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1 //===- VirtualFileSystem.cpp - Virtual File System Layer --------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 // This file implements the VirtualFileSystem interface.
10 //===----------------------------------------------------------------------===//
11 
12 #include "clang/Basic/VirtualFileSystem.h"
13 #include "clang/Basic/FileManager.h"
14 #include "llvm/ADT/DenseMap.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/ADT/StringSet.h"
18 #include "llvm/ADT/iterator_range.h"
19 #include "llvm/Config/llvm-config.h"
20 #include "llvm/Support/Debug.h"
21 #include "llvm/Support/Errc.h"
22 #include "llvm/Support/MemoryBuffer.h"
23 #include "llvm/Support/Path.h"
24 #include "llvm/Support/Process.h"
25 #include "llvm/Support/YAMLParser.h"
26 #include <atomic>
27 #include <memory>
28 #include <utility>
29 
30 // For chdir.
31 #ifdef LLVM_ON_WIN32
32 #  include <direct.h>
33 #else
34 #  include <unistd.h>
35 #endif
36 
37 using namespace clang;
38 using namespace clang::vfs;
39 using namespace llvm;
40 using llvm::sys::fs::file_status;
41 using llvm::sys::fs::file_type;
42 using llvm::sys::fs::perms;
43 using llvm::sys::fs::UniqueID;
44 
Status(const file_status & Status)45 Status::Status(const file_status &Status)
46     : UID(Status.getUniqueID()), MTime(Status.getLastModificationTime()),
47       User(Status.getUser()), Group(Status.getGroup()), Size(Status.getSize()),
48       Type(Status.type()), Perms(Status.permissions()), IsVFSMapped(false)  {}
49 
Status(StringRef Name,UniqueID UID,sys::TimeValue MTime,uint32_t User,uint32_t Group,uint64_t Size,file_type Type,perms Perms)50 Status::Status(StringRef Name, UniqueID UID, sys::TimeValue MTime,
51                uint32_t User, uint32_t Group, uint64_t Size, file_type Type,
52                perms Perms)
53     : Name(Name), UID(UID), MTime(MTime), User(User), Group(Group), Size(Size),
54       Type(Type), Perms(Perms), IsVFSMapped(false) {}
55 
copyWithNewName(const Status & In,StringRef NewName)56 Status Status::copyWithNewName(const Status &In, StringRef NewName) {
57   return Status(NewName, In.getUniqueID(), In.getLastModificationTime(),
58                 In.getUser(), In.getGroup(), In.getSize(), In.getType(),
59                 In.getPermissions());
60 }
61 
copyWithNewName(const file_status & In,StringRef NewName)62 Status Status::copyWithNewName(const file_status &In, StringRef NewName) {
63   return Status(NewName, In.getUniqueID(), In.getLastModificationTime(),
64                 In.getUser(), In.getGroup(), In.getSize(), In.type(),
65                 In.permissions());
66 }
67 
equivalent(const Status & Other) const68 bool Status::equivalent(const Status &Other) const {
69   return getUniqueID() == Other.getUniqueID();
70 }
isDirectory() const71 bool Status::isDirectory() const {
72   return Type == file_type::directory_file;
73 }
isRegularFile() const74 bool Status::isRegularFile() const {
75   return Type == file_type::regular_file;
76 }
isOther() const77 bool Status::isOther() const {
78   return exists() && !isRegularFile() && !isDirectory() && !isSymlink();
79 }
isSymlink() const80 bool Status::isSymlink() const {
81   return Type == file_type::symlink_file;
82 }
isStatusKnown() const83 bool Status::isStatusKnown() const {
84   return Type != file_type::status_error;
85 }
exists() const86 bool Status::exists() const {
87   return isStatusKnown() && Type != file_type::file_not_found;
88 }
89 
~File()90 File::~File() {}
91 
~FileSystem()92 FileSystem::~FileSystem() {}
93 
94 ErrorOr<std::unique_ptr<MemoryBuffer>>
getBufferForFile(const llvm::Twine & Name,int64_t FileSize,bool RequiresNullTerminator,bool IsVolatile)95 FileSystem::getBufferForFile(const llvm::Twine &Name, int64_t FileSize,
96                              bool RequiresNullTerminator, bool IsVolatile) {
