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Diffstat (limited to 'include/llvm/Support/VirtualFileSystem.h')
| -rw-r--r-- | include/llvm/Support/VirtualFileSystem.h | 764 | 
1 files changed, 764 insertions, 0 deletions
diff --git a/include/llvm/Support/VirtualFileSystem.h b/include/llvm/Support/VirtualFileSystem.h new file mode 100644 index 000000000000..61c3d2f46e9c --- /dev/null +++ b/include/llvm/Support/VirtualFileSystem.h @@ -0,0 +1,764 @@ +//===- 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/Path.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); +  } +  std::error_code isLocal(const Twine &Path, bool &Result) override { +    return FS->isLocal(Path, Result); +  } + +protected: +  FileSystem &getUnderlyingFS() { return *FS; } + +private: +  IntrusiveRefCntPtr<FileSystem> FS; + +  virtual void anchor(); +}; + +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; +}; + +class VFSFromYamlDirIterImpl; +class RedirectingFileSystemParser; + +/// A virtual file system parsed from a YAML file. +/// +/// Currently, this class allows creating virtual directories and mapping +/// virtual file paths to existing external files, available in \c ExternalFS. +/// +/// The basic structure of the parsed file is: +/// \verbatim +/// { +///   'version': <version number>, +///   <optional configuration> +///   'roots': [ +///              <directory entries> +///            ] +/// } +/// \endverbatim +/// +/// All configuration options are optional. +///   'case-sensitive': <boolean, default=true> +///   'use-external-names': <boolean, default=true> +///   'overlay-relative': <boolean, default=false> +///   'fallthrough': <boolean, default=true> +/// +/// Virtual directories are represented as +/// \verbatim +/// { +///   'type': 'directory', +///   'name': <string>, +///   'contents': [ <file or directory entries> ] +/// } +/// \endverbatim +/// +/// The default attributes for virtual directories are: +/// \verbatim +/// MTime = now() when created +/// Perms = 0777 +/// User = Group = 0 +/// Size = 0 +/// UniqueID = unspecified unique value +/// \endverbatim +/// +/// Re-mapped files are represented as +/// \verbatim +/// { +///   'type': 'file', +///   'name': <string>, +///   'use-external-name': <boolean> # Optional +///   'external-contents': <path to external file> +/// } +/// \endverbatim +/// +/// and inherit their attributes from the external contents. +/// +/// In both cases, the 'name' field may contain multiple path components (e.g. +/// /path/to/file). However, any directory that contains more than one child +/// must be uniquely represented by a directory entry. +class RedirectingFileSystem : public vfs::FileSystem { +public: +  enum EntryKind { EK_Directory, EK_File }; + +  /// A single file or directory in the VFS. +  class Entry { +    EntryKind Kind; +    std::string Name; + +  public: +    Entry(EntryKind K, StringRef Name) : Kind(K), Name(Name) {} +    virtual ~Entry() = default; + +    StringRef getName() const { return Name; } +    EntryKind getKind() const { return Kind; } +  }; + +  class RedirectingDirectoryEntry : public Entry { +    std::vector<std::unique_ptr<Entry>> Contents; +    Status S; + +  public: +    RedirectingDirectoryEntry(StringRef Name, +                              std::vector<std::unique_ptr<Entry>> Contents, +                              Status S) +        : Entry(EK_Directory, Name), Contents(std::move(Contents)), +          S(std::move(S)) {} +    RedirectingDirectoryEntry(StringRef Name, Status S) +        : Entry(EK_Directory, Name), S(std::move(S)) {} + +    Status getStatus() { return S; } + +    void addContent(std::unique_ptr<Entry> Content) { +      Contents.push_back(std::move(Content)); +    } + +    Entry *getLastContent() const { return Contents.back().get(); } + +    using iterator = decltype(Contents)::iterator; + +    iterator contents_begin() { return Contents.begin(); } +    iterator contents_end() { return Contents.end(); } + +    static bool classof(const Entry *E) { return E->getKind() == EK_Directory; } +  }; + +  class RedirectingFileEntry : public Entry { +  public: +    enum NameKind { NK_NotSet, NK_External, NK_Virtual }; + +  private: +    std::string ExternalContentsPath; +    NameKind