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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_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