third_party/WebKit/Source/core/workers/WorkletModuleResponsesMap.h

// 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.

#ifndef WorkletModuleResponsesMap_h
#define WorkletModuleResponsesMap_h

#include "core/CoreExport.h"
#include "core/loader/modulescript/ModuleScriptCreationParams.h"
#include "core/workers/WorkerOrWorkletModuleFetchCoordinator.h"
#include "platform/heap/Heap.h"
#include "platform/heap/HeapAllocator.h"
#include "platform/loader/fetch/FetchParameters.h"
#include "platform/loader/fetch/ResourceFetcher.h"
#include "platform/weborigin/KURL.h"
#include "platform/weborigin/KURLHash.h"

namespace blink {

// WorkletModuleResponsesMap implements the module responses map concept and the
// "fetch a worklet script" algorithm:
// https://drafts.css-houdini.org/worklets/#module-responses-map
// https://drafts.css-houdini.org/worklets/#fetch-a-worklet-script
//
// This acts as a cache for creation params (including source code) of module
// scripts, but also performs fetch when needed. The creation params are added
// and retrieved using Fetch(). If a module script for a given URL has already
// been fetched, Fetch() returns the cached creation params. Otherwise, Fetch()
// internally creates DocumentModuleScriptFetcher with thie ResourceFetcher that
// is given to its ctor. Once the module script is fetched, its creation params
// are cached and Fetch() returns it.
//
// TODO(nhiroki): Rename this to WorkletModuleFetchCoordinator, and revise the
// class-level comment.
class CORE_EXPORT WorkletModuleResponsesMap
    : public GarbageCollectedFinalized<WorkletModuleResponsesMap>,
      public WorkerOrWorkletModuleFetchCoordinator {
  USING_GARBAGE_COLLECTED_MIXIN(WorkletModuleResponsesMap);

 public:
  explicit WorkletModuleResponsesMap(ResourceFetcher*);

  // Fetches a module script. If the script is already fetched, synchronously
  // calls Client::OnFetched(). Otherwise, it's called on the completion of the
  // fetch. See also the class-level comment.
  void Fetch(FetchParameters&, Client*);

  // Invalidates an inflight module script fetch, and calls OnFailed() for
  // waiting clients.
  void Invalidate(const KURL&);

  // Called when the associated document is destroyed. Aborts all waiting
  // clients and clears the map. Following Fetch() calls are simply ignored.
  void Dispose();

  void Trace(blink::Visitor*);

 private:
  class Entry;

  bool is_available_ = true;

  Member<ResourceFetcher> fetcher_;

  // TODO(nhiroki): Keep the insertion order of top-level modules to replay
  // addModule() calls for a newly created global scope.
  // See https://drafts.css-houdini.org/worklets/#creating-a-workletglobalscope
  HeapHashMap<KURL, Member<Entry>> entries_;
};

}  // namespace blink

#endif  // WorkletModuleResponsesMap_h