UseName; + +  public: +    RedirectingFileEntry(StringRef Name, StringRef ExternalContentsPath, +                         NameKind UseName) +        : Entry(EK_File, Name), ExternalContentsPath(ExternalContentsPath), +          UseName(UseName) {} + +    StringRef getExternalContentsPath() const { return ExternalContentsPath; } + +    /// whether to use the external path as the name for this file. +    bool useExternalName(bool GlobalUseExternalName) const { +      return UseName == NK_NotSet ? GlobalUseExternalName +                                  : (UseName == NK_External); +    } + +    NameKind getUseName() const { return UseName; } + +    static bool classof(const Entry *E) { return E->getKind() == EK_File; } +  }; + +private: +  friend class VFSFromYamlDirIterImpl; +  friend class RedirectingFileSystemParser; + +  /// The root(s) of the virtual file system. +  std::vector<std::unique_ptr<Entry>> Roots; + +  /// The file system to use for external references. +  IntrusiveRefCntPtr<FileSystem> ExternalFS; + +  /// If IsRelativeOverlay is set, this represents the directory +  /// path that should be prefixed to each 'external-contents' entry +  /// when reading from YAML files. +  std::string ExternalContentsPrefixDir; + +  /// @name Configuration +  /// @{ + +  /// Whether to perform case-sensitive comparisons. +  /// +  /// Currently, case-insensitive matching only works correctly with ASCII. +  bool CaseSensitive = true; + +  /// IsRelativeOverlay marks whether a ExternalContentsPrefixDir path must +  /// be prefixed in every 'external-contents' when reading from YAML files. +  bool IsRelativeOverlay = false; + +  /// Whether to use to use the value of 'external-contents' for the +  /// names of files.  This global value is overridable on a per-file basis. +  bool UseExternalNames = true; + +  /// Whether to attempt a file lookup in external file system after it wasn't +  /// found in VFS. +  bool IsFallthrough = true; +  /// @} + +  /// Virtual file paths and external files could be canonicalized without "..", +  /// "." and "./" in their paths. FIXME: some unittests currently fail on +  /// win32 when using remove_dots and remove_leading_dotslash on paths. +  bool UseCanonicalizedPaths = +#ifdef _WIN32 +      false; +#else +      true; +#endif + +  RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> ExternalFS) +      : ExternalFS(std::move(ExternalFS)) {} + +  /// Looks up the path <tt>[Start, End)</tt> in \p From, possibly +  /// recursing into the contents of \p From if it is a directory. +  ErrorOr<Entry *> lookupPath(llvm::sys::path::const_iterator Start, +                              llvm::sys::path::const_iterator End, +                              Entry *From) const; + +  /// Get the status of a given an \c Entry. +  ErrorOr<Status> status(const Twine &Path, Entry *E); + +public: +  /// Looks up \p Path in \c Roots. +  ErrorOr<Entry *> lookupPath(const Twine &Path) const; + +  /// Parses \p Buffer, which is expected to be in YAML format and +  /// returns a virtual file system representing its contents. +  static RedirectingFileSystem * +  create(std::unique_ptr<MemoryBuffer> Buffer, +         SourceMgr::DiagHandlerTy DiagHandler, StringRef YAMLFilePath, +         void *DiagContext, IntrusiveRefCntPtr<FileSystem> ExternalFS); + +  ErrorOr<Status> status(const Twine &Path) override; +  ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override; + +  std::error_code getRealPath(const Twine &Path, +                              SmallVectorImpl<char> &Output) const 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; + +  directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override; + +  void setExternalContentsPrefixDir(StringRef PrefixDir); + +  StringRef getExternalContentsPrefixDir() const; + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +  LLVM_DUMP_METHOD void dump() const; +  LLVM_DUMP_METHOD void dumpEntry(Entry *E, int NumSpaces = 0) const; +#endif +}; + +/// 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()); +  } + +  const std::vector<YAMLVFSEntry> &getMappings() const { return Mappings; } + +  void write(llvm::raw_ostream &OS); +}; + +} // namespace vfs +} // namespace llvm + +#endif // LLVM_SUPPORT_VIRTUALFILESYSTEM_H  | 
