1//===- VirtualFileSystem.h - Virtual File System Layer ----------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9/// \file
10/// Defines the virtual file system interface vfs::FileSystem.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_VIRTUALFILESYSTEM_H
15#define LLVM_SUPPORT_VIRTUALFILESYSTEM_H
16
17#include "llvm/ADT/IntrusiveRefCntPtr.h"
18#include "llvm/ADT/None.h"
19#include "llvm/ADT/Optional.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/ADT/StringRef.h"
22#include "llvm/Support/Chrono.h"
23#include "llvm/Support/ErrorOr.h"
24#include "llvm/Support/FileSystem.h"
25#include "llvm/Support/Path.h"
26#include "llvm/Support/SourceMgr.h"
27#include <cassert>
28#include <cstdint>
29#include <ctime>
30#include <memory>
31#include <stack>
32#include <string>
33#include <system_error>
34#include <utility>
35#include <vector>
36
37namespace llvm {
38
39class MemoryBuffer;
40class MemoryBufferRef;
41class Twine;
42
43namespace vfs {
44
45/// The result of a \p status operation.
46class Status {
47 std::string Name;
48 llvm::sys::fs::UniqueID UID;
49 llvm::sys::TimePoint<> MTime;
50 uint32_t User;
51 uint32_t Group;
52 uint64_t Size;
53 llvm::sys::fs::file_type Type = llvm::sys::fs::file_type::status_error;
54 llvm::sys::fs::perms Perms;
55
56public:
57 // FIXME: remove when files support multiple names
58 bool IsVFSMapped = false;
59
60 Status() = default;
61 Status(const llvm::sys::fs::file_status &Status);
62 Status(const Twine &Name, llvm::sys::fs::UniqueID UID,
63 llvm::sys::TimePoint<> MTime, uint32_t User, uint32_t Group,
64 uint64_t Size, llvm::sys::fs::file_type Type,
65 llvm::sys::fs::perms Perms);
66
67 /// Get a copy of a Status with a different name.
68 static Status copyWithNewName(const Status &In, const Twine &NewName);
69 static Status copyWithNewName(const llvm::sys::fs::file_status &In,
70 const Twine &NewName);
71
72 /// Returns the name that should be used for this file or directory.
73 StringRef getName() const { return Name; }
74
75 /// @name Status interface from llvm::sys::fs
76 /// @{
77 llvm::sys::fs::file_type getType() const { return Type; }
78 llvm::sys::fs::perms getPermissions() const { return Perms; }
79 llvm::sys::TimePoint<> getLastModificationTime() const { return MTime; }
80 llvm::sys::fs::UniqueID getUniqueID() const { return UID; }
81 uint32_t getUser() const { return User; }
82 uint32_t getGroup() const { return Group; }
83 uint64_t getSize() const { return Size; }
84 /// @}
85 /// @name Status queries
86 /// These are static queries in llvm::sys::fs.
87 /// @{
88 bool equivalent(const Status &Other) const;
89 bool isDirectory() const;
90 bool isRegularFile() const;
91 bool isOther() const;
92 bool isSymlink() const;
93 bool isStatusKnown() const;
94 bool exists() const;
95 /// @}
96};
97
98/// Represents an open file.
99class File {
100public:
101 /// Destroy the file after closing it (if open).
102 /// Sub-classes should generally call close() inside their destructors. We
103 /// cannot do that from the base class, since close is virtual.
104 virtual ~File();
105
106 /// Get the status of the file.
107 virtual llvm::ErrorOr<Status> status() = 0;
108
109 /// Get the name of the file
110 virtual llvm::ErrorOr<std::string> getName() {
111 if (auto Status = status())
112 return Status->getName().str();
113 else
114 return Status.getError();
115 }
116
117 /// Get the contents of the file as a \p MemoryBuffer.
118 virtual llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
119 getBuffer(const Twine &Name, int64_t FileSize = -1,
120 bool RequiresNullTerminator = true, bool IsVolatile = false) = 0;
121
122 /// Closes the file.
123 virtual std::error_code close() = 0;
124};
125
126/// A member of a directory, yielded by a directory_iterator.
127/// Only information available on most platforms is included.
