimeDelta kOneSecond = base::TimeDelta::FromMilliseconds(1000);

    uint64 amt_since_last = position - last_upload_position_;
    base::TimeDelta time_since_last = base::TimeTicks::Now() -
                                      last_upload_ticks_;

    bool is_finished = (size == position);
    bool enough_new_progress = (amt_since_last > (size /
                                                  kHalfPercentIncrements));
    bool too_much_time_passed = time_since_last > kOneSecond;

    if (is_finished || enough_new_progress || too_much_time_passed) {
      owner_loop_->PostTask(FROM_HERE, NewRunnableMethod(
          this, &RequestProxy::NotifyUploadProgress, position, size));
      last_upload_ticks_ = base::TimeTicks::Now();
      last_upload_position_ = position;
    }
  }

  void PopulateResponseInfo(net::URLRequest* request,
                            ResourceResponseInfo* info) const {
    info->request_time = request->request_time();
    info->response_time = request->response_time();
    info->headers = request->response_headers();
    request->GetMimeType(&info->mime_type);
    request->GetCharset(&info->charset);
    info->content_length = request->GetExpectedContentSize();
    if (downloaded_file_)
      info->download_file_path = downloaded_file_->path();
    SimpleAppCacheSystem::GetExtraResponseInfo(
        request,
        &info->appcache_id,
        &info->appcache_manifest_url);
  }

  scoped_ptr<net::URLRequest> request_;

  // Support for request.download_to_file behavior.
  bool download_to_file_;
  net::FileStream file_stream_;
  scoped_refptr<DeletableFileReference> downloaded_file_;

  // Size of our async IO data buffers
  static const int kDataSize = 16*1024;

  // read buffer for async IO
  scoped_refptr<net::IOBuffer> buf_;

  MessageLoop* owner_loop_;

  // This is our peer in WebKit (implemented as ResourceHandleInternal). We do
  // not manage its lifetime, and we may only access it from the owner's
  // message loop (owner_loop_).
  ResourceLoaderBridge::Peer* peer_;

  // Timer used to pull upload progress info.
  base::RepeatingTimer<RequestProxy> upload_progress_timer_;

  // Info used to determine whether or not to send an upload progress update.
  uint64 last_upload_position_;
  base::TimeTicks last_upload_ticks_;
};

//-----------------------------------------------------------------------------

class SyncRequestProxy : public RequestProxy {
 public:
  explicit SyncRequestProxy(ResourceLoaderBridge::SyncLoadResponse* result)
      : result_(result), event_(true, false) {
  }

  void WaitForCompletion() {
    if (!event_.Wait())
      NOTREACHED();
  }

  // --------------------------------------------------------------------------
  // Event hooks that run on the IO thread:

  virtual void OnReceivedRedirect(
      const GURL& new_url,
      const ResourceResponseInfo& info,
      bool* defer_redirect) {
    // TODO(darin): It would be much better if this could live in WebCore, but
    // doing so requires API changes at all levels.  Similar code exists in
    // WebCore/platform/network/cf/ResourceHandleCFNet.cpp :-(
    if (new_url.GetOrigin() != result_->url.GetOrigin()) {
      DLOG(WARNING) << "Cross origin redirect denied";
      Cancel();
      return;
    }
    result_->url = new_url;
  }

  virtual void OnReceivedResponse(const ResourceResponseInfo& info) {
    *static_cast<ResourceResponseInfo*>(result_) = info;
  }

  virtual void OnReceivedData(int bytes_read) {
    if (download_to_file_)
      file_stream_.Write(buf_->data(), bytes_read, NULL);
    else
      result_->data.append(buf_->data(), bytes_read);
    AsyncReadData();  // read more (may recurse)
  }

  virtual void OnCompletedRequest(const net::URLRequestStatus& status,
                                  const std::string& security_info,
                                  const base::Time& complete_time) {
    if (download_to_file_)
      file_stream_.Close();
    result_->status = status;
    event_.Signal();
  }

 private:
  ResourceLoaderBridge::SyncLoadResponse* result_;
  base::WaitableEvent event_;
};

