1 files changed, 630 insertions, 0 deletions
diff --git a/xbmc/filesystem/FileCache.cpp b/xbmc/filesystem/FileCache.cpp
new file mode 100644
index 0000000..4f2e07b
--- /dev/null
+++ b/xbmc/filesystem/FileCache.cpp
@@ -0,0 +1,630 @@
+/*
+ *  Copyright (C) 2005-2018 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#include "FileCache.h"
+
+#include "CircularCache.h"
+#include "ServiceBroker.h"
+#include "URL.h"
+#include "settings/AdvancedSettings.h"
+#include "settings/SettingsComponent.h"
+#include "threads/Thread.h"
+#include "utils/log.h"
+
+#include <mutex>
+
+#if !defined(TARGET_WINDOWS)
+#include "platform/posix/ConvUtils.h"
+#endif
+
+#include <algorithm>
+#include <cassert>
+#include <chrono>
+#include <inttypes.h>
+#include <memory>
+
+#ifdef TARGET_POSIX
+#include "platform/posix/ConvUtils.h"
+#endif
+
+using namespace XFILE;
+using namespace std::chrono_literals;
+
+class CWriteRate
+{
+public:
+  CWriteRate()
+  {
+    m_stamp = std::chrono::steady_clock::now();
+    m_pos   = 0;
+    m_size = 0;
+    m_time = std::chrono::milliseconds(0);
+  }
+
+  void Reset(int64_t pos, bool bResetAll = true)
+  {
+    m_stamp = std::chrono::steady_clock::now();
+    m_pos   = pos;
+
+    if (bResetAll)
+    {
+      m_size  = 0;
+      m_time = std::chrono::milliseconds(0);
+    }
+  }
+
+  uint32_t Rate(int64_t pos, uint32_t time_bias = 0)
+  {
+    auto ts = std::chrono::steady_clock::now();
+
+    m_size += (pos - m_pos);
+    m_time += std::chrono::duration_cast<std::chrono::milliseconds>(ts - m_stamp);
+    m_pos = pos;
+    m_stamp = ts;
+
+    if (m_time == std::chrono::milliseconds(0))
+      return 0;
+
+    return static_cast<uint32_t>(1000 * (m_size / (m_time.count() + time_bias)));
+  }
+
+private:
+  std::chrono::time_point<std::chrono::steady_clock> m_stamp;
+  int64_t  m_pos;
+  std::chrono::milliseconds m_time;
+  int64_t  m_size;
+};
+
+
+CFileCache::CFileCache(const unsigned int flags)
+  : CThread("FileCache"),
+    m_seekPossible(0),
+    m_nSeekResult(0),
+    m_seekPos(0),
+    m_readPos(0),
+    m_writePos(0),
+    m_chunkSize(0),
+    m_writeRate(0),
+    m_writeRateActual(0),
+    m_writeRateLowSpeed(0),
+    m_forwardCacheSize(0),
+    m_bFilling(false),
+    m_fileSize(0),
+    m_flags(flags)
+{
+}
+
+CFileCache::~CFileCache()
+{
+  Close();
+}
+
+IFile *CFileCache::GetFileImp()
+{
+  return m_source.GetImplementation();
+}
+
+bool CFileCache::Open(const CURL& url)
+{
+  Close();
+
+  std::unique_lock<CCriticalSection> lock(m_sync);
+
+  m_sourcePath = url.GetRedacted();
+
+  CLog::Log(LOGDEBUG, "CFileCache::{} - <{}> opening", __FUNCTION__, m_sourcePath);
+
+  // opening the source file.