128class directory_entry {
129 std::string Path;
130 llvm::sys::fs::file_type Type = llvm::sys::fs::file_type::type_unknown;
131
132public:
133 directory_entry() = default;
134 directory_entry(std::string Path, llvm::sys::fs::file_type Type)
135 : Path(std::move(Path)), Type(Type) {}
136
137 llvm::StringRef path() const { return Path; }
138 llvm::sys::fs::file_type type() const { return Type; }
139};
140
141namespace detail {
142
143/// An interface for virtual file systems to provide an iterator over the
144/// (non-recursive) contents of a directory.
145struct DirIterImpl {
146 virtual ~DirIterImpl();
147
148 /// Sets \c CurrentEntry to the next entry in the directory on success,
149 /// to directory_entry() at end, or returns a system-defined \c error_code.
150 virtual std::error_code increment() = 0;
151
152 directory_entry CurrentEntry;
153};
154
155} // namespace detail
156
157/// An input iterator over the entries in a virtual path, similar to
158/// llvm::sys::fs::directory_iterator.
159class directory_iterator {
160 std::shared_ptr<detail::DirIterImpl> Impl; // Input iterator semantics on copy
161
162public:
163 directory_iterator(std::shared_ptr<detail::DirIterImpl> I)
164 : Impl(std::move(I)) {
165 assert(Impl.get() != nullptr && "requires non-null implementation");
166 if (Impl->CurrentEntry.path().empty())
167 Impl.reset(); // Normalize the end iterator to Impl == nullptr.
168 }
169
170 /// Construct an 'end' iterator.
171 directory_iterator() = default;
172
173 /// Equivalent to operator++, with an error code.
174 directory_iterator &increment(std::error_code &EC) {
175 assert(Impl && "attempting to increment past end");
176 EC = Impl->increment();
177 if (Impl->CurrentEntry.path().empty())
178 Impl.reset(); // Normalize the end iterator to Impl == nullptr.
179 return *this;
180 }
181
182 const directory_entry &operator*() const { return Impl->CurrentEntry; }
183 const directory_entry *operator->() const { return &Impl->CurrentEntry; }
184
185 bool operator==(const directory_iterator &RHS) const {
186 if (Impl && RHS.Impl)
187 return Impl->CurrentEntry.path() == RHS.Impl->CurrentEntry.path();
188 return !Impl && !RHS.Impl;
189 }
190 bool operator!=(const directory_iterator &RHS) const {
191 return !(*this == RHS);
192 }
193};
194
195class FileSystem;
196
197namespace detail {
198
199/// Keeps state for the recursive_directory_iterator.
200struct RecDirIterState {
201 std::stack<directory_iterator, std::vector<directory_iterator>> Stack;
202 bool HasNoPushRequest = false;
203};
204
205} // end namespace detail
206
207/// An input iterator over the recursive contents of a virtual path,
208/// similar to llvm::sys::fs::recursive_directory_iterator.
209class recursive_directory_iterator {
210 FileSystem *FS;
211 std::shared_ptr<detail::RecDirIterState>
212 State; // Input iterator semantics on copy.
213
214public:
215 recursive_directory_iterator(FileSystem &FS, const Twine &Path,
216 std::error_code &EC);
217
218 /// Construct an 'end' iterator.
219 recursive_directory_iterator() = default;
220
221 /// Equivalent to operator++, with an error code.
222 recursive_directory_iterator &increment(std::error_code &EC);
223
224 const directory_entry &operator*() const { return *State->Stack.top(); }
225 const directory_entry *operator->() const { return &*State->Stack.top(); }
226
227 bool operator==(const recursive_directory_iterator &Other) const {
228 return State == Other.State; // identity
229 }
230 bool operator!=(const recursive_directory_iterator &RHS) const {
231 return !(*this == RHS);
232 }
233
234 /// Gets the current level. Starting path is at level 0.
235 int level() const {
236 assert(!State->Stack.empty() &&
237 "Cannot get level without any iteration state");
238 return State->Stack.size() - 1;
239 }
240
241 void no_push() { State->HasNoPushRequest = true; }
242};
243
244/// The virtual file system interface.
245class FileSystem : public llvm::ThreadSafeRefCountedBase<FileSystem> {
246public:
247 virtual ~FileSystem();
248
249 /// Get the status of the entry at \p Path, if one exists.
250 virtual llvm::ErrorOr<Status> status(const Twine &Path) = 0;
251
252 /// Get a \p File object for the file at \p Path, if one exists.
253 virtual llvm::ErrorOr<std::unique_ptr<File>>
254 openFileForRead(const Twine &Path) = 0;
255
256 /// This is a convenience method that opens a file, gets its content and then
257 /// closes the file.
