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//===- VirtualFileSystem.h - Virtual File System Layer ----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// Defines the virtual file system interface vfs::FileSystem.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H
#define LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/Chrono.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/SourceMgr.h"
#include <cassert>
#include <cstdint>
#include <ctime>
#include <memory>
#include <stack>
#include <string>
#include <system_error>
#include <utility>
#include <vector>
namespace llvm {
class MemoryBuffer;
} // namespace llvm
namespace clang {
namespace vfs {
/// The result of a \p status operation.
class Status {
std::string Name;
llvm::sys::fs::UniqueID UID;
llvm::sys::TimePoint<> MTime;
uint32_t User;
uint32_t Group;
uint64_t Size;
llvm::sys::fs::file_type Type = llvm::sys::fs::file_type::status_error;
llvm::sys::fs::perms Perms;
public:
// FIXME: remove when files support multiple names
bool IsVFSMapped = false;
Status() = default;
Status(const llvm::sys::fs::file_status &Status);
Status(StringRef Name, llvm::sys::fs::UniqueID UID,
llvm::sys::TimePoint<> MTime, uint32_t User, uint32_t Group,
uint64_t Size, llvm::sys::fs::file_type Type,
llvm::sys::fs::perms Perms);
/// Get a copy of a Status with a different name.
static Status copyWithNewName(const Status &In, StringRef NewName);
static Status copyWithNewName(const llvm::sys::fs::file_status &In,
StringRef NewName);
/// Returns the name that should be used for this file or directory.
StringRef getName() const { return Name; }
/// @name Status interface from llvm::sys::fs
/// @{
llvm::sys::fs::file_type getType() const { return Type; }
llvm::sys::fs::perms getPermissions() const { return Perms; }
llvm::sys::TimePoint<> getLastModificationTime() const { return MTime; }
llvm::sys::fs::UniqueID getUniqueID() const { return UID; }
uint32_t getUser() const { return User; }
uint32_t getGroup() const { return Group; }
uint64_t getSize() const { return Size; }
/// @}
/// @name Status queries
/// These are static queries in llvm::sys::fs.
/// @{
bool equivalent(const Status &Other) const;
bool isDirectory() const;
bool isRegularFile() const;
bool isOther() const;
bool isSymlink() const;
bool isStatusKnown() const;
bool exists() const;
/// @}
};
/// Represents an open file.
class File {
public:
/// Destroy the file after closing it (if open).
/// Sub-classes should generally call close() inside their destructors. We
/// cannot do that from the base class, since close is virtual.
virtual ~File();
/// Get the status of the file.
virtual llvm::ErrorOr<Status> status() = 0;
/// Get the name of the file
virtual llvm::ErrorOr<std::string> getName() {
if (auto Status = status())
return Status->getName().str();
else
return Status.getError();
}
/// Get the contents of the file as a \p MemoryBuffer.
virtual llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBuffer(const Twine &Name, int64_t FileSize = -1,
bool RequiresNullTerminator = true, bool IsVolatile = false) = 0;
/// Closes the file.
virtual std::error_code close() = 0;
};
namespace detail {
/// An interface for virtual file systems to provide an iterator over the
/// (non-recursive) contents of a directory.
struct DirIterImpl {
virtual ~DirIterImpl();
/// Sets \c CurrentEntry to the next entry in the directory on success,
/// or returns a system-defined \c error_code.
virtual std::error_code increment() = 0;
Status CurrentEntry;
};
} // namespace detail
/// An input iterator over the entries in a virtual path, similar to
/// llvm::sys::fs::directory_iterator.
class directory_iterator {
std::shared_ptr<detail::DirIterImpl> Impl; // Input iterator semantics on copy
public:
directory_iterator(std::shared_ptr<detail::DirIterImpl> I)
: Impl(std::move(I)) {
assert(Impl.get() != nullptr && "requires non-null implementation");
if (!Impl->CurrentEntry.isStatusKnown())
Impl.reset(); // Normalize the end iterator to Impl == nullptr.
}
/// Construct an 'end' iterator.
directory_iterator() = default;
/// Equivalent to operator++, with an error code.
directory_iterator &increment(std::error_code &EC) {
assert(Impl && "attempting to increment past end");
EC = Impl->increment();
if (!Impl->CurrentEntry.isStatusKnown())
Impl.reset(); // Normalize the end iterator to Impl == nullptr.
return *this;
}
const Status &operator*() const { return Impl->CurrentEntry; }
const Status *operator->() const { return &Impl->CurrentEntry; }
bool operator==(const directory_iterator &RHS) const {
if (Impl && RHS.Impl)
return Impl->CurrentEntry.equivalent(RHS.Impl->CurrentEntry);
return !Impl && !RHS.Impl;
}
bool operator!=(const directory_iterator &RHS) const {
return !(*this == RHS);
}
};
class FileSystem;
/// An input iterator over the recursive contents of a virtual path,
/// similar to llvm::sys::fs::recursive_directory_iterator.
