// Copyright 2018 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/url_loader_throttle_provider_impl.h"

#include <utility>

#include "base/bind.h"
#include "base/command_line.h"
#include "base/feature_list.h"
#include "base/threading/thread_task_runner_handle.h"
#include "chrome/common/google_url_loader_throttle.h"
#include "chrome/common/prerender.mojom.h"
#include "chrome/common/prerender_url_loader_throttle.h"
#include "chrome/renderer/chrome_content_renderer_client.h"
#include "chrome/renderer/chrome_render_thread_observer.h"
#include "chrome/renderer/prerender/prerender_dispatcher.h"
#include "chrome/renderer/prerender/prerender_helper.h"
#include "chrome/renderer/subresource_redirect/subresource_redirect_params.h"
#include "chrome/renderer/subresource_redirect/subresource_redirect_url_loader_throttle.h"
#include "components/data_reduction_proxy/content/common/data_reduction_proxy_url_loader_throttle.h"
#include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
#include "components/data_reduction_proxy/core/common/data_reduction_proxy_throttle_manager.h"
#include "components/safe_browsing/features.h"
#include "components/safe_browsing/renderer/renderer_url_loader_throttle.h"
#include "content/public/common/content_features.h"
#include "content/public/common/service_names.mojom.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/render_thread.h"
#include "content/public/renderer/render_view.h"
#include "services/service_manager/public/cpp/connector.h"
#include "services/service_manager/public/cpp/interface_provider.h"
#include "url/gurl.h"

#if BUILDFLAG(ENABLE_EXTENSIONS)
#include "extensions/common/switches.h"
#include "extensions/renderer/extension_throttle_manager.h"
#include "extensions/renderer/guest_view/mime_handler_view/mime_handler_view_container.h"
#endif

#if defined(OS_CHROMEOS)
#include "chrome/renderer/chromeos_merge_session_loader_throttle.h"
#endif  // defined(OS_CHROMEOS)

namespace {

chrome::mojom::PrerenderCanceler* GetPrerenderCanceller(int render_frame_id) {
  content::RenderFrame* render_frame =
      content::RenderFrame::FromRoutingID(render_frame_id);
  if (!render_frame)
    return nullptr;
  prerender::PrerenderHelper* helper =
      prerender::PrerenderHelper::Get(render_frame);
  if (!helper)
    return nullptr;

  auto* canceler = new chrome::mojom::PrerenderCancelerPtr;
  render_frame->GetRemoteInterfaces()->GetInterface(canceler);
  base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, canceler);
  return canceler->get();
}

#if BUILDFLAG(ENABLE_EXTENSIONS)
std::unique_ptr<extensions::ExtensionThrottleManager>
CreateExtensionThrottleManager() {
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          extensions::switches::kDisableExtensionsHttpThrottling)) {
    return nullptr;
  }
  return std::make_unique<extensions::ExtensionThrottleManager>();
}

void SetExtensionThrottleManagerTestPolicy(
    extensions::ExtensionThrottleManager* extension_throttle_manager) {
  // Requests issued within within |kUserGestureWindowMs| of a user gesture
  // are also considered as user gestures (see
  // resource_dispatcher_host_impl.cc), so these tests need to bypass the
  // checking of the net::LOAD_MAYBE_USER_GESTURE load flag in the manager
  // in order to test the throttling logic.
  extension_throttle_manager->SetIgnoreUserGestureLoadFlagForTests(true);
  std::unique_ptr<net::BackoffEntry::Policy> policy(
      new net::BackoffEntry::Policy{
          // Number of initial errors (in sequence) to ignore before
          // applying exponential back-off rules.
          1,

          // Initial delay for exponential back-off in ms.
          10 * 60 * 1000,

          // Factor by which the waiting time will be multiplied.
          10,

          // Fuzzing percentage. ex: 10% will spread requests randomly
          // between 90%-100% of the calculated time.
          0.1,