258 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
259 getBufferForFile(const Twine &Name, int64_t FileSize = -1,
260 bool RequiresNullTerminator = true, bool IsVolatile = false);
261
262 /// Get a directory_iterator for \p Dir.
263 /// \note The 'end' iterator is directory_iterator().
264 virtual directory_iterator dir_begin(const Twine &Dir,
265 std::error_code &EC) = 0;
266
267 /// Set the working directory. This will affect all following operations on
268 /// this file system and may propagate down for nested file systems.
269 virtual std::error_code setCurrentWorkingDirectory(const Twine &Path) = 0;
270
271 /// Get the working directory of this file system.
272 virtual llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const = 0;
273
274 /// Gets real path of \p Path e.g. collapse all . and .. patterns, resolve
275 /// symlinks. For real file system, this uses `llvm::sys::fs::real_path`.
276 /// This returns errc::operation_not_permitted if not implemented by subclass.
277 virtual std::error_code getRealPath(const Twine &Path,
278 SmallVectorImpl<char> &Output) const;
279
280 /// Check whether a file exists. Provided for convenience.
281 bool exists(const Twine &Path);
282
283 /// Is the file mounted on a local filesystem?
284 virtual std::error_code isLocal(const Twine &Path, bool &Result);
285
286 /// Make \a Path an absolute path.
287 ///
288 /// Makes \a Path absolute using the current directory if it is not already.
289 /// An empty \a Path will result in the current directory.
290 ///
291 /// /absolute/path => /absolute/path
292 /// relative/../path => <current-directory>/relative/../path
293 ///
294 /// \param Path A path that is modified to be an absolute path.
295 /// \returns success if \a path has been made absolute, otherwise a
296 /// platform-specific error_code.
297 virtual std::error_code makeAbsolute(SmallVectorImpl<char> &Path) const;
298};
299
300/// Gets an \p vfs::FileSystem for the 'real' file system, as seen by
301/// the operating system.
302/// The working directory is linked to the process's working directory.
303/// (This is usually thread-hostile).
304IntrusiveRefCntPtr<FileSystem> getRealFileSystem();
305
306/// Create an \p vfs::FileSystem for the 'real' file system, as seen by
307/// the operating system.
308/// It has its own working directory, independent of (but initially equal to)
309/// that of the process.
310std::unique_ptr<FileSystem> createPhysicalFileSystem();
311
312/// A file system that allows overlaying one \p AbstractFileSystem on top
313/// of another.
314///
315/// Consists of a stack of >=1 \p FileSystem objects, which are treated as being
316/// one merged file system. When there is a directory that exists in more than
317/// one file system, the \p OverlayFileSystem contains a directory containing
318/// the union of their contents. The attributes (permissions, etc.) of the
319/// top-most (most recently added) directory are used. When there is a file
320/// that exists in more than one file system, the file in the top-most file
321/// system overrides the other(s).
322class OverlayFileSystem : public FileSystem {
323 using FileSystemList = SmallVector<IntrusiveRefCntPtr<FileSystem>, 1>;
324
325 /// The stack of file systems, implemented as a list in order of
326 /// their addition.
327 FileSystemList FSList;
328
329public:
330 OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> Base);
331
332 /// Pushes a file system on top of the stack.
333 void pushOverlay(IntrusiveRefCntPtr<FileSystem> FS);
334
335 llvm::ErrorOr<Status> status(const Twine &Path) override;
336 llvm::ErrorOr<std::unique_ptr<File>>
337 openFileForRead(const Twine &Path) override;
338 directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
339 llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
340 std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
341 std::error_code isLocal(const Twine &Path, bool &Result) override;
342 std::error_code getRealPath(const Twine &Path,
343 SmallVectorImpl<char> &Output) const override;
344
345 using iterator = FileSystemList::reverse_iterator;
346 using const_iterator = FileSystemList::const_reverse_iterator;
347 using reverse_iterator = FileSystemList::iterator;
348 using const_reverse_iterator = FileSystemList::const_iterator;
349
350 /// Get an iterator pointing to the most recently added file system.
351 iterator overlays_begin() { return FSList.rbegin(); }
352 const_iterator overlays_begin() const { return FSList.rbegin(); }
353
354 /// Get an iterator pointing one-past the least recently added file system.
