Summary:
This reverts the previous commit 1d7048c598
, which broke the build.
Did a `git revert 1d7048c`.
Closes https://github.com/facebook/rocksdb/pull/2627
Differential Revision: D5476473
Pulled By: sagar0
fbshipit-source-id: 4756ff5c0dfc88c17eceb00e02c36176de728d06
181 lines
5.5 KiB
C++
181 lines
5.5 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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//
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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/internal_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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Cleanable::Cleanable() {
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cleanup_.function = nullptr;
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cleanup_.next = nullptr;
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}
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Cleanable::~Cleanable() { DoCleanup(); }
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// If the entire linked list was on heap we could have simply add attach one
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// link list to another. However the head is an embeded object to avoid the cost
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// of creating objects for most of the use cases when the Cleanable has only one
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// Cleanup to do. We could put evernything on heap if benchmarks show no
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// negative impact on performance.
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// Also we need to iterate on the linked list since there is no pointer to the
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// tail. We can add the tail pointer but maintainin it might negatively impact
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// the perforamnce for the common case of one cleanup where tail pointer is not
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// needed. Again benchmarks could clarify that.
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// Even without a tail pointer we could iterate on the list, find the tail, and
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// have only that node updated without the need to insert the Cleanups one by
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// one. This however would be redundant when the source Cleanable has one or a
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// few Cleanups which is the case most of the time.
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// TODO(myabandeh): if the list is too long we should maintain a tail pointer
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// and have the entire list (minus the head that has to be inserted separately)
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// merged with the target linked list at once.
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void Cleanable::DelegateCleanupsTo(Cleanable* other) {
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assert(other != nullptr);
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if (cleanup_.function == nullptr) {
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return;
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}
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Cleanup* c = &cleanup_;
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other->RegisterCleanup(c->function, c->arg1, c->arg2);
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c = c->next;
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while (c != nullptr) {
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Cleanup* next = c->next;
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other->RegisterCleanup(c);
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c = next;
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}
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cleanup_.function = nullptr;
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cleanup_.next = nullptr;
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}
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void Cleanable::RegisterCleanup(Cleanable::Cleanup* c) {
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assert(c != nullptr);
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if (cleanup_.function == nullptr) {
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cleanup_.function = c->function;
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cleanup_.arg1 = c->arg1;
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cleanup_.arg2 = c->arg2;
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delete c;
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} else {
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c->next = cleanup_.next;
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cleanup_.next = c;
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}
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}
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void Cleanable::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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Status Iterator::GetProperty(std::string prop_name, std::string* prop) {
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if (prop == nullptr) {
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return Status::InvalidArgument("prop is nullptr");
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}
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if (prop_name == "rocksdb.iterator.is-key-pinned") {
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*prop = "0";
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return Status::OK();
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}
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return Status::InvalidArgument("Undentified property.");
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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 SeekForPrev(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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class EmptyInternalIterator : public InternalIterator {
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public:
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explicit EmptyInternalIterator(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 SeekForPrev(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* NewErrorIterator(const Status& status) {
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return new EmptyIterator(status);
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}
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InternalIterator* NewEmptyInternalIterator() {
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return new EmptyInternalIterator(Status::OK());
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}
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InternalIterator* NewEmptyInternalIterator(Arena* arena) {
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if (arena == nullptr) {
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return NewEmptyInternalIterator();
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} else {
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auto mem = arena->AllocateAligned(sizeof(EmptyIterator));
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return new (mem) EmptyInternalIterator(Status::OK());
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}
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}
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InternalIterator* NewErrorInternalIterator(const Status& status) {
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return new EmptyInternalIterator(status);
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}
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InternalIterator* NewErrorInternalIterator(const Status& status, Arena* arena) {
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if (arena == nullptr) {
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return NewErrorInternalIterator(status);
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} else {
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auto mem = arena->AllocateAligned(sizeof(EmptyIterator));
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return new (mem) EmptyInternalIterator(status);
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}
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}
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} // namespace rocksdb
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