leveldb/port/port_posix.h
gabor@google.com f57e23351f Platform detection during build, plus compatibility patches for machines without <cstdatomic>.
This revision adds two major changes:
1. build_detect_platform which generates build_config.mk
   with platform-dependent flags for the build process
2. /port/atomic_pointer.h with anAtomicPointerimplementation
   for platforms without <cstdatomic>

Some of this code is loosely based on patches submitted to the 
LevelDB mailing list at https://groups.google.com/forum/#!forum/leveldb
Tip of the hat to Dave Smith and Edouard A, who both sent patches.

The presence of Snappy (http://code.google.com/p/snappy/) and
cstdatomic are now both detected in the build_detect_platform
script (1.) which gets executing during make.

For (2.), instead of broadly importing atomicops_* from Chromium or
the Google performance tools, we chose to just implement AtomicPointer 
and the limited atomic load and store operations it needs. 
This resulted in much less code and fewer files - everything is 
contained in atomic_pointer.h.



git-svn-id: https://leveldb.googlecode.com/svn/trunk@34 62dab493-f737-651d-591e-8d6aee1b9529
2011-06-29 00:30:50 +00:00

118 lines
2.4 KiB
C++

// Copyright (c) 2011 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.
//
// See port_example.h for documentation for the following types/functions.
#ifndef STORAGE_LEVELDB_PORT_PORT_POSIX_H_
#define STORAGE_LEVELDB_PORT_PORT_POSIX_H_
#if defined(OS_MACOSX)
#include <machine/endian.h>
#elif defined(OS_SOLARIS)
#include <sys/isa_defs.h>
#ifdef _LITTLE_ENDIAN
#define LITTLE_ENDIAN
#else
#define BIG_ENDIAN
#endif
#else
#include <endian.h>
#endif
#include <pthread.h>
#ifdef SNAPPY
#include <snappy.h>
#endif
#include <stdint.h>
#include <string>
#include "port/atomic_pointer.h"
#ifdef LITTLE_ENDIAN
#define IS_LITTLE_ENDIAN true
#else
#define IS_LITTLE_ENDIAN (__BYTE_ORDER == __LITTLE_ENDIAN)
#endif
#if defined(OS_MACOSX) || defined(OS_SOLARIS)
#define fread_unlocked fread
#define fwrite_unlocked fwrite
#define fflush_unlocked fflush
#endif
#if defined(OS_MACOSX)
#define fdatasync fsync
#endif
namespace leveldb {
namespace port {
static const bool kLittleEndian = IS_LITTLE_ENDIAN;
class CondVar;
class Mutex {
public:
Mutex();
~Mutex();
void Lock();
void Unlock();
void AssertHeld() { }
private:
friend class CondVar;
pthread_mutex_t mu_;
// No copying
Mutex(const Mutex&);
void operator=(const Mutex&);
};
class CondVar {
public:
explicit CondVar(Mutex* mu);
~CondVar();
void Wait();
void Signal();
void SignalAll();
private:
pthread_cond_t cv_;
Mutex* mu_;
};
inline bool Snappy_Compress(const char* input, size_t input_length,
::std::string* output) {
#ifdef SNAPPY
output->resize(snappy::MaxCompressedLength(input_length));
size_t outlen;
snappy::RawCompress(input, input_length, &(*output)[0], &outlen);
output->resize(outlen);
return true;
#endif
return false;
}
inline bool Snappy_Uncompress(const char* input_data, size_t input_length,
::std::string* output) {
#ifdef SNAPPY
size_t ulength;
if (!snappy::GetUncompressedLength(input_data, ulength, &ulength)) {
return false;
}
output->resize(ulength);
return snappy::RawUncompress(input_data, input_length, &(*output)[0]);
#endif
return false;
}
inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
return false;
}
} // namespace port
} // namespace leveldb
#endif // STORAGE_LEVELDB_PORT_PORT_POSIX_H_