355 iterator overlays_end() { return FSList.rend(); }
356 const_iterator overlays_end() const { return FSList.rend(); }
357
358 /// Get an iterator pointing to the least recently added file system.
359 reverse_iterator overlays_rbegin() { return FSList.begin(); }
360 const_reverse_iterator overlays_rbegin() const { return FSList.begin(); }
361
362 /// Get an iterator pointing one-past the most recently added file system.
363 reverse_iterator overlays_rend() { return FSList.end(); }
364 const_reverse_iterator overlays_rend() const { return FSList.end(); }
365};
366
367/// By default, this delegates all calls to the underlying file system. This
368/// is useful when derived file systems want to override some calls and still
369/// proxy other calls.
370class ProxyFileSystem : public FileSystem {
371public:
372 explicit ProxyFileSystem(IntrusiveRefCntPtr<FileSystem> FS)
373 : FS(std::move(FS)) {}
374
375 llvm::ErrorOr<Status> status(const Twine &Path) override {
376 return FS->status(Path);
377 }
378 llvm::ErrorOr<std::unique_ptr<File>>
379 openFileForRead(const Twine &Path) override {
380 return FS->openFileForRead(Path);
381 }
382 directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override {
383 return FS->dir_begin(Dir, EC);
384 }
385 llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
386 return FS->getCurrentWorkingDirectory();
387 }
388 std::error_code setCurrentWorkingDirectory(const Twine &Path) override {
389 return FS->setCurrentWorkingDirectory(Path);
390 }
391 std::error_code getRealPath(const Twine &Path,
392 SmallVectorImpl<char> &Output) const override {
393 return FS->getRealPath(Path, Output);
394 }
395 std::error_code isLocal(const Twine &Path, bool &Result) override {
396 return FS->isLocal(Path, Result);
397 }
398
399protected:
400 FileSystem &getUnderlyingFS() { return *FS; }
401
402private:
403 IntrusiveRefCntPtr<FileSystem> FS;
404
405 virtual void anchor();
406};
407
408namespace detail {
409
410class InMemoryDirectory;
411class InMemoryFile;
412
413} // namespace detail
414
415/// An in-memory file system.
416class InMemoryFileSystem : public FileSystem {
417 std::unique_ptr<detail::InMemoryDirectory> Root;
418 std::string WorkingDirectory;
419 bool UseNormalizedPaths = true;
420
421 /// If HardLinkTarget is non-null, a hardlink is created to the To path which
422 /// must be a file. If it is null then it adds the file as the public addFile.
423 bool addFile(const Twine &Path, time_t ModificationTime,
424 std::unique_ptr<llvm::MemoryBuffer> Buffer,
425 Optional<uint32_t> User, Optional<uint32_t> Group,
426 Optional<llvm::sys::fs::file_type> Type,
427 Optional<llvm::sys::fs::perms> Perms,
428 const detail::InMemoryFile *HardLinkTarget);
429
430public:
431 explicit InMemoryFileSystem(bool UseNormalizedPaths = true);
432 ~InMemoryFileSystem() override;
433
434 /// Add a file containing a buffer or a directory to the VFS with a
435 /// path. The VFS owns the buffer. If present, User, Group, Type
436 /// and Perms apply to the newly-created file or directory.
437 /// \return true if the file or directory was successfully added,
438 /// false if the file or directory already exists in the file system with
439 /// different contents.
440 bool addFile(const Twine &Path, time_t ModificationTime,
441 std::unique_ptr<llvm::MemoryBuffer> Buffer,
442 Optional<uint32_t> User = None, Optional<uint32_t> Group = None,
443 Optional<llvm::sys::fs::file_type> Type = None,
444 Optional<llvm::sys::fs::perms> Perms = None);
445
446 /// Add a hard link to a file.
447 /// Here hard links are not intended to be fully equivalent to the classical
448 /// filesystem. Both the hard link and the file share the same buffer and
449 /// status (and thus have the same UniqueID). Because of this there is no way
450 /// to distinguish between the link and the file after the link has been
451 /// added.
452 ///
453 /// The To path must be an existing file or a hardlink. The From file must not
454 /// have been added before. The To Path must not be a directory. The From Node
455 /// is added as a hard link which points to the resolved file of To Node.
456 /// \return true if the above condition is satisfied and hardlink was
457 /// successfully created, false otherwise.
