//===- clang/Basic/FileEntry.h - File references ----------------*- 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Defines interfaces for clang::FileEntry and clang::FileEntryRef.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_BASIC_FILEENTRY_H
#define LLVM_CLANG_BASIC_FILEENTRY_H
#include "clang/Basic/CustomizableOptional.h"
#include "clang/Basic/DirectoryEntry.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FileSystem/UniqueID.h"
#include <optional>
#include <utility>
namespace llvm {
class MemoryBuffer;
namespace vfs {
class File;
} // namespace vfs
} // namespace llvm
namespace clang {
class FileEntryRef;
namespace optional_detail {
/// Forward declare a template specialization for OptionalStorage.
template <> class OptionalStorage<clang::FileEntryRef>;
} // namespace optional_detail
class FileEntry;
/// A reference to a \c FileEntry that includes the name of the file as it was
/// accessed by the FileManager's client.
class FileEntryRef {
public:
/// The name of this FileEntry. If a VFS uses 'use-external-name', this is
/// the redirected name. See getRequestedName().
StringRef getName() const { return getBaseMapEntry().first(); }
/// The name of this FileEntry, as originally requested without applying any
/// remappings for VFS 'use-external-name'.
///
/// FIXME: this should be the semantics of getName(). See comment in
/// FileManager::getFileRef().
StringRef getNameAsRequested() const { return ME->first(); }
const FileEntry &getFileEntry() const {
return *getBaseMapEntry().second->V.get<FileEntry *>();
}
DirectoryEntryRef getDir() const { return *getBaseMapEntry().second->Dir; }
inline off_t getSize() const;
inline unsigned getUID() const;
inline const llvm::sys::fs::UniqueID &getUniqueID() const;
inline time_t getModificationTime() const;
inline bool isNamedPipe() const;
inline void closeFile() const;
/// Check if the underlying FileEntry is the same, intentially ignoring
/// whether the file was referenced with the same spelling of the filename.
friend bool operator==(const FileEntryRef &LHS, const FileEntryRef &RHS) {
return &LHS.getFileEntry() == &RHS.getFileEntry();
}
friend bool operator==(const FileEntry *LHS, const FileEntryRef &RHS) {
return LHS == &RHS.getFileEntry();
}
friend bool operator==(const FileEntryRef &LHS, const FileEntry *RHS) {
return &LHS.getFileEntry() == RHS;
}
friend bool operator!=(const FileEntryRef &LHS, const FileEntryRef &RHS) {
return !(LHS == RHS);
}
friend bool operator!=(const FileEntry *LHS, const FileEntryRef &RHS) {
return !(LHS == RHS);
}
friend bool operator!=(const FileEntryRef &LHS, const FileEntry *RHS) {
return !(LHS == RHS);
}
/// Hash code is based on the FileEntry, not the specific named reference,
/// just like operator==.
friend llvm::hash_code hash_value(FileEntryRef Ref) {
return llvm::hash_value(&Ref.getFileEntry());
}
struct MapValue;
/// Type used in the StringMap.
using MapEntry = llvm::StringMapEntry<llvm::ErrorOr<MapValue>>;
/// Type stored in the StringMap.
struct MapValue {
/// The pointer at another MapEntry is used when the FileManager should
/// silently forward from one name to another, which occurs in Redirecting
/// VFSs that use external names. In that case, the \c FileEntryRef
/// returned by the \c FileManager will have the external name, and not the
/// name that was used to lookup the file.
///
/// The second type is really a `const MapEntry *`, but that confuses
/// gcc5.3. Once that's no longer supported, change this back.
llvm::PointerUnion<FileEntry *, const void *> V;
/// Directory the file was found in. Set if and only if V is a FileEntry.
OptionalDirectoryEntryRef Dir;
MapValue() = delete;
MapValue(FileEntry &FE, DirectoryEntryRef Dir) : V(&FE), Dir(Dir) {}
MapValue(MapEntry &ME) : V(&ME) {}
};
/// Check if RHS referenced the file in exactly the same way.
bool isSameRef(const FileEntryRef &RHS) const { return ME == RHS.ME; }
/// Allow FileEntryRef to degrade into 'const FileEntry*' to facilitate
/// incremental adoption.
///
/// The goal is to avoid code churn due to dances like the following:
/// \code
/// // Old code.
/// lvalue = rvalue;
///
/// // Temporary code from an incremental patch.
/// lvalue = &rvalue.getFileEntry();
///
/// // Final code.
/// lvalue = rvalue;
/// \endcode
///
/// FIXME: Once FileEntryRef is "everywhere" and FileEntry::LastRef and
/// FileEntry::getName have been deleted, delete this implicit conversion.
operator const FileEntry *() const { return &getFileEntry(); }
FileEntryRef() = delete;
explicit FileEntryRef(const MapEntry &ME) : ME(&ME) {
assert(ME.second && "Expected payload");
assert(ME.second->V && "Expected non-null");
}
/// Expose the underlying MapEntry to simplify packing in a PointerIntPair or
/// PointerUnion and allow construction in Optional.
const clang::FileEntryRef::MapEntry &getMapEntry() const { return *ME; }
/// Retrieve the base MapEntry after redirects.
const MapEntry &getBaseMapEntry() const {
const MapEntry *ME = this->ME;
while (const void *Next = ME->second->V.dyn_cast<const void *>())
ME = static_cast<const MapEntry *>(Next);
return *ME;
}
private:
friend class FileMgr::MapEntryOptionalStorage<FileEntryRef>;
struct optional_none_tag {};
// Private constructor for use by OptionalStorage.
