// Copyright 2014 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 "extensions/renderer/script_injection.h"

#include <map>
#include <utility>

#include "base/bind.h"
#include "base/feature_list.h"
#include "base/lazy_instance.h"
#include "base/macros.h"
#include "base/metrics/histogram_macros.h"
#include "base/timer/elapsed_timer.h"
#include "base/values.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/v8_value_converter.h"
#include "extensions/common/extension_features.h"
#include "extensions/common/extension_messages.h"
#include "extensions/common/identifiability_metrics.h"
#include "extensions/common/mojom/host_id.mojom.h"
#include "extensions/common/mojom/injection_type.mojom-shared.h"
#include "extensions/renderer/dom_activity_logger.h"
#include "extensions/renderer/extension_frame_helper.h"
#include "extensions/renderer/extensions_renderer_client.h"
#include "extensions/renderer/script_injection_callback.h"
#include "extensions/renderer/scripts_run_info.h"
#include "services/metrics/public/cpp/ukm_source_id.h"
#include "third_party/blink/public/platform/web_isolated_world_info.h"
#include "third_party/blink/public/platform/web_security_origin.h"
#include "third_party/blink/public/platform/web_string.h"
#include "third_party/blink/public/web/web_document.h"
#include "third_party/blink/public/web/web_local_frame.h"
#include "third_party/blink/public/web/web_script_source.h"
#include "url/gurl.h"

namespace extensions {

namespace {

using IsolatedWorldMap = std::map<std::string, int>;
base::LazyInstance<IsolatedWorldMap>::DestructorAtExit g_isolated_worlds =
    LAZY_INSTANCE_INITIALIZER;

const int64_t kInvalidRequestId = -1;

// The id of the next pending injection.
int64_t g_next_pending_id = 0;

// Gets the isolated world ID to use for the given |injection_host|. If no
// isolated world has been created for that |injection_host| one will be created
// and initialized.
int GetIsolatedWorldIdForInstance(const InjectionHost* injection_host) {
  static int g_next_isolated_world_id =
      ExtensionsRendererClient::Get()->GetLowestIsolatedWorldId();

  IsolatedWorldMap& isolated_worlds = g_isolated_worlds.Get();

  int id = 0;
  const std::string& key = injection_host->id().id;
  auto iter = isolated_worlds.find(key);
  if (iter != isolated_worlds.end()) {
    id = iter->second;
  } else {
    id = g_next_isolated_world_id++;
    // This map will tend to pile up over time, but realistically, you're never
    // going to have enough injection hosts for it to matter.
    isolated_worlds[key] = id;
  }

  blink::WebIsolatedWorldInfo info;
  info.security_origin =
      blink::WebSecurityOrigin::Create(injection_host->url());
  info.human_readable_name = blink::WebString::FromUTF8(injection_host->name());
  info.stable_id = blink::WebString::FromUTF8(key);

  const std::string* csp = injection_host->GetContentSecurityPolicy();
  if (csp)
    info.content_security_policy = blink::WebString::FromUTF8(*csp);

  // Even though there may be an existing world for this |injection_host|'s key,
  // the properties may have changed (e.g. due to an extension update).
  // Overwrite any existing entries.
  blink::SetIsolatedWorldInfo(id, info);

  return id;
}

// This class manages its own lifetime.
class TimedScriptInjectionCallback : public ScriptInjectionCallback {
 public:
  TimedScriptInjectionCallback(base::WeakPtr<ScriptInjection> injection)
      : ScriptInjectionCallback(
            base::BindOnce(&TimedScriptInjectionCallback::OnCompleted,
                           base::Unretained(this))),
        injection_(injection) {}
  ~TimedScriptInjectionCallback() override {}

  void OnCompleted(const std::vector<v8::Local<v8::Value>>& result) {
    if (injection_) {
      base::TimeTicks timestamp(base::TimeTicks::Now());
      absl::optional<base::TimeDelta> elapsed;
      // If the script will never execute (such as if the context is destroyed),
      // willExecute() will not be called, but OnCompleted() will. Only log a
      // time for execution if the script, in fact, executed.
      if (!start_time_.is_null())
        elapsed = timestamp - start_time_;
      injection_->OnJsInjectionCompleted(result, elapsed);
    }
  }

  void WillExecute() override {
    start_time_ = base::TimeTicks::Now();
  }

 private:
  base::WeakPtr<ScriptInjection> injection_;
  base::TimeTicks start_time_;
};