458 bool addHardLink(const Twine &From, const Twine &To);
459
460 /// Add a buffer to the VFS with a path. The VFS does not own the buffer.
461 /// If present, User, Group, Type and Perms apply to the newly-created file
462 /// or directory.
463 /// \return true if the file or directory was successfully added,
464 /// false if the file or directory already exists in the file system with
465 /// different contents.
466 bool addFileNoOwn(const Twine &Path, time_t ModificationTime,
467 const llvm::MemoryBufferRef &Buffer,
468 Optional<uint32_t> User = None,
469 Optional<uint32_t> Group = None,
470 Optional<llvm::sys::fs::file_type> Type = None,
471 Optional<llvm::sys::fs::perms> Perms = None);
472
473 std::string toString() const;
474
475 /// Return true if this file system normalizes . and .. in paths.
476 bool useNormalizedPaths() const { return UseNormalizedPaths; }
477
478 llvm::ErrorOr<Status> status(const Twine &Path) override;
479 llvm::ErrorOr<std::unique_ptr<File>>
480 openFileForRead(const Twine &Path) override;
481 directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
482
483 llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
484 return WorkingDirectory;
485 }
486 /// Canonicalizes \p Path by combining with the current working
487 /// directory and normalizing the path (e.g. remove dots). If the current
488 /// working directory is not set, this returns errc::operation_not_permitted.
489 ///
490 /// This doesn't resolve symlinks as they are not supported in in-memory file
491 /// system.
492 std::error_code getRealPath(const Twine &Path,
493 SmallVectorImpl<char> &Output) const override;
494 std::error_code isLocal(const Twine &Path, bool &Result) override;
495 std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
496};
497
498/// Get a globally unique ID for a virtual file or directory.
499llvm::sys::fs::UniqueID getNextVirtualUniqueID();
500
501/// Gets a \p FileSystem for a virtual file system described in YAML
502/// format.
503std::unique_ptr<FileSystem>
504getVFSFromYAML(std::unique_ptr<llvm::MemoryBuffer> Buffer,
505 llvm::SourceMgr::DiagHandlerTy DiagHandler,
506 StringRef YAMLFilePath, void *DiagContext = nullptr,
507 IntrusiveRefCntPtr<FileSystem> ExternalFS = getRealFileSystem());
508
509struct YAMLVFSEntry {
510 template <typename T1, typename T2>
511 YAMLVFSEntry(T1 &&VPath, T2 &&RPath, bool IsDirectory = false)
512 : VPath(std::forward<T1>(VPath)), RPath(std::forward<T2>(RPath)),
513 IsDirectory(IsDirectory) {}
514 std::string VPath;
515 std::string RPath;
516 bool IsDirectory = false;
517};
518
519class RedirectingFSDirIterImpl;
520class RedirectingFileSystemParser;
521
522/// A virtual file system parsed from a YAML file.
523///
524/// Currently, this class allows creating virtual files and directories. Virtual
525/// files map to existing external files in \c ExternalFS, and virtual
526/// directories may either map to existing directories in \c ExternalFS or list
527/// their contents in the form of other virtual directories and/or files.
528///
529/// The basic structure of the parsed file is:
530/// \verbatim
531/// {
532/// 'version': <version number>,
533/// <optional configuration>
534/// 'roots': [
535/// <directory entries>
536/// ]
537/// }
538/// \endverbatim
539///
540/// All configuration options are optional.
541/// 'case-sensitive': <boolean, default=(true for Posix, false for Windows)>
542/// 'use-external-names': <boolean, default=true>
543/// 'overlay-relative': <boolean, default=false>
544/// 'fallthrough': <boolean, default=true>
545///
546/// Virtual directories that list their contents are represented as
547/// \verbatim
548/// {
549/// 'type': 'directory',
550/// 'name': <string>,
551/// 'contents': [ <file or directory entries> ]
552/// }
553/// \endverbatim
554///
555/// The default attributes for such virtual directories are:
556/// \verbatim
557/// MTime = now() when created
558/// Perms = 0777
559/// User = Group = 0
560/// Size = 0
561/// UniqueID = unspecified unique value
562/// \endverbatim
563///
564/// When a path prefix matches such a directory, the next component in the path
565/// is matched against the entries in the 'contents' array.
