brillo/http/http_transport_curl.cc - aosp/platform/external/libchromeos - Git at Google

 // Copyright 2014 The Chromium OS 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 <brillo/http/http_transport_curl.h>

 #include <limits>

 #include <base/bind.h>
 #include <base/logging.h>
 #include <base/message_loop/message_loop.h>
 #include <brillo/http/http_connection_curl.h>
 #include <brillo/http/http_request.h>
 #include <brillo/strings/string_utils.h>

 namespace {

 const char kCACertificatePath[] =
 #ifdef __ANDROID__
     "/system/etc/security/cacerts";
 #else
     "/usr/share/brillo-ca-certificates";
 #endif

 }  // namespace

 namespace brillo {
 namespace http {
 namespace curl {

 // This is a class that stores connection data on particular CURL socket
 // and provides file descriptor watcher to monitor read and/or write operations
 // on the socket's file descriptor.
 class Transport::SocketPollData : public base::MessageLoopForIO::Watcher {
  public:
   SocketPollData(const std::shared_ptr<CurlInterface>& curl_interface,
                  CURLM* curl_multi_handle,
                  Transport* transport,
                  curl_socket_t socket_fd)
       : curl_interface_(curl_interface),
         curl_multi_handle_(curl_multi_handle),
         transport_(transport),
         socket_fd_(socket_fd) {}

   // Returns the pointer for the socket-specific file descriptor watcher.
   base::MessageLoopForIO::FileDescriptorWatcher* GetWatcher() {
     return &file_descriptor_watcher_;
   }

  private:
   // Overrides from base::MessageLoopForIO::Watcher.
   void OnFileCanReadWithoutBlocking(int fd) override {
     OnSocketReady(fd, CURL_CSELECT_IN);
   }
   void OnFileCanWriteWithoutBlocking(int fd) override {
     OnSocketReady(fd, CURL_CSELECT_OUT);
   }

   // Data on the socket is available to be read from or written to.
   // Notify CURL of the action it needs to take on the socket file descriptor.
   void OnSocketReady(int fd, int action) {
     CHECK_EQ(socket_fd_, fd) << "Unexpected socket file descriptor";
     int still_running_count = 0;
     CURLMcode code = curl_interface_->MultiSocketAction(
         curl_multi_handle_, socket_fd_, action, &still_running_count);
     CHECK_NE(CURLM_CALL_MULTI_PERFORM, code)
         << "CURL should no longer return CURLM_CALL_MULTI_PERFORM here";

     if (code == CURLM_OK)
       transport_->ProcessAsyncCurlMessages();
   }

   // The CURL interface to use.
   std::shared_ptr<CurlInterface> curl_interface_;
   // CURL multi-handle associated with the transport.
   CURLM* curl_multi_handle_;
   // Transport object itself.
   Transport* transport_;
   // The socket file descriptor for the connection.
   curl_socket_t socket_fd_;
   // File descriptor watcher to notify us of asynchronous I/O on the FD.
   base::MessageLoopForIO::FileDescriptorWatcher file_descriptor_watcher_;

   DISALLOW_COPY_AND_ASSIGN(SocketPollData);
 };

 // The request data associated with an asynchronous operation on a particular
 // connection.
 struct Transport::AsyncRequestData {
   // Success/error callbacks to be invoked at the end of the request.
   SuccessCallback success_callback;
   ErrorCallback error_callback;
   // We store a connection here to make sure the object is alive for
   // as long as asynchronous operation is running.
   std::shared_ptr<Connection> connection;
   // The ID of this request.
   RequestID request_id;
 };

 Transport::Transport(const std::shared_ptr<CurlInterface>& curl_interface)
     : curl_interface_{curl_interface} {
   VLOG(2) << "curl::Transport created";
 }

 Transport::Transport(const std::shared_ptr<CurlInterface>& curl_interface,
                      const std::string& proxy)
     : curl_interface_{curl_interface}, proxy_{proxy} {
   VLOG(2) << "curl::Transport created with proxy " << proxy;
 }

 Transport::~Transport() {
   ShutDownAsyncCurl();
   VLOG(2) << "curl::Transport destroyed";
 }

 std::shared_ptr<http::Connection> Transport::CreateConnection(
     const std::string& url,
     const std::string& method,
     const HeaderList& headers,
     const std::string& user_agent,
     const std::string& referer,
     brillo::ErrorPtr* error) {
   std::shared_ptr<http::Connection> connection;
   CURL* curl_handle = curl_interface_->EasyInit();
   if (!curl_handle) {
     LOG(ERROR) << "Failed to initialize CURL";
     brillo::Error::AddTo(error, FROM_HERE, http::kErrorDomain,
                          "curl_init_failed", "Failed to initialize CURL");
     return connection;
   }