97   auto F = openFileForRead(Name);
98   if (!F)
99     return F.getError();
100 
101   return (*F)->getBuffer(Name, FileSize, RequiresNullTerminator, IsVolatile);
102 }
103 
makeAbsolute(SmallVectorImpl<char> & Path) const104 std::error_code FileSystem::makeAbsolute(SmallVectorImpl<char> &Path) const {
105   if (llvm::sys::path::is_absolute(Path))
106     return std::error_code();
107 
108   auto WorkingDir = getCurrentWorkingDirectory();
109   if (!WorkingDir)
110     return WorkingDir.getError();
111 
112   return llvm::sys::fs::make_absolute(WorkingDir.get(), Path);
113 }
114 
exists(const Twine & Path)115 bool FileSystem::exists(const Twine &Path) {
116   auto Status = status(Path);
117   return Status && Status->exists();
118 }
119 
120 #ifndef NDEBUG
isTraversalComponent(StringRef Component)121 static bool isTraversalComponent(StringRef Component) {
122   return Component.equals("..") || Component.equals(".");
123 }
124 
pathHasTraversal(StringRef Path)125 static bool pathHasTraversal(StringRef Path) {
126   using namespace llvm::sys;
127   for (StringRef Comp : llvm::make_range(path::begin(Path), path::end(Path)))
128     if (isTraversalComponent(Comp))
129       return true;
130   return false;
131 }
132 #endif
133 
134 //===-----------------------------------------------------------------------===/
135 // RealFileSystem implementation
136 //===-----------------------------------------------------------------------===/
137 
138 namespace {
139 /// \brief Wrapper around a raw file descriptor.
140 class RealFile : public File {
141   int FD;
142   Status S;
143   std::string RealName;
144   friend class RealFileSystem;
RealFile(int FD,StringRef NewName,StringRef NewRealPathName)145   RealFile(int FD, StringRef NewName, StringRef NewRealPathName)
146       : FD(FD), S(NewName, {}, {}, {}, {}, {},
147                   llvm::sys::fs::file_type::status_error, {}),
148         RealName(NewRealPathName.str()) {
149     assert(FD >= 0 && "Invalid or inactive file descriptor");
150   }
151 
152 public:
153   ~RealFile() override;
154   ErrorOr<Status> status() override;
155   ErrorOr<std::string> getName() override;
156   ErrorOr<std::unique_ptr<MemoryBuffer>> getBuffer(const Twine &Name,
157                                                    int64_t FileSize,
158                                                    bool RequiresNullTerminator,
159                                                    bool IsVolatile) override;
160   std::error_code close() override;
161 };
162 } // end anonymous namespace
~RealFile()163 RealFile::~RealFile() { close(); }
164 
status()165 ErrorOr<Status> RealFile::status() {
166   assert(FD != -1 && "cannot stat closed file");
167   if (!S.isStatusKnown()) {
168     file_status RealStatus;
169     if (std::error_code EC = sys::fs::status(FD, RealStatus))
170       return EC;
171     S = Status::copyWithNewName(RealStatus, S.getName());
172   }
173   return S;
174 }
175 
getName()176 ErrorOr<std::string> RealFile::getName() {
177   return RealName.empty() ? S.getName().str() : RealName;
178 }
179 
180 ErrorOr<std::unique_ptr<MemoryBuffer>>
getBuffer(const Twine & Name,int64_t FileSize,bool RequiresNullTerminator,bool IsVolatile)181 RealFile::getBuffer(const Twine &Name, int64_t FileSize,
182                     bool RequiresNullTerminator, bool IsVolatile) {
183   assert(FD != -1 && "cannot get buffer for closed file");
184   return MemoryBuffer::getOpenFile(FD, Name, FileSize, RequiresNullTerminator,
185                                    IsVolatile);
186 }
187 
close()188 std::error_code RealFile::close() {
189   std::error_code EC = sys::Process::SafelyCloseFileDescriptor(FD);
190   FD = -1;
191   return EC;
192 }
193 
194 namespace {
195 /// \brief The file system according to your operating system.