}  // namespace

// Watches for the deletion of a RenderFrame, after which is_valid will return
// false.
class ScriptInjection::FrameWatcher : public content::RenderFrameObserver {
 public:
  FrameWatcher(content::RenderFrame* render_frame,
               ScriptInjection* injection)
      : content::RenderFrameObserver(render_frame),
        injection_(injection) {}
  ~FrameWatcher() override {}

 private:
  void WillDetach() override { injection_->invalidate_render_frame(); }
  void OnDestruct() override { injection_->invalidate_render_frame(); }

  ScriptInjection* injection_;

  DISALLOW_COPY_AND_ASSIGN(FrameWatcher);
};

// static
std::string ScriptInjection::GetHostIdForIsolatedWorld(int isolated_world_id) {
  const IsolatedWorldMap& isolated_worlds = g_isolated_worlds.Get();

  for (const auto& iter : isolated_worlds) {
    if (iter.second == isolated_world_id)
      return iter.first;
  }
  return std::string();
}

// static
void ScriptInjection::RemoveIsolatedWorld(const std::string& host_id) {
  g_isolated_worlds.Get().erase(host_id);
}

ScriptInjection::ScriptInjection(
    std::unique_ptr<ScriptInjector> injector,
    content::RenderFrame* render_frame,
    std::unique_ptr<const InjectionHost> injection_host,
    mojom::RunLocation run_location,
    bool log_activity)
    : injector_(std::move(injector)),
      render_frame_(render_frame),
      injection_host_(std::move(injection_host)),
      run_location_(run_location),
      request_id_(kInvalidRequestId),
      ukm_source_id_(ukm::SourceIdObj::FromInt64(
          render_frame_->GetWebFrame()->GetDocument().GetUkmSourceId())),
      complete_(false),
      did_inject_js_(false),
      log_activity_(log_activity),
      frame_watcher_(new FrameWatcher(render_frame, this)) {
  CHECK(injection_host_.get());
}

ScriptInjection::~ScriptInjection() {
  if (!complete_)
    NotifyWillNotInject(ScriptInjector::WONT_INJECT);
}

ScriptInjection::InjectionResult ScriptInjection::TryToInject(
    mojom::RunLocation current_location,
    ScriptsRunInfo* scripts_run_info,
    StatusUpdatedCallback async_updated_callback) {
  if (current_location < run_location_)
    return INJECTION_WAITING;  // Wait for the right location.

  if (request_id_ != kInvalidRequestId) {
    // We're waiting for permission right now, try again later.
    return INJECTION_WAITING;
  }

  if (!injection_host_) {
    NotifyWillNotInject(ScriptInjector::EXTENSION_REMOVED);
    return INJECTION_FINISHED;  // We're done.
  }

  blink::WebLocalFrame* web_frame = render_frame_->GetWebFrame();
  switch (injector_->CanExecuteOnFrame(
      injection_host_.get(), web_frame,
      ExtensionFrameHelper::Get(render_frame_)->tab_id())) {
    case PermissionsData::PageAccess::kDenied:
      NotifyWillNotInject(ScriptInjector::NOT_ALLOWED);
      return INJECTION_FINISHED;  // We're done.
    case PermissionsData::PageAccess::kWithheld:
      RequestPermissionFromBrowser(std::move(async_updated_callback));
      return INJECTION_WAITING;  // Wait around for permission.
    case PermissionsData::PageAccess::kAllowed:
      InjectionResult result = Inject(scripts_run_info);
      // If the injection is blocked, we need to set the manager so we can
      // notify it upon completion.
      if (result == INJECTION_BLOCKED)
        async_completion_callback_ = std::move(async_updated_callback);
      return result;
  }

  NOTREACHED();
  return INJECTION_FINISHED;
}

ScriptInjection::InjectionResult ScriptInjection::OnPermissionGranted(
    ScriptsRunInfo* scripts_run_info) {
  if (!injection_host_) {
    NotifyWillNotInject(ScriptInjector::EXTENSION_REMOVED);
    return INJECTION_FINISHED;
  }

