io_cache.h

// Copyright 2015 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
 
#ifndef PACKAGER_FILE_IO_CACHE_H_
#define PACKAGER_FILE_IO_CACHE_H_
 
#include <cstdint>
#include <vector>
 
#include <absl/synchronization/mutex.h>
 
#include <packager/macros/classes.h>
 
namespace shaka {
 
class IoCache {
 public:
  explicit IoCache(uint64_t cache_size);
  ~IoCache();
 
  uint64_t Read(void* buffer, uint64_t size);
 
  uint64_t Write(const void* buffer, uint64_t size);
 
  void Clear();
 
  void Close();
 
  bool closed() { return closed_; }
 
  void Reopen();
 
  uint64_t BytesCached();
 
  uint64_t BytesFree();
 
  void WaitUntilEmptyOrClosed();
 
 private:
  uint64_t BytesCachedInternal();
  uint64_t BytesFreeInternal();
 
  const uint64_t cache_size_;
  absl::Mutex mutex_;
  absl::CondVar read_event_ ABSL_GUARDED_BY(mutex_);
  absl::CondVar write_event_ ABSL_GUARDED_BY(mutex_);
  std::vector<uint8_t> circular_buffer_ ABSL_GUARDED_BY(mutex_);
  const uint8_t* end_ptr_ ABSL_GUARDED_BY(mutex_);
  uint8_t* r_ptr_ ABSL_GUARDED_BY(mutex_);
  uint8_t* w_ptr_ ABSL_GUARDED_BY(mutex_);
  bool closed_ ABSL_GUARDED_BY(mutex_);
 
  DISALLOW_COPY_AND_ASSIGN(IoCache);
};
 
}  // namespace shaka
 
#endif  // PACKAGER_FILE_IO_CACHE_H