   LOG(INFO) << "Sending a " << method << " request to " << url;
   CURLcode code = curl_interface_->EasySetOptStr(curl_handle, CURLOPT_URL, url);

   if (code == CURLE_OK) {
     code = curl_interface_->EasySetOptStr(curl_handle, CURLOPT_CAPATH,
                                           kCACertificatePath);
   }
   if (code == CURLE_OK) {
     code =
         curl_interface_->EasySetOptInt(curl_handle, CURLOPT_SSL_VERIFYPEER, 1);
   }
   if (code == CURLE_OK) {
     code =
         curl_interface_->EasySetOptInt(curl_handle, CURLOPT_SSL_VERIFYHOST, 2);
   }
   if (code == CURLE_OK && !user_agent.empty()) {
     code = curl_interface_->EasySetOptStr(
         curl_handle, CURLOPT_USERAGENT, user_agent);
   }
   if (code == CURLE_OK && !referer.empty()) {
     code =
         curl_interface_->EasySetOptStr(curl_handle, CURLOPT_REFERER, referer);
   }
   if (code == CURLE_OK && !proxy_.empty()) {
     code = curl_interface_->EasySetOptStr(curl_handle, CURLOPT_PROXY, proxy_);
   }
   if (code == CURLE_OK) {
     int64_t timeout_ms = connection_timeout_.InMillisecondsRoundedUp();

     if (timeout_ms > 0 && timeout_ms <= std::numeric_limits<int>::max()) {
       code = curl_interface_->EasySetOptInt(
           curl_handle, CURLOPT_TIMEOUT_MS,
           static_cast<int>(timeout_ms));
     }
   }

   // Setup HTTP request method and optional request body.
   if (code == CURLE_OK) {
     if (method == request_type::kGet) {
       code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_HTTPGET, 1);
     } else if (method == request_type::kHead) {
       code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_NOBODY, 1);
     } else if (method == request_type::kPut) {
       code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_UPLOAD, 1);
     } else {
       // POST and custom request methods
       code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_POST, 1);
       if (code == CURLE_OK) {
         code = curl_interface_->EasySetOptPtr(
             curl_handle, CURLOPT_POSTFIELDS, nullptr);
       }
       if (code == CURLE_OK && method != request_type::kPost) {
         code = curl_interface_->EasySetOptStr(
             curl_handle, CURLOPT_CUSTOMREQUEST, method);
       }
     }
   }

   if (code != CURLE_OK) {
     AddEasyCurlError(error, FROM_HERE, code, curl_interface_.get());
     curl_interface_->EasyCleanup(curl_handle);
     return connection;
   }

   connection = std::make_shared<http::curl::Connection>(
       curl_handle, method, curl_interface_, shared_from_this());
   if (!connection->SendHeaders(headers, error)) {
     connection.reset();
   }
   return connection;
 }

 void Transport::RunCallbackAsync(const tracked_objects::Location& from_here,
                                  const base::Closure& callback) {
   base::MessageLoopForIO::current()->PostTask(from_here, callback);
 }

 RequestID Transport::StartAsyncTransfer(http::Connection* connection,
                                         const SuccessCallback& success_callback,
                                         const ErrorCallback& error_callback) {
   brillo::ErrorPtr error;
   if (!SetupAsyncCurl(&error)) {
     RunCallbackAsync(
         FROM_HERE, base::Bind(error_callback, 0, base::Owned(error.release())));
     return 0;
   }

   RequestID request_id = ++last_request_id_;

   auto curl_connection = static_cast<http::curl::Connection*>(connection);
   std::unique_ptr<AsyncRequestData> request_data{new AsyncRequestData};
   // Add the request data to |async_requests_| before adding the CURL handle
   // in case CURL feels like calling the socket callback synchronously which
   // will need the data to be in |async_requests_| map already.
   request_data->success_callback = success_callback;
   request_data->error_callback = error_callback;
   request_data->connection =
       std::static_pointer_cast<Connection>(curl_connection->shared_from_this());
   request_data->request_id = request_id;
   async_requests_.emplace(curl_connection, std::move(request_data));
   request_id_map_.emplace(request_id, curl_connection);

   // Add the connection's CURL handle to the multi-handle.
   CURLMcode code = curl_interface_->MultiAddHandle(
       curl_multi_handle_, curl_connection->curl_handle_);
   if (code != CURLM_OK) {
     brillo::ErrorPtr error;
     AddMultiCurlError(&error, FROM_HERE, code, curl_interface_.get());
     RunCallbackAsync(
         FROM_HERE, base::Bind(error_callback, 0, base::Owned(error.release())));
     async_requests_.erase(curl_connection);
     request_id_map_.erase(request_id);
     return 0;
   }
   LOG(INFO) << "Started asynchronous HTTP request with ID " << request_id;
   return request_id;
 }

 bool Transport::CancelRequest(RequestID request_id) {
   auto p = request_id_map_.find(request_id);
   if (p == request_id_map_.end()) {
     // The request must have been completed already...
     // This is not necessarily an error condition, so fail gracefully.
     LOG(WARNING) << "HTTP request #" << request_id << " not found";
     return false;
   }
   LOG(INFO) << "Canceling HTTP request #" << request_id;
   CleanAsyncConnection(p->second);
   return true;
 }

