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rocksdb/table/iterator.cc

92 lines
2.5 KiB

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