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//===--- FS.cpp - 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
//
//===----------------------------------------------------------------------===//
#include "FS.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/None.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/VirtualFileSystem.h"
namespace clang {
namespace clangd {
PreambleFileStatusCache::PreambleFileStatusCache(llvm::StringRef MainFilePath){
assert(llvm::sys::path::is_absolute(MainFilePath));
llvm::SmallString<256> MainFileCanonical(MainFilePath);
llvm::sys::path::remove_dots(MainFileCanonical, /*remove_dot_dot=*/true);
this->MainFilePath = std::string(MainFileCanonical.str());
}
void PreambleFileStatusCache::update(const llvm::vfs::FileSystem &FS,
llvm::vfs::Status S) {
// Canonicalize path for later lookup, which is usually by absolute path.
llvm::SmallString<32> PathStore(S.getName());
if (FS.makeAbsolute(PathStore))
return;
llvm::sys::path::remove_dots(PathStore, /*remove_dot_dot=*/true);
// Do not cache status for the main file.
if (PathStore == MainFilePath)
return;
// Stores the latest status in cache as it can change in a preamble build.
StatCache.insert({PathStore, std::move(S)});
}
llvm::Optional<llvm::vfs::Status>
PreambleFileStatusCache::lookup(llvm::StringRef File) const {
// Canonicalize to match the cached form.
// Lookup tends to be first by absolute path, so no need to make absolute.
llvm::SmallString<256> PathLookup(File);
llvm::sys::path::remove_dots(PathLookup, /*remove_dot_dot=*/true);
auto I = StatCache.find(PathLookup);
if (I != StatCache.end())
// Returned Status name should always match the requested File.
return llvm::vfs::Status::copyWithNewName(I->getValue(), File);
return None;
}
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
PreambleFileStatusCache::getProducingFS(
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
// This invalidates old status in cache if files are re-`open()`ed or
// re-`stat()`ed in case file status has changed during preamble build.
class CollectFS : public llvm::vfs::ProxyFileSystem {
public:
CollectFS(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
PreambleFileStatusCache &StatCache)
: ProxyFileSystem(std::move(FS)), StatCache(StatCache) {}
llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>
openFileForRead(const llvm::Twine &Path) override {
auto File = getUnderlyingFS().openFileForRead(Path);
if (!File || !*File)
return File;
// Eagerly stat opened file, as the followup `status` call on the file
// doesn't necessarily go through this FS. This puts some extra work on
// preamble build, but it should be worth it as preamble can be reused
// many times (e.g. code completion) and the repeated status call is
// likely to be cached in the underlying file system anyway.
if (auto S = File->get()->status())
StatCache.update(getUnderlyingFS(), std::move(*S));
return File;
}
llvm::ErrorOr<llvm::vfs::Status> status(const llvm::Twine &Path) override {
auto S = getUnderlyingFS().status(Path);
if (S)
StatCache.update(getUnderlyingFS(), *S);
return S;
}
private:
PreambleFileStatusCache &StatCache;
};
return llvm::IntrusiveRefCntPtr<CollectFS>(
new CollectFS(std::move(FS), *this));
}
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
PreambleFileStatusCache::getConsumingFS(
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) const {
class CacheVFS : public llvm::vfs::ProxyFileSystem {
public:
CacheVFS(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
const PreambleFileStatusCache &StatCache)
: ProxyFileSystem(std::move(FS)), StatCache(StatCache) {}
llvm::ErrorOr<llvm::vfs::Status> status(const llvm::Twine &Path) override {
if (auto S = StatCache.lookup(Path.str()))
return *S;
return getUnderlyingFS().status(Path);
}
private:
const PreambleFileStatusCache &StatCache;
};
return llvm::IntrusiveRefCntPtr<CacheVFS>(new CacheVFS(std::move(FS), *this));
}
Path removeDots(PathRef File) {
llvm::SmallString<128> CanonPath(File);
llvm::sys::path::remove_dots(CanonPath, /*remove_dot_dot=*/true);
return CanonPath.str().str();
}
} // namespace clangd
} // namespace clang
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