From 4de9594f6fbfd69043239a5705b5f32065f02d34 Mon Sep 17 00:00:00 2001
From: costan <costan@google.com>
Date: Mon, 23 Apr 2018 16:15:21 -0700
Subject: [PATCH] Add move constructor to Status.
This will result in smaller code generation when Status instances are
passed around.
Benchmarks don't indicate a significant change either way.
CPU: 48 * Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz
CPUCache: 30720 KB
Keys: 16 bytes each
Values: 100 bytes each (50 bytes after compression)
Entries: 1000000
RawSize: 110.6 MB (estimated)
FileSize: 62.9 MB (estimated)
Baseline:
fillseq : 3.589 micros/op; 30.8 MB/s
fillsync : 4165.299 micros/op; 0.0 MB/s (1000 ops)
fillrandom : 5.864 micros/op; 18.9 MB/s
overwrite : 7.830 micros/op; 14.1 MB/s
readrandom : 5.534 micros/op; (1000000 of 1000000 found)
readrandom : 4.292 micros/op; (1000000 of 1000000 found)
readseq : 0.312 micros/op; 354.1 MB/s
readreverse : 0.501 micros/op; 220.8 MB/s
compact : 886211.000 micros/op;
readrandom : 3.518 micros/op; (1000000 of 1000000 found)
readseq : 0.251 micros/op; 441.2 MB/s
readreverse : 0.456 micros/op; 242.4 MB/s
fill100K : 1329.723 micros/op; 71.7 MB/s (1000 ops)
crc32c : 1.976 micros/op; 1976.7 MB/s (4K per op)
snappycomp : 4.705 micros/op; 830.2 MB/s (output: 55.1%)
snappyuncomp : 0.958 micros/op; 4079.1 MB/s
acquireload : 0.727 micros/op; (each op is 1000 loads)
New:
fillseq : 3.129 micros/op; 35.4 MB/s
fillsync : 2748.099 micros/op; 0.0 MB/s (1000 ops)
fillrandom : 5.394 micros/op; 20.5 MB/s
overwrite : 7.253 micros/op; 15.3 MB/s
readrandom : 5.655 micros/op; (1000000 of 1000000 found)
readrandom : 4.425 micros/op; (1000000 of 1000000 found)
readseq : 0.298 micros/op; 371.3 MB/s
readreverse : 0.508 micros/op; 217.9 MB/s
compact : 885842.000 micros/op;
readrandom : 3.545 micros/op; (1000000 of 1000000 found)
readseq : 0.252 micros/op; 438.2 MB/s
readreverse : 0.425 micros/op; 260.2 MB/s
fill100K : 1418.347 micros/op; 67.2 MB/s (1000 ops)
crc32c : 1.987 micros/op; 1966.0 MB/s (4K per op)
snappycomp : 4.767 micros/op; 819.4 MB/s (output: 55.1%)
snappyuncomp : 0.916 micros/op; 4264.9 MB/s
acquireload : 0.665 micros/op; (each op is 1000 loads)
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=194002392
---
CMakeLists.txt | 1 +
include/leveldb/status.h | 30 +++++++++++++++++++-----------
util/status_test.cc | 42 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 62 insertions(+), 11 deletions(-)
create mode 100644 util/status_test.cc
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4bf3df3..d49c31e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -277,6 +277,7 @@ if(LEVELDB_BUILD_TESTS)
leveldb_test("${PROJECT_SOURCE_DIR}/issues/issue200_test.cc")
leveldb_test("${PROJECT_SOURCE_DIR}/util/env_test.cc")
+ leveldb_test("${PROJECT_SOURCE_DIR}/util/status_test.cc")
if(NOT BUILD_SHARED_LIBS)
leveldb_test("${PROJECT_SOURCE_DIR}/db/autocompact_test.cc")
diff --git a/include/leveldb/status.h b/include/leveldb/status.h
index 39d692d..ee9fac2 100644
--- a/include/leveldb/status.h
+++ b/include/leveldb/status.h
@@ -13,6 +13,7 @@
#ifndef STORAGE_LEVELDB_INCLUDE_STATUS_H_
#define STORAGE_LEVELDB_INCLUDE_STATUS_H_
+#include <algorithm>
#include <string>
#include "leveldb/export.h"
#include "leveldb/slice.h"
@@ -22,12 +23,14 @@ namespace leveldb {
class LEVELDB_EXPORT Status {
public:
// Create a success status.
- Status() : state_(nullptr) { }
+ Status() noexcept : state_(nullptr) { }
~Status() { delete[] state_; }
- // Copy the specified status.
- Status(const Status& s);
- void operator=(const Status& s);
+ Status(const Status& rhs);
+ Status& operator=(const Status& rhs);
+
+ Status(Status&& rhs) noexcept : state_(rhs.state_) { rhs.state_ = nullptr; }
+ Status& operator=(Status&& rhs) noexcept;
// Return a success status.
static Status OK() { return Status(); }
@@ -96,16 +99,21 @@ class LEVELDB_EXPORT Status {
static const char* CopyState(const char* s);
};
-inline Status::Status(const Status& s) {
- state_ = (s.state_ == nullptr) ? nullptr : CopyState(s.state_);
+inline Status::Status(const Status& rhs) {
+ state_ = (rhs.state_ == nullptr) ? nullptr : CopyState(rhs.state_);
}
-inline void Status::operator=(const Status& s) {
- // The following condition catches both aliasing (when this == &s),
- // and the common case where both s and *this are ok.
- if (state_ != s.state_) {
+inline Status& Status::operator=(const Status& rhs) {
+ // The following condition catches both aliasing (when this == &rhs),
+ // and the common case where both rhs and *this are ok.
+ if (state_ != rhs.state_) {
delete[] state_;
- state_ = (s.state_ == nullptr) ? nullptr : CopyState(s.state_);
+ state_ = (rhs.state_ == nullptr) ? nullptr : CopyState(rhs.state_);
}
+ return *this;
+}
+inline Status& Status::operator=(Status&& rhs) noexcept {
+ std::swap(state_, rhs.state_);
+ return *this;
}
} // namespace leveldb
diff --git a/util/status_test.cc b/util/status_test.cc
new file mode 100644
index 0000000..7ed3b9e
--- /dev/null
+++ b/util/status_test.cc
@@ -0,0 +1,42 @@
+// Copyright (c) 2018 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 <utility>
+
+#include "leveldb/slice.h"
+#include "leveldb/status.h"
+#include "util/testharness.h"
+
+namespace leveldb {
+
+TEST(Status, MoveConstructor) {
+ {
+ Status ok = Status::OK();
+ Status ok2 = std::move(ok);
+
+ ASSERT_TRUE(ok2.ok());
+ }
+
+ {
+ Status status = Status::NotFound("custom NotFound status message");
+ Status status2 = std::move(status);
+
+ ASSERT_TRUE(status2.IsNotFound());
+ ASSERT_EQ("NotFound: custom NotFound status message", status2.ToString());
+ }
+
+ {
+ Status self_moved = Status::IOError("custom IOError status message");
+
+ // Needed to bypass compiler warning about explicit move-assignment.
+ Status& self_moved_reference = self_moved;
+ self_moved_reference = std::move(self_moved);
+ }
+}
+
+} // namespace leveldb
+
+int main(int argc, char** argv) {
+ return leveldb::test::RunAllTests();
+}