class recursive_directory_iterator {
using IterState =
std::stack<directory_iterator, std::vector<directory_iterator>>;
FileSystem *FS;
std::shared_ptr<IterState> State; // Input iterator semantics on copy.
public:
recursive_directory_iterator(FileSystem &FS, const Twine &Path,
std::error_code &EC);
/// Construct an 'end' iterator.
recursive_directory_iterator() = default;
/// Equivalent to operator++, with an error code.
recursive_directory_iterator &increment(std::error_code &EC);
const Status &operator*() const { return *State->top(); }
const Status *operator->() const { return &*State->top(); }
bool operator==(const recursive_directory_iterator &Other) const {
return State == Other.State; // identity
}
bool operator!=(const recursive_directory_iterator &RHS) const {
return !(*this == RHS);
}
/// Gets the current level. Starting path is at level 0.
int level() const {
assert(!State->empty() && "Cannot get level without any iteration state");
return State->size()-1;
}
};
/// The virtual file system interface.
class FileSystem : public llvm::ThreadSafeRefCountedBase<FileSystem> {
public:
virtual ~FileSystem();
/// Get the status of the entry at \p Path, if one exists.
virtual llvm::ErrorOr<Status> status(const Twine &Path) = 0;
/// Get a \p File object for the file at \p Path, if one exists.
virtual llvm::ErrorOr<std::unique_ptr<File>>
openFileForRead(const Twine &Path) = 0;
/// This is a convenience method that opens a file, gets its content and then
/// closes the file.
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBufferForFile(const Twine &Name, int64_t FileSize = -1,
bool RequiresNullTerminator = true, bool IsVolatile = false);
/// Get a directory_iterator for \p Dir.
/// \note The 'end' iterator is directory_iterator().
virtual directory_iterator dir_begin(const Twine &Dir,
std::error_code &EC) = 0;
/// Set the working directory. This will affect all following operations on
/// this file system and may propagate down for nested file systems.
virtual std::error_code setCurrentWorkingDirectory(const Twine &Path) = 0;
/// Get the working directory of this file system.
virtual llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const = 0;
/// Gets real path of \p Path e.g. collapse all . and .. patterns, resolve
/// symlinks. For real file system, this uses `llvm::sys::fs::real_path`.
/// This returns errc::operation_not_permitted if not implemented by subclass.
virtual std::error_code getRealPath(const Twine &Path,
SmallVectorImpl<char> &Output) const;
/// Check whether a file exists. Provided for convenience.
bool exists(const Twine &Path);
/// Make \a Path an absolute path.
///
/// Makes \a Path absolute using the current directory if it is not already.
/// An empty \a Path will result in the current directory.
///
/// /absolute/path => /absolute/path
/// relative/../path => <current-directory>/relative/../path
///
/// \param Path A path that is modified to be an absolute path.
/// \returns success if \a path has been made absolute, otherwise a
/// platform-specific error_code.
std::error_code makeAbsolute(SmallVectorImpl<char> &Path) const;
};
/// Gets an \p vfs::FileSystem for the 'real' file system, as seen by
/// the operating system.
IntrusiveRefCntPtr<FileSystem> getRealFileSystem();
/// A file system that allows overlaying one \p AbstractFileSystem on top
/// of another.
///
/// Consists of a stack of >=1 \p FileSystem objects, which are treated as being
/// one merged file system. When there is a directory that exists in more than
/// one file system, the \p OverlayFileSystem contains a directory containing
/// the union of their contents. The attributes (permissions, etc.) of the
/// top-most (most recently added) directory are used. When there is a file
/// that exists in more than one file system, the file in the top-most file
/// system overrides the other(s).
class OverlayFileSystem : public FileSystem {
using FileSystemList = SmallVector<IntrusiveRefCntPtr<FileSystem>, 1>;
/// The stack of file systems, implemented as a list in order of
/// their addition.
FileSystemList FSList;
public:
OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> Base);
/// Pushes a file system on top of the stack.
void pushOverlay(IntrusiveRefCntPtr<FileSystem> FS);
llvm::ErrorOr<Status> status(const Twine &Path) override;
llvm::ErrorOr<std::unique_ptr<File>>
openFileForRead(const Twine &Path) override;
directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
std::error_code getRealPath(const Twine &Path,
SmallVectorImpl<char> &Output) const override;
using iterator = FileSystemList::reverse_iterator;
using const_iterator = FileSystemList::const_reverse_iterator;
/// Get an iterator pointing to the most recently added file system.
iterator overlays_begin() { return FSList.rbegin(); }
const_iterator overlays_begin() const { return FSList.rbegin(); }
/// Get an iterator pointing one-past the least recently added file
/// system.
iterator overlays_end() { return FSList.rend(); }
const_iterator overlays_end() const { return FSList.rend(); }
};
namespace detail {
class InMemoryDirectory;
} // namespace detail
/// An in-memory file system.
class InMemoryFileSystem : public FileSystem {
std::unique_ptr<detail::InMemoryDirectory> Root;
std::string WorkingDirectory;
bool UseNormalizedPaths = true;
public:
explicit InMemoryFileSystem(bool UseNormalizedPaths = true);
~InMemoryFileSystem() override;
/// Add a file containing a buffer or a directory to the VFS with a
/// path. The VFS owns the buffer. If present, User, Group, Type
/// and Perms apply to the newly-created file or directory.