+  if (!m_source.Open(url.Get(), READ_NO_CACHE | READ_TRUNCATED | READ_CHUNKED))
+  {
+    CLog::Log(LOGERROR, "CFileCache::{} - <{}> failed to open", __FUNCTION__, m_sourcePath);
+    Close();
+    return false;
+  }
+
+  m_source.IoControl(IOCTRL_SET_CACHE, this);
+
+  bool retry = false;
+  m_source.IoControl(IOCTRL_SET_RETRY, &retry); // We already handle retrying ourselves
+
+  // check if source can seek
+  m_seekPossible = m_source.IoControl(IOCTRL_SEEK_POSSIBLE, NULL);
+
+  // Determine the best chunk size we can use
+  m_chunkSize = CFile::DetermineChunkSize(
+      m_source.GetChunkSize(),
+      CServiceBroker::GetSettingsComponent()->GetAdvancedSettings()->m_cacheChunkSize);
+  CLog::Log(LOGDEBUG,
+            "CFileCache::{} - <{}> source chunk size is {}, setting cache chunk size to {}",
+            __FUNCTION__, m_sourcePath, m_source.GetChunkSize(), m_chunkSize);
+
+  m_fileSize = m_source.GetLength();
+
+  if (!m_pCache)
+  {
+    if (CServiceBroker::GetSettingsComponent()->GetAdvancedSettings()->m_cacheMemSize == 0)
+    {
+      // Use cache on disk
+      m_pCache = std::unique_ptr<CSimpleFileCache>(new CSimpleFileCache()); // C++14 - Replace with std::make_unique
+      m_forwardCacheSize = 0;
+    }
+    else
+    {
+      size_t cacheSize;
+      if (m_fileSize > 0 && m_fileSize < CServiceBroker::GetSettingsComponent()->GetAdvancedSettings()->m_cacheMemSize && !(m_flags & READ_AUDIO_VIDEO))
+      {
+        // Cap cache size by filesize, but not for audio/video files as those may grow.
+        // We don't need to take into account READ_MULTI_STREAM here as that's only used for audio/video
+        cacheSize = m_fileSize;
+
+        // Cap chunk size by cache size
+        if (m_chunkSize > cacheSize)
+          m_chunkSize = cacheSize;
+      }
+      else
+      {
+        cacheSize = CServiceBroker::GetSettingsComponent()->GetAdvancedSettings()->m_cacheMemSize;
+
+        // NOTE: READ_MULTI_STREAM is only used with READ_AUDIO_VIDEO
+        if (m_flags & READ_MULTI_STREAM)
+        {
+          // READ_MULTI_STREAM requires double buffering, so use half the amount of memory for each buffer
+          cacheSize /= 2;
+        }
+
+        // Make sure cache can at least hold 2 chunks
+        if (cacheSize < m_chunkSize * 2)
+          cacheSize = m_chunkSize * 2;
+      }
+
+      if (m_flags & READ_MULTI_STREAM)
+        CLog::Log(LOGDEBUG, "CFileCache::{} - <{}> using double memory cache each sized {} bytes",
+                  __FUNCTION__, m_sourcePath, cacheSize);
+      else
+        CLog::Log(LOGDEBUG, "CFileCache::{} - <{}> using single memory cache sized {} bytes",
+                  __FUNCTION__, m_sourcePath, cacheSize);
+
+      const size_t back = cacheSize / 4;
+      const size_t front = cacheSize - back;
+
+      m_pCache = std::unique_ptr<CCircularCache>(new CCircularCache(front, back)); // C++14 - Replace with std::make_unique
+      m_forwardCacheSize = front;
+    }
+
+    if (m_flags & READ_MULTI_STREAM)
+    {
+      // If READ_MULTI_STREAM flag is set: Double buffering is required
+      m_pCache = std::unique_ptr<CDoubleCache>(new CDoubleCache(m_pCache.release())); // C++14 - Replace with std::make_unique
+    }
+  }
+
+  // open cache strategy
+  if (!m_pCache || m_pCache->Open() != CACHE_RC_OK)
+  {
+    CLog::Log(LOGERROR, "CFileCache::{} - <{}> failed to open cache", __FUNCTION__, m_sourcePath);
+    Close();
+    return false;
+  }
+
+  m_readPos = 0;
+  m_writePos = 0;
+  m_writeRate = 1024 * 1024;
+  m_writeRateActual = 0;
+  m_writeRateLowSpeed = 0;
+  m_bFilling = true;
+  m_seekEvent.Reset();
+  m_seekEnded.Reset();
+
+  CThread::Create(false);
+
+  return true;
+}
+
+void CFileCache::Process()
+{
+  if (!m_pCache)
+  {
+    CLog::Log(LOGERROR, "CFileCache::{} - <{}> sanity failed. no cache strategy", __FUNCTION__,
+              m_sourcePath);
+    return;
+  }
+
+  // create our read buffer
+  std::unique_ptr<char[]> buffer(new char[m_chunkSize]);
+  if (buffer == nullptr)
+  {
+    CLog::Log(LOGERROR, "CFileCache::{} - <{}> failed to allocate read buffer", __FUNCTION__,
+              m_sourcePath);
+    return;
+  }
+
+  CWriteRate limiter;
+  CWriteRate average;
+
+  while (!m_bStop)
+  {
+    // Update filesize