 void Transport::SetDefaultTimeout(base::TimeDelta timeout) {
   connection_timeout_ = timeout;
 }

 void Transport::AddEasyCurlError(brillo::ErrorPtr* error,
                                  const tracked_objects::Location& location,
                                  CURLcode code,
                                  CurlInterface* curl_interface) {
   brillo::Error::AddTo(error, location, "curl_easy_error",
                        brillo::string_utils::ToString(code),
                        curl_interface->EasyStrError(code));
 }

 void Transport::AddMultiCurlError(brillo::ErrorPtr* error,
                                   const tracked_objects::Location& location,
                                   CURLMcode code,
                                   CurlInterface* curl_interface) {
   brillo::Error::AddTo(error, location, "curl_multi_error",
                        brillo::string_utils::ToString(code),
                        curl_interface->MultiStrError(code));
 }

 bool Transport::SetupAsyncCurl(brillo::ErrorPtr* error) {
   if (curl_multi_handle_)
     return true;

   curl_multi_handle_ = curl_interface_->MultiInit();
   if (!curl_multi_handle_) {
     LOG(ERROR) << "Failed to initialize CURL";
     brillo::Error::AddTo(error, FROM_HERE, http::kErrorDomain,
                          "curl_init_failed", "Failed to initialize CURL");
     return false;
   }

   CURLMcode code = curl_interface_->MultiSetSocketCallback(
       curl_multi_handle_, &Transport::MultiSocketCallback, this);
   if (code == CURLM_OK) {
     code = curl_interface_->MultiSetTimerCallback(
         curl_multi_handle_, &Transport::MultiTimerCallback, this);
   }
   if (code != CURLM_OK) {
     AddMultiCurlError(error, FROM_HERE, code, curl_interface_.get());
     return false;
   }
   return true;
 }

 void Transport::ShutDownAsyncCurl() {
   if (!curl_multi_handle_)
     return;
   LOG_IF(WARNING, !poll_data_map_.empty())
       << "There are pending requests at the time of transport's shutdown";
   // Make sure we are not leaking any memory here.
   for (const auto& pair : poll_data_map_)
     delete pair.second;
   poll_data_map_.clear();
   curl_interface_->MultiCleanup(curl_multi_handle_);
   curl_multi_handle_ = nullptr;
 }

 int Transport::MultiSocketCallback(CURL* easy,
                                    curl_socket_t s,
                                    int what,
                                    void* userp,
                                    void* socketp) {
   auto transport = static_cast<Transport*>(userp);
   CHECK(transport) << "Transport must be set for this callback";
   auto poll_data = static_cast<SocketPollData*>(socketp);
   if (!poll_data) {
     // We haven't attached polling data to this socket yet. Let's do this now.
     poll_data = new SocketPollData{transport->curl_interface_,
                                    transport->curl_multi_handle_,
                                    transport,
                                    s};
     transport->poll_data_map_.emplace(std::make_pair(easy, s), poll_data);
     transport->curl_interface_->MultiAssign(
         transport->curl_multi_handle_, s, poll_data);
   }

   if (what == CURL_POLL_NONE) {
     return 0;
   } else if (what == CURL_POLL_REMOVE) {
     // Remove the attached data from the socket.
     transport->curl_interface_->MultiAssign(
         transport->curl_multi_handle_, s, nullptr);
     transport->poll_data_map_.erase(std::make_pair(easy, s));

     // Make sure we stop watching the socket file descriptor now, before
     // we schedule the SocketPollData for deletion.
     poll_data->GetWatcher()->StopWatchingFileDescriptor();
     // This method can be called indirectly from SocketPollData::OnSocketReady,
     // so delay destruction of SocketPollData object till the next loop cycle.
     base::MessageLoopForIO::current()->DeleteSoon(FROM_HERE, poll_data);
     return 0;
   }

   base::MessageLoopForIO::Mode watch_mode = base::MessageLoopForIO::WATCH_READ;
   switch (what) {
     case CURL_POLL_IN:
       watch_mode = base::MessageLoopForIO::WATCH_READ;
       break;
     case CURL_POLL_OUT:
       watch_mode = base::MessageLoopForIO::WATCH_WRITE;
       break;
     case CURL_POLL_INOUT:
       watch_mode = base::MessageLoopForIO::WATCH_READ_WRITE;
       break;
     default:
       LOG(FATAL) << "Unknown CURL socket action: " << what;
       break;
   }

   // WatchFileDescriptor() can be called with the same controller object
   // (watcher) to amend the watch mode, however this has cumulative effect.
   // For example, if we were watching a file descriptor for READ operations
   // and now call it to watch for WRITE, it will end up watching for both
   // READ and WRITE. This is not what we want here, so stop watching the
   // file descriptor on previous controller before starting with a different
   // mode.
   if (!poll_data->GetWatcher()->StopWatchingFileDescriptor())
     LOG(WARNING) << "Failed to stop watching the previous socket descriptor";
   CHECK(base::MessageLoopForIO::current()->WatchFileDescriptor(
       s, true, watch_mode, poll_data->GetWatcher(), poll_data))
       << "Failed to watch the CURL socket.";
   return 0;
 }

