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//===-- FileCollector.cpp ---------------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "llvm/Support/FileCollector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Process.h"
using namespace llvm;
FileCollectorBase::FileCollectorBase() = default;
FileCollectorBase::~FileCollectorBase() = default;
void FileCollectorBase::addFile(const Twine &File) {
std::lock_guard<std::mutex> lock(Mutex);
std::string FileStr = File.str();
if (markAsSeen(FileStr))
void FileCollectorBase::addDirectory(const Twine &Dir) {
std::error_code EC;
addDirectoryImpl(Dir, vfs::getRealFileSystem(), EC);
static bool isCaseSensitivePath(StringRef Path) {
SmallString<256> TmpDest = Path, UpperDest, RealDest;
// Remove component traversals, links, etc.
if (sys::fs::real_path(Path, TmpDest))
return true; // Current default value in vfs.yaml
Path = TmpDest;
// Change path to all upper case and ask for its real path, if the latter
// exists and is equal to path, it's not case sensitive. Default to case
// sensitive in the absence of real_path, since this is the YAMLVFSWriter
// default.
UpperDest = Path.upper();
if (!sys::fs::real_path(UpperDest, RealDest) && Path.equals(RealDest))
return false;
return true;
FileCollector::FileCollector(std::string Root, std::string OverlayRoot)
: Root(Root), OverlayRoot(OverlayRoot) {
assert(sys::path::is_absolute(Root) && "Root not absolute");
assert(sys::path::is_absolute(OverlayRoot) && "OverlayRoot not absolute");
void FileCollector::PathCanonicalizer::updateWithRealPath(
SmallVectorImpl<char> &Path) {
StringRef SrcPath(Path.begin(), Path.size());
StringRef Filename = sys::path::filename(SrcPath);
StringRef Directory = sys::path::parent_path(SrcPath);
// Use real_path to fix any symbolic link component present in the directory
// part of the path, caching the search because computing the real path is
// expensive.
SmallString<256> RealPath;
auto DirWithSymlink = CachedDirs.find(Directory);
if (DirWithSymlink == CachedDirs.end()) {
// FIXME: Should this be a call to FileSystem::getRealpath(), in some
// cases? What if there is nothing on disk?
if (sys::fs::real_path(Directory, RealPath))
CachedDirs[Directory] = std::string(RealPath.str());
} else {
RealPath = DirWithSymlink->second;
// Finish recreating the path by appending the original filename, since we
// don't need to resolve symlinks in the filename.
// FIXME: If we can cope with this, maybe we can cope without calling
// getRealPath() at all when there's no ".." component.
sys::path::append(RealPath, Filename);
// Swap to create the output.
/// Make Path absolute.
static void makeAbsolute(SmallVectorImpl<char> &Path) {
// We need an absolute src path to append to the root.
// Canonicalize src to a native path to avoid mixed separator styles.
// Remove redundant leading "./" pieces and consecutive separators.
Path.erase(Path.begin(), sys::path::remove_leading_dotslash(
StringRef(Path.begin(), Path.size()))
FileCollector::PathCanonicalizer::canonicalize(StringRef SrcPath) {
PathStorage Paths;
Paths.VirtualPath = SrcPath;
// If a ".." component is present after a symlink component, remove_dots may
// lead to the wrong real destination path. Let the source be canonicalized
// like that but make sure we always use the real path for the destination.
Paths.CopyFrom = Paths.VirtualPath;
// Canonicalize the virtual path by removing "..", "." components.
sys::path::remove_dots(Paths.VirtualPath, /*remove_dot_dot=*/true);
return Paths;
void FileCollector::addFileImpl(StringRef SrcPath) {
PathCanonicalizer::PathStorage Paths = Canonicalizer.canonicalize(SrcPath);
SmallString<256> DstPath = StringRef(Root);
sys::path::append(DstPath, sys::path::relative_path(Paths.CopyFrom));
// Always map a canonical src path to its real path into the YAML, by doing
// this we map different virtual src paths to the same entry in the VFS
// overlay, which is a way to emulate symlink inside the VFS; this is also
// needed for correctness, not doing that can lead to module redefinition
// errors.