566///
567/// Re-mapped directories, on the other hand, are represented as
568/// /// \verbatim
569/// {
570/// 'type': 'directory-remap',
571/// 'name': <string>,
572/// 'use-external-name': <boolean>, # Optional
573/// 'external-contents': <path to external directory>
574/// }
575/// \endverbatim
576///
577/// and inherit their attributes from the external directory. When a path
578/// prefix matches such an entry, the unmatched components are appended to the
579/// 'external-contents' path, and the resulting path is looked up in the
580/// external file system instead.
581///
582/// Re-mapped files are represented as
583/// \verbatim
584/// {
585/// 'type': 'file',
586/// 'name': <string>,
587/// 'use-external-name': <boolean>, # Optional
588/// 'external-contents': <path to external file>
589/// }
590/// \endverbatim
591///
592/// Their attributes and file contents are determined by looking up the file at
593/// their 'external-contents' path in the external file system.
594///
595/// For 'file', 'directory' and 'directory-remap' entries the 'name' field may
596/// contain multiple path components (e.g. /path/to/file). However, any
597/// directory in such a path that contains more than one child must be uniquely
598/// represented by a 'directory' entry.
599class RedirectingFileSystem : public vfs::FileSystem {
600public:
601 enum EntryKind { EK_Directory, EK_DirectoryRemap, EK_File };
602 enum NameKind { NK_NotSet, NK_External, NK_Virtual };
603
604 /// A single file or directory in the VFS.
605 class Entry {
606 EntryKind Kind;
607 std::string Name;
608
609 public:
610 Entry(EntryKind K, StringRef Name) : Kind(K), Name(Name) {}
611 virtual ~Entry() = default;
612
613 StringRef getName() const { return Name; }
614 EntryKind getKind() const { return Kind; }
615 };
616
617 /// A directory in the vfs with explicitly specified contents.
618 class DirectoryEntry : public Entry {
619 std::vector<std::unique_ptr<Entry>> Contents;
620 Status S;
621
622 public:
623 /// Constructs a directory entry with explicitly specified contents.
624 DirectoryEntry(StringRef Name, std::vector<std::unique_ptr<Entry>> Contents,
625 Status S)
626 : Entry(EK_Directory, Name), Contents(std::move(Contents)),
627 S(std::move(S)) {}
628
629 /// Constructs an empty directory entry.
630 DirectoryEntry(StringRef Name, Status S)
631 : Entry(EK_Directory, Name), S(std::move(S)) {}
632
633 Status getStatus() { return S; }
634
635 void addContent(std::unique_ptr<Entry> Content) {
636 Contents.push_back(std::move(Content));
637 }
638
639 Entry *getLastContent() const { return Contents.back().get(); }
640
641 using iterator = decltype(Contents)::iterator;
642
643 iterator contents_begin() { return Contents.begin(); }
644 iterator contents_end() { return Contents.end(); }
645
646 static bool classof(const Entry *E) { return E->getKind() == EK_Directory; }
647 };
648
649 /// A file or directory in the vfs that is mapped to a file or directory in
650 /// the external filesystem.
651 class RemapEntry : public Entry {
652 std::string ExternalContentsPath;
653 NameKind UseName;
654
655 protected:
656 RemapEntry(EntryKind K, StringRef Name, StringRef ExternalContentsPath,
657 NameKind UseName)
658 : Entry(K, Name), ExternalContentsPath(ExternalContentsPath),
659 UseName(UseName) {}
660
661 public:
662 StringRef getExternalContentsPath() const { return ExternalContentsPath; }
663
664 /// Whether to use the external path as the name for this file or directory.
665 bool useExternalName(bool GlobalUseExternalName) const {
666 return UseName == NK_NotSet ? GlobalUseExternalName
667 : (UseName == NK_External);
668 }
669
670 NameKind getUseName() const { return UseName; }
671
672 static bool classof(const Entry *E) {
673 switch (E->getKind()) {
674 case EK_DirectoryRemap:
675 LLVM_FALLTHROUGH;
676 case EK_File:
677 return true;
678 case EK_Directory:
679 return false;
680 }
681 llvm_unreachable("invalid entry kind");
682 }
683 };
684
685 /// A directory in the vfs that maps to a directory in the external file
686 /// system.
687 class DirectoryRemapEntry : public RemapEntry {
688 public:
689 DirectoryRemapEntry(StringRef Name, StringRef ExternalContentsPath,
690 NameKind UseName)
691 : RemapEntry(EK_DirectoryRemap, Name, ExternalContentsPath, UseName) {}
692
693 static bool classof(const Entry *E) {
694 return E->getKind() == EK_DirectoryRemap;
695 }
696 };
697
698 /// A file in the vfs that maps to a file in the external file system.