FileEntryRef(optional_none_tag) : ME(nullptr) {}
bool hasOptionalValue() const { return ME; }
friend struct llvm::DenseMapInfo<FileEntryRef>;
struct dense_map_empty_tag {};
struct dense_map_tombstone_tag {};
// Private constructors for use by DenseMapInfo.
FileEntryRef(dense_map_empty_tag)
: ME(llvm::DenseMapInfo<const MapEntry *>::getEmptyKey()) {}
FileEntryRef(dense_map_tombstone_tag)
: ME(llvm::DenseMapInfo<const MapEntry *>::getTombstoneKey()) {}
bool isSpecialDenseMapKey() const {
return isSameRef(FileEntryRef(dense_map_empty_tag())) ||
isSameRef(FileEntryRef(dense_map_tombstone_tag()));
}
const MapEntry *ME;
};
static_assert(sizeof(FileEntryRef) == sizeof(const FileEntry *),
"FileEntryRef must avoid size overhead");
static_assert(std::is_trivially_copyable<FileEntryRef>::value,
"FileEntryRef must be trivially copyable");
using OptionalFileEntryRef = CustomizableOptional<FileEntryRef>;
namespace optional_detail {
/// Customize OptionalStorage<FileEntryRef> to use FileEntryRef and its
/// optional_none_tag to keep it the size of a single pointer.
template <>
class OptionalStorage<clang::FileEntryRef>
: public clang::FileMgr::MapEntryOptionalStorage<clang::FileEntryRef> {
using StorageImpl =
clang::FileMgr::MapEntryOptionalStorage<clang::FileEntryRef>;
public:
OptionalStorage() = default;
template <class... ArgTypes>
explicit OptionalStorage(std::in_place_t, ArgTypes &&...Args)
: StorageImpl(std::in_place_t{}, std::forward<ArgTypes>(Args)...) {}
OptionalStorage &operator=(clang::FileEntryRef Ref) {
StorageImpl::operator=(Ref);
return *this;
}
};
static_assert(sizeof(OptionalFileEntryRef) == sizeof(FileEntryRef),
"OptionalFileEntryRef must avoid size overhead");
static_assert(std::is_trivially_copyable<OptionalFileEntryRef>::value,
"OptionalFileEntryRef should be trivially copyable");
} // end namespace optional_detail
} // namespace clang
namespace llvm {
/// Specialisation of DenseMapInfo for FileEntryRef.
template <> struct DenseMapInfo<clang::FileEntryRef> {
static inline clang::FileEntryRef getEmptyKey() {
return clang::FileEntryRef(clang::FileEntryRef::dense_map_empty_tag());
}
static inline clang::FileEntryRef getTombstoneKey() {
return clang::FileEntryRef(clang::FileEntryRef::dense_map_tombstone_tag());
}
static unsigned getHashValue(clang::FileEntryRef Val) {
return hash_value(Val);
}
static bool isEqual(clang::FileEntryRef LHS, clang::FileEntryRef RHS) {
// Catch the easy cases: both empty, both tombstone, or the same ref.
if (LHS.isSameRef(RHS))
return true;
// Confirm LHS and RHS are valid.
if (LHS.isSpecialDenseMapKey() || RHS.isSpecialDenseMapKey())
return false;
// It's safe to use operator==.
return LHS == RHS;
}
};
} // end namespace llvm
namespace clang {
/// Wrapper around OptionalFileEntryRef that degrades to 'const FileEntry*',
/// facilitating incremental patches to propagate FileEntryRef.
///
/// This class can be used as return value or field where it's convenient for
/// an OptionalFileEntryRef to degrade to a 'const FileEntry*'. The purpose
/// is to avoid code churn due to dances like the following:
/// \code
/// // Old code.
/// lvalue = rvalue;
///
/// // Temporary code from an incremental patch.
/// OptionalFileEntryRef MaybeF = rvalue;
/// lvalue = MaybeF ? &MaybeF.getFileEntry() : nullptr;
///
/// // Final code.
