Support move semantics for PinnableSlice (#6374)

Summary:
It's logically correct for PinnableSlice to support move semantics to transfer ownership of the pinned memory region. This PR adds both move constructor and move assignment to PinnableSlice.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6374

Test Plan:
A set of unit tests for the move semantics are added in slice_test.
So `make slice_test && ./slice_test`.

Differential Revision: D19739254

Pulled By: cheng-chang

fbshipit-source-id: f898bd811bb05b2d87384ec58b645e9915e8e0b1
main
Cheng Chang 5 years ago committed by Facebook Github Bot
parent 25fbdc5a31
commit b42fa1497f
  1. 1
      CMakeLists.txt
  2. 4
      Makefile
  3. 7
      TARGETS
  4. 5
      include/rocksdb/slice.h
  5. 1
      src.mk
  6. 31
      util/slice.cc
  7. 175
      util/slice_test.cc

@ -1033,6 +1033,7 @@ if(WITH_TESTS)
util/random_test.cc
util/rate_limiter_test.cc
util/repeatable_thread_test.cc
util/slice_test.cc
util/slice_transform_test.cc
util/timer_queue_test.cc
util/thread_list_test.cc

@ -503,6 +503,7 @@ TESTS = \
data_block_hash_index_test \
cache_test \
corruption_test \
slice_test \
slice_transform_test \
dbformat_test \
fault_injection_test \
@ -1291,6 +1292,9 @@ corruption_test: db/corruption_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARN
crc32c_test: util/crc32c_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(AM_LINK)
slice_test: util/slice_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(AM_LINK)
slice_transform_test: util/slice_transform_test.o $(LIBOBJECTS) $(TESTHARNESS)
$(AM_LINK)

@ -1309,6 +1309,13 @@ ROCKS_TESTS = [
[],
[],
],
[
"slice_test",
"util/slice_test.cc",
"serial",
[],
[],
],
[
"slice_transform_test",
"util/slice_transform_test.cc",

@ -147,6 +147,9 @@ class PinnableSlice : public Slice, public Cleanable {
PinnableSlice() { buf_ = &self_space_; }
explicit PinnableSlice(std::string* buf) { buf_ = buf; }
PinnableSlice(PinnableSlice&& other);
PinnableSlice& operator=(PinnableSlice&& other);
// No copy constructor and copy assignment allowed.
PinnableSlice(PinnableSlice&) = delete;
PinnableSlice& operator=(PinnableSlice&) = delete;
@ -214,7 +217,7 @@ class PinnableSlice : public Slice, public Cleanable {
inline std::string* GetSelf() { return buf_; }
inline bool IsPinned() { return pinned_; }
inline bool IsPinned() const { return pinned_; }
private:
friend class PinnableSlice4Test;

@ -424,6 +424,7 @@ MAIN_SOURCES = \
util/rate_limiter_test.cc \
util/random_test.cc \
util/repeatable_thread_test.cc \
util/slice_test.cc \
util/slice_transform_test.cc \
util/timer_queue_test.cc \
util/thread_list_test.cc \

@ -209,4 +209,35 @@ const SliceTransform* NewNoopTransform() {
return new NoopTransform;
}
PinnableSlice::PinnableSlice(PinnableSlice&& other) {
*this = std::move(other);
}
PinnableSlice& PinnableSlice::operator=(PinnableSlice&& other) {
if (this != &other) {
Cleanable::Reset();
Cleanable::operator=(std::move(other));
size_ = other.size_;
pinned_ = other.pinned_;
if (pinned_) {
data_ = other.data_;
// When it's pinned, buf should no longer be of use.
} else {
if (other.buf_ == &other.self_space_) {
self_space_ = std::move(other.self_space_);
buf_ = &self_space_;
data_ = buf_->data();
} else {
buf_ = other.buf_;
data_ = other.data_;
}
}
other.self_space_.clear();
other.buf_ = &other.self_space_;
other.pinned_ = false;
other.PinSelf();
}
return *this;
}
} // namespace rocksdb

