llvm/clang-tools-extra/clangd/FS.h

//===--- FS.h - File system related utils ------------------------*- C++-*-===//
//
// 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_FS_H
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_FS_H

#include "support/Path.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/VirtualFileSystem.h"
#include <optional>

namespace clang {
namespace clangd {

/// Records status information for files open()ed or stat()ed during preamble
/// build (except for the main file), so we can avoid stat()s on the underlying
/// FS when reusing the preamble. For example, code completion can re-stat files
/// when getting FileID for source locations stored in preamble (e.g. checking
/// whether a location is in the main file).
///
/// The cache is keyed by absolute path of file name in cached status, as this
/// is what preamble stores.
///
/// The cache is not thread-safe when updates happen, so the use pattern should
/// be:
///   - One FS writes to the cache from one thread (or several but strictly
///   sequenced), e.g. when building preamble.
///   - Sequence point (no writes after this point, no reads before).
///   - Several FSs can read from the cache, e.g. code completions.
///
/// Note that the cache is only valid when reusing preamble.
class PreambleFileStatusCache { … };

/// Returns a version of \p File that doesn't contain dots and dot dots.
/// e.g /a/b/../c -> /a/c
///     /a/b/./c -> /a/b/c
/// FIXME: We should avoid encountering such paths in clangd internals by
/// filtering everything we get over LSP, CDB, etc.
Path removeDots(PathRef File);

} // namespace clangd
} // namespace clang

#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_FS_H