 // CURL actually uses "long" types in callback signatures, so we must comply.
 int Transport::MultiTimerCallback(CURLM* multi,
                                   long timeout_ms,  // NOLINT(runtime/int)
                                   void* userp) {
   auto transport = static_cast<Transport*>(userp);
   // Cancel any previous timer callbacks.
   transport->weak_ptr_factory_for_timer_.InvalidateWeakPtrs();
   if (timeout_ms >= 0) {
     base::MessageLoopForIO::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&Transport::OnTimer,
                  transport->weak_ptr_factory_for_timer_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(timeout_ms));
   }
   return 0;
 }

 void Transport::OnTimer() {
   if (curl_multi_handle_) {
     int still_running_count = 0;
     curl_interface_->MultiSocketAction(
         curl_multi_handle_, CURL_SOCKET_TIMEOUT, 0, &still_running_count);
     ProcessAsyncCurlMessages();
   }
 }

 void Transport::ProcessAsyncCurlMessages() {
   CURLMsg* msg = nullptr;
   int msgs_left = 0;
   while ((msg = curl_interface_->MultiInfoRead(curl_multi_handle_,
                                                &msgs_left))) {
     if (msg->msg == CURLMSG_DONE) {
       // Async I/O complete for a connection. Invoke the user callbacks.
       Connection* connection = nullptr;
       CHECK_EQ(CURLE_OK,
                curl_interface_->EasyGetInfoPtr(
                    msg->easy_handle,
                    CURLINFO_PRIVATE,
                    reinterpret_cast<void**>(&connection)));
       CHECK(connection != nullptr);
       OnTransferComplete(connection, msg->data.result);
     }
   }
 }

 void Transport::OnTransferComplete(Connection* connection, CURLcode code) {
   auto p = async_requests_.find(connection);
   CHECK(p != async_requests_.end()) << "Unknown connection";
   AsyncRequestData* request_data = p->second.get();
   LOG(INFO) << "HTTP request # " << request_data->request_id
             << " has completed "
             << (code == CURLE_OK ? "successfully" : "with an error");
   if (code != CURLE_OK) {
     brillo::ErrorPtr error;
     AddEasyCurlError(&error, FROM_HERE, code, curl_interface_.get());
     RunCallbackAsync(FROM_HERE,
                      base::Bind(request_data->error_callback,
                                 p->second->request_id,
                                 base::Owned(error.release())));
   } else {
     LOG(INFO) << "Response: " << connection->GetResponseStatusCode() << " ("
               << connection->GetResponseStatusText() << ")";
     brillo::ErrorPtr error;
     // Rewind the response data stream to the beginning so the clients can
     // read the data back.
     const auto& stream = request_data->connection->response_data_stream_;
     if (stream && stream->CanSeek() && !stream->SetPosition(0, &error)) {
       RunCallbackAsync(FROM_HERE,
                        base::Bind(request_data->error_callback,
                                   p->second->request_id,
                                   base::Owned(error.release())));
     } else {
       std::unique_ptr<Response> resp{new Response{request_data->connection}};
       RunCallbackAsync(FROM_HERE,
                        base::Bind(request_data->success_callback,
                                   p->second->request_id,
                                   base::Passed(&resp)));
     }
   }
   // In case of an error on CURL side, we would have dispatched the error
   // callback and we need to clean up the current connection, however the
   // error callback has no reference to the connection itself and
   // |async_requests_| is the only reference to the shared pointer that
   // maintains the lifetime of |connection| and possibly even this Transport
   // object instance. As a result, if we call CleanAsyncConnection() directly,
   // there is a chance that this object might be deleted.
   // Instead, schedule an asynchronous task to clean up the connection.
   RunCallbackAsync(FROM_HERE,
                    base::Bind(&Transport::CleanAsyncConnection,
                               weak_ptr_factory_.GetWeakPtr(),
                               connection));
 }

 void Transport::CleanAsyncConnection(Connection* connection) {
   auto p = async_requests_.find(connection);
   CHECK(p != async_requests_.end()) << "Unknown connection";
   // Remove the request data from the map first, since this might be the only
   // reference to the Connection class and even possibly to this Transport.
   auto request_data = std::move(p->second);

   // Remove associated request ID.
   request_id_map_.erase(request_data->request_id);

   // Remove the connection's CURL handle from multi-handle.
   curl_interface_->MultiRemoveHandle(curl_multi_handle_,
                                      connection->curl_handle_);

   // Remove all the socket data associated with this connection.
   auto iter = poll_data_map_.begin();
   while (iter != poll_data_map_.end()) {
     if (iter->first.first == connection->curl_handle_)
       iter = poll_data_map_.erase(iter);
     else
       ++iter;
   }
   // Remove pending asynchronous request data.
   // This must be last since there is a chance of this object being
   // destroyed as the result. See the comment in Transport::OnTransferComplete.
   async_requests_.erase(p);
 }

