root/chrome/renderer/extensions/request_sender.cc

DEFINITIONS

1. previous_tab_id_
2. source_tab_id_
3. InsertRequest
4. RemoveRequest
5. GetNextRequestId
6. StartRequest
7. HandleResponse
8. InvalidateSource

// Copyright (c) 2012 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 "chrome/renderer/extensions/request_sender.h"

#include "base/values.h"
#include "chrome/renderer/extensions/chrome_v8_context.h"
#include "chrome/renderer/extensions/dispatcher.h"
#include "content/public/renderer/render_view.h"
#include "extensions/common/extension_messages.h"
#include "third_party/WebKit/public/web/WebDocument.h"
#include "third_party/WebKit/public/web/WebFrame.h"
#include "third_party/WebKit/public/web/WebUserGestureIndicator.h"

namespace extensions {

// Contains info relevant to a pending API request.
struct PendingRequest {
 public :
  PendingRequest(const std::string& name, RequestSender::Source* source)
      : name(name), source(source) {
  }

  std::string name;
  RequestSender::Source* source;
};

RequestSender::ScopedTabID::ScopedTabID(RequestSender* request_sender,
                                        int tab_id)
    : request_sender_(request_sender),
      tab_id_(tab_id),
      previous_tab_id_(request_sender->source_tab_id_) {
  request_sender_->source_tab_id_ = tab_id;
}

RequestSender::ScopedTabID::~ScopedTabID() {
  DCHECK_EQ(tab_id_, request_sender_->source_tab_id_);
  request_sender_->source_tab_id_ = previous_tab_id_;
}

RequestSender::RequestSender(Dispatcher* dispatcher)
    : dispatcher_(dispatcher),
      source_tab_id_(-1) {
}

RequestSender::~RequestSender() {
}

void RequestSender::InsertRequest(int request_id,
                                  PendingRequest* pending_request) {
  DCHECK_EQ(0u, pending_requests_.count(request_id));
  pending_requests_[request_id].reset(pending_request);
}

linked_ptr<PendingRequest> RequestSender::RemoveRequest(int request_id) {
  PendingRequestMap::iterator i = pending_requests_.find(request_id);
  if (i == pending_requests_.end())
    return linked_ptr<PendingRequest>();
  linked_ptr<PendingRequest> result = i->second;
  pending_requests_.erase(i);
  return result;
}

int RequestSender::GetNextRequestId() const {
  static int next_request_id = 0;
  return next_request_id++;
}

void RequestSender::StartRequest(Source* source,
                                 const std::string& name,
                                 int request_id,
                                 bool has_callback,
                                 bool for_io_thread,
                                 base::ListValue* value_args) {
  ChromeV8Context* context = source->GetContext();
  if (!context)
    return;

  // Get the current RenderView so that we can send a routed IPC message from
  // the correct source.
  content::RenderView* renderview = context->GetRenderView();
  if (!renderview)
    return;

  const std::set<std::string>& function_names = dispatcher_->function_names();
  if (function_names.find(name) == function_names.end()) {
    NOTREACHED() << "Unexpected function " << name <<
        ". Did you remember to register it with ExtensionFunctionRegistry?";
    return;
  }

  // TODO(koz): See if we can make this a CHECK.
  if (!dispatcher_->CheckContextAccessToExtensionAPI(name, context))
    return;

  GURL source_url;
  if (blink::WebFrame* webframe = context->web_frame())
    source_url = webframe->document().url();

  InsertRequest(request_id, new PendingRequest(name, source));

  ExtensionHostMsg_Request_Params params;
  params.name = name;
  params.arguments.Swap(value_args);
  params.extension_id = context->GetExtensionID();
  params.source_url = source_url;
  params.source_tab_id = source_tab_id_;
  params.request_id = request_id;
  params.has_callback = has_callback;
  params.user_gesture =
      blink::WebUserGestureIndicator::isProcessingUserGesture();
  if (for_io_thread) {
    renderview->Send(new ExtensionHostMsg_RequestForIOThread(
        renderview->GetRoutingID(), params));
  } else {
    renderview->Send(new ExtensionHostMsg_Request(
        renderview->GetRoutingID(), params));
  }
}

void RequestSender::HandleResponse(int request_id,
                                   bool success,
                                   const base::ListValue& response,
                                   const std::string& error) {
  linked_ptr<PendingRequest> request = RemoveRequest(request_id);

  if (!request.get()) {
    // This can happen if a context is destroyed while a request is in flight.
    return;
  }

  request->source->OnResponseReceived(request->name, request_id, success,
                                      response, error);
}

void RequestSender::InvalidateSource(Source* source) {
  for (PendingRequestMap::iterator it = pending_requests_.begin();
       it != pending_requests_.end();) {
    if (it->second->source == source)
      pending_requests_.erase(it++);
    else
      ++it;
  }
}

}  // namespace extensions