e628f59e87
Summary: This PR does the following: -> Creates a WinFileSystem class. This class is the Windows equivalent of the PosixFileSystem and will be used on Windows systems. -> Introduces a CustomEnv class. A CustomEnv is an Env that takes a FileSystem as constructor argument. I believe there will only ever be two implementations of this class (PosixEnv and WinEnv). There is still a CustomEnvWrapper class that takes an Env and a FileSystem and wraps the Env calls with the input Env but uses the FileSystem for the FileSystem calls -> Eliminates the public uses of the LegacyFileSystemWrapper. With this change in place, there are effectively the following patterns of Env: - "Base Env classes" (PosixEnv, WinEnv). These classes implement the core Env functions (e.g. Threads) and have a hard-coded input FileSystem. These classes inherit from CompositeEnv, implement the core Env functions (threads) and delegate the FileSystem-like calls to the input file system. - Wrapped Composite Env classes (MemEnv). These classes take in an Env and a FileSystem. The core env functions are re-directed to the wrapped env. The file system calls are redirected to the input file system - Legacy Wrapped Env classes. These classes take in an Env input (but no FileSystem). The core env functions are re-directed to the wrapped env. A "Legacy File System" is created using this env and the file system calls directed to the env itself. With these changes in place, the PosixEnv becomes a singleton -- there is only ever one created. Any other use of the PosixEnv is via another wrapped env. This cleans up some of the issues with the env construction and destruction. Additionally, there were places in the code that required had an Env when they required a FileSystem. Many of these places would wrap the Env with a LegacyFileSystemWrapper instead of using the env->GetFileSystem(). These places were changed, thereby removing layers of additional redirection (LegacyFileSystem --> Env --> Env::FileSystem). Pull Request resolved: https://github.com/facebook/rocksdb/pull/7703 Reviewed By: zhichao-cao Differential Revision: D25762190 Pulled By: anand1976 fbshipit-source-id: 1a088e97fc916f28ac69c149cd1dcad0ab31704b
46 lines
1.3 KiB
C++
46 lines
1.3 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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#if defined(OS_WIN)
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#include <mutex>
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#include "port/win/env_win.h"
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#include "rocksdb/env.h"
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#include "test_util/sync_point.h"
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#include "util/compression_context_cache.h"
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#include "util/thread_local.h"
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namespace ROCKSDB_NAMESPACE {
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namespace port {
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// We choose not to destroy the env because joining the threads from the
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// system loader
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// which destroys the statics (same as from DLLMain) creates a system loader
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// dead-lock.
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// in this manner any remaining threads are terminated OK.
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namespace {
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std::once_flag winenv_once_flag;
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Env* envptr;
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};
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}
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Env* Env::Default() {
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using namespace port;
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ThreadLocalPtr::InitSingletons();
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CompressionContextCache::InitSingleton();
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INIT_SYNC_POINT_SINGLETONS();
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std::call_once(winenv_once_flag, []() { envptr = new WinEnv(); });
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return envptr;
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}
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} // namespace ROCKSDB_NAMESPACE
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#endif
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