//-----------------------------------------------------------------------------

class ResourceLoaderBridgeImpl : public ResourceLoaderBridge {
 public:
  ResourceLoaderBridgeImpl(
      const webkit_glue::ResourceLoaderBridge::RequestInfo& request_info)
      : params_(new RequestParams),
        proxy_(NULL) {
    params_->method = request_info.method;
    params_->url = request_info.url;
    params_->first_party_for_cookies = request_info.first_party_for_cookies;
    params_->referrer = request_info.referrer;
    params_->headers = request_info.headers;
    params_->load_flags = request_info.load_flags;
    params_->request_type = request_info.request_type;
    params_->appcache_host_id = request_info.appcache_host_id;
    params_->download_to_file = request_info.download_to_file;
  }

  virtual ~ResourceLoaderBridgeImpl() {
    if (proxy_) {
      proxy_->DropPeer();
      // Let the proxy die on the IO thread
      g_io_thread->message_loop()->ReleaseSoon(FROM_HERE, proxy_);
    }
  }

  // --------------------------------------------------------------------------
  // ResourceLoaderBridge implementation:

  virtual void AppendDataToUpload(const char* data, int data_len) {
    DCHECK(params_.get());
    if (!params_->upload)
      params_->upload = new net::UploadData();
    params_->upload->AppendBytes(data, data_len);
  }

  virtual void AppendFileRangeToUpload(
      const FilePath& file_path,
      uint64 offset,
      uint64 length,
      const base::Time& expected_modification_time) {
    DCHECK(params_.get());
    if (!params_->upload)
      params_->upload = new net::UploadData();
    params_->upload->AppendFileRange(file_path, offset, length,
                                     expected_modification_time);
  }

  virtual void AppendBlobToUpload(const GURL& blob_url) {
    DCHECK(params_.get());
    if (!params_->upload)
      params_->upload = new net::UploadData();
    params_->upload->AppendBlob(blob_url);
  }

  virtual void SetUploadIdentifier(int64 identifier) {
    DCHECK(params_.get());
    if (!params_->upload)
      params_->upload = new net::UploadData();
    params_->upload->set_identifier(identifier);
  }

  virtual bool Start(Peer* peer) {
    DCHECK(!proxy_);

    if (!SimpleResourceLoaderBridge::EnsureIOThread())
      return false;

    proxy_ = new RequestProxy();
    proxy_->AddRef();

    proxy_->Start(peer, params_.release());

    return true;  // Any errors will be reported asynchronously.
  }

  virtual void Cancel() {
    DCHECK(proxy_);
    proxy_->Cancel();
  }

  virtual void SetDefersLoading(bool value) {
    // TODO(darin): implement me
  }

  virtual void SyncLoad(SyncLoadResponse* response) {
    DCHECK(!proxy_);

    if (!SimpleResourceLoaderBridge::EnsureIOThread())
      return;

    // this may change as the result of a redirect
    response->url = params_->url;

    proxy_ = new SyncRequestProxy(response);
    proxy_->AddRef();

    proxy_->Start(NULL, params_.release());

    static_cast<SyncRequestProxy*>(proxy_)->WaitForCompletion();
  }

 private:
  // Ownership of params_ is transfered to the proxy when the proxy is created.
  scoped_ptr<RequestParams> params_;

  // The request proxy is allocated when we start the request, and then it
  // sticks around until this ResourceLoaderBridge is destroyed.
  RequestProxy* proxy_;
};

//-----------------------------------------------------------------------------

class CookieSetter : public base::RefCountedThreadSafe<CookieSetter> {
 public:
  void Set(const GURL& url, const std::string& cookie) {
    DCHECK(MessageLoop::current() == g_io_thread->message_loop());
    g_request_context->cookie_store()->SetCookie(url, cookie);
  }

 private:
  friend class base::RefCountedThreadSafe<CookieSetter>;

  ~CookieSetter() {}
};

class CookieGetter : public base::RefCountedThreadSafe<CookieGetter> {
 public:
  CookieGetter() : event_(false, false) {
  }

  void Get(const GURL& url) {
    result_ = g_request_context->cookie_store()->GetCookies(url);
    event_.Signal();
  }

  std::string GetResult() {
    if (!event_.Wait())
      NOTREACHED();
    return result_;
  }

 private:
  friend class base::RefCountedThreadSafe<CookieGetter>;

  ~CookieGetter() {}

  base::WaitableEvent event_;
  std::string result_;
};

}  // anonymous namespace

//-----------------------------------------------------------------------------

namespace webkit_glue {

// Factory function.
ResourceLoaderBridge* ResourceLoaderBridge::Create(
    const webkit_glue::ResourceLoaderBridge::RequestInfo& request_info) {
  return new ResourceLoaderBridgeImpl(request_info);
}

