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// Copyright (c) 2018 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_PORT_PORT_STDCXX_H_
#define STORAGE_LEVELDB_PORT_PORT_STDCXX_H_
// port/port_config.h availability is automatically detected via __has_include
// in newer compilers. If LEVELDB_HAS_PORT_CONFIG_H is defined, it overrides the
// configuration detection.
#if defined(LEVELDB_HAS_PORT_CONFIG_H)
#if LEVELDB_HAS_PORT_CONFIG_H
#include "port/port_config.h"
#endif // LEVELDB_HAS_PORT_CONFIG_H
#elif defined(__has_include)
#if __has_include("port/port_config.h")
#include "port/port_config.h"
#endif // __has_include("port/port_config.h")
#endif // defined(LEVELDB_HAS_PORT_CONFIG_H)
#if HAVE_CRC32C
#include <crc32c/crc32c.h>
#endif // HAVE_CRC32C
#if HAVE_SNAPPY
#include <snappy.h>
#endif // HAVE_SNAPPY
#include <stddef.h>
#include <stdint.h>
#include <cassert>
#include <condition_variable> // NOLINT
#include <mutex> // NOLINT
#include <string>
#include "port/atomic_pointer.h"
#include "port/thread_annotations.h"
namespace leveldb {
namespace port {
static const bool kLittleEndian = !LEVELDB_IS_BIG_ENDIAN;
class CondVar;
// Thinly wraps std::mutex.
class LOCKABLE Mutex {
public:
Mutex() = default;
~Mutex() = default;
Mutex(const Mutex&) = delete;
Mutex& operator=(const Mutex&) = delete;
void Lock() EXCLUSIVE_LOCK_FUNCTION() { mu_.lock(); }
void Unlock() UNLOCK_FUNCTION() { mu_.unlock(); }
void AssertHeld() ASSERT_EXCLUSIVE_LOCK() { }
private:
friend class CondVar;
std::mutex mu_;
};
// Thinly wraps std::condition_variable.
class CondVar {
public:
explicit CondVar(Mutex* mu) : mu_(mu) { assert(mu != nullptr); }
~CondVar() = default;
CondVar(const CondVar&) = delete;
CondVar& operator=(const CondVar&) = delete;
void Wait() {
std::unique_lock<std::mutex> lock(mu_->mu_, std::adopt_lock);
cv_.wait(lock);
lock.release();
}
void Signal() { cv_.notify_one(); }
void SignalAll() { cv_.notify_all(); }
private:
std::condition_variable cv_;
Mutex* const mu_;
};
using OnceType = std::once_flag;
#define LEVELDB_ONCE_INIT {}
// Thinly wraps std::call_once.
inline void InitOnce(OnceType* once, void (*initializer)()) {
std::call_once(*once, *initializer);
}
inline bool Snappy_Compress(const char* input, size_t length,
::std::string* output) {
#if HAVE_SNAPPY
output->resize(snappy::MaxCompressedLength(length));
size_t outlen;
snappy::RawCompress(input, length, &(*output)[0], &outlen);
output->resize(outlen);
return true;
#endif // HAVE_SNAPPY
return false;
}
inline bool Snappy_GetUncompressedLength(const char* input, size_t length,
size_t* result) {
#if HAVE_SNAPPY
return snappy::GetUncompressedLength(input, length, result);
#else
return false;
#endif // HAVE_SNAPPY
}
inline bool Snappy_Uncompress(const char* input, size_t length, char* output) {
#if HAVE_SNAPPY
return snappy::RawUncompress(input, length, output);
#else
return false;
#endif // HAVE_SNAPPY
}
inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
return false;
}
inline uint32_t AcceleratedCRC32C(uint32_t crc, const char* buf, size_t size) {
#if HAVE_CRC32C
return ::crc32c::Extend(crc, reinterpret_cast<const uint8_t*>(buf), size);
#else
return 0;
#endif // HAVE_CRC32C
}
} // namespace port
} // namespace leveldb
#endif // STORAGE_LEVELDB_PORT_PORT_STDCXX_H_
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