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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CONTENT_BROWSER_STREAMS_STREAM_REGISTRY_H_
      6 #define CONTENT_BROWSER_STREAMS_STREAM_REGISTRY_H_
      7 
      8 #include <map>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/memory/ref_counted.h"
     12 #include "base/threading/non_thread_safe.h"
     13 #include "content/common/content_export.h"
     14 #include "url/gurl.h"
     15 
     16 namespace content {
     17 
     18 class Stream;
     19 
     20 // Maintains a mapping of blob: URLs to active streams.
     21 class CONTENT_EXPORT StreamRegistry : public base::NonThreadSafe {
     22  public:
     23   StreamRegistry();
     24   virtual ~StreamRegistry();
     25 
     26   // Registers a stream, and sets its URL.
     27   void RegisterStream(scoped_refptr<Stream> stream);
     28 
     29   // Clones a stream.  Returns true on success, or false if |src_url| doesn't
     30   // exist.
     31   bool CloneStream(const GURL& url, const GURL& src_url);
     32 
     33   void UnregisterStream(const GURL& url);
     34 
     35   // Called by Stream instances to request increase of memory usage. If the
     36   // total memory usage for this registry is going to exceed the limit,
     37   // returns false. Otherwise, updates |total_memory_usage_| and returns true.
     38   //
     39   // |current_size| is the up-to-date size of ByteStream of the Stream instance
     40   // and |increase| must be the amount of data going to be added to the Stream
     41   // instance.
     42   bool UpdateMemoryUsage(const GURL& url, size_t current_size, size_t increase);
     43 
     44   // Gets the stream associated with |url|.  Returns NULL if there is no such
     45   // stream.
     46   scoped_refptr<Stream> GetStream(const GURL& url);
     47 
     48   void set_max_memory_usage_for_testing(size_t size) {
     49     max_memory_usage_ = size;
     50   }
     51 
     52  private:
     53   typedef std::map<GURL, scoped_refptr<Stream> > StreamMap;
     54 
     55   StreamMap streams_;
     56 
     57   size_t total_memory_usage_;
     58 
     59   // Maximum amount of memory allowed to use for Stream instances registered
     60   // with this registry.
     61   size_t max_memory_usage_;
     62 
     63   DISALLOW_COPY_AND_ASSIGN(StreamRegistry);
     64 };
     65 
     66 }  // namespace content
     67 
     68 #endif  // CONTENT_BROWSER_STREAMS_STREAM_REGISTRY_H_
     69