diff options
author | vitalyisaev <vitalyisaev@yandex-team.com> | 2023-06-29 10:00:50 +0300 |
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committer | vitalyisaev <vitalyisaev@yandex-team.com> | 2023-06-29 10:00:50 +0300 |
commit | 6ffe9e53658409f212834330e13564e4952558f6 (patch) | |
tree | 85b1e00183517648b228aafa7c8fb07f5276f419 /contrib/libs/clang14/lib/Basic/FileSystemStatCache.cpp | |
parent | 726057070f9c5a91fc10fde0d5024913d10f1ab9 (diff) | |
download | ydb-6ffe9e53658409f212834330e13564e4952558f6.tar.gz |
YQ Connector: support managed ClickHouse
Со стороны dqrun можно обратиться к инстансу коннектора, который работает на streaming стенде, и извлечь данные из облачного CH.
Diffstat (limited to 'contrib/libs/clang14/lib/Basic/FileSystemStatCache.cpp')
-rw-r--r-- | contrib/libs/clang14/lib/Basic/FileSystemStatCache.cpp | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/contrib/libs/clang14/lib/Basic/FileSystemStatCache.cpp b/contrib/libs/clang14/lib/Basic/FileSystemStatCache.cpp new file mode 100644 index 00000000000..415a4e2025d --- /dev/null +++ b/contrib/libs/clang14/lib/Basic/FileSystemStatCache.cpp @@ -0,0 +1,120 @@ +//===- FileSystemStatCache.cpp - Caching for 'stat' calls -----------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file defines the FileSystemStatCache interface. +// +//===----------------------------------------------------------------------===// + +#include "clang/Basic/FileSystemStatCache.h" +#include "llvm/Support/Chrono.h" +#include "llvm/Support/ErrorOr.h" +#include "llvm/Support/Path.h" +#include "llvm/Support/VirtualFileSystem.h" +#include <utility> + +using namespace clang; + +void FileSystemStatCache::anchor() {} + +/// FileSystemStatCache::get - Get the 'stat' information for the specified +/// path, using the cache to accelerate it if possible. This returns true if +/// the path does not exist or false if it exists. +/// +/// If isFile is true, then this lookup should only return success for files +/// (not directories). If it is false this lookup should only return +/// success for directories (not files). On a successful file lookup, the +/// implementation can optionally fill in FileDescriptor with a valid +/// descriptor and the client guarantees that it will close it. +std::error_code +FileSystemStatCache::get(StringRef Path, llvm::vfs::Status &Status, + bool isFile, std::unique_ptr<llvm::vfs::File> *F, + FileSystemStatCache *Cache, + llvm::vfs::FileSystem &FS) { + bool isForDir = !isFile; + std::error_code RetCode; + + // If we have a cache, use it to resolve the stat query. + if (Cache) + RetCode = Cache->getStat(Path, Status, isFile, F, FS); + else if (isForDir || !F) { + // If this is a directory or a file descriptor is not needed and we have + // no cache, just go to the file system. + llvm::ErrorOr<llvm::vfs::Status> StatusOrErr = FS.status(Path); + if (!StatusOrErr) { + RetCode = StatusOrErr.getError(); + } else { + Status = *StatusOrErr; + } + } else { + // Otherwise, we have to go to the filesystem. We can always just use + // 'stat' here, but (for files) the client is asking whether the file exists + // because it wants to turn around and *open* it. It is more efficient to + // do "open+fstat" on success than it is to do "stat+open". + // + // Because of this, check to see if the file exists with 'open'. If the + // open succeeds, use fstat to get the stat info. + auto OwnedFile = FS.openFileForRead(Path); + + if (!OwnedFile) { + // If the open fails, our "stat" fails. + RetCode = OwnedFile.getError(); + } else { + // Otherwise, the open succeeded. Do an fstat to get the information + // about the file. We'll end up returning the open file descriptor to the + // client to do what they please with it. + llvm::ErrorOr<llvm::vfs::Status> StatusOrErr = (*OwnedFile)->status(); + if (StatusOrErr) { + Status = *StatusOrErr; + *F = std::move(*OwnedFile); + } else { + // fstat rarely fails. If it does, claim the initial open didn't + // succeed. + *F = nullptr; + RetCode = StatusOrErr.getError(); + } + } + } + + // If the path doesn't exist, return failure. + if (RetCode) + return RetCode; + + // If the path exists, make sure that its "directoryness" matches the clients + // demands. + if (Status.isDirectory() != isForDir) { + // If not, close the file if opened. + if (F) + *F = nullptr; + return std::make_error_code( + Status.isDirectory() ? + std::errc::is_a_directory : std::errc::not_a_directory); + } + + return std::error_code(); +} + +std::error_code +MemorizeStatCalls::getStat(StringRef Path, llvm::vfs::Status &Status, + bool isFile, + std::unique_ptr<llvm::vfs::File> *F, + llvm::vfs::FileSystem &FS) { + auto err = get(Path, Status, isFile, F, nullptr, FS); + if (err) { + // Do not cache failed stats, it is easy to construct common inconsistent + // situations if we do, and they are not important for PCH performance + // (which currently only needs the stats to construct the initial + // FileManager entries). + return err; + } + + // Cache file 'stat' results and directories with absolutely paths. + if (!Status.isDirectory() || llvm::sys::path::is_absolute(Path)) + StatCalls[Path] = Status; + + return std::error_code(); +} |