          // Maximum amount of time we are willing to delay our request in ms.
          15 * 60 * 1000,

          // Time to keep an entry from being discarded even when it
          // has no significant state, -1 to never discard.
          -1,

          // Don't use initial delay unless the last request was an error.
          false,
      });
  extension_throttle_manager->SetBackoffPolicyForTests(std::move(policy));
}
#endif

}  // namespace

URLLoaderThrottleProviderImpl::URLLoaderThrottleProviderImpl(
    content::URLLoaderThrottleProviderType type,
    ChromeContentRendererClient* chrome_content_renderer_client)
    : type_(type),
      chrome_content_renderer_client_(chrome_content_renderer_client) {
  DETACH_FROM_THREAD(thread_checker_);

  content::RenderThread::Get()->GetConnector()->BindInterface(
      content::mojom::kBrowserServiceName,
      mojo::MakeRequest(&safe_browsing_info_));

  if (data_reduction_proxy::params::IsEnabledWithNetworkService()) {
    content::RenderThread::Get()->GetConnector()->BindInterface(
        content::mojom::kBrowserServiceName,
        mojo::MakeRequest(&data_reduction_proxy_info_));
  }
}

URLLoaderThrottleProviderImpl::~URLLoaderThrottleProviderImpl() {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
}

URLLoaderThrottleProviderImpl::URLLoaderThrottleProviderImpl(
    const URLLoaderThrottleProviderImpl& other)
    : type_(other.type_),
      chrome_content_renderer_client_(other.chrome_content_renderer_client_) {
  DETACH_FROM_THREAD(thread_checker_);
  if (other.safe_browsing_)
    other.safe_browsing_->Clone(mojo::MakeRequest(&safe_browsing_info_));
  if (other.data_reduction_proxy_) {
    other.data_reduction_proxy_->Clone(
        mojo::MakeRequest(&data_reduction_proxy_info_));
  }
  // An ad_delay_factory_ is created, rather than cloning the existing one.
}

std::unique_ptr<content::URLLoaderThrottleProvider>
URLLoaderThrottleProviderImpl::Clone() {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
  if (safe_browsing_info_)
    safe_browsing_.Bind(std::move(safe_browsing_info_));
  if (data_reduction_proxy_info_)
    data_reduction_proxy_.Bind(std::move(data_reduction_proxy_info_));
  return base::WrapUnique(new URLLoaderThrottleProviderImpl(*this));
}

std::vector<std::unique_ptr<blink::URLLoaderThrottle>>
URLLoaderThrottleProviderImpl::CreateThrottles(
    int render_frame_id,
    const blink::WebURLRequest& request,
    content::ResourceType resource_type) {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);

  std::vector<std::unique_ptr<blink::URLLoaderThrottle>> throttles;

  // Some throttles have already been added in the browser for frame resources.
  // Don't add them for frame requests.
  bool is_frame_resource = content::IsResourceTypeFrame(resource_type);

  DCHECK(!is_frame_resource ||
         type_ == content::URLLoaderThrottleProviderType::kFrame);

  if (data_reduction_proxy::params::IsEnabledWithNetworkService()) {
    if (data_reduction_proxy_info_)
      data_reduction_proxy_.Bind(std::move(data_reduction_proxy_info_));
    if (!data_reduction_proxy_manager_) {
      data_reduction_proxy_manager_ = std::make_unique<
          data_reduction_proxy::DataReductionProxyThrottleManager>(
          data_reduction_proxy_.get(),
          data_reduction_proxy::mojom::DataReductionProxyThrottleConfigPtr());
    }
    throttles.push_back(
        std::make_unique<
            data_reduction_proxy::DataReductionProxyURLLoaderThrottle>(
            net::HttpRequestHeaders(), data_reduction_proxy_manager_.get()));
  }

