64324e329e
Summary: As you know, almost all compilers support "pragma once" keyword instead of using include guards. To be keep consistency between header files, all header files are edited. Besides this, try to fix some warnings about loss of data. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4339 Differential Revision: D9654990 Pulled By: ajkr fbshipit-source-id: c2cf3d2d03a599847684bed81378c401920ca848
102 lines
3.5 KiB
C++
102 lines
3.5 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// 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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// This file contains the specification, but not the implementations,
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// of the types/operations/etc. that should be defined by a platform
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// specific port_<platform>.h file. Use this file as a reference for
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// how to port this package to a new platform.
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#pragma once
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namespace rocksdb {
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namespace port {
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// TODO(jorlow): Many of these belong more in the environment class rather than
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// here. We should try moving them and see if it affects perf.
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// The following boolean constant must be true on a little-endian machine
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// and false otherwise.
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static const bool kLittleEndian = true /* or some other expression */;
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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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// Lock the mutex. Waits until other lockers have exited.
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// Will deadlock if the mutex is already locked by this thread.
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void Lock();
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// Unlock the mutex.
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// REQUIRES: This mutex was locked by this thread.
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void Unlock();
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// Optionally crash if this thread does not hold this mutex.
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// The implementation must be fast, especially if NDEBUG is
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// defined. The implementation is allowed to skip all checks.
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void AssertHeld();
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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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// Atomically release *mu and block on this condition variable until
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// either a call to SignalAll(), or a call to Signal() that picks
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// this thread to wakeup.
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// REQUIRES: this thread holds *mu
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void Wait();
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// If there are some threads waiting, wake up at least one of them.
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void Signal();
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// Wake up all waiting threads.
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void SignallAll();
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};
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// Thread-safe initialization.
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// Used as follows:
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// static port::OnceType init_control = LEVELDB_ONCE_INIT;
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// static void Initializer() { ... do something ...; }
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// ...
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// port::InitOnce(&init_control, &Initializer);
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typedef intptr_t OnceType;
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#define LEVELDB_ONCE_INIT 0
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extern void InitOnce(port::OnceType*, void (*initializer)());
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// ------------------ Compression -------------------
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// Store the snappy compression of "input[0,input_length-1]" in *output.
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// Returns false if snappy is not supported by this port.
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extern bool Snappy_Compress(const char* input, size_t input_length,
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std::string* output);
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// If input[0,input_length-1] looks like a valid snappy compressed
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// buffer, store the size of the uncompressed data in *result and
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// return true. Else return false.
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extern bool Snappy_GetUncompressedLength(const char* input, size_t length,
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size_t* result);
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// Attempt to snappy uncompress input[0,input_length-1] into *output.
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// Returns true if successful, false if the input is invalid lightweight
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// compressed data.
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//
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// REQUIRES: at least the first "n" bytes of output[] must be writable
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// where "n" is the result of a successful call to
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// Snappy_GetUncompressedLength.
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extern bool Snappy_Uncompress(const char* input_data, size_t input_length,
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char* output);
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} // namespace port
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} // namespace rocksdb
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