// Issue the proxy resolve request on the io thread, and wait
// for the result.
bool FindProxyForUrl(const GURL& url, std::string* proxy_list) {
  DCHECK(g_request_context);

  scoped_refptr<net::SyncProxyServiceHelper> sync_proxy_service(
      new net::SyncProxyServiceHelper(g_io_thread->message_loop(),
      g_request_context->proxy_service()));

  net::ProxyInfo proxy_info;
  int rv = sync_proxy_service->ResolveProxy(url, &proxy_info,
                                            net::BoundNetLog());
  if (rv == net::OK) {
    *proxy_list = proxy_info.ToPacString();
  }

  return rv == net::OK;
}

}  // namespace webkit_glue

//-----------------------------------------------------------------------------

// static
void SimpleResourceLoaderBridge::Init(
    const FilePath& cache_path,
    net::HttpCache::Mode cache_mode,
    bool no_proxy) {
  // Make sure to stop any existing IO thread since it may be using the
  // current request context.
  Shutdown();

  DCHECK(!g_request_context_params);
  DCHECK(!g_request_context);
  DCHECK(!g_io_thread);

  g_request_context_params = new TestShellRequestContextParams(
      cache_path, cache_mode, no_proxy);
}

// static
void SimpleResourceLoaderBridge::Shutdown() {
  if (g_io_thread) {
    delete g_io_thread;
    g_io_thread = NULL;

    DCHECK(g_cache_thread);
    delete g_cache_thread;
    g_cache_thread = NULL;

    DCHECK(!g_request_context) << "should have been nulled by thread dtor";
  } else {
    delete g_request_context_params;
    g_request_context_params = NULL;
  }
}

// static
void SimpleResourceLoaderBridge::SetCookie(const GURL& url,
                                           const GURL& first_party_for_cookies,
                                           const std::string& cookie) {
  // Proxy to IO thread to synchronize w/ network loading.

  if (!EnsureIOThread()) {
    NOTREACHED();
    return;
  }

  scoped_refptr<CookieSetter> cookie_setter(new CookieSetter());
  g_io_thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
      cookie_setter.get(), &CookieSetter::Set, url, cookie));
}

// static
std::string SimpleResourceLoaderBridge::GetCookies(
    const GURL& url, const GURL& first_party_for_cookies) {
  // Proxy to IO thread to synchronize w/ network loading

  if (!EnsureIOThread()) {
    NOTREACHED();
    return std::string();
  }

  scoped_refptr<CookieGetter> getter(new CookieGetter());

  g_io_thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
      getter.get(), &CookieGetter::Get, url));

  return getter->GetResult();
}

// static
bool SimpleResourceLoaderBridge::EnsureIOThread() {
  if (g_io_thread)
    return true;

#if defined(OS_MACOSX) || defined(OS_WIN)
  // We want to be sure to init NSPR on the main thread.
  crypto::EnsureNSPRInit();
#endif

  // Create the cache thread. We want the cache thread to outlive the IO thread,
  // so its lifetime is bonded to the IO thread lifetime.
  DCHECK(!g_cache_thread);
  g_cache_thread = new base::Thread("cache");
  CHECK(g_cache_thread->StartWithOptions(
      base::Thread::Options(MessageLoop::TYPE_IO, 0)));

  g_io_thread = new IOThread();
  base::Thread::Options options;
  options.message_loop_type = MessageLoop::TYPE_IO;
  return g_io_thread->StartWithOptions(options);
}

// static
void SimpleResourceLoaderBridge::SetAcceptAllCookies(bool accept_all_cookies) {
  if (g_request_context_params) {
    g_request_context_params->accept_all_cookies = accept_all_cookies;
    DCHECK(!g_request_context);
    DCHECK(!g_io_thread);
  } else {
    g_io_thread->SetAcceptAllCookies(accept_all_cookies);
  }
}

// static
scoped_refptr<base::MessageLoopProxy>
    SimpleResourceLoaderBridge::GetCacheThread() {
  return g_cache_thread->message_loop_proxy();
}

// static
scoped_refptr<base::MessageLoopProxy>
    SimpleResourceLoaderBridge::GetIoThread() {
  if (!EnsureIOThread()) {
    LOG(DFATAL) << "Failed to create IO thread.";
    return NULL;
  }
  return g_io_thread->message_loop_proxy();
}