 }  // namespace curl
 }  // namespace http
 }  // namespace brillo
	// Copyright 2014 The Chromium OS 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 <brillo/http/http_transport_curl.h>

	#include <limits>

	#include <base/bind.h>
	#include <base/logging.h>
	#include <base/message_loop/message_loop.h>
	#include <brillo/http/http_connection_curl.h>
	#include <brillo/http/http_request.h>
	#include <brillo/strings/string_utils.h>

	namespace {

	const char kCACertificatePath[] =
	#ifdef __ANDROID__
	"/system/etc/security/cacerts";
	#else
	"/usr/share/brillo-ca-certificates";
	#endif

	} // namespace

	namespace brillo {
	namespace http {
	namespace curl {

	// This is a class that stores connection data on particular CURL socket
	// and provides file descriptor watcher to monitor read and/or write operations
	// on the socket's file descriptor.
	class Transport::SocketPollData : public base::MessageLoopForIO::Watcher {
	public:
	SocketPollData(const std::shared_ptr<CurlInterface>& curl_interface,
	CURLM* curl_multi_handle,
	Transport* transport,
	curl_socket_t socket_fd)
	: curl_interface_(curl_interface),
	curl_multi_handle_(curl_multi_handle),
	transport_(transport),
	socket_fd_(socket_fd) {}

	// Returns the pointer for the socket-specific file descriptor watcher.
	base::MessageLoopForIO::FileDescriptorWatcher* GetWatcher() {
	return &file_descriptor_watcher_;
	}

	private:
	// Overrides from base::MessageLoopForIO::Watcher.
	void OnFileCanReadWithoutBlocking(int fd) override {
	OnSocketReady(fd, CURL_CSELECT_IN);
	}
	void OnFileCanWriteWithoutBlocking(int fd) override {
	OnSocketReady(fd, CURL_CSELECT_OUT);
	}

	// Data on the socket is available to be read from or written to.
	// Notify CURL of the action it needs to take on the socket file descriptor.
	void OnSocketReady(int fd, int action) {
	CHECK_EQ(socket_fd_, fd) << "Unexpected socket file descriptor";
	int still_running_count = 0;
	CURLMcode code = curl_interface_->MultiSocketAction(
	curl_multi_handle_, socket_fd_, action, &still_running_count);
	CHECK_NE(CURLM_CALL_MULTI_PERFORM, code)
	<< "CURL should no longer return CURLM_CALL_MULTI_PERFORM here";

	if (code == CURLM_OK)
	transport_->ProcessAsyncCurlMessages();
	}

	// The CURL interface to use.
	std::shared_ptr<CurlInterface> curl_interface_;
	// CURL multi-handle associated with the transport.
	CURLM* curl_multi_handle_;
	// Transport object itself.
	Transport* transport_;
	// The socket file descriptor for the connection.
	curl_socket_t socket_fd_;
	// File descriptor watcher to notify us of asynchronous I/O on the FD.
	base::MessageLoopForIO::FileDescriptorWatcher file_descriptor_watcher_;

	DISALLOW_COPY_AND_ASSIGN(SocketPollData);
	};

	// The request data associated with an asynchronous operation on a particular
	// connection.
	struct Transport::AsyncRequestData {
	// Success/error callbacks to be invoked at the end of the request.
	SuccessCallback success_callback;
	ErrorCallback error_callback;
	// We store a connection here to make sure the object is alive for
	// as long as asynchronous operation is running.
	std::shared_ptr<Connection> connection;
	// The ID of this request.
	RequestID request_id;
	};

	Transport::Transport(const std::shared_ptr<CurlInterface>& curl_interface)
	: curl_interface_{curl_interface} {
	VLOG(2) << "curl::Transport created";
	}

	Transport::Transport(const std::shared_ptr<CurlInterface>& curl_interface,
	const std::string& proxy)
	: curl_interface_{curl_interface}, proxy_{proxy} {
	VLOG(2) << "curl::Transport created with proxy " << proxy;
	}

	Transport::~Transport() {
	ShutDownAsyncCurl();
	VLOG(2) << "curl::Transport destroyed";
	}

	std::shared_ptr<http::Connection> Transport::CreateConnection(
	const std::string& url,
	const std::string& method,
	const HeaderList& headers,
	const std::string& user_agent,
	const std::string& referer,
	brillo::ErrorPtr* error) {
	std::shared_ptr<http::Connection> connection;
	CURL* curl_handle = curl_interface_->EasyInit();
	if (!curl_handle) {
	LOG(ERROR) << "Failed to initialize CURL";
	brillo::Error::AddTo(error, FROM_HERE, http::kErrorDomain,
	"curl_init_failed", "Failed to initialize CURL");
	return connection;
	}

