third_party/WebKit/Source/core/dom/ModulatorImpl.cpp

// Copyright 2017 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 "core/dom/ModulatorImpl.h"

#include "core/dom/Document.h"
#include "core/dom/ExecutionContext.h"
#include "core/dom/ModuleMap.h"
#include "core/dom/ModuleScript.h"
#include "core/dom/ScriptModuleResolverImpl.h"
#include "core/dom/TaskRunnerHelper.h"
#include "core/frame/LocalFrame.h"
#include "core/loader/modulescript/ModuleScriptFetchRequest.h"
#include "core/loader/modulescript/ModuleScriptLoaderRegistry.h"
#include "core/loader/modulescript/ModuleTreeLinkerRegistry.h"
#include "platform/loader/fetch/ResourceFetcher.h"

namespace blink {

ModulatorImpl* ModulatorImpl::Create(RefPtr<ScriptState> script_state,
                                     Document& document) {
  return new ModulatorImpl(
      std::move(script_state),
      TaskRunnerHelper::Get(TaskType::kNetworking, &document),
      document.Fetcher());
}

ModulatorImpl::ModulatorImpl(RefPtr<ScriptState> script_state,
                             RefPtr<WebTaskRunner> task_runner,
                             ResourceFetcher* fetcher)
    : script_state_(std::move(script_state)),
      task_runner_(std::move(task_runner)),
      fetcher_(fetcher),
      map_(this, ModuleMap::Create(this)),
      loader_registry_(ModuleScriptLoaderRegistry::Create()),
      tree_linker_registry_(ModuleTreeLinkerRegistry::Create()),
      script_module_resolver_(ScriptModuleResolverImpl::Create(this)) {
  DCHECK(script_state_);
  DCHECK(task_runner_);
  DCHECK(fetcher_);
}

ModulatorImpl::~ModulatorImpl() {}

ReferrerPolicy ModulatorImpl::GetReferrerPolicy() {
  return GetExecutionContext()->GetReferrerPolicy();
}

SecurityOrigin* ModulatorImpl::GetSecurityOrigin() {
  return GetExecutionContext()->GetSecurityOrigin();
}

void ModulatorImpl::FetchTree(const ModuleScriptFetchRequest& request,
                              ModuleTreeClient* client) {
  // Step 1. Perform the internal module script graph fetching procedure given
  // url, settings object, destination, cryptographic nonce, parser state,
  // credentials mode, settings object, a new empty list, "client", and with the
  // top-level module fetch flag set. If the caller of this algorithm specified
  // custom perform the fetch steps, pass those along as well.

  // Note: "Fetch a module script graph" algorithm doesn't have "referrer" as
  // its argument.
  DCHECK(request.GetReferrer().IsNull());

  AncestorList empty_ancestor_list;
  FetchTreeInternal(request, empty_ancestor_list,
                    ModuleGraphLevel::kTopLevelModuleFetch, client);

  // Step 2. When the internal module script graph fetching procedure
  // asynchronously completes with result, asynchronously complete this
  // algorithm with result.
  // Note: We delegate to ModuleTreeLinker to notify ModuleTreeClient.
}

void ModulatorImpl::FetchTreeInternal(const ModuleScriptFetchRequest& request,
                                      const AncestorList& ancestor_list,
                                      ModuleGraphLevel level,
                                      ModuleTreeClient* client) {
  tree_linker_registry_->Fetch(request, ancestor_list, level, this, client);
}

void ModulatorImpl::FetchSingle(const ModuleScriptFetchRequest& request,
                                ModuleGraphLevel level,
                                SingleModuleClient* client) {
  map_->FetchSingleModuleScript(request, level, client);
}

void ModulatorImpl::FetchNewSingleModule(
    const ModuleScriptFetchRequest& request,
    ModuleGraphLevel level,
    ModuleScriptLoaderClient* client) {
  loader_registry_->Fetch(request, level, this, fetcher_.Get(), client);
}

ModuleScript* ModulatorImpl::GetFetchedModuleScript(const KURL& url) {
  return map_->GetFetchedModuleScript(url);
}

ScriptModule ModulatorImpl::CompileModule(
    const String& provided_source,
    const String& url_str,
    AccessControlStatus access_control_status) {
  // Implements Steps 3-6 of
  // https://html.spec.whatwg.org/multipage/webappapis.html#creating-a-module-script

  // Step 3. Let realm be the provided environment settings object's Realm.
  // Note: Realm is v8::Context.

  // Step 4. If scripting is disabled for the given environment settings
  // object's responsible browsing context, then let script source be the empty
  // string. Otherwise, let script source be the provided script source.
  String script_source;
  if (GetExecutionContext()->CanExecuteScripts(kAboutToExecuteScript))
    script_source = provided_source;

  // Step 5. Let result be ParseModule(script source, realm, script).
  // Step 6. If result is a List of errors, report the exception given by the
  // first element of result for script, return null, and abort these steps.
  // Note: reporting is routed via V8Initializer::messageHandlerInMainThread.
  ScriptState::Scope scope(script_state_.Get());
  return ScriptModule::Compile(script_state_->GetIsolate(), script_source,
                               url_str, access_control_status);
}

ScriptValue ModulatorImpl::InstantiateModule(ScriptModule script_module) {
  ScriptState::Scope scope(script_state_.Get());
  return script_module.Instantiate(script_state_.Get());
}

Vector<String> ModulatorImpl::ModuleRequestsFromScriptModule(
    ScriptModule script_module) {
  ScriptState::Scope scope(script_state_.Get());
  return script_module.ModuleRequests(script_state_.Get());
}

inline ExecutionContext* ModulatorImpl::GetExecutionContext() const {
  return ExecutionContext::From(script_state_.Get());
}

DEFINE_TRACE(ModulatorImpl) {
  Modulator::Trace(visitor);
  visitor->Trace(fetcher_);
  visitor->Trace(map_);
  visitor->Trace(loader_registry_);
  visitor->Trace(tree_linker_registry_);
  visitor->Trace(script_module_resolver_);
}

DEFINE_TRACE_WRAPPERS(ModulatorImpl) {
  visitor->TraceWrappers(map_);
}

}  // namespace blink