/// lvalue = rvalue;
/// \endcode
///
/// FIXME: Once FileEntryRef is "everywhere" and FileEntry::LastRef and
/// FileEntry::getName have been deleted, delete this class and replace
/// instances with OptionalFileEntryRef.
class OptionalFileEntryRefDegradesToFileEntryPtr : public OptionalFileEntryRef {
public:
OptionalFileEntryRefDegradesToFileEntryPtr() = default;
OptionalFileEntryRefDegradesToFileEntryPtr(
OptionalFileEntryRefDegradesToFileEntryPtr &&) = default;
OptionalFileEntryRefDegradesToFileEntryPtr(
const OptionalFileEntryRefDegradesToFileEntryPtr &) = default;
OptionalFileEntryRefDegradesToFileEntryPtr &
operator=(OptionalFileEntryRefDegradesToFileEntryPtr &&) = default;
OptionalFileEntryRefDegradesToFileEntryPtr &
operator=(const OptionalFileEntryRefDegradesToFileEntryPtr &) = default;
OptionalFileEntryRefDegradesToFileEntryPtr(std::nullopt_t) {}
OptionalFileEntryRefDegradesToFileEntryPtr(FileEntryRef Ref)
: OptionalFileEntryRef(Ref) {}
OptionalFileEntryRefDegradesToFileEntryPtr(OptionalFileEntryRef MaybeRef)
: OptionalFileEntryRef(MaybeRef) {}
OptionalFileEntryRefDegradesToFileEntryPtr &operator=(std::nullopt_t) {
OptionalFileEntryRef::operator=(std::nullopt);
return *this;
}
OptionalFileEntryRefDegradesToFileEntryPtr &operator=(FileEntryRef Ref) {
OptionalFileEntryRef::operator=(Ref);
return *this;
}
OptionalFileEntryRefDegradesToFileEntryPtr &
operator=(OptionalFileEntryRef MaybeRef) {
OptionalFileEntryRef::operator=(MaybeRef);
return *this;
}
/// Degrade to 'const FileEntry *' to allow FileEntry::LastRef and
/// FileEntry::getName have been deleted, delete this class and replace
/// instances with OptionalFileEntryRef
operator const FileEntry *() const {
return has_value() ? &(*this)->getFileEntry() : nullptr;
}
};
static_assert(
std::is_trivially_copyable<
OptionalFileEntryRefDegradesToFileEntryPtr>::value,
"OptionalFileEntryRefDegradesToFileEntryPtr should be trivially copyable");
inline bool operator==(const FileEntry *LHS, const OptionalFileEntryRef &RHS) {
return LHS == (RHS ? &RHS->getFileEntry() : nullptr);
}
inline bool operator==(const OptionalFileEntryRef &LHS, const FileEntry *RHS) {
return (LHS ? &LHS->getFileEntry() : nullptr) == RHS;
}
inline bool operator!=(const FileEntry *LHS, const OptionalFileEntryRef &RHS) {
return !(LHS == RHS);
}
inline bool operator!=(const OptionalFileEntryRef &LHS, const FileEntry *RHS) {
return !(LHS == RHS);
}
/// Cached information about one file (either on disk
/// or in the virtual file system).
///
/// If the 'File' member is valid, then this FileEntry has an open file
/// descriptor for the file.
class FileEntry {
friend class FileManager;
friend class FileEntryTestHelper;
FileEntry();
FileEntry(const FileEntry &) = delete;
FileEntry &operator=(const FileEntry &) = delete;
std::string RealPathName; // Real path to the file; could be empty.
off_t Size = 0; // File size in bytes.
time_t ModTime = 0; // Modification time of file.
const DirectoryEntry *Dir = nullptr; // Directory file lives in.
llvm::sys::fs::UniqueID UniqueID;
unsigned UID = 0; // A unique (small) ID for the file.
bool IsNamedPipe = false;
/// The open file, if it is owned by the \p FileEntry.
mutable std::unique_ptr<llvm::vfs::File> File;
/// The file content, if it is owned by the \p FileEntry.
std::unique_ptr<llvm::MemoryBuffer> Content;
// First access name for this FileEntry.
//
// This is Optional only to allow delayed construction (FileEntryRef has no
// default constructor). It should always have a value in practice.
//
// TODO: remove this once everyone that needs a name uses FileEntryRef.
OptionalFileEntryRef LastRef;
public:
~FileEntry();
StringRef getName() const { return LastRef->getName(); }
FileEntryRef getLastRef() const { return *LastRef; }
StringRef tryGetRealPathName() const { return RealPathName; }
off_t getSize() const { return Size; }
unsigned getUID() const { return UID; }
const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
time_t getModificationTime() const { return ModTime; }
/// Return the directory the file lives in.
const DirectoryEntry *getDir() const { return Dir; }
/// Check whether the file is a named pipe (and thus can't be opened by
/// the native FileManager methods).
bool isNamedPipe() const { return IsNamedPipe; }
void closeFile() const;
};
off_t FileEntryRef::getSize() const { return getFileEntry().getSize(); }
unsigned FileEntryRef::getUID() const { return getFileEntry().getUID(); }
const llvm::sys::fs::UniqueID &FileEntryRef::getUniqueID() const {
return getFileEntry().getUniqueID();
}
time_t FileEntryRef::getModificationTime() const {
return getFileEntry().getModificationTime();
}
bool FileEntryRef::isNamedPipe() const { return getFileEntry().isNamedPipe(); }
void FileEntryRef::closeFile() const { getFileEntry().closeFile(); }
} // end namespace clang
#endif // LLVM_CLANG_BASIC_FILEENTRY_H