  return Inject(scripts_run_info);
}

void ScriptInjection::OnHostRemoved() {
  injection_host_.reset(nullptr);
}

void ScriptInjection::RequestPermissionFromBrowser(
    StatusUpdatedCallback async_updated_callback) {
  // If we are just notifying the browser of the injection, then send an
  // invalid request (which is treated like a notification).
  request_id_ = g_next_pending_id++;
  ExtensionFrameHelper::Get(render_frame_)
      ->GetLocalFrameHost()
      ->RequestScriptInjectionPermission(
          host_id().id, injector_->script_type(), run_location_,
          base::BindOnce(&ScriptInjection::HandlePermission,
                         weak_ptr_factory_.GetWeakPtr(),
                         std::move(async_updated_callback)));
}

void ScriptInjection::NotifyWillNotInject(
    ScriptInjector::InjectFailureReason reason) {
  complete_ = true;
  injector_->OnWillNotInject(reason);
}

void ScriptInjection::HandlePermission(
    StatusUpdatedCallback async_updated_callback,
    bool granted) {
  if (!granted)
    return;
  std::move(async_updated_callback).Run(InjectionStatus::kPermitted, this);
}

ScriptInjection::InjectionResult ScriptInjection::Inject(
    ScriptsRunInfo* scripts_run_info) {
  DCHECK(injection_host_);
  DCHECK(scripts_run_info);
  DCHECK(!complete_);
  bool should_inject_js = injector_->ShouldInjectJs(
      run_location_, scripts_run_info->executing_scripts[host_id().id]);
  bool should_inject_or_remove_css = injector_->ShouldInjectOrRemoveCss(
      run_location_, scripts_run_info->injected_stylesheets[host_id().id]);

  // This can happen if the extension specified a script to
  // be run in multiple rules, and the script has already run.
  // See crbug.com/631247.
  if (!should_inject_js && !should_inject_or_remove_css) {
    return INJECTION_FINISHED;
  }

  if (should_inject_js)
    InjectJs(&(scripts_run_info->executing_scripts[host_id().id]),
             &(scripts_run_info->num_js));
  if (should_inject_or_remove_css)
    InjectOrRemoveCss(&(scripts_run_info->injected_stylesheets[host_id().id]),
                      &(scripts_run_info->num_css));

  complete_ = did_inject_js_ || !should_inject_js;

  if (complete_) {
    if (host_id().type == mojom::HostID::HostType::kExtensions)
      RecordContentScriptInjection(ukm_source_id_, host_id().id);
    injector_->OnInjectionComplete(std::move(execution_result_), run_location_);
  } else {
    ++scripts_run_info->num_blocking_js;
  }

  return complete_ ? INJECTION_FINISHED : INJECTION_BLOCKED;
}

void ScriptInjection::InjectJs(std::set<std::string>* executing_scripts,
                               size_t* num_injected_js_scripts) {
  DCHECK(!did_inject_js_);
  std::vector<blink::WebScriptSource> sources = injector_->GetJsSources(
      run_location_, executing_scripts, num_injected_js_scripts);
  DCHECK(!sources.empty());
  int world_id = GetIsolatedWorldIdForInstance(injection_host_.get());
  bool is_user_gesture = injector_->IsUserGesture();

  std::unique_ptr<blink::WebScriptExecutionCallback> callback(
      new TimedScriptInjectionCallback(weak_ptr_factory_.GetWeakPtr()));

  base::ElapsedTimer exec_timer;
  if (injection_host_->id().type == mojom::HostID::HostType::kExtensions &&
      log_activity_) {
    DOMActivityLogger::AttachToWorld(world_id, injection_host_->id().id);
  }

  // For content scripts executing during page load, we run them asynchronously
  // in order to reduce UI jank experienced by the user. (We don't do this for
  // kDocumentStart scripts, because there's no UI to jank until after those
  // run, so we run them as soon as we can.)
  // Note: We could potentially also run deferred and browser-driven scripts
  // asynchronously; however, these are rare enough that there probably isn't
  // UI jank. If this changes, we can update this.
  bool should_execute_asynchronously =
      injector_->script_type() == mojom::InjectionType::kContentScript &&
      (run_location_ == mojom::RunLocation::kDocumentEnd ||
       run_location_ == mojom::RunLocation::kDocumentIdle);
  blink::WebLocalFrame::ScriptExecutionType execution_option =
      should_execute_asynchronously
          ? blink::WebLocalFrame::kAsynchronousBlockingOnload
          : blink::WebLocalFrame::kSynchronous;

  render_frame_->GetWebFrame()->RequestExecuteScriptInIsolatedWorld(
      world_id, &sources.front(), sources.size(), is_user_gesture,
      execution_option, callback.release(),
      blink::BackForwardCacheAware::kPossiblyDisallow);
}

