s/const auto/const auto&/ when doing loop (#6477)

Summary:
this silences following warning from clang-11
```
rocksdb/db/db_impl/db_impl_compaction_flush.cc:1040:21: warning: loop variable 'newf' of type 'const std::pair<int, rocksdb::FileMetaData>' creates a copy from type 'const
std::pair<int\
, rocksdb::FileMetaData>' [-Wrange-loop-analysis]
    for (const auto newf : c->edit()->GetNewFiles()) {
                    ^
rocksdb/db/db_impl/db_impl_compaction_flush.cc:1040:10: note: use reference type 'const std::pair<int, rocksdb::FileMetaData> &' to prevent copying
    for (const auto newf : c->edit()->GetNewFiles()) {
         ^~~~~~~~~~~~~~~~~
                    &
```
Signed-off-by: Kefu Chai <tchaikov@gmail.com>
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6477

Differential Revision: D20211850

Pulled By: ltamasi

fbshipit-source-id: 3e89e13a12bba79f1b934d46b7c4c0576cdafb01
This commit is contained in:
Kefu Chai 2020-03-03 08:39:14 -08:00 committed by Facebook Github Bot
parent 48d8d076a3
commit 03dbd11ead

View File

@ -1037,7 +1037,7 @@ Status DBImpl::CompactFilesImpl(
}
if (output_file_names != nullptr) {
for (const auto newf : c->edit()->GetNewFiles()) {
for (const auto& newf : c->edit()->GetNewFiles()) {
(*output_file_names)
.push_back(TableFileName(c->immutable_cf_options()->cf_paths,
newf.second.fd.GetNumber(),
@ -1137,7 +1137,7 @@ void DBImpl::NotifyOnCompactionBegin(ColumnFamilyData* cfd, Compaction* c,
}
}
}
for (const auto newf : c->edit()->GetNewFiles()) {
for (const auto& newf : c->edit()->GetNewFiles()) {
const FileMetaData& meta = newf.second;
const FileDescriptor& desc = meta.fd;
const uint64_t file_number = desc.GetNumber();