699 class FileEntry : public RemapEntry {
700 public:
701 FileEntry(StringRef Name, StringRef ExternalContentsPath, NameKind UseName)
702 : RemapEntry(EK_File, Name, ExternalContentsPath, UseName) {}
703
704 static bool classof(const Entry *E) { return E->getKind() == EK_File; }
705 };
706
707 /// Represents the result of a path lookup into the RedirectingFileSystem.
708 struct LookupResult {
709 /// The entry the looked-up path corresponds to.
710 Entry *E;
711
712 private:
713 /// When the found Entry is a DirectoryRemapEntry, stores the path in the
714 /// external file system that the looked-up path in the virtual file system
715 // corresponds to.
716 Optional<std::string> ExternalRedirect;
717
718 public:
719 LookupResult(Entry *E, sys::path::const_iterator Start,
720 sys::path::const_iterator End);
721
722 /// If the found Entry maps the the input path to a path in the external
723 /// file system (i.e. it is a FileEntry or DirectoryRemapEntry), returns
724 /// that path.
725 Optional<StringRef> getExternalRedirect() const {
726 if (isa<DirectoryRemapEntry>(E))
727 return StringRef(*ExternalRedirect);
728 if (auto *FE = dyn_cast<FileEntry>(E))
729 return FE->getExternalContentsPath();
730 return None;
731 }
732 };
733
734private:
735 friend class RedirectingFSDirIterImpl;
736 friend class RedirectingFileSystemParser;
737
738 bool shouldUseExternalFS() const { return IsFallthrough; }
739
740 /// Canonicalize path by removing ".", "..", "./", components. This is
741 /// a VFS request, do not bother about symlinks in the path components
742 /// but canonicalize in order to perform the correct entry search.
743 std::error_code makeCanonical(SmallVectorImpl<char> &Path) const;
744
745 /// Whether to fall back to the external file system when an operation fails
746 /// with the given error code on a path associated with the provided Entry.
747 bool shouldFallBackToExternalFS(std::error_code EC, Entry *E = nullptr) const;
748
749 // In a RedirectingFileSystem, keys can be specified in Posix or Windows
750 // style (or even a mixture of both), so this comparison helper allows
751 // slashes (representing a root) to match backslashes (and vice versa). Note
752 // that, other than the root, path components should not contain slashes or
753 // backslashes.
754 bool pathComponentMatches(llvm::StringRef lhs, llvm::StringRef rhs) const {
755 if ((CaseSensitive ? lhs.equals(rhs) : lhs.equals_lower(rhs)))
756 return true;
757 return (lhs == "/" && rhs == "\\") || (lhs == "\\" && rhs == "/");
758 }
759
760 /// The root(s) of the virtual file system.
761 std::vector<std::unique_ptr<Entry>> Roots;
762
763 /// The current working directory of the file system.
764 std::string WorkingDirectory;
765
766 /// The file system to use for external references.
767 IntrusiveRefCntPtr<FileSystem> ExternalFS;
768
769 /// If IsRelativeOverlay is set, this represents the directory
770 /// path that should be prefixed to each 'external-contents' entry
771 /// when reading from YAML files.
772 std::string ExternalContentsPrefixDir;
773
774 /// @name Configuration
775 /// @{
776
777 /// Whether to perform case-sensitive comparisons.
778 ///
779 /// Currently, case-insensitive matching only works correctly with ASCII.
780 bool CaseSensitive =
781#ifdef _WIN32
782 false;
783#else
784 true;
785#endif
786
787 /// IsRelativeOverlay marks whether a ExternalContentsPrefixDir path must
788 /// be prefixed in every 'external-contents' when reading from YAML files.
789 bool IsRelativeOverlay = false;
790
791 /// Whether to use to use the value of 'external-contents' for the
792 /// names of files. This global value is overridable on a per-file basis.
793 bool UseExternalNames = true;
794
795 /// Whether to attempt a file lookup in external file system after it wasn't
796 /// found in VFS.
797 bool IsFallthrough = true;
798 /// @}
799
800 RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> ExternalFS);
801
802 /// Looks up the path <tt>[Start, End)</tt> in \p From, possibly recursing
803 /// into the contents of \p From if it is a directory. Returns a LookupResult
804 /// giving the matched entry and, if that entry is a FileEntry or
805 /// DirectoryRemapEntry, the path it redirects to in the external file system.
