text: // Copyright 2015 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 CachedMetadataHandler_h
  #define CachedMetadataHandler_h
  
  #include <stdint.h>
  #include "platform/heap/Handle.h"
  #include "platform/wtf/Forward.h"
  
  namespace blink {
  
  class CachedMetadata;
  
  // Handler class for caching operations.
  class CachedMetadataHandler
      : public GarbageCollectedFinalized<CachedMetadataHandler> {
   public:
    enum CacheType {
      kSendToPlatform,  // send cache data to blink::Platform::cacheMetadata
      kCacheLocally     // cache only in Resource's member variables
    };
    virtual ~CachedMetadataHandler() {}
    DEFINE_INLINE_VIRTUAL_TRACE() {}
    // Caches the given metadata in association with this resource and suggests
    // that the platform persist it. The dataTypeID is a pseudo-randomly chosen
    // identifier that is used to distinguish data generated by the caller.
    virtual void SetCachedMetadata(uint32_t data_type_id,
                                   const char*,
                                   size_t,
                                   CacheType = kSendToPlatform) = 0;
    // Reset existing metadata, to allow setting new data.
    virtual void ClearCachedMetadata(CacheType = kCacheLocally) = 0;
    // Returns cached metadata of the given type associated with this resource.
    // This cached metadata can be pruned at any time.
    virtual RefPtr<CachedMetadata> GetCachedMetadata(
        uint32_t data_type_id) const = 0;
    // Returns the encoding to which the cache is specific.
    virtual String Encoding() const = 0;
  
   protected:
    CachedMetadataHandler() {}
  };
  }  // namespace blink
  
  #endif  // CachedMetadataHandler_h
  