86 lines
2.7 KiB
C++
86 lines
2.7 KiB
C++
// 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.h>
|
|
|
|
namespace shaka {
|
|
|
|
/// Declaration of class which implements a thread-safe circular buffer.
|
|
class IoCache {
|
|
public:
|
|
explicit IoCache(uint64_t cache_size);
|
|
~IoCache();
|
|
|
|
/// Read data from the cache. This function may block until there is data in
|
|
/// the cache.
|
|
/// @param buffer is a buffer into which to read the data from the cache.
|
|
/// @param size is the size of @a buffer.
|
|
/// @return the number of bytes read into @a buffer, or 0 if the call
|
|
/// unblocked because the cache has been closed and is empty.
|
|
uint64_t Read(void* buffer, uint64_t size);
|
|
|
|
/// Write data to the cache. This function may block until there is enough
|
|
/// room in the cache.
|
|
/// @param buffer is a buffer containing the data to be written to the cache.
|
|
/// @param size is the size of the data to be written to the cache.
|
|
/// @return the amount of data written to the buffer (which will equal
|
|
/// @a data), or 0 if the call unblocked because the cache has been
|
|
/// closed.
|
|
uint64_t Write(const void* buffer, uint64_t size);
|
|
|
|
/// Empties the cache.
|
|
void Clear();
|
|
|
|
/// Close the cache. This will call any blocking calls to unblock, and the
|
|
/// cache won't be usable until Reopened.
|
|
void Close();
|
|
|
|
/// @return true if the cache is closed, false otherwise.
|
|
bool closed() { return closed_; }
|
|
|
|
/// Reopens the cache. Any data still in the cache will be lost.
|
|
void Reopen();
|
|
|
|
/// Returns the number of bytes in the cache.
|
|
/// @return the number of bytes in the cache.
|
|
uint64_t BytesCached();
|
|
|
|
/// Returns the number of free bytes in the cache.
|
|
/// @return the number of free bytes in the cache.
|
|
uint64_t BytesFree();
|
|
|
|
/// Waits until the cache is empty or has been closed.
|
|
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
|