@ -0,0 +1,175 @@
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "port/port.h"
#include "port/stack_trace.h"
#include "rocksdb/slice.h"
#include "test_util/testharness.h"
#include "test_util/testutil.h"
namespace rocksdb {
// Use this to keep track of the cleanups that were actually performed
void Multiplier(void* arg1, void* arg2) {
int* res = reinterpret_cast<int*>(arg1);
int* num = reinterpret_cast<int*>(arg2);
*res *= *num;
}
class PinnableSliceTest : public testing::Test {
public:
void AssertEmpty(const PinnableSlice& slice) {
ASSERT_EQ(0, slice.size());
ASSERT_FALSE(slice.IsPinned());
}
void AssertSameData(const std::string& expected,
const PinnableSlice& slice) {
std::string got;
got.assign(slice.data(), slice.size());
ASSERT_EQ(expected, got);
}
// Asserts that pinnable is in a clean state after being moved to
// another PinnableSlice.
// It asserts by trying to pin the slice.
void AssertCleanState(PinnableSlice& pinnable, const Slice& slice) {
AssertEmpty(pinnable);
pinnable.PinSelf(slice);
AssertSameData(slice.ToString(), pinnable);
int res = 1;
int n2 = 2;
pinnable.PinSlice(slice, Multiplier, &res, &n2);
AssertSameData(slice.ToString(), pinnable);
ASSERT_EQ(1, res);
pinnable.Reset();
ASSERT_EQ(2, res);
}
};
TEST_F(PinnableSliceTest, Move) {
int n2 = 2;
int res = 1;
const std::string const_str1 = "123";
const std::string const_str2 = "ABC";
Slice slice1(const_str1);
Slice slice2(const_str2);
{
// Test move constructor on a pinned slice.
res = 1;
PinnableSlice v1;
v1.PinSlice(slice1, Multiplier, &res, &n2);
PinnableSlice v2(std::move(v1));
// Since v1's Cleanable has been moved to v2,
// no cleanup should happen in Reset.
v1.Reset();
ASSERT_EQ(1, res);
AssertSameData(const_str1, v2);
AssertCleanState(v1, slice2);
}
// v2 is cleaned up.
ASSERT_EQ(2, res);
{
// Test move constructor on an unpinned slice.
PinnableSlice v1;
v1.PinSelf(slice1);
PinnableSlice v2(std::move(v1));
AssertSameData(const_str1, v2);
AssertCleanState(v1, slice2);
}
{
// Test move assignment from a pinned slice to
// another pinned slice.
res = 1;
PinnableSlice v1;
v1.PinSlice(slice1, Multiplier, &res, &n2);
PinnableSlice v2;
v2.PinSlice(slice2, Multiplier, &res, &n2);
v2 = std::move(v1);
// v2's Cleanable will be Reset before moving
// anything from v1.
ASSERT_EQ(2, res);
// Since v1's Cleanable has been moved to v2,
// no cleanup should happen in Reset.
v1.Reset();
ASSERT_EQ(2, res);
AssertSameData(const_str1, v2);
AssertCleanState(v1, slice2);
}
// The Cleanable moved from v1 to v2 will be Reset.
ASSERT_EQ(4, res);
{
// Test move assignment from a pinned slice to
// an unpinned slice.
res = 1;
PinnableSlice v1;
v1.PinSlice(slice1, Multiplier, &res, &n2);
PinnableSlice v2;
v2.PinSelf(slice2);
v2 = std::move(v1);
// Since v1's Cleanable has been moved to v2,
// no cleanup should happen in Reset.
v1.Reset();
ASSERT_EQ(1, res);
AssertSameData(const_str1, v2);
AssertCleanState(v1, slice2);
}
// The Cleanable moved from v1 to v2 will be Reset.
ASSERT_EQ(2, res);
{
// Test move assignment from an upinned slice to
// another unpinned slice.
PinnableSlice v1;
v1.PinSelf(slice1);
PinnableSlice v2;
v2.PinSelf(slice2);
v2 = std::move(v1);
AssertSameData(const_str1, v2);
AssertCleanState(v1, slice2);
}
{
// Test move assignment from an upinned slice to
// a pinned slice.
res = 1;
PinnableSlice v1;
v1.PinSelf(slice1);
PinnableSlice v2;
v2.PinSlice(slice2, Multiplier, &res, &n2);
v2 = std::move(v1);
// v2's Cleanable will be Reset before moving
// anything from v1.
ASSERT_EQ(2, res);
AssertSameData(const_str1, v2);
AssertCleanState(v1, slice2);
}
// No Cleanable is moved from v1 to v2, so no more cleanup.
ASSERT_EQ(2, res);
}
} // namespace rocksdb
int main(int argc, char** argv) {
rocksdb::port::InstallStackTraceHandler();
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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