+    m_fileSize = m_source.GetLength();
+
+    // check for seek events
+    if (m_seekEvent.Wait(0ms))
+    {
+      m_seekEvent.Reset();
+      const int64_t cacheMaxPos = m_pCache->CachedDataEndPosIfSeekTo(m_seekPos);
+      const bool cacheReachEOF = (cacheMaxPos == m_fileSize);
+
+      bool sourceSeekFailed = false;
+      if (!cacheReachEOF)
+      {
+        m_nSeekResult = m_source.Seek(cacheMaxPos, SEEK_SET);
+        if (m_nSeekResult != cacheMaxPos)
+        {
+          CLog::Log(LOGERROR, "CFileCache::{} - <{}> error {} seeking. Seek returned {}",
+                    __FUNCTION__, m_sourcePath, GetLastError(), m_nSeekResult);
+          m_seekPossible = m_source.IoControl(IOCTRL_SEEK_POSSIBLE, NULL);
+          sourceSeekFailed = true;
+        }
+      }
+
+      if (!sourceSeekFailed)
+      {
+        const bool bCompleteReset = m_pCache->Reset(m_seekPos);
+        m_readPos = m_seekPos;
+        m_writePos = m_pCache->CachedDataEndPos();
+        assert(m_writePos == cacheMaxPos);
+        average.Reset(m_writePos, bCompleteReset); // Can only recalculate new average from scratch after a full reset (empty cache)
+        limiter.Reset(m_writePos);
+        m_nSeekResult = m_seekPos;
+        if (bCompleteReset)
+        {
+          CLog::Log(LOGDEBUG,
+                    "CFileCache::{} - <{}> cache completely reset for seek to position {}",
+                    __FUNCTION__, m_sourcePath, m_seekPos);
+          m_bFilling = true;
+          m_writeRateLowSpeed = 0;
+        }
+      }
+
+      m_seekEnded.Set();
+    }
+
+    while (m_writeRate)
+    {
+      if (m_writePos - m_readPos < m_writeRate * CServiceBroker::GetSettingsComponent()->GetAdvancedSettings()->m_cacheReadFactor)
+      {
+        limiter.Reset(m_writePos);
+        break;
+      }
+
+      if (limiter.Rate(m_writePos) < m_writeRate * CServiceBroker::GetSettingsComponent()->GetAdvancedSettings()->m_cacheReadFactor)
+        break;
+
+      if (m_seekEvent.Wait(100ms))
+      {
+        if (!m_bStop)
+          m_seekEvent.Set();
+        break;
+      }
+    }
+
+    const int64_t maxWrite = m_pCache->GetMaxWriteSize(m_chunkSize);
+    int64_t maxSourceRead = m_chunkSize;
+    // Cap source read size by space available between current write position and EOF
+    if (m_fileSize != 0)
+      maxSourceRead = std::min(maxSourceRead, m_fileSize - m_writePos);
+
+    /* Only read from source if there's enough write space in the cache
+     * else we may keep disposing data and seeking back on (slow) source
+     */
+    if (maxWrite < maxSourceRead)
+    {
+      // Wait until sufficient cache write space is available
+      m_pCache->m_space.Wait(5ms);
+      continue;
+    }
+
+    ssize_t iRead = 0;
+    if (maxSourceRead > 0)
+      iRead = m_source.Read(buffer.get(), maxSourceRead);
+    if (iRead <= 0)
+    {
+      // Check for actual EOF and retry as long as we still have data in our cache
+      if (m_writePos < m_fileSize && m_pCache->WaitForData(0, 0ms) > 0)
+      {
+        CLog::Log(LOGWARNING, "CFileCache::{} - <{}> source read returned {}! Will retry",
+                  __FUNCTION__, m_sourcePath, iRead);
+
+        // Wait a bit:
+        if (m_seekEvent.Wait(2000ms))
+        {
+          if (!m_bStop)
+            m_seekEvent.Set(); // hack so that later we realize seek is needed
+        }
+
+        // and retry:
+        continue; // while (!m_bStop)
+      }
+      else
+      {
+        if (iRead < 0)
+          CLog::Log(LOGERROR,
+                    "{} - <{}> source read failed with {}!", __FUNCTION__, m_sourcePath, iRead);
+        else if (m_fileSize == 0)
+          CLog::Log(LOGDEBUG,
+                    "CFileCache::{} - <{}> source read didn't return any data! Hit eof(?)",
+                    __FUNCTION__, m_sourcePath);
+        else if (m_writePos < m_fileSize)
+          CLog::Log(LOGERROR,
+                    "CFileCache::{} - <{}> source read didn't return any data before eof!",
+                    __FUNCTION__, m_sourcePath);
+        else
+          CLog::Log(LOGDEBUG, "CFileCache::{} - <{}> source read hit eof", __FUNCTION__,
+                    m_sourcePath);
+
+        m_pCache->EndOfInput();
+
+        // The thread event will now also cause the wait of an event to return a false.