	LOG(INFO) << "Sending a " << method << " request to " << url;
	CURLcode code = curl_interface_->EasySetOptStr(curl_handle, CURLOPT_URL, url);

	if (code == CURLE_OK) {
	code = curl_interface_->EasySetOptStr(curl_handle, CURLOPT_CAPATH,
	kCACertificatePath);
	}
	if (code == CURLE_OK) {
	code =
	curl_interface_->EasySetOptInt(curl_handle, CURLOPT_SSL_VERIFYPEER, 1);
	}
	if (code == CURLE_OK) {
	code =
	curl_interface_->EasySetOptInt(curl_handle, CURLOPT_SSL_VERIFYHOST, 2);
	}
	if (code == CURLE_OK && !user_agent.empty()) {
	code = curl_interface_->EasySetOptStr(
	curl_handle, CURLOPT_USERAGENT, user_agent);
	}
	if (code == CURLE_OK && !referer.empty()) {
	code =
	curl_interface_->EasySetOptStr(curl_handle, CURLOPT_REFERER, referer);
	}
	if (code == CURLE_OK && !proxy_.empty()) {
	code = curl_interface_->EasySetOptStr(curl_handle, CURLOPT_PROXY, proxy_);
	}
	if (code == CURLE_OK) {
	int64_t timeout_ms = connection_timeout_.InMillisecondsRoundedUp();

	if (timeout_ms > 0 && timeout_ms <= std::numeric_limits<int>::max()) {
	code = curl_interface_->EasySetOptInt(
	curl_handle, CURLOPT_TIMEOUT_MS,
	static_cast<int>(timeout_ms));
	}
	}

	// Setup HTTP request method and optional request body.
	if (code == CURLE_OK) {
	if (method == request_type::kGet) {
	code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_HTTPGET, 1);
	} else if (method == request_type::kHead) {
	code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_NOBODY, 1);
	} else if (method == request_type::kPut) {
	code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_UPLOAD, 1);
	} else {
	// POST and custom request methods
	code = curl_interface_->EasySetOptInt(curl_handle, CURLOPT_POST, 1);
	if (code == CURLE_OK) {
	code = curl_interface_->EasySetOptPtr(
	curl_handle, CURLOPT_POSTFIELDS, nullptr);
	}
	if (code == CURLE_OK && method != request_type::kPost) {
	code = curl_interface_->EasySetOptStr(
	curl_handle, CURLOPT_CUSTOMREQUEST, method);
	}
	}
	}

	if (code != CURLE_OK) {
	AddEasyCurlError(error, FROM_HERE, code, curl_interface_.get());
	curl_interface_->EasyCleanup(curl_handle);
	return connection;
	}

	connection = std::make_shared<http::curl::Connection>(
	curl_handle, method, curl_interface_, shared_from_this());
	if (!connection->SendHeaders(headers, error)) {
	connection.reset();
	}
	return connection;
	}

	void Transport::RunCallbackAsync(const tracked_objects::Location& from_here,
	const base::Closure& callback) {
	base::MessageLoopForIO::current()->PostTask(from_here, callback);
	}

	RequestID Transport::StartAsyncTransfer(http::Connection* connection,
	const SuccessCallback& success_callback,
	const ErrorCallback& error_callback) {
	brillo::ErrorPtr error;
	if (!SetupAsyncCurl(&error)) {
	RunCallbackAsync(
	FROM_HERE, base::Bind(error_callback, 0, base::Owned(error.release())));
	return 0;
	}

	RequestID request_id = ++last_request_id_;

	auto curl_connection = static_cast<http::curl::Connection*>(connection);
	std::unique_ptr<AsyncRequestData> request_data{new AsyncRequestData};
	// Add the request data to \|async_requests_\| before adding the CURL handle
	// in case CURL feels like calling the socket callback synchronously which
	// will need the data to be in \|async_requests_\| map already.
	request_data->success_callback = success_callback;
	request_data->error_callback = error_callback;
	request_data->connection =
	std::static_pointer_cast<Connection>(curl_connection->shared_from_this());
	request_data->request_id = request_id;
	async_requests_.emplace(curl_connection, std::move(request_data));
	request_id_map_.emplace(request_id, curl_connection);

	// Add the connection's CURL handle to the multi-handle.
	CURLMcode code = curl_interface_->MultiAddHandle(
	curl_multi_handle_, curl_connection->curl_handle_);
	if (code != CURLM_OK) {
	brillo::ErrorPtr error;
	AddMultiCurlError(&error, FROM_HERE, code, curl_interface_.get());
	RunCallbackAsync(
	FROM_HERE, base::Bind(error_callback, 0, base::Owned(error.release())));
	async_requests_.erase(curl_connection);
	request_id_map_.erase(request_id);
	return 0;
	}
	LOG(INFO) << "Started asynchronous HTTP request with ID " << request_id;
	return request_id;
	}

	bool Transport::CancelRequest(RequestID request_id) {
	auto p = request_id_map_.find(request_id);
	if (p == request_id_map_.end()) {
	// The request must have been completed already...
	// This is not necessarily an error condition, so fail gracefully.
	LOG(WARNING) << "HTTP request #" << request_id << " not found";
	return false;
	}
	LOG(INFO) << "Canceling HTTP request #" << request_id;
	CleanAsyncConnection(p->second);
	return true;
	}

	void Transport::SetDefaultTimeout(base::TimeDelta timeout) {
	connection_timeout_ = timeout;
	}

