mirror of https://github.com/facebook/rocksdb.git
100 lines
2.6 KiB
C++
100 lines
2.6 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same 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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#include "rocksdb/iterator.h"
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#include "table/iterator_wrapper.h"
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#include "util/arena.h"
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namespace rocksdb {
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Iterator::Iterator() {
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cleanup_.function = nullptr;
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cleanup_.next = nullptr;
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}
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Iterator::~Iterator() {
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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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void Iterator::RegisterCleanup(CleanupFunction func, void* arg1, void* arg2) {
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assert(func != nullptr);
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Cleanup* c;
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if (cleanup_.function == nullptr) {
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c = &cleanup_;
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} else {
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c = new Cleanup;
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c->next = cleanup_.next;
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cleanup_.next = c;
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}
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c->function = func;
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c->arg1 = arg1;
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c->arg2 = arg2;
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}
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namespace {
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class EmptyIterator : public Iterator {
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public:
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explicit EmptyIterator(const Status& s) : status_(s) { }
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virtual bool Valid() const override { return false; }
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virtual void Seek(const Slice& target) override {}
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virtual void SeekToFirst() override {}
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virtual void SeekToLast() override {}
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virtual void Next() override { assert(false); }
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virtual void Prev() override { assert(false); }
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Slice key() const override {
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assert(false);
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return Slice();
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}
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Slice value() const override {
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assert(false);
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return Slice();
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}
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virtual Status status() const override { return status_; }
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private:
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Status status_;
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};
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} // namespace
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Iterator* NewEmptyIterator() {
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return new EmptyIterator(Status::OK());
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}
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Iterator* NewEmptyIterator(Arena* arena) {
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if (arena == nullptr) {
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return NewEmptyIterator();
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} else {
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auto mem = arena->AllocateAligned(sizeof(EmptyIterator));
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return new (mem) EmptyIterator(Status::OK());
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}
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}
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Iterator* NewErrorIterator(const Status& status) {
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return new EmptyIterator(status);
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}
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Iterator* NewErrorIterator(const Status& status, Arena* arena) {
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if (arena == nullptr) {
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return NewErrorIterator(status);
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} else {
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auto mem = arena->AllocateAligned(sizeof(EmptyIterator));
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return new (mem) EmptyIterator(status);
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}
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}
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} // namespace rocksdb
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