addFileToMapping(Paths.VirtualPath, DstPath);
FileCollector::addDirectoryImpl(const llvm::Twine &Dir,
IntrusiveRefCntPtr<vfs::FileSystem> FS,
std::error_code &EC) {
auto It = FS->dir_begin(Dir, EC);
if (EC)
return It;
for (; !EC && It != llvm::vfs::directory_iterator(); It.increment(EC)) {
if (It->type() == sys::fs::file_type::regular_file ||
It->type() == sys::fs::file_type::directory_file ||
It->type() == sys::fs::file_type::symlink_file) {
if (EC)
return It;
// Return a new iterator.
return FS->dir_begin(Dir, EC);
/// Set the access and modification time for the given file from the given
/// status object.
static std::error_code
copyAccessAndModificationTime(StringRef Filename,
const sys::fs::file_status &Stat) {
int FD;
if (auto EC =
sys::fs::openFileForWrite(Filename, FD, sys::fs::CD_OpenExisting))
return EC;
if (auto EC = sys::fs::setLastAccessAndModificationTime(
FD, Stat.getLastAccessedTime(), Stat.getLastModificationTime()))
return EC;
if (auto EC = sys::Process::SafelyCloseFileDescriptor(FD))
return EC;
return {};
std::error_code FileCollector::copyFiles(bool StopOnError) {
auto Err = sys::fs::create_directories(Root, /*IgnoreExisting=*/true);
if (Err) {
return Err;
std::lock_guard<std::mutex> lock(Mutex);
for (auto &entry : VFSWriter.getMappings()) {
// Get the status of the original file/directory.
sys::fs::file_status Stat;
if (std::error_code EC = sys::fs::status(entry.VPath, Stat)) {
if (StopOnError)
return EC;
// Continue if the file doesn't exist.
if (Stat.type() == sys::fs::file_type::file_not_found)
// Create directory tree.
if (std::error_code EC =
/*IgnoreExisting=*/true)) {
if (StopOnError)
return EC;
if (Stat.type() == sys::fs::file_type::directory_file) {
// Construct a directory when it's just a directory entry.
if (std::error_code EC =
/*IgnoreExisting=*/true)) {
if (StopOnError)
return EC;
// Copy file over.
if (std::error_code EC = sys::fs::copy_file(entry.VPath, entry.RPath)) {
if (StopOnError)
return EC;
// Copy over permissions.
if (auto perms = sys::fs::getPermissions(entry.VPath)) {
if (std::error_code EC = sys::fs::setPermissions(entry.RPath, *perms)) {
if (StopOnError)
return EC;
// Copy over modification time.
copyAccessAndModificationTime(entry.RPath, Stat);
return {};
std::error_code FileCollector::writeMapping(StringRef MappingFile) {
std::lock_guard<std::mutex> lock(Mutex);
std::error_code EC;
raw_fd_ostream os(MappingFile, EC, sys::fs::OF_TextWithCRLF);
if (EC)
return EC;
return {};
namespace llvm {
class FileCollectorFileSystem : public vfs::FileSystem {
explicit FileCollectorFileSystem(IntrusiveRefCntPtr<vfs::FileSystem> FS,
std::shared_ptr<FileCollector> Collector)
: FS(std::move(FS)), Collector(std::move(Collector)) {}
llvm::ErrorOr<llvm::vfs::Status> status(const Twine &Path) override {
auto Result = FS->status(Path);
if (Result && Result->exists())
return Result;
openFileForRead(const Twine &Path) override {
auto Result = FS->openFileForRead(Path);
if (Result && *Result)
return Result;
llvm::vfs::directory_iterator dir_begin(const llvm::Twine &Dir,
std::error_code &EC) override {
return Collector->addDirectoryImpl(Dir, FS, EC);
std::error_code getRealPath(const Twine &Path,
SmallVectorImpl<char> &Output) const override {
auto EC = FS->getRealPath(Path, Output);
if (!EC) {
if (Output.size() > 0)
return EC;
std::error_code isLocal(const Twine &Path, bool &Result) override {
return FS->isLocal(Path, Result);
llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
return FS->getCurrentWorkingDirectory();
std::error_code setCurrentWorkingDirectory(const llvm::Twine &Path) override {
return FS->setCurrentWorkingDirectory(Path);
IntrusiveRefCntPtr<vfs::FileSystem> FS;
std::shared_ptr<FileCollector> Collector;
} // namespace llvm
FileCollector::createCollectorVFS(IntrusiveRefCntPtr<vfs::FileSystem> BaseFS,
std::shared_ptr<FileCollector> Collector) {
return new FileCollectorFileSystem(std::move(BaseFS), std::move(Collector));