rocksdb/db/flush_scheduler.cc
Yi Wu 296545a2c7 Fix clang analyzer errors
Summary:
Fixing erros reported by clang static analyzer.
* Removing some unused variables.
* Adding assertions to fix false positives reported by clang analyzer.
* Adding `__clang_analyzer__` macro to suppress false positive warnings.

Test Plan:
    USE_CLANG=1 OPT=-g make analyze -j64

Reviewers: andrewkr, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D60549
2016-07-08 17:50:51 -07:00

85 lines
2.1 KiB
C++

// Copyright (c) 2011-present, 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.
#include "db/flush_scheduler.h"
#include <cassert>
#include "db/column_family.h"
namespace rocksdb {
void FlushScheduler::ScheduleFlush(ColumnFamilyData* cfd) {
#ifndef NDEBUG
{
std::lock_guard<std::mutex> lock(checking_mutex_);
assert(checking_set_.count(cfd) == 0);
checking_set_.insert(cfd);
}
#endif // NDEBUG
cfd->Ref();
// Suppress false positive clang analyzer warnings.
#ifndef __clang_analyzer__
Node* node = new Node{cfd, head_.load(std::memory_order_relaxed)};
while (!head_.compare_exchange_strong(
node->next, node, std::memory_order_relaxed, std::memory_order_relaxed)) {
// failing CAS updates the first param, so we are already set for
// retry. TakeNextColumnFamily won't happen until after another
// inter-thread synchronization, so we don't even need release
// semantics for this CAS
}
#endif // __clang_analyzer__
}
ColumnFamilyData* FlushScheduler::TakeNextColumnFamily() {
while (true) {
if (Empty()) {
return nullptr;
}
// dequeue the head
Node* node = head_.load(std::memory_order_relaxed);
head_.store(node->next, std::memory_order_relaxed);
ColumnFamilyData* cfd = node->column_family;
delete node;
#ifndef NDEBUG
{
auto iter = checking_set_.find(cfd);
assert(iter != checking_set_.end());
checking_set_.erase(iter);
}
#endif // NDEBUG
if (!cfd->IsDropped()) {
// success
return cfd;
}
// no longer relevant, retry
if (cfd->Unref()) {
delete cfd;
}
}
}
bool FlushScheduler::Empty() {
auto rv = head_.load(std::memory_order_relaxed) == nullptr;
assert(rv == checking_set_.empty());
return rv;
}
void FlushScheduler::Clear() {
ColumnFamilyData* cfd;
while ((cfd = TakeNextColumnFamily()) != nullptr) {
if (cfd->Unref()) {
delete cfd;
}
}
assert(Empty());
}
} // namespace rocksdb