196 class RealFileSystem : public FileSystem {
197 public:
198   ErrorOr<Status> status(const Twine &Path) override;
199   ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override;
200   directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
201 
202   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
203   std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
204 };
205 } // end anonymous namespace
206 
status(const Twine & Path)207 ErrorOr<Status> RealFileSystem::status(const Twine &Path) {
208   sys::fs::file_status RealStatus;
209   if (std::error_code EC = sys::fs::status(Path, RealStatus))
210     return EC;
211   return Status::copyWithNewName(RealStatus, Path.str());
212 }
213 
214 ErrorOr<std::unique_ptr<File>>
openFileForRead(const Twine & Name)215 RealFileSystem::openFileForRead(const Twine &Name) {
216   int FD;
217   SmallString<256> RealName;
218   if (std::error_code EC = sys::fs::openFileForRead(Name, FD, &RealName))
219     return EC;
220   return std::unique_ptr<File>(new RealFile(FD, Name.str(), RealName.str()));
221 }
222 
getCurrentWorkingDirectory() const223 llvm::ErrorOr<std::string> RealFileSystem::getCurrentWorkingDirectory() const {
224   SmallString<256> Dir;
225   if (std::error_code EC = llvm::sys::fs::current_path(Dir))
226     return EC;
227   return Dir.str().str();
228 }
229 
setCurrentWorkingDirectory(const Twine & Path)230 std::error_code RealFileSystem::setCurrentWorkingDirectory(const Twine &Path) {
231   // FIXME: chdir is thread hostile; on the other hand, creating the same
232   // behavior as chdir is complex: chdir resolves the path once, thus
233   // guaranteeing that all subsequent relative path operations work
234   // on the same path the original chdir resulted in. This makes a
235   // difference for example on network filesystems, where symlinks might be
236   // switched during runtime of the tool. Fixing this depends on having a
237   // file system abstraction that allows openat() style interactions.
238   SmallString<256> Storage;
239   StringRef Dir = Path.toNullTerminatedStringRef(Storage);
240   if (int Err = ::chdir(Dir.data()))
241     return std::error_code(Err, std::generic_category());
242   return std::error_code();
243 }
244 
getRealFileSystem()245 IntrusiveRefCntPtr<FileSystem> vfs::getRealFileSystem() {
246   static IntrusiveRefCntPtr<FileSystem> FS = new RealFileSystem();
247   return FS;
248 }
249 
250 namespace {
251 class RealFSDirIter : public clang::vfs::detail::DirIterImpl {
252   std::string Path;
253   llvm::sys::fs::directory_iterator Iter;
254 public:
RealFSDirIter(const Twine & _Path,std::error_code & EC)255   RealFSDirIter(const Twine &_Path, std::error_code &EC)
256       : Path(_Path.str()), Iter(Path, EC) {
257     if (!EC && Iter != llvm::sys::fs::directory_iterator()) {
258       llvm::sys::fs::file_status S;
259       EC = Iter->status(S);
260       if (!EC)
261         CurrentEntry = Status::copyWithNewName(S, Iter->path());
262     }
263   }
264 
increment()265   std::error_code increment() override {
266     std::error_code EC;
267     Iter.increment(EC);
268     if (EC) {
269       return EC;
270     } else if (Iter == llvm::sys::fs::directory_iterator()) {
271       CurrentEntry = Status();
272     } else {
273       llvm::sys::fs::file_status S;
274       EC = Iter->status(S);
275       CurrentEntry = Status::copyWithNewName(S, Iter->path());
276     }
277     return EC;
278   }
279 };
280 }
281 
dir_begin(const Twine & Dir,std::error_code & EC)282 directory_iterator RealFileSystem::dir_begin(const Twine &Dir,
283                                              std::error_code &EC) {
284   return directory_iterator(std::make_shared<RealFSDirIter>(Dir, EC));
285 }
286 
287 //===-----------------------------------------------------------------------===/
288 // OverlayFileSystem implementation
289 //===-----------------------------------------------------------------------===/
OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> BaseFS)290 OverlayFileSystem::OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> BaseFS) {
291   FSList.push_back(std::move(BaseFS));
292 }
293 
pushOverlay(IntrusiveRefCntPtr<FileSystem> FS)294 void OverlayFileSystem::pushOverlay(IntrusiveRefCntPtr<FileSystem> FS) {
295   FSList.push_back(FS);
296   // Synchronize added file systems by duplicating the working directory from
297   // the first one in the list.
