Hide ProtocolHandler implementation

Move ProtocolHandler implementation and fields into DBusProtocolHandler
and extract a ProtocolHandler interface.

Bug: 25932908
Test: `mmma -j16 system/webservd`

Change-Id: I9100387f331e899da9bf44202ce2becf5fad4895
diff --git a/libwebserv/dbus_protocol_handler.cc b/libwebserv/dbus_protocol_handler.cc
new file mode 100644
index 0000000..ff7e8b9
--- /dev/null
+++ b/libwebserv/dbus_protocol_handler.cc
@@ -0,0 +1,318 @@
+// Copyright 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "libwebserv/dbus_protocol_handler.h"
+
+#include <tuple>
+
+#include <base/logging.h>
+#include <brillo/map_utils.h>
+#include <brillo/streams/file_stream.h>
+#include <brillo/streams/stream_utils.h>
+
+#include "dbus_bindings/org.chromium.WebServer.RequestHandler.h"
+#include "libwebserv/dbus_server.h"
+#include "libwebserv/protocol_handler.h"
+#include "libwebserv/request.h"
+#include "libwebserv/request_handler_callback.h"
+#include "libwebserv/response_impl.h"
+#include "webservd/dbus-proxies.h"
+
+namespace libwebserv {
+
+namespace {
+
+// Dummy callback for async D-Bus errors.
+void IgnoreDBusError(brillo::Error* error) {}
+
+// Copies the data from |src_stream| to the destination stream represented
+// by a file descriptor |fd|.
+void WriteResponseData(brillo::StreamPtr src_stream,
+                       const dbus::FileDescriptor& fd) {
+  int dupfd = dup(fd.value());
+  auto dest_stream =
+      brillo::FileStream::FromFileDescriptor(dupfd, true, nullptr);
+  CHECK(dest_stream);
+  // Dummy callbacks for success/error of data-copy operation. We ignore both
+  // notifications here.
+  auto on_success = [](brillo::StreamPtr, brillo::StreamPtr, uint64_t) {};
+  auto on_error = [](brillo::StreamPtr, brillo::StreamPtr,
+                     const brillo::Error*) {};
+  brillo::stream_utils::CopyData(
+      std::move(src_stream), std::move(dest_stream), base::Bind(on_success),
+      base::Bind(on_error));
+}
+
+}  // anonymous namespace
+
+DBusProtocolHandler::DBusProtocolHandler(const std::string& name,
+                                         DBusServer* server)
+    : name_{name}, server_{server} {
+}
+
+DBusProtocolHandler::~DBusProtocolHandler() {
+  // Remove any existing handlers, so the web server knows that we don't
+  // need them anymore.
+
+  // We need to get a copy of the map keys since removing the handlers will
+  // modify the map in the middle of the loop and that's not a good thing.
+  auto handler_ids = brillo::GetMapKeys(request_handlers_);
+  for (int handler_id : handler_ids) {
+    RemoveHandler(handler_id);
+  }
+}
+bool DBusProtocolHandler::IsConnected() const {
+  return !proxies_.empty();
+}
+
+std::string DBusProtocolHandler::GetName() const {
+  return name_;
+}
+
+std::set<uint16_t> DBusProtocolHandler::GetPorts() const {
+  std::set<uint16_t> ports;
+  for (const auto& pair : proxies_)
+    ports.insert(pair.second->port());
+  return ports;
+}
+
+std::set<std::string> DBusProtocolHandler::GetProtocols() const {
+  std::set<std::string> protocols;
+  for (const auto& pair : proxies_)
+    protocols.insert(pair.second->protocol());
+  return protocols;
+}
+
+brillo::Blob DBusProtocolHandler::GetCertificateFingerprint() const {
+  brillo::Blob fingerprint;
+  for (const auto& pair : proxies_) {
+    fingerprint = pair.second->certificate_fingerprint();
+    if (!fingerprint.empty())
+      break;
+  }
+  return fingerprint;
+}
+
+int DBusProtocolHandler::AddHandler(
+    const std::string& url,
+    const std::string& method,
+    std::unique_ptr<RequestHandlerInterface> handler) {
+  request_handlers_.emplace(
+      ++last_handler_id_,
+      HandlerMapEntry{url, method,
+                      std::map<ProtocolHandlerProxyInterface*, std::string>{},
+                      std::move(handler)});
+  // For each instance of remote protocol handler object sharing the same name,
+  // add the request handler.