	void Transport::AddEasyCurlError(brillo::ErrorPtr* error,
	const tracked_objects::Location& location,
	CURLcode code,
	CurlInterface* curl_interface) {
	brillo::Error::AddTo(error, location, "curl_easy_error",
	brillo::string_utils::ToString(code),
	curl_interface->EasyStrError(code));
	}

	void Transport::AddMultiCurlError(brillo::ErrorPtr* error,
	const tracked_objects::Location& location,
	CURLMcode code,
	CurlInterface* curl_interface) {
	brillo::Error::AddTo(error, location, "curl_multi_error",
	brillo::string_utils::ToString(code),
	curl_interface->MultiStrError(code));
	}

	bool Transport::SetupAsyncCurl(brillo::ErrorPtr* error) {
	if (curl_multi_handle_)
	return true;

	curl_multi_handle_ = curl_interface_->MultiInit();
	if (!curl_multi_handle_) {
	LOG(ERROR) << "Failed to initialize CURL";
	brillo::Error::AddTo(error, FROM_HERE, http::kErrorDomain,
	"curl_init_failed", "Failed to initialize CURL");
	return false;
	}

	CURLMcode code = curl_interface_->MultiSetSocketCallback(
	curl_multi_handle_, &Transport::MultiSocketCallback, this);
	if (code == CURLM_OK) {
	code = curl_interface_->MultiSetTimerCallback(
	curl_multi_handle_, &Transport::MultiTimerCallback, this);
	}
	if (code != CURLM_OK) {
	AddMultiCurlError(error, FROM_HERE, code, curl_interface_.get());
	return false;
	}
	return true;
	}

	void Transport::ShutDownAsyncCurl() {
	if (!curl_multi_handle_)
	return;
	LOG_IF(WARNING, !poll_data_map_.empty())
	<< "There are pending requests at the time of transport's shutdown";
	// Make sure we are not leaking any memory here.
	for (const auto& pair : poll_data_map_)
	delete pair.second;
	poll_data_map_.clear();
	curl_interface_->MultiCleanup(curl_multi_handle_);
	curl_multi_handle_ = nullptr;
	}

	int Transport::MultiSocketCallback(CURL* easy,
	curl_socket_t s,
	int what,
	void* userp,
	void* socketp) {
	auto transport = static_cast<Transport*>(userp);
	CHECK(transport) << "Transport must be set for this callback";
	auto poll_data = static_cast<SocketPollData*>(socketp);
	if (!poll_data) {
	// We haven't attached polling data to this socket yet. Let's do this now.
	poll_data = new SocketPollData{transport->curl_interface_,
	transport->curl_multi_handle_,
	transport,
	s};
	transport->poll_data_map_.emplace(std::make_pair(easy, s), poll_data);
	transport->curl_interface_->MultiAssign(
	transport->curl_multi_handle_, s, poll_data);
	}

	if (what == CURL_POLL_NONE) {
	return 0;
	} else if (what == CURL_POLL_REMOVE) {
	// Remove the attached data from the socket.
	transport->curl_interface_->MultiAssign(
	transport->curl_multi_handle_, s, nullptr);
	transport->poll_data_map_.erase(std::make_pair(easy, s));

	// Make sure we stop watching the socket file descriptor now, before
	// we schedule the SocketPollData for deletion.
	poll_data->GetWatcher()->StopWatchingFileDescriptor();
	// This method can be called indirectly from SocketPollData::OnSocketReady,
	// so delay destruction of SocketPollData object till the next loop cycle.
	base::MessageLoopForIO::current()->DeleteSoon(FROM_HERE, poll_data);
	return 0;
	}

	base::MessageLoopForIO::Mode watch_mode = base::MessageLoopForIO::WATCH_READ;
	switch (what) {
	case CURL_POLL_IN:
	watch_mode = base::MessageLoopForIO::WATCH_READ;
	break;
	case CURL_POLL_OUT:
	watch_mode = base::MessageLoopForIO::WATCH_WRITE;
	break;
	case CURL_POLL_INOUT:
	watch_mode = base::MessageLoopForIO::WATCH_READ_WRITE;
	break;
	default:
	LOG(FATAL) << "Unknown CURL socket action: " << what;
	break;
	}

	// WatchFileDescriptor() can be called with the same controller object
	// (watcher) to amend the watch mode, however this has cumulative effect.
	// For example, if we were watching a file descriptor for READ operations
	// and now call it to watch for WRITE, it will end up watching for both
	// READ and WRITE. This is not what we want here, so stop watching the
	// file descriptor on previous controller before starting with a different
	// mode.
	if (!poll_data->GetWatcher()->StopWatchingFileDescriptor())
	LOG(WARNING) << "Failed to stop watching the previous socket descriptor";
	CHECK(base::MessageLoopForIO::current()->WatchFileDescriptor(
	s, true, watch_mode, poll_data->GetWatcher(), poll_data))
	<< "Failed to watch the CURL socket.";
	return 0;
	}

