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125 行
2.6 KiB
125 行
2.6 KiB
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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//
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// See port_example.h for documentation for the following types/functions.
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#ifndef STORAGE_LEVELDB_PORT_PORT_OSX_H_
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#define STORAGE_LEVELDB_PORT_PORT_OSX_H_
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#include <libkern/OSAtomic.h>
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#include <machine/endian.h>
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#include <pthread.h>
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#include <stdint.h>
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#include <string>
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namespace leveldb {
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// The following 4 methods implemented here for the benefit of env_posix.cc.
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inline size_t fread_unlocked(void *a, size_t b, size_t c, FILE *d) {
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return fread(a, b, c, d);
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}
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inline size_t fwrite_unlocked(const void *a, size_t b, size_t c, FILE *d) {
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return fwrite(a, b, c, d);
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}
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inline int fflush_unlocked(FILE *f) {
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return fflush(f);
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}
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inline int fdatasync(int fd) {
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return fsync(fd);
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}
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namespace port {
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static const bool kLittleEndian = (__DARWIN_BYTE_ORDER == __DARWIN_LITTLE_ENDIAN);
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// ------------------ Threading -------------------
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// A Mutex represents an exclusive lock.
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class Mutex {
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public:
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Mutex();
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~Mutex();
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void Lock();
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void Unlock();
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void AssertHeld() { }
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private:
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friend class CondVar;
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pthread_mutex_t mu_;
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// No copying
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Mutex(const Mutex&);
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void operator=(const Mutex&);
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};
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class CondVar {
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public:
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explicit CondVar(Mutex* mu);
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~CondVar();
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void Wait();
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void Signal();
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void SignalAll();
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private:
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pthread_cond_t cv_;
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Mutex* mu_;
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};
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inline void MemoryBarrier() {
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#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
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// See http://gcc.gnu.org/ml/gcc/2003-04/msg01180.html for a discussion on
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// this idiom. Also see http://en.wikipedia.org/wiki/Memory_ordering.
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__asm__ __volatile__("" : : : "memory");
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#else
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OSMemoryBarrier();
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#endif
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}
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class AtomicPointer {
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private:
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void* ptr_;
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public:
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AtomicPointer() { }
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explicit AtomicPointer(void* p) : ptr_(p) {}
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inline void* Acquire_Load() const {
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void* ptr = ptr_;
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MemoryBarrier();
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return ptr;
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}
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inline void Release_Store(void* v) {
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MemoryBarrier();
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ptr_ = v;
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}
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inline void* NoBarrier_Load() const {
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return ptr_;
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}
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inline void NoBarrier_Store(void* v) {
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ptr_ = v;
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}
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};
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inline bool Snappy_Compress(const char* input, size_t input_length,
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std::string* output) {
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return false;
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}
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inline bool Snappy_Uncompress(const char* input_data, size_t input_length,
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std::string* output) {
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return false;
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}
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inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
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return false;
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}
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}
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}
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#endif // STORAGE_LEVELDB_PORT_PORT_OSX_H_
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