/// \return true if the file or directory was successfully added,
/// false if the file or directory already exists in the file system with
/// different contents.
bool addFile(const Twine &Path, time_t ModificationTime,
std::unique_ptr<llvm::MemoryBuffer> Buffer,
Optional<uint32_t> User = None, Optional<uint32_t> Group = None,
Optional<llvm::sys::fs::file_type> Type = None,
Optional<llvm::sys::fs::perms> Perms = None);
/// Add a buffer to the VFS with a path. The VFS does not own the buffer.
/// If present, User, Group, Type and Perms apply to the newly-created file
/// or directory.
/// \return true if the file or directory was successfully added,
/// false if the file or directory already exists in the file system with
/// different contents.
bool addFileNoOwn(const Twine &Path, time_t ModificationTime,
llvm::MemoryBuffer *Buffer,
Optional<uint32_t> User = None,
Optional<uint32_t> Group = None,
Optional<llvm::sys::fs::file_type> Type = None,
Optional<llvm::sys::fs::perms> Perms = None);
std::string toString() const;
/// Return true if this file system normalizes . and .. in paths.
bool useNormalizedPaths() const { return UseNormalizedPaths; }
llvm::ErrorOr<Status> status(const Twine &Path) override;
llvm::ErrorOr<std::unique_ptr<File>>
openFileForRead(const Twine &Path) override;
directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
return WorkingDirectory;
}
/// Canonicalizes \p Path by combining with the current working
/// directory and normalizing the path (e.g. remove dots). If the current
/// working directory is not set, this returns errc::operation_not_permitted.
///
/// This doesn't resolve symlinks as they are not supported in in-memory file
/// system.
std::error_code getRealPath(const Twine &Path,
SmallVectorImpl<char> &Output) const override;
std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
};
/// Get a globally unique ID for a virtual file or directory.
llvm::sys::fs::UniqueID getNextVirtualUniqueID();
/// Gets a \p FileSystem for a virtual file system described in YAML
/// format.
IntrusiveRefCntPtr<FileSystem>
getVFSFromYAML(std::unique_ptr<llvm::MemoryBuffer> Buffer,
llvm::SourceMgr::DiagHandlerTy DiagHandler,
StringRef YAMLFilePath,
void *DiagContext = nullptr,
IntrusiveRefCntPtr<FileSystem> ExternalFS = getRealFileSystem());
struct YAMLVFSEntry {
template <typename T1, typename T2> YAMLVFSEntry(T1 &&VPath, T2 &&RPath)
: VPath(std::forward<T1>(VPath)), RPath(std::forward<T2>(RPath)) {}
std::string VPath;
std::string RPath;
};
/// Collect all pairs of <virtual path, real path> entries from the
/// \p YAMLFilePath. This is used by the module dependency collector to forward
/// the entries into the reproducer output VFS YAML file.
void collectVFSFromYAML(
std::unique_ptr<llvm::MemoryBuffer> Buffer,
llvm::SourceMgr::DiagHandlerTy DiagHandler, StringRef YAMLFilePath,
SmallVectorImpl<YAMLVFSEntry> &CollectedEntries,
void *DiagContext = nullptr,
IntrusiveRefCntPtr<FileSystem> ExternalFS = getRealFileSystem());
class YAMLVFSWriter {
std::vector<YAMLVFSEntry> Mappings;
Optional<bool> IsCaseSensitive;
Optional<bool> IsOverlayRelative;
Optional<bool> UseExternalNames;
Optional<bool> IgnoreNonExistentContents;
std::string OverlayDir;
public:
YAMLVFSWriter() = default;
void addFileMapping(StringRef VirtualPath, StringRef RealPath);
void setCaseSensitivity(bool CaseSensitive) {
IsCaseSensitive = CaseSensitive;
}
void setUseExternalNames(bool UseExtNames) {
UseExternalNames = UseExtNames;
}
void setIgnoreNonExistentContents(bool IgnoreContents) {
IgnoreNonExistentContents = IgnoreContents;
}
void setOverlayDir(StringRef OverlayDirectory) {
IsOverlayRelative = true;
OverlayDir.assign(OverlayDirectory.str());
}
void write(llvm::raw_ostream &OS);
};
} // namespace vfs
} // namespace clang
#endif // LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H