+        if (AbortableWait(m_seekEvent) == WAIT_SIGNALED)
+        {
+          m_pCache->ClearEndOfInput();
+          if (!m_bStop)
+            m_seekEvent.Set(); // hack so that later we realize seek is needed
+        }
+        else
+          break; // while (!m_bStop)
+      }
+    }
+
+    int iTotalWrite = 0;
+    while (!m_bStop && (iTotalWrite < iRead))
+    {
+      int iWrite = 0;
+      iWrite = m_pCache->WriteToCache(buffer.get() + iTotalWrite, iRead - iTotalWrite);
+
+      // write should always work. all handling of buffering and errors should be
+      // done inside the cache strategy. only if unrecoverable error happened, WriteToCache would return error and we break.
+      if (iWrite < 0)
+      {
+        CLog::Log(LOGERROR, "CFileCache::{} - <{}> error writing to cache", __FUNCTION__,
+                  m_sourcePath);
+        m_bStop = true;
+        break;
+      }
+      else if (iWrite == 0)
+      {
+        m_pCache->m_space.Wait(5ms);
+      }
+
+      iTotalWrite += iWrite;
+
+      // check if seek was asked. otherwise if cache is full we'll freeze.
+      if (m_seekEvent.Wait(0ms))
+      {
+        if (!m_bStop)
+          m_seekEvent.Set(); // make sure we get the seek event later.
+        break;
+      }
+    }
+
+    m_writePos += iTotalWrite;
+
+    // under estimate write rate by a second, to
+    // avoid uncertainty at start of caching
+    m_writeRateActual = average.Rate(m_writePos, 1000);
+
+   /* NOTE: We can only reliably test for low speed condition, when the cache is *really*
+    * filling. This is because as soon as it's full the average-
+    * rate will become approximately the current-rate which can flag false
+    * low read-rate conditions.
+    */
+    if (m_bFilling && m_forwardCacheSize != 0)
+    {
+      const int64_t forward = m_pCache->WaitForData(0, 0ms);
+      if (forward + m_chunkSize >= m_forwardCacheSize)
+      {
+        if (m_writeRateActual < m_writeRate)
+          m_writeRateLowSpeed = m_writeRateActual;
+
+        m_bFilling = false;
+      }
+    }
+  }
+}
+
+void CFileCache::OnExit()
+{
+  m_bStop = true;
+
+  // make sure cache is set to mark end of file (read may be waiting).
+  if (m_pCache)
+    m_pCache->EndOfInput();
+
+  // just in case someone's waiting...
+  m_seekEnded.Set();
+}
+
+bool CFileCache::Exists(const CURL& url)
+{
+  return CFile::Exists(url.Get());
+}
+
+int CFileCache::Stat(const CURL& url, struct __stat64* buffer)
+{
+  return CFile::Stat(url.Get(), buffer);
+}
+
+ssize_t CFileCache::Read(void* lpBuf, size_t uiBufSize)
+{
+  std::unique_lock<CCriticalSection> lock(m_sync);
+  if (!m_pCache)
+  {
+    CLog::Log(LOGERROR, "CFileCache::{} - <{}> sanity failed. no cache strategy!", __FUNCTION__,
+              m_sourcePath);
+    return -1;
+  }
+  int64_t iRc;
+
+  if (uiBufSize > SSIZE_MAX)
+    uiBufSize = SSIZE_MAX;
+
+retry:
+  // attempt to read
+  iRc = m_pCache->ReadFromCache((char *)lpBuf, uiBufSize);
+  if (iRc > 0)
+  {
+    m_readPos += iRc;
+    return (int)iRc;
+  }
+
+  if (iRc == CACHE_RC_WOULD_BLOCK)
+  {
+    // just wait for some data to show up
+    iRc = m_pCache->WaitForData(1, 10s);
+    if (iRc > 0)
+      goto retry;
+  }
+
+  if (iRc == CACHE_RC_TIMEOUT)
+  {
+    CLog::Log(LOGWARNING, "CFileCache::{} - <{}> timeout waiting for data", __FUNCTION__,
