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
80 lines
2.5 KiB
C++
80 lines
2.5 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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// 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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// An iterator yields a sequence of key/value pairs from a source.
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// The following class defines the interface. Multiple implementations
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// are provided by this library. In particular, iterators are provided
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// to access the contents of a Table or a DB.
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//
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// Multiple threads can invoke const methods on an Iterator without
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// external synchronization, but if any of the threads may call a
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// non-const method, all threads accessing the same Iterator must use
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// external synchronization.
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#pragma once
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namespace rocksdb {
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class Cleanable {
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public:
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Cleanable();
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~Cleanable();
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// No copy constructor and copy assignment allowed.
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Cleanable(Cleanable&) = delete;
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Cleanable& operator=(Cleanable&) = delete;
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// Move constructor and move assignment is allowed.
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Cleanable(Cleanable&&);
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Cleanable& operator=(Cleanable&&);
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// Clients are allowed to register function/arg1/arg2 triples that
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// will be invoked when this iterator is destroyed.
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//
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// Note that unlike all of the preceding methods, this method is
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// not abstract and therefore clients should not override it.
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typedef void (*CleanupFunction)(void* arg1, void* arg2);
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void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
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void DelegateCleanupsTo(Cleanable* other);
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// DoCleanup and also resets the pointers for reuse
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inline void Reset() {
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DoCleanup();
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cleanup_.function = nullptr;
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cleanup_.next = nullptr;
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}
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protected:
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struct Cleanup {
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CleanupFunction function;
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void* arg1;
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void* arg2;
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Cleanup* next;
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};
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Cleanup cleanup_;
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// It also becomes the owner of c
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void RegisterCleanup(Cleanup* c);
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private:
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// Performs all the cleanups. It does not reset the pointers. Making it
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// private
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// to prevent misuse
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inline void DoCleanup() {
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if (cleanup_.function != nullptr) {
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(*cleanup_.function)(cleanup_.arg1, cleanup_.arg2);
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for (Cleanup* c = cleanup_.next; c != nullptr;) {
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(*c->function)(c->arg1, c->arg2);
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Cleanup* next = c->next;
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delete c;
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c = next;
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}
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}
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}
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};
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} // namespace rocksdb
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