+  for (const auto& pair : proxies_) {
+    pair.second->AddRequestHandlerAsync(
+        url,
+        method,
+        server_->service_name_,
+        base::Bind(&DBusProtocolHandler::AddHandlerSuccess,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   last_handler_id_,
+                   pair.second),
+        base::Bind(&DBusProtocolHandler::AddHandlerError,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   last_handler_id_));
+  }
+  return last_handler_id_;
+}
+
+int DBusProtocolHandler::AddHandlerCallback(
+    const std::string& url,
+    const std::string& method,
+    const base::Callback<RequestHandlerInterface::HandlerSignature>&
+        handler_callback) {
+  std::unique_ptr<RequestHandlerInterface> handler{
+      new RequestHandlerCallback{handler_callback}};
+  return AddHandler(url, method, std::move(handler));
+}
+
+bool DBusProtocolHandler::RemoveHandler(int handler_id) {
+  auto p = request_handlers_.find(handler_id);
+  if (p == request_handlers_.end())
+    return false;
+
+  for (const auto& pair : p->second.remote_handler_ids) {
+    pair.first->RemoveRequestHandlerAsync(
+        pair.second,
+        base::Bind(&base::DoNothing),
+        base::Bind(&IgnoreDBusError));
+  }
+
+  request_handlers_.erase(p);
+  return true;
+}
+
+void DBusProtocolHandler::Connect(ProtocolHandlerProxyInterface* proxy) {
+  proxies_.emplace(proxy->GetObjectPath(), proxy);
+  for (const auto& pair : request_handlers_) {
+    proxy->AddRequestHandlerAsync(
+        pair.second.url,
+        pair.second.method,
+        server_->service_name_,
+        base::Bind(&DBusProtocolHandler::AddHandlerSuccess,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   pair.first,
+                   proxy),
+        base::Bind(&DBusProtocolHandler::AddHandlerError,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   pair.first));
+  }
+}
+
+void DBusProtocolHandler::Disconnect(const dbus::ObjectPath& object_path) {
+  proxies_.erase(object_path);
+  if (proxies_.empty())
+    remote_handler_id_map_.clear();
+  for (auto& pair : request_handlers_)
+    pair.second.remote_handler_ids.clear();
+}
+
+void DBusProtocolHandler::AddHandlerSuccess(
+    int handler_id,
+    ProtocolHandlerProxyInterface* proxy,
+    const std::string& remote_handler_id) {
+  auto p = request_handlers_.find(handler_id);
+  CHECK(p != request_handlers_.end());
+  p->second.remote_handler_ids.emplace(proxy, remote_handler_id);
+
+  remote_handler_id_map_.emplace(remote_handler_id, handler_id);
+}
+
+void DBusProtocolHandler::AddHandlerError(int handler_id,
+                                          brillo::Error* error) {
+  // Nothing to do at the moment.
