llvm-project/clang-tools-extra/clangd/support/ThreadsafeFS.h

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//===--- ThreadsafeFS.h ------------------------------------------*- 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_SUPPORT_THREADSAFEFS_H
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SUPPORT_THREADSAFEFS_H
#include "Path.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/Support/VirtualFileSystem.h"
#include <memory>
namespace clang {
namespace clangd {
/// Wrapper for vfs::FileSystem for use in multithreaded programs like clangd.
/// As FileSystem is not threadsafe, concurrent threads must each obtain one.
/// Implementations may choose to depend on Context::current() e.g. to implement
/// snapshot semantics. clangd will not create vfs::FileSystems for use in
/// different contexts, so either ThreadsafeFS::view or the returned FS may
/// contain this logic.
class ThreadsafeFS {
public:
virtual ~ThreadsafeFS() = default;
/// Obtain a vfs::FileSystem with an arbitrary initial working directory.
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
view(llvm::NoneType CWD) const {
return viewImpl();
}
/// Obtain a vfs::FileSystem with a specified working directory.
/// If the working directory can't be set (e.g. doesn't exist), logs and
/// returns the FS anyway.
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> view(PathRef CWD) const;
private:
/// Overridden by implementations to provide a vfs::FileSystem.
/// This is distinct from view(NoneType) to avoid GCC's -Woverloaded-virtual.
virtual llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> viewImpl() const = 0;
};
class RealThreadsafeFS : public ThreadsafeFS {
private:
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> viewImpl() const override;
};
} // namespace clangd
} // namespace clang
#endif