text: // 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.
  
  #ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_STORAGE_STORAGE_CONTROLLER_H_
  #define THIRD_PARTY_BLINK_RENDERER_MODULES_STORAGE_STORAGE_CONTROLLER_H_
  
  #include "base/callback.h"
  #include "base/sequence_checker.h"
  #include "mojo/public/cpp/bindings/pending_receiver.h"
  #include "mojo/public/cpp/bindings/receiver.h"
  #include "mojo/public/cpp/bindings/remote.h"
  #include "third_party/blink/public/common/dom_storage/session_storage_namespace_id.h"
  #include "third_party/blink/public/mojom/dom_storage/dom_storage.mojom-blink.h"
  #include "third_party/blink/renderer/modules/modules_export.h"
  #include "third_party/blink/renderer/modules/storage/storage_area.h"
  #include "third_party/blink/renderer/platform/heap/persistent.h"
  #include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
  
  namespace base {
  class SingleThreadTaskRunner;
  }
  
  namespace blink {
  
  class CachedStorageArea;
  class InspectorDOMStorageAgent;
  class LocalDOMWindow;
  class LocalFrame;
  class StorageNamespace;
  
  // Singleton that manages the creation & accounting for DOMStorage objects. It
  // does this by holding weak references to all session storage namespaces, and
  // owning the local storage namespace internally. The total cache size is
  // exposed with `TotalCacheSize()`, and `ClearAreasIfNeeded()` will - if our
  // total cache size is larger than `total_cache_limit` - clear away any cache
  // areas in live namespaces that no longer have references from Blink objects.
  //
  // SessionStorage StorageNamespace objects are created with
  // `CreateSessionStorageNamespace` and live as a supplement on the Page.
  //
  // The LocalStorage StorageNamespace object is owned internally, and
  // StorageController delegates the following methods to that namespace:
  // GetLocalStorageArea, AddLocalStorageInspectorStorageAgent,
  // RemoveLocalStorageInspectorStorageAgent
  class MODULES_EXPORT StorageController : public mojom::blink::DomStorageClient {
    USING_FAST_MALLOC(StorageController);
  
   public:
    // Returns the one global StorageController instance.
    static StorageController* GetInstance();
  
    static bool CanAccessStorageArea(LocalFrame* frame,
                                     StorageArea::StorageType type);
  
    // Visible for testing.
    struct DomStorageConnection {
      mojo::Remote<mojom::blink::DomStorage> dom_storage_remote;
      mojo::PendingReceiver<mojom::blink::DomStorageClient> client_receiver;
    };
    StorageController(DomStorageConnection connection,
                      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
                      size_t total_cache_limit);
  
    // Creates a MakeGarbageCollected<StorageNamespace> for Session storage, and
    // holds a weak reference for accounting & clearing. If there is already a
    // StorageNamespace created for the given id, it is returned.
    StorageNamespace* CreateSessionStorageNamespace(const String& namespace_id);
  
    // Returns the total size of all cached areas in namespaces this controller
    // knows of.
    size_t TotalCacheSize() const;
  
    // Cleans up unused areas if the total cache size is over the cache limit.
    void ClearAreasIfNeeded();
  
    // Methods that delegate to the internal StorageNamespace used for
    // LocalStorage:
  
    scoped_refptr<CachedStorageArea> GetLocalStorageArea(
        const LocalDOMWindow* local_dom_window,
        mojo::PendingRemote<mojom::blink::StorageArea> local_storage_area = {});
    void AddLocalStorageInspectorStorageAgent(InspectorDOMStorageAgent* agent);
    void RemoveLocalStorageInspectorStorageAgent(InspectorDOMStorageAgent* agent);
  
    mojom::blink::DomStorage* dom_storage() const {
      return dom_storage_remote_.get();
    }
  
    scoped_refptr<base::SingleThreadTaskRunner> TaskRunner() {
      return task_runner_;
    }
  
   private:
    void EnsureLocalStorageNamespaceCreated();
  
    // mojom::blink::DomStorageClient:
    void ResetStorageAreaAndNamespaceConnections() override;
  
    scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
    Persistent<HeapHashMap<String, WeakMember<StorageNamespace>>> namespaces_;
    Persistent<StorageNamespace> local_storage_namespace_;
    size_t total_cache_limit_;
  
    mojo::Remote<mojom::blink::DomStorage> dom_storage_remote_;
    mojo::Receiver<mojom::blink::DomStorageClient> dom_storage_client_receiver_{
        this};
  
    SEQUENCE_CHECKER(sequence_checker_);
  };
  
  }  // namespace blink
  
  #endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_STORAGE_STORAGE_CONTROLLER_H_
  