+}
+
+bool DBusProtocolHandler::ProcessRequest(const std::string& protocol_handler_id,
+                                     const std::string& remote_handler_id,
+                                     const std::string& request_id,
+                                     std::unique_ptr<Request> request,
+                                     brillo::ErrorPtr* error) {
+  request_id_map_.emplace(request_id, protocol_handler_id);
+  auto id_iter = remote_handler_id_map_.find(remote_handler_id);
+  if (id_iter == remote_handler_id_map_.end()) {
+    brillo::Error::AddToPrintf(error, FROM_HERE,
+                               brillo::errors::dbus::kDomain,
+                               DBUS_ERROR_FAILED,
+                               "Unknown request handler '%s'",
+                               remote_handler_id.c_str());
+    return false;
+  }
+  auto handler_iter = request_handlers_.find(id_iter->second);
+  if (handler_iter == request_handlers_.end()) {
+    brillo::Error::AddToPrintf(error, FROM_HERE,
+                               brillo::errors::dbus::kDomain,
+                               DBUS_ERROR_FAILED,
+                               "Handler # %d is no longer available",
+                               id_iter->second);
+    return false;
+  }
+  handler_iter->second.handler->HandleRequest(
+      std::move(request),
+      std::unique_ptr<Response>{new ResponseImpl{this, request_id}});
+  return true;
+}
+
+void DBusProtocolHandler::CompleteRequest(
+    const std::string& request_id,
+    int status_code,
+    const std::multimap<std::string, std::string>& headers,
+    brillo::StreamPtr data_stream) {
+  ProtocolHandlerProxyInterface* proxy =
+      GetRequestProtocolHandlerProxy(request_id);
+  if (!proxy)
+    return;
+
+  std::vector<std::tuple<std::string, std::string>> header_list;
+  header_list.reserve(headers.size());
+  for (const auto& pair : headers)
+    header_list.emplace_back(pair.first, pair.second);
+
+  int64_t data_size = -1;
+  if (data_stream->CanGetSize())
+    data_size = data_stream->GetRemainingSize();
+  proxy->CompleteRequestAsync(
+      request_id, status_code, header_list, data_size,
+      base::Bind(&WriteResponseData, base::Passed(&data_stream)),
+      base::Bind(&IgnoreDBusError));
+}
+
+void DBusProtocolHandler::GetFileData(
+    const std::string& request_id,
+    int file_id,
+    const base::Callback<void(brillo::StreamPtr)>& success_callback,
+    const base::Callback<void(brillo::Error*)>& error_callback) {
+  ProtocolHandlerProxyInterface* proxy =
+      GetRequestProtocolHandlerProxy(request_id);
+  CHECK(proxy);
+
+  // Store the success/error callback in a shared object so it can be referenced
+  // by the two wrapper callbacks. Since the original callbacks MAY contain
+  // move-only types, copying the base::Callback object is generally unsafe and
+  // may destroy the source object of the copy (despite the fact that it is
+  // constant). So, here we move both callbacks to |Callbacks| structure and
+  // use a shared pointer to it in both success and error callback wrappers.
+  struct Callbacks {
+    base::Callback<void(brillo::StreamPtr)> on_success;
+    base::Callback<void(brillo::Error*)> on_error;
+  };
+  auto callbacks = std::make_shared<Callbacks>();
+  callbacks->on_success = success_callback;
+  callbacks->on_error = error_callback;
+
+  auto on_success = [callbacks](const dbus::FileDescriptor& fd) {
+    brillo::ErrorPtr error;
+    // Unfortunately there is no way to take ownership of the file descriptor
+    // since |fd| is a const reference, so duplicate the descriptor.
+    int dupfd = dup(fd.value());
+    auto stream = brillo::FileStream::FromFileDescriptor(dupfd, true, &error);
+    if (!stream)
+      return callbacks->on_error.Run(error.get());
+    callbacks->on_success.Run(std::move(stream));
+  };
+  auto on_error = [callbacks](brillo::Error* error) {
+    callbacks->on_error.Run(error);
+  };
+
+  proxy->GetRequestFileDataAsync(request_id, file_id, base::Bind(on_success),
+                                 base::Bind(on_error));
+}
+
+DBusProtocolHandler::ProtocolHandlerProxyInterface*
+DBusProtocolHandler::GetRequestProtocolHandlerProxy(
+    const std::string& request_id) const {
+  auto iter = request_id_map_.find(request_id);
+  if (iter == request_id_map_.end()) {
+    LOG(ERROR) << "Can't find pending request with ID " << request_id;
+    return nullptr;
+  }
+  std::string handler_id = iter->second;
+  auto find_proxy_by_id = [handler_id](decltype(*proxies_.begin()) pair) {
+    return pair.second->id() == handler_id;
+  };
+  auto proxy_iter = std::find_if(proxies_.begin(), proxies_.end(),
+                                 find_proxy_by_id);
+  if (proxy_iter == proxies_.end()) {
+    LOG(WARNING) << "Completing a request after the handler proxy is removed";
+    return nullptr;
+  }
+  return proxy_iter->second;
+}
+
+
+}  // namespace libwebserv