//===- 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_SUPPORT_VIRTUALFILESYSTEM_H #define LLVM_SUPPORT_VIRTUALFILESYSTEM_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 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; }; /// A member of a directory, yielded by a directory_iterator. /// Only information available on most platforms is included. class directory_entry { std::string Path; llvm::sys::fs::file_type Type; public: directory_entry() = default; directory_entry(std::string Path, llvm::sys::fs::file_type Type) : Path(std::move(Path)), Type(Type) {} llvm::StringRef path() const { return Path; } llvm::sys::fs::file_type type() const { return Type; } }; 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, /// to directory_entry() at end, or returns a system-defined \c error_code. virtual std::error_code increment() = 0; directory_entry 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.path().empty()) 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.path().empty()) Impl.reset(); // Normalize the end iterator to Impl == nullptr. return *this; } const directory_entry &operator*() const { return Impl->CurrentEntry; } const directory_entry *operator->() const { return &Impl->CurrentEntry; } bool operator==(const directory_iterator &RHS) const { if (Impl && RHS.Impl) return Impl->CurrentEntry.path() == RHS.Impl->CurrentEntry.path(); return !Impl && !RHS.Impl; } bool operator!=(const directory_iterator &RHS) const { return !(*this == RHS); } }; class FileSystem; namespace detail { /// Keeps state for the recursive_directory_iterator. struct RecDirIterState { std::stack<directory_iterator, std::vector<directory_iterator>> Stack; bool HasNoPushRequest = false; }; } // end namespace detail /// An input iterator over the recursive contents of a virtual path, /// similar to llvm::sys::fs::recursive_directory_iterator. class recursive_directory_iterator { FileSystem *FS; std::shared_ptr<detail::RecDirIterState> 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 directory_entry &operator*() const { return *State->Stack.top(); } const directory_entry *operator->() const { return &*State->Stack.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->Stack.empty() && "Cannot get level without any iteration state"); return State->Stack.size() - 1; } void no_push() { State->HasNoPushRequest = true; } }; /// 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); /// Is the file mounted on a local filesystem? virtual std::error_code isLocal(const Twine &Path, bool &Result); /// 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 isLocal(const Twine &Path, bool &Result) 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(); } }; /// By default, this delegates all calls to the underlying file system. This /// is useful when derived file systems want to override some calls and still /// proxy other calls. class ProxyFileSystem : public FileSystem { public: explicit ProxyFileSystem(IntrusiveRefCntPtr<FileSystem> FS) : FS(std::move(FS)) {} llvm::ErrorOr<Status> status(const Twine &Path) override { return FS->status(Path); } llvm::ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override { return FS->openFileForRead(Path); } directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override { return FS->dir_begin(Dir, EC); } llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override { return FS->getCurrentWorkingDirectory(); } std::error_code setCurrentWorkingDirectory(const Twine &Path) override { return FS->setCurrentWorkingDirectory(Path); } std::error_code getRealPath(const Twine &Path, SmallVectorImpl<char> &Output) const override { return FS->getRealPath(Path, Output); } protected: FileSystem &getUnderlyingFS() { return *FS; } private: IntrusiveRefCntPtr<FileSystem> FS; }; namespace detail { class InMemoryDirectory; class InMemoryFile; } // namespace detail /// An in-memory file system. class InMemoryFileSystem : public FileSystem { std::unique_ptr<detail::InMemoryDirectory> Root; std::string WorkingDirectory; bool UseNormalizedPaths = true; /// If HardLinkTarget is non-null, a hardlink is created to the To path which /// must be a file. If it is null then it adds the file as the public addFile. bool addFile(const Twine &Path, time_t ModificationTime, std::unique_ptr<llvm::MemoryBuffer> Buffer, Optional<uint32_t> User, Optional<uint32_t> Group, Optional<llvm::sys::fs::file_type> Type, Optional<llvm::sys::fs::perms> Perms, const detail::InMemoryFile *HardLinkTarget); 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 hard link to a file. /// Here hard links are not intended to be fully equivalent to the classical /// filesystem. Both the hard link and the file share the same buffer and /// status (and thus have the same UniqueID). Because of this there is no way /// to distinguish between the link and the file after the link has been /// added. /// /// The To path must be an existing file or a hardlink. The From file must not /// have been added before. The To Path must not be a directory. The From Node /// is added as a hard link which points to the resolved file of To Node. /// \return true if the above condition is satisfied and hardlink was /// successfully created, false otherwise. bool addHardLink(const Twine &From, const Twine &To); /// 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 isLocal(const Twine &Path, bool &Result) 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; 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 setOverlayDir(StringRef OverlayDirectory) { IsOverlayRelative = true; OverlayDir.assign(OverlayDirectory.str()); } void write(llvm::raw_ostream &OS); }; } // namespace vfs } // namespace llvm #endif // LLVM_SUPPORT_VIRTUALFILESYSTEM_H