xbmc/filesystem/CacheStrategy.h

   1 /*
   2  *  Copyright (C) 2005-2018 Team Kodi
   3  *  This file is part of Kodi - https://kodi.tv
   4  *
   5  *  SPDX-License-Identifier: GPL-2.0-or-later
   6  *  See LICENSES/README.md for more information.
   7  */
   8
   9 #pragma once
  10
  11 #include "threads/Event.h"
  12
  13 #include <stdint.h>
  14 #include <string>
  15
  16 namespace XFILE {
  17
  18 #define CACHE_RC_OK  0
  19 #define CACHE_RC_ERROR -1
  20 #define CACHE_RC_WOULD_BLOCK -2
  21 #define CACHE_RC_TIMEOUT -3
  22
  23 class IFile; // forward declaration
  24
  25 class CCacheStrategy{
  26 public:
  27   virtual ~CCacheStrategy();
  28
  29   virtual int Open() = 0;
  30   virtual void Close() = 0;
  31
  32   virtual size_t GetMaxWriteSize(const size_t& iRequestSize) = 0;
  33   virtual int WriteToCache(const char *pBuffer, size_t iSize) = 0;
  34   virtual int ReadFromCache(char *pBuffer, size_t iMaxSize) = 0;
  35   virtual int64_t WaitForData(uint32_t iMinAvail, std::chrono::milliseconds timeout) = 0;
  36
  37   virtual int64_t Seek(int64_t iFilePosition) = 0;
  38
  39   /*!
  40    \brief Reset cache position
  41    \param iSourcePosition position to reset to
  42    \return Whether a full reset was performed, or not (e.g. only cache swap)
  43    \sa CCacheStrategy
  44    */
  45   virtual bool Reset(int64_t iSourcePosition) = 0;
  46
  47   virtual void EndOfInput(); // mark the end of the input stream so that Read will know when to return EOF
  48   virtual bool IsEndOfInput();
  49   virtual void ClearEndOfInput();
  50
  51   virtual int64_t CachedDataEndPosIfSeekTo(int64_t iFilePosition) = 0;
  52   virtual int64_t CachedDataStartPos() = 0;
  53   virtual int64_t CachedDataEndPos() = 0;
  54   virtual bool IsCachedPosition(int64_t iFilePosition) = 0;
  55
  56   virtual CCacheStrategy *CreateNew() = 0;
  57
  58   CEvent m_space;
  59 protected:
  60   bool  m_bEndOfInput = false;
  61 };
  62
  63 /**
  64 */
  65 class CSimpleFileCache : public CCacheStrategy {
  66 public:
  67   CSimpleFileCache();
  68   ~CSimpleFileCache() override;
  69
  70   int Open() override;
  71   void Close() override;
  72
  73   size_t GetMaxWriteSize(const size_t& iRequestSize) override;
  74   int WriteToCache(const char *pBuffer, size_t iSize) override;
  75   int ReadFromCache(char *pBuffer, size_t iMaxSize) override;
  76   int64_t WaitForData(uint32_t iMinAvail, std::chrono::milliseconds timeout) override;
  77
  78   int64_t Seek(int64_t iFilePosition) override;
  79   bool Reset(int64_t iSourcePosition) override;
  80   void EndOfInput() override;
  81
  82   int64_t CachedDataEndPosIfSeekTo(int64_t iFilePosition) override;
  83   int64_t CachedDataStartPos() override;
  84   int64_t CachedDataEndPos() override;
  85   bool IsCachedPosition(int64_t iFilePosition) override;
  86
  87   CCacheStrategy *CreateNew() override;
  88
  89   int64_t  GetAvailableRead();
  90
  91 protected:
  92   std::string m_filename;
  93   IFile*   m_cacheFileRead;
  94   IFile*   m_cacheFileWrite;
  95   CEvent*  m_hDataAvailEvent;
  96   volatile int64_t m_nStartPosition = 0;
  97   volatile int64_t m_nWritePosition = 0;
  98   volatile int64_t m_nReadPosition = 0;
  99 };
 100
 101 class CDoubleCache : public CCacheStrategy{
 102 public:
 103   explicit CDoubleCache(CCacheStrategy *impl);
 104   ~CDoubleCache() override;
 105
 106   int Open() override;
 107   void Close() override;
 108
 109   size_t GetMaxWriteSize(const size_t& iRequestSize) override;
 110   int WriteToCache(const char *pBuffer, size_t iSize) override;
 111   int ReadFromCache(char *pBuffer, size_t iMaxSize) override;
 112   int64_t WaitForData(uint32_t iMinAvail, std::chrono::milliseconds timeout) override;
 113
 114   int64_t Seek(int64_t iFilePosition) override;
 115   bool Reset(int64_t iSourcePosition) override;
 116   void EndOfInput() override;
 117   bool IsEndOfInput() override;
 118   void ClearEndOfInput() override;
 119
 120   int64_t CachedDataEndPosIfSeekTo(int64_t iFilePosition) override;
 121   int64_t CachedDataStartPos() override;
 122   int64_t CachedDataEndPos() override;
 123   bool IsCachedPosition(int64_t iFilePosition) override;
 124
 125   CCacheStrategy *CreateNew() override;
 126
 127 protected:
 128   CCacheStrategy *m_pCache;
 129   CCacheStrategy *m_pCacheOld;
 130 };
 131
 132 }
 133