806 ErrorOr<LookupResult> lookupPathImpl(llvm::sys::path::const_iterator Start,
807 llvm::sys::path::const_iterator End,
808 Entry *From) const;
809
810 /// Get the status for a path with the provided \c LookupResult.
811 ErrorOr<Status> status(const Twine &Path, const LookupResult &Result);
812
813public:
814 /// Looks up \p Path in \c Roots and returns a LookupResult giving the
815 /// matched entry and, if the entry was a FileEntry or DirectoryRemapEntry,
816 /// the path it redirects to in the external file system.
817 ErrorOr<LookupResult> lookupPath(StringRef Path) const;
818
819 /// Parses \p Buffer, which is expected to be in YAML format and
820 /// returns a virtual file system representing its contents.
821 static std::unique_ptr<RedirectingFileSystem>
822 create(std::unique_ptr<MemoryBuffer> Buffer,
823 SourceMgr::DiagHandlerTy DiagHandler, StringRef YAMLFilePath,
824 void *DiagContext, IntrusiveRefCntPtr<FileSystem> ExternalFS);
825
826 /// Redirect each of the remapped files from first to second.
827 static std::unique_ptr<RedirectingFileSystem>
828 create(ArrayRef<std::pair<std::string, std::string>> RemappedFiles,
829 bool UseExternalNames, FileSystem &ExternalFS);
830
831 ErrorOr<Status> status(const Twine &Path) override;
832 ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override;
833
834 std::error_code getRealPath(const Twine &Path,
835 SmallVectorImpl<char> &Output) const override;
836
837 llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
838
839 std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
840
841 std::error_code isLocal(const Twine &Path, bool &Result) override;
842
843 std::error_code makeAbsolute(SmallVectorImpl<char> &Path) const override;
844
845 directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
846
847 void setExternalContentsPrefixDir(StringRef PrefixDir);
848
849 StringRef getExternalContentsPrefixDir() const;
850
851 void setFallthrough(bool Fallthrough);
852
853 std::vector<llvm::StringRef> getRoots() const;
854
855 void dump(raw_ostream &OS) const;
856 void dumpEntry(raw_ostream &OS, Entry *E, int NumSpaces = 0) const;
857#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
858 LLVM_DUMP_METHOD void dump() const;
859#endif
860};
861
862/// Collect all pairs of <virtual path, real path> entries from the
863/// \p YAMLFilePath. This is used by the module dependency collector to forward
864/// the entries into the reproducer output VFS YAML file.
865void collectVFSFromYAML(
866 std::unique_ptr<llvm::MemoryBuffer> Buffer,
867 llvm::SourceMgr::DiagHandlerTy DiagHandler, StringRef YAMLFilePath,
868 SmallVectorImpl<YAMLVFSEntry> &CollectedEntries,
869 void *DiagContext = nullptr,
870 IntrusiveRefCntPtr<FileSystem> ExternalFS = getRealFileSystem());
871
872class YAMLVFSWriter {
873 std::vector<YAMLVFSEntry> Mappings;
874 Optional<bool> IsCaseSensitive;
875 Optional<bool> IsOverlayRelative;
876 Optional<bool> UseExternalNames;
877 std::string OverlayDir;
878
879 void addEntry(StringRef VirtualPath, StringRef RealPath, bool IsDirectory);
880
881public:
882 YAMLVFSWriter() = default;
883
884 void addFileMapping(StringRef VirtualPath, StringRef RealPath);
885 void addDirectoryMapping(StringRef VirtualPath, StringRef RealPath);
886
887 void setCaseSensitivity(bool CaseSensitive) {
888 IsCaseSensitive = CaseSensitive;
889 }
890
891 void setUseExternalNames(bool UseExtNames) { UseExternalNames = UseExtNames; }
892
893 void setOverlayDir(StringRef OverlayDirectory) {
894 IsOverlayRelative = true;
895 OverlayDir.assign(OverlayDirectory.str());
896 }
897
898 const std::vector<YAMLVFSEntry> &getMappings() const { return Mappings; }
899
900 void write(llvm::raw_ostream &OS);
901};
902
903} // namespace vfs
904} // namespace llvm
905
906#endif // LLVM_SUPPORT_VIRTUALFILESYSTEM_H
907