+              m_sourcePath);
+    return -1;
+  }
+
+  if (iRc == 0)
+    return 0;
+
+  // unknown error code
+  CLog::Log(LOGERROR, "CFileCache::{} - <{}> cache strategy returned unknown error code {}",
+            __FUNCTION__, m_sourcePath, (int)iRc);
+  return -1;
+}
+
+int64_t CFileCache::Seek(int64_t iFilePosition, int iWhence)
+{
+  std::unique_lock<CCriticalSection> lock(m_sync);
+
+  if (!m_pCache)
+  {
+    CLog::Log(LOGERROR, "CFileCache::{} - <{}> sanity failed. no cache strategy!", __FUNCTION__,
+              m_sourcePath);
+    return -1;
+  }
+
+  int64_t iCurPos = m_readPos;
+  int64_t iTarget = iFilePosition;
+  if (iWhence == SEEK_END)
+    iTarget = m_fileSize + iTarget;
+  else if (iWhence == SEEK_CUR)
+    iTarget = iCurPos + iTarget;
+  else if (iWhence != SEEK_SET)
+    return -1;
+
+  if (iTarget == m_readPos)
+    return m_readPos;
+
+  if ((m_nSeekResult = m_pCache->Seek(iTarget)) != iTarget)
+  {
+    if (m_seekPossible == 0)
+      return m_nSeekResult;
+
+    // Never request closer to end than one chunk. Speeds up tag reading
+    m_seekPos = std::min(iTarget, std::max((int64_t)0, m_fileSize - m_chunkSize));
+
+    m_seekEvent.Set();
+    while (!m_seekEnded.Wait(100ms))
+    {
+      // SeekEnded will never be set if FileCache thread is not running
+      if (!CThread::IsRunning())
+        return -1;
+    }
+
+    /* wait for any remaining data */
+    if(m_seekPos < iTarget)
+    {
+      CLog::Log(LOGDEBUG, "CFileCache::{} - <{}> waiting for position {}", __FUNCTION__,
+                m_sourcePath, iTarget);
+      if (m_pCache->WaitForData(static_cast<uint32_t>(iTarget - m_seekPos), 10s) <
+          iTarget - m_seekPos)
+      {
+        CLog::Log(LOGWARNING, "CFileCache::{} - <{}> failed to get remaining data", __FUNCTION__,
+                  m_sourcePath);
+        return -1;
+      }
+      m_pCache->Seek(iTarget);
+    }
+    m_readPos = iTarget;
+    m_seekEvent.Reset();
+  }
+  else
+    m_readPos = iTarget;
+
+  return iTarget;
+}
+
+void CFileCache::Close()
+{
+  StopThread();
+
+  std::unique_lock<CCriticalSection> lock(m_sync);
+  if (m_pCache)
+    m_pCache->Close();
+
+  m_source.Close();
+}
+
+int64_t CFileCache::GetPosition()
+{
+  return m_readPos;
+}
+
+int64_t CFileCache::GetLength()
+{
+  return m_fileSize;
+}
+
+void CFileCache::StopThread(bool bWait /*= true*/)
+{
+  m_bStop = true;
+  //Process could be waiting for seekEvent
+  m_seekEvent.Set();
+  CThread::StopThread(bWait);
+}
+
+const std::string CFileCache::GetProperty(XFILE::FileProperty type, const std::string &name) const
+{
+  if (!m_source.GetImplementation())
+    return IFile::GetProperty(type, name);
+
+  return m_source.GetImplementation()->GetProperty(type, name);
+}
+
+int CFileCache::IoControl(EIoControl request, void* param)
+{
+  if (request == IOCTRL_CACHE_STATUS)
+  {
+    SCacheStatus* status = (SCacheStatus*)param;
+    status->forward = m_pCache->WaitForData(0, 0ms);
+    status->maxrate = m_writeRate;
+    status->currate = m_writeRateActual;
+    status->lowrate = m_writeRateLowSpeed;
+    m_writeRateLowSpeed = 0; // Reset low speed condition
+    return 0;
+  }
+
+  if (request == IOCTRL_CACHE_SETRATE)
+  {
+    m_writeRate = *static_cast<uint32_t*>(param);
+    return 0;
+  }
+
+  if (request == IOCTRL_SEEK_POSSIBLE)
+    return m_seekPossible;
+
+  return -1;
+}