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1//===--- ThreadsafeFS.h ------------------------------------------*- C++-*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_SUPPORT_THREADSAFEFS_H10#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SUPPORT_THREADSAFEFS_H11 12#include "Path.h"13#include "llvm/ADT/IntrusiveRefCntPtr.h"14#include "llvm/Support/VirtualFileSystem.h"15#include <memory>16 17namespace clang {18namespace clangd {19 20/// Wrapper for vfs::FileSystem for use in multithreaded programs like clangd.21/// As FileSystem is not threadsafe, concurrent threads must each obtain one.22/// Implementations may choose to depend on Context::current() e.g. to implement23/// snapshot semantics. clangd will not create vfs::FileSystems for use in24/// different contexts, so either ThreadsafeFS::view or the returned FS may25/// contain this logic.26class ThreadsafeFS {27public:28 virtual ~ThreadsafeFS() = default;29 30 /// Obtain a vfs::FileSystem with an arbitrary initial working directory.31 llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>32 view(std::nullopt_t CWD) const {33 return viewImpl();34 }35 36 /// Obtain a vfs::FileSystem with a specified working directory.37 /// If the working directory can't be set (e.g. doesn't exist), logs and38 /// returns the FS anyway.39 llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> view(PathRef CWD) const;40 41private:42 /// Overridden by implementations to provide a vfs::FileSystem.43 /// This is distinct from view(NoneType) to avoid GCC's -Woverloaded-virtual.44 virtual llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> viewImpl() const = 0;45};46 47class RealThreadsafeFS : public ThreadsafeFS {48private:49 llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> viewImpl() const override;50};51 52} // namespace clangd53} // namespace clang54 55#endif56