void ScriptInjection::OnJsInjectionCompleted(
    const std::vector<v8::Local<v8::Value>>& results,
    absl::optional<base::TimeDelta> elapsed) {
  DCHECK(!did_inject_js_);

  if (injection_host_->id().type == mojom::HostID::HostType::kExtensions &&
      elapsed) {
    UMA_HISTOGRAM_TIMES("Extensions.InjectedScriptExecutionTime", *elapsed);
    switch (run_location_) {
      case mojom::RunLocation::kDocumentStart:
        UMA_HISTOGRAM_TIMES(
            "Extensions.InjectedScriptExecutionTime.DocumentStart", *elapsed);
        break;
      case mojom::RunLocation::kDocumentEnd:
        UMA_HISTOGRAM_TIMES(
            "Extensions.InjectedScriptExecutionTime.DocumentEnd", *elapsed);
        break;
      case mojom::RunLocation::kDocumentIdle:
        UMA_HISTOGRAM_TIMES(
            "Extensions.InjectedScriptExecutionTime.DocumentIdle", *elapsed);
        break;
      default:
        break;
    }
  }

  bool expects_results = injector_->ExpectsResults();
  if (expects_results) {
    if (!results.empty() && !results.back().IsEmpty()) {
      // Right now, we only support returning single results (per frame).
      // It's safe to always use the main world context when converting
      // here. V8ValueConverterImpl shouldn't actually care about the
      // context scope, and it switches to v8::Object's creation context
      // when encountered.
      v8::Local<v8::Context> context =
          render_frame_->GetWebFrame()->MainWorldScriptContext();
      // We use the final result, since it is the most meaningful (the result
      // after running all scripts). Additionally, the final script can
      // reference values from the previous scripts, so could return them if
      // desired.
      execution_result_ = content::V8ValueConverter::Create()->FromV8Value(
          results.back(), context);
    }
    if (!execution_result_.get())
      execution_result_ = std::make_unique<base::Value>();
  }
  did_inject_js_ = true;
  if (host_id().type == mojom::HostID::HostType::kExtensions)
    RecordContentScriptInjection(ukm_source_id_, host_id().id);

  // If |async_completion_callback_| is set, it means the script finished
  // asynchronously, and we should run it.
  if (!async_completion_callback_.is_null()) {
    complete_ = true;
    injector_->OnInjectionComplete(std::move(execution_result_), run_location_);
    // Warning: this object can be destroyed after this line!
    std::move(async_completion_callback_).Run(InjectionStatus::kFinished, this);
  }
}

void ScriptInjection::InjectOrRemoveCss(
    std::set<std::string>* injected_stylesheets,
    size_t* num_injected_stylesheets) {
  std::vector<ScriptInjector::CSSSource> css_sources = injector_->GetCssSources(
      run_location_, injected_stylesheets, num_injected_stylesheets);
  blink::WebLocalFrame* web_frame = render_frame_->GetWebFrame();

  blink::WebDocument::CSSOrigin blink_css_origin =
      blink::WebDocument::kAuthorOrigin;
  switch (injector_->GetCssOrigin()) {
    case mojom::CSSOrigin::kUser:
      blink_css_origin = blink::WebDocument::kUserOrigin;
      break;
    case mojom::CSSOrigin::kAuthor:
      blink_css_origin = blink::WebDocument::kAuthorOrigin;
      break;
  }

  mojom::CSSInjection::Operation operation =
      injector_->GetCSSInjectionOperation();
  for (const auto& source : css_sources) {
    switch (operation) {
      case mojom::CSSInjection::Operation::kRemove:
        DCHECK(!source.key.IsEmpty())
            << "An injection key is required to remove CSS.";
        // CSS deletion can be thought of as the inverse of CSS injection
        // (i.e. x - y = x + -y and x | y = ~(~x & ~y)), so it is handled here
        // in the injection function.
        //
        // TODO(https://crbug.com/1116061): Extend this API's capabilities to
        // also remove CSS added by content scripts?
        web_frame->GetDocument().RemoveInsertedStyleSheet(source.key,
                                                          blink_css_origin);
        break;
      case mojom::CSSInjection::Operation::kAdd:
        web_frame->GetDocument().InsertStyleSheet(
            source.code, &source.key, blink_css_origin,
            blink::BackForwardCacheAware::kPossiblyDisallow);
        break;
    }
  }
}

}  // namespace extensions