forked from OSchip/llvm-project
116 lines
4.3 KiB
C++
116 lines
4.3 KiB
C++
//===--- FS.cpp - File system related utils ----------------------*- C++-*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "FS.h"
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#include "clang/Basic/LLVM.h"
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#include "llvm/ADT/None.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/VirtualFileSystem.h"
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namespace clang {
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namespace clangd {
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PreambleFileStatusCache::PreambleFileStatusCache(llvm::StringRef MainFilePath){
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assert(llvm::sys::path::is_absolute(MainFilePath));
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llvm::SmallString<256> MainFileCanonical(MainFilePath);
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llvm::sys::path::remove_dots(MainFileCanonical, /*remove_dot_dot=*/true);
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this->MainFilePath = MainFileCanonical.str();
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}
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void PreambleFileStatusCache::update(const llvm::vfs::FileSystem &FS,
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llvm::vfs::Status S) {
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// Canonicalize path for later lookup, which is usually by absolute path.
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llvm::SmallString<32> PathStore(S.getName());
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if (FS.makeAbsolute(PathStore))
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return;
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llvm::sys::path::remove_dots(PathStore, /*remove_dot_dot=*/true);
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// Do not cache status for the main file.
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if (PathStore == MainFilePath)
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return;
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// Stores the latest status in cache as it can change in a preamble build.
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StatCache.insert({PathStore, std::move(S)});
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}
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llvm::Optional<llvm::vfs::Status>
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PreambleFileStatusCache::lookup(llvm::StringRef File) const {
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// Canonicalize to match the cached form.
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// Lookup tends to be first by absolute path, so no need to make absolute.
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llvm::SmallString<256> PathLookup(File);
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llvm::sys::path::remove_dots(PathLookup, /*remove_dot_dot=*/true);
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auto I = StatCache.find(PathLookup);
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if (I != StatCache.end())
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// Returned Status name should always match the requested File.
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return llvm::vfs::Status::copyWithNewName(I->getValue(), File);
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return None;
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}
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llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
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PreambleFileStatusCache::getProducingFS(
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llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
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// This invalidates old status in cache if files are re-`open()`ed or
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// re-`stat()`ed in case file status has changed during preamble build.
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class CollectFS : public llvm::vfs::ProxyFileSystem {
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public:
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CollectFS(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
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PreambleFileStatusCache &StatCache)
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: ProxyFileSystem(std::move(FS)), StatCache(StatCache) {}
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llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>
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openFileForRead(const llvm::Twine &Path) override {
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auto File = getUnderlyingFS().openFileForRead(Path);
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if (!File || !*File)
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return File;
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// Eagerly stat opened file, as the followup `status` call on the file
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// doesn't necessarily go through this FS. This puts some extra work on
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// preamble build, but it should be worth it as preamble can be reused
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// many times (e.g. code completion) and the repeated status call is
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// likely to be cached in the underlying file system anyway.
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if (auto S = File->get()->status())
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StatCache.update(getUnderlyingFS(), std::move(*S));
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return File;
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}
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llvm::ErrorOr<llvm::vfs::Status> status(const llvm::Twine &Path) override {
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auto S = getUnderlyingFS().status(Path);
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if (S)
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StatCache.update(getUnderlyingFS(), *S);
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return S;
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}
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private:
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PreambleFileStatusCache &StatCache;
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};
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return llvm::IntrusiveRefCntPtr<CollectFS>(
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new CollectFS(std::move(FS), *this));
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}
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llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
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PreambleFileStatusCache::getConsumingFS(
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llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) const {
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class CacheVFS : public llvm::vfs::ProxyFileSystem {
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public:
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CacheVFS(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
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const PreambleFileStatusCache &StatCache)
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: ProxyFileSystem(std::move(FS)), StatCache(StatCache) {}
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llvm::ErrorOr<llvm::vfs::Status> status(const llvm::Twine &Path) override {
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if (auto S = StatCache.lookup(Path.str()))
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return *S;
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return getUnderlyingFS().status(Path);
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}
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private:
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const PreambleFileStatusCache &StatCache;
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};
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return llvm::IntrusiveRefCntPtr<CacheVFS>(new CacheVFS(std::move(FS), *this));
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}
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} // namespace clangd
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} // namespace clang
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