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// 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.
#include "leveldb/iterator.h"
namespace leveldb {
Iterator::Iterator() {
cleanup_head_.function = nullptr;
cleanup_head_.next = nullptr;
}
Iterator::~Iterator() {
if (!cleanup_head_.IsEmpty()) {
cleanup_head_.Run();
for (CleanupNode* node = cleanup_head_.next; node != nullptr;) {
node->Run();
CleanupNode* next_node = node->next;
delete node;
node = next_node;
}
}
}
void Iterator::RegisterCleanup(CleanupFunction func, void* arg1, void* arg2) {
assert(func != nullptr);
CleanupNode* node;
if (cleanup_head_.IsEmpty()) {
node = &cleanup_head_;
} else {
node = new CleanupNode();
node->next = cleanup_head_.next;
cleanup_head_.next = node;
}
node->function = func;
node->arg1 = arg1;
node->arg2 = arg2;
}
namespace {
class EmptyIterator : public Iterator {
public:
EmptyIterator(const Status& s) : status_(s) {}
~EmptyIterator() override = default;
bool Valid() const override { return false; }
void Seek(const Slice& target) override {}
void SeekToFirst() override {}
void SeekToLast() override {}
void Next() override { assert(false); }
void Prev() override { assert(false); }
Slice key() const override {
assert(false);
return Slice();
}
Slice value() const override {
assert(false);
return Slice();
}
Status status() const override { return status_; }
private:
Status status_;
};
} // anonymous namespace
Iterator* NewEmptyIterator() { return new EmptyIterator(Status::OK()); }
Iterator* NewErrorIterator(const Status& status) {
return new EmptyIterator(status);
}
} // namespace leveldb
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