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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
commit | e6918187568dbd01842d8d1d2c808ce16a894239 (patch) | |
tree | 64f88b554b444a49f656b6c656111a145cbbaa28 /src/rocksdb/port/port_example.h | |
parent | Initial commit. (diff) | |
download | ceph-e6918187568dbd01842d8d1d2c808ce16a894239.tar.xz ceph-e6918187568dbd01842d8d1d2c808ce16a894239.zip |
Adding upstream version 18.2.2.upstream/18.2.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/rocksdb/port/port_example.h | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/src/rocksdb/port/port_example.h b/src/rocksdb/port/port_example.h new file mode 100644 index 000000000..794149a69 --- /dev/null +++ b/src/rocksdb/port/port_example.h @@ -0,0 +1,101 @@ +// Copyright (c) 2011-present, Facebook, Inc. All rights reserved. +// This source code is licensed under both the GPLv2 (found in the +// COPYING file in the root directory) and Apache 2.0 License +// (found in the LICENSE.Apache file in the root directory). +// +// 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. +// +// This file contains the specification, but not the implementations, +// of the types/operations/etc. that should be defined by a platform +// specific port_<platform>.h file. Use this file as a reference for +// how to port this package to a new platform. + +#pragma once + +namespace ROCKSDB_NAMESPACE { +namespace port { + +// TODO(jorlow): Many of these belong more in the environment class rather than +// here. We should try moving them and see if it affects perf. + +// The following boolean constant must be true on a little-endian machine +// and false otherwise. +static const bool kLittleEndian = true /* or some other expression */; + +// ------------------ Threading ------------------- + +// A Mutex represents an exclusive lock. +class Mutex { + public: + Mutex(); + ~Mutex(); + + // Lock the mutex. Waits until other lockers have exited. + // Will deadlock if the mutex is already locked by this thread. + void Lock(); + + // Unlock the mutex. + // REQUIRES: This mutex was locked by this thread. + void Unlock(); + + // Optionally crash if this thread does not hold this mutex. + // The implementation must be fast, especially if NDEBUG is + // defined. The implementation is allowed to skip all checks. + void AssertHeld(); +}; + +class CondVar { + public: + explicit CondVar(Mutex* mu); + ~CondVar(); + + // Atomically release *mu and block on this condition variable until + // either a call to SignalAll(), or a call to Signal() that picks + // this thread to wakeup. + // REQUIRES: this thread holds *mu + void Wait(); + + // If there are some threads waiting, wake up at least one of them. + void Signal(); + + // Wake up all waiting threads. + void SignallAll(); +}; + +// Thread-safe initialization. +// Used as follows: +// static port::OnceType init_control = LEVELDB_ONCE_INIT; +// static void Initializer() { ... do something ...; } +// ... +// port::InitOnce(&init_control, &Initializer); +using OnceType = intptr_t; +#define LEVELDB_ONCE_INIT 0 +extern void InitOnce(port::OnceType*, void (*initializer)()); + +// ------------------ Compression ------------------- + +// Store the snappy compression of "input[0,input_length-1]" in *output. +// Returns false if snappy is not supported by this port. +extern bool Snappy_Compress(const char* input, size_t input_length, + std::string* output); + +// If input[0,input_length-1] looks like a valid snappy compressed +// buffer, store the size of the uncompressed data in *result and +// return true. Else return false. +extern bool Snappy_GetUncompressedLength(const char* input, size_t length, + size_t* result); + +// Attempt to snappy uncompress input[0,input_length-1] into *output. +// Returns true if successful, false if the input is invalid lightweight +// compressed data. +// +// REQUIRES: at least the first "n" bytes of output[] must be writable +// where "n" is the result of a successful call to +// Snappy_GetUncompressedLength. +extern bool Snappy_Uncompress(const char* input_data, size_t input_length, + char* output); + +} // namespace port +} // namespace ROCKSDB_NAMESPACE |