// 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 "chrome/browser/renderer_host/download_throttling_resource_handler.h"

#include "chrome/browser/renderer_host/download_resource_handler.h"
#include "net/base/io_buffer.h"

DownloadThrottlingResourceHandler::DownloadThrottlingResourceHandler(
    ResourceDispatcherHost* host,
    URLRequest* request,
    const GURL& url,
    int render_process_host_id,
    int render_view_id,
    int request_id,
    bool in_complete)
    : host_(host),
      request_(request),
      url_(url),
      render_process_host_id_(render_process_host_id),
      render_view_id_(render_view_id),
      request_id_(request_id),
      tmp_buffer_length_(0),
      ignore_on_read_complete_(in_complete) {
  // Pause the request.
  host_->PauseRequest(render_process_host_id_, request_id_, true);
  host_->download_request_manager()->CanDownloadOnIOThread(
      render_process_host_id_, render_view_id, this);
 }

DownloadThrottlingResourceHandler::~DownloadThrottlingResourceHandler() {
}

bool DownloadThrottlingResourceHandler::OnUploadProgress(int request_id,
                                                         uint64 position,
                                                         uint64 size) {
  if (download_handler_.get())
    return download_handler_->OnUploadProgress(request_id, position, size);
  return true;
}

bool DownloadThrottlingResourceHandler::OnRequestRedirected(int request_id,
                                                            const GURL& url) {
  if (download_handler_.get())
    return download_handler_->OnRequestRedirected(request_id, url);
  url_ = url;
  return true;
}

bool DownloadThrottlingResourceHandler::OnResponseStarted(
    int request_id,
    ResourceResponse* response) {
  if (download_handler_.get())
    return download_handler_->OnResponseStarted(request_id, response);
  response_ = response;
  return true;
}

bool DownloadThrottlingResourceHandler::OnWillRead(int request_id,
                                                   net::IOBuffer** buf,
                                                   int* buf_size,
                                                   int min_size) {
  if (download_handler_.get())
    return download_handler_->OnWillRead(request_id, buf, buf_size, min_size);

  // We should only have this invoked once, as such we only deal with one
  // tmp buffer.
  DCHECK(!tmp_buffer_.get());
  if (min_size < 0)
    min_size = 1024;
  tmp_buffer_ = new net::IOBuffer(min_size);
  *buf = tmp_buffer_.get();
  *buf_size = min_size;
  return true;
}

bool DownloadThrottlingResourceHandler::OnReadCompleted(int request_id,
                                                        int* bytes_read) {
  if (ignore_on_read_complete_) {
    // See comments above definition for details on this.
    ignore_on_read_complete_ = false;
    return true;
  }
  if (!*bytes_read)
    return true;

  if (tmp_buffer_.get()) {
    DCHECK(!tmp_buffer_length_);
    tmp_buffer_length_ = *bytes_read;
    if (download_handler_.get())
      CopyTmpBufferToDownloadHandler();
    return true;
  }
  if (download_handler_.get())
    return download_handler_->OnReadCompleted(request_id, bytes_read);
  return true;
}

bool DownloadThrottlingResourceHandler::OnResponseCompleted(
    int request_id,
    const URLRequestStatus& status,
    const std::string& security_info) {
  if (download_handler_.get())
    return download_handler_->OnResponseCompleted(request_id, status,
                                                  security_info);

  // For a download, if ResourceDispatcher::Read() fails,
  // ResourceDispatcher::OnresponseStarted() will call
  // OnResponseCompleted(), and we will end up here with an error
  // status.
  if (!status.is_success())
    return false;
  NOTREACHED();
  return true;
}

void DownloadThrottlingResourceHandler::CancelDownload() {
  host_->CancelRequest(render_process_host_id_, request_id_, false);
}

void DownloadThrottlingResourceHandler::ContinueDownload() {
  DCHECK(!download_handler_.get());
  download_handler_ =
      new DownloadResourceHandler(host_,
                                  render_process_host_id_,
                                  render_view_id_,
                                  request_id_,
                                  url_,
                                  host_->download_file_manager(),
                                  request_,
                                  false);
  if (response_.get())
    download_handler_->OnResponseStarted(request_id_, response_.get());

  if (tmp_buffer_length_)
    CopyTmpBufferToDownloadHandler();

  // And let the request continue.
  host_->PauseRequest(render_process_host_id_, request_id_, false);
}

void DownloadThrottlingResourceHandler::CopyTmpBufferToDownloadHandler() {
  // Copy over the tmp buffer.
  net::IOBuffer* buffer;
  int buf_size;
  if (download_handler_->OnWillRead(request_id_, &buffer, &buf_size,
                                    tmp_buffer_length_)) {
    CHECK(buf_size >= tmp_buffer_length_);
    memcpy(buffer->data(), tmp_buffer_->data(), tmp_buffer_length_);
    download_handler_->OnReadCompleted(request_id_, &tmp_buffer_length_);
  }
  tmp_buffer_length_ = 0;
  tmp_buffer_ = NULL;
}