  if (!is_frame_resource) {
    if (safe_browsing_info_)
      safe_browsing_.Bind(std::move(safe_browsing_info_));
    throttles.push_back(
        std::make_unique<safe_browsing::RendererURLLoaderThrottle>(
            safe_browsing_.get(), render_frame_id));
  }

  if (type_ == content::URLLoaderThrottleProviderType::kFrame &&
      !is_frame_resource) {
    content::RenderFrame* render_frame =
        content::RenderFrame::FromRoutingID(render_frame_id);
    auto* prerender_helper =
        render_frame ? prerender::PrerenderHelper::Get(
                           render_frame->GetRenderView()->GetMainRenderFrame())
                     : nullptr;
    if (prerender_helper) {
      auto throttle = std::make_unique<prerender::PrerenderURLLoaderThrottle>(
          prerender_helper->prerender_mode(),
          prerender_helper->histogram_prefix(),
          base::BindOnce(GetPrerenderCanceller, render_frame_id),
          base::ThreadTaskRunnerHandle::Get());
      prerender_helper->AddThrottle(throttle->AsWeakPtr());
      if (prerender_helper->prerender_mode() == prerender::PREFETCH_ONLY) {
        auto* prerender_dispatcher =
            chrome_content_renderer_client_->prerender_dispatcher();
        prerender_dispatcher->IncrementPrefetchCount();
        throttle->set_destruction_closure(base::BindOnce(
            &prerender::PrerenderDispatcher::DecrementPrefetchCount,
            base::Unretained(prerender_dispatcher)));
      }
      throttles.push_back(std::move(throttle));
    }
  }

#if BUILDFLAG(ENABLE_EXTENSIONS)
  if (type_ == content::URLLoaderThrottleProviderType::kFrame &&
      resource_type == content::ResourceType::kObject) {
    content::RenderFrame* render_frame =
        content::RenderFrame::FromRoutingID(render_frame_id);
    auto mime_handlers =
        extensions::MimeHandlerViewContainer::FromRenderFrame(render_frame);
    GURL gurl(request.Url());
    for (auto* handler : mime_handlers) {
      auto throttle = handler->MaybeCreatePluginThrottle(gurl);
      if (throttle) {
        throttles.push_back(std::move(throttle));
        break;
      }
    }
  }

  if (!extension_throttle_manager_)
    extension_throttle_manager_ = CreateExtensionThrottleManager();

  if (extension_throttle_manager_) {
    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
            extensions::switches::kSetExtensionThrottleTestParams)) {
      SetExtensionThrottleManagerTestPolicy(extension_throttle_manager_.get());
    }

    std::unique_ptr<blink::URLLoaderThrottle> throttle =
        extension_throttle_manager_->MaybeCreateURLLoaderThrottle(request);
    if (throttle)
      throttles.push_back(std::move(throttle));
  }
#endif

  throttles.push_back(std::make_unique<GoogleURLLoaderThrottle>(
      ChromeRenderThreadObserver::is_incognito_process(),
      ChromeRenderThreadObserver::GetDynamicParams()));

#if defined(OS_CHROMEOS)
  throttles.push_back(std::make_unique<MergeSessionLoaderThrottle>(
      chrome_content_renderer_client_->GetChromeObserver()
          ->chromeos_listener()));
#endif  // defined(OS_CHROMEOS)

  if (subresource_redirect::ShouldForceEnableSubresourceRedirect() &&
      resource_type == content::ResourceType::kImage &&
      GURL(request.Url()).SchemeIs(url::kHttpsScheme)) {
    throttles.push_back(
        std::make_unique<
            subresource_redirect::SubresourceRedirectURLLoaderThrottle>());
  }

  return throttles;
}

void URLLoaderThrottleProviderImpl::SetOnline(bool is_online) {
#if BUILDFLAG(ENABLE_EXTENSIONS)
  if (extension_throttle_manager_)
    extension_throttle_manager_->SetOnline(is_online);
#endif
}