	// CURL actually uses "long" types in callback signatures, so we must comply.
	int Transport::MultiTimerCallback(CURLM* multi,
	long timeout_ms, // NOLINT(runtime/int)
	void* userp) {
	auto transport = static_cast<Transport*>(userp);
	// Cancel any previous timer callbacks.
	transport->weak_ptr_factory_for_timer_.InvalidateWeakPtrs();
	if (timeout_ms >= 0) {
	base::MessageLoopForIO::current()->PostDelayedTask(
	FROM_HERE,
	base::Bind(&Transport::OnTimer,
	transport->weak_ptr_factory_for_timer_.GetWeakPtr()),
	base::TimeDelta::FromMilliseconds(timeout_ms));
	}
	return 0;
	}

	void Transport::OnTimer() {
	if (curl_multi_handle_) {
	int still_running_count = 0;
	curl_interface_->MultiSocketAction(
	curl_multi_handle_, CURL_SOCKET_TIMEOUT, 0, &still_running_count);
	ProcessAsyncCurlMessages();
	}
	}

	void Transport::ProcessAsyncCurlMessages() {
	CURLMsg* msg = nullptr;
	int msgs_left = 0;
	while ((msg = curl_interface_->MultiInfoRead(curl_multi_handle_,
	&msgs_left))) {
	if (msg->msg == CURLMSG_DONE) {
	// Async I/O complete for a connection. Invoke the user callbacks.
	Connection* connection = nullptr;
	CHECK_EQ(CURLE_OK,
	curl_interface_->EasyGetInfoPtr(
	msg->easy_handle,
	CURLINFO_PRIVATE,
	reinterpret_cast<void**>(&connection)));
	CHECK(connection != nullptr);
	OnTransferComplete(connection, msg->data.result);
	}
	}
	}

	void Transport::OnTransferComplete(Connection* connection, CURLcode code) {
	auto p = async_requests_.find(connection);
	CHECK(p != async_requests_.end()) << "Unknown connection";
	AsyncRequestData* request_data = p->second.get();
	LOG(INFO) << "HTTP request # " << request_data->request_id
	<< " has completed "
	<< (code == CURLE_OK ? "successfully" : "with an error");
	if (code != CURLE_OK) {
	brillo::ErrorPtr error;
	AddEasyCurlError(&error, FROM_HERE, code, curl_interface_.get());
	RunCallbackAsync(FROM_HERE,
	base::Bind(request_data->error_callback,
	p->second->request_id,
	base::Owned(error.release())));
	} else {
	LOG(INFO) << "Response: " << connection->GetResponseStatusCode() << " ("
	<< connection->GetResponseStatusText() << ")";
	brillo::ErrorPtr error;
	// Rewind the response data stream to the beginning so the clients can
	// read the data back.
	const auto& stream = request_data->connection->response_data_stream_;
	if (stream && stream->CanSeek() && !stream->SetPosition(0, &error)) {
	RunCallbackAsync(FROM_HERE,
	base::Bind(request_data->error_callback,
	p->second->request_id,
	base::Owned(error.release())));
	} else {
	std::unique_ptr<Response> resp{new Response{request_data->connection}};
	RunCallbackAsync(FROM_HERE,
	base::Bind(request_data->success_callback,
	p->second->request_id,
	base::Passed(&resp)));
	}
	}
	// In case of an error on CURL side, we would have dispatched the error
	// callback and we need to clean up the current connection, however the
	// error callback has no reference to the connection itself and
	// \|async_requests_\| is the only reference to the shared pointer that
	// maintains the lifetime of \|connection\| and possibly even this Transport
	// object instance. As a result, if we call CleanAsyncConnection() directly,
	// there is a chance that this object might be deleted.
	// Instead, schedule an asynchronous task to clean up the connection.
	RunCallbackAsync(FROM_HERE,
	base::Bind(&Transport::CleanAsyncConnection,
	weak_ptr_factory_.GetWeakPtr(),
	connection));
	}

	void Transport::CleanAsyncConnection(Connection* connection) {
	auto p = async_requests_.find(connection);
	CHECK(p != async_requests_.end()) << "Unknown connection";
	// Remove the request data from the map first, since this might be the only
	// reference to the Connection class and even possibly to this Transport.
	auto request_data = std::move(p->second);

	// Remove associated request ID.
	request_id_map_.erase(request_data->request_id);

	// Remove the connection's CURL handle from multi-handle.
	curl_interface_->MultiRemoveHandle(curl_multi_handle_,
	connection->curl_handle_);

	// Remove all the socket data associated with this connection.
	auto iter = poll_data_map_.begin();
	while (iter != poll_data_map_.end()) {
	if (iter->first.first == connection->curl_handle_)
	iter = poll_data_map_.erase(iter);
	else
	++iter;
	}
	// Remove pending asynchronous request data.
	// This must be last since there is a chance of this object being
	// destroyed as the result. See the comment in Transport::OnTransferComplete.
	async_requests_.erase(p);
	}

	} // namespace curl
	} // namespace http
	} // namespace brillo