298   FS->setCurrentWorkingDirectory(getCurrentWorkingDirectory().get());
299 }
300 
status(const Twine & Path)301 ErrorOr<Status> OverlayFileSystem::status(const Twine &Path) {
302   // FIXME: handle symlinks that cross file systems
303   for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
304     ErrorOr<Status> Status = (*I)->status(Path);
305     if (Status || Status.getError() != llvm::errc::no_such_file_or_directory)
306       return Status;
307   }
308   return make_error_code(llvm::errc::no_such_file_or_directory);
309 }
310 
311 ErrorOr<std::unique_ptr<File>>
openFileForRead(const llvm::Twine & Path)312 OverlayFileSystem::openFileForRead(const llvm::Twine &Path) {
313   // FIXME: handle symlinks that cross file systems
314   for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
315     auto Result = (*I)->openFileForRead(Path);
316     if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
317       return Result;
318   }
319   return make_error_code(llvm::errc::no_such_file_or_directory);
320 }
321 
322 llvm::ErrorOr<std::string>
getCurrentWorkingDirectory() const323 OverlayFileSystem::getCurrentWorkingDirectory() const {
324   // All file systems are synchronized, just take the first working directory.
325   return FSList.front()->getCurrentWorkingDirectory();
326 }
327 std::error_code
setCurrentWorkingDirectory(const Twine & Path)328 OverlayFileSystem::setCurrentWorkingDirectory(const Twine &Path) {
329   for (auto &FS : FSList)
330     if (std::error_code EC = FS->setCurrentWorkingDirectory(Path))
331       return EC;
332   return std::error_code();
333 }
334 
~DirIterImpl()335 clang::vfs::detail::DirIterImpl::~DirIterImpl() { }
336 
337 namespace {
338 class OverlayFSDirIterImpl : public clang::vfs::detail::DirIterImpl {
339   OverlayFileSystem &Overlays;
340   std::string Path;
341   OverlayFileSystem::iterator CurrentFS;
342   directory_iterator CurrentDirIter;
343   llvm::StringSet<> SeenNames;
344 
incrementFS()345   std::error_code incrementFS() {
346     assert(CurrentFS != Overlays.overlays_end() && "incrementing past end");
347     ++CurrentFS;
348     for (auto E = Overlays.overlays_end(); CurrentFS != E; ++CurrentFS) {
349       std::error_code EC;
350       CurrentDirIter = (*CurrentFS)->dir_begin(Path, EC);
351       if (EC && EC != errc::no_such_file_or_directory)
352         return EC;
353       if (CurrentDirIter != directory_iterator())
354         break; // found
355     }
356     return std::error_code();
357   }
358 
incrementDirIter(bool IsFirstTime)359   std::error_code incrementDirIter(bool IsFirstTime) {
360     assert((IsFirstTime || CurrentDirIter != directory_iterator()) &&
361            "incrementing past end");
362     std::error_code EC;
363     if (!IsFirstTime)
364       CurrentDirIter.increment(EC);
365     if (!EC && CurrentDirIter == directory_iterator())
366       EC = incrementFS();
367     return EC;
368   }
369 
incrementImpl(bool IsFirstTime)370   std::error_code incrementImpl(bool IsFirstTime) {
371     while (true) {
372       std::error_code EC = incrementDirIter(IsFirstTime);
373       if (EC || CurrentDirIter == directory_iterator()) {
374         CurrentEntry = Status();
375         return EC;
376       }
377       CurrentEntry = *CurrentDirIter;
378       StringRef Name = llvm::sys::path::filename(CurrentEntry.getName());
379       if (SeenNames.insert(Name).second)
380         return EC; // name not seen before
381     }
382     llvm_unreachable("returned above");
383   }
384 
385 public:
OverlayFSDirIterImpl(const Twine & Path,OverlayFileSystem & FS,std::error_code & EC)386   OverlayFSDirIterImpl(const Twine &Path, OverlayFileSystem &FS,
387                        std::error_code &EC)
388       : Overlays(FS), Path(Path.str()), CurrentFS(Overlays.overlays_begin()) {
389     CurrentDirIter = (*CurrentFS)->dir_begin(Path, EC);
390     EC = incrementImpl(true);
391   }
392 
increment()393   std::error_code increment() override { return incrementImpl(false); }
394 };
395 } // end anonymous namespace
396 
dir_begin(const Twine & Dir,std::error_code & EC)397 directory_iterator OverlayFileSystem::dir_begin(const Twine &Dir,
398                                                 std::error_code &EC) {
399   return directory_iterator(
400       std::make_shared<OverlayFSDirIterImpl>(Dir, *this, EC));
401 }
402 
403 namespace clang {
404 namespace vfs {
405 namespace detail {
406 
407 enum InMemoryNodeKind { IME_File, IME_Directory };
408 
409 /// The in memory file system is a tree of Nodes. Every node can either be a
410 /// file or a directory.
411 class InMemoryNode {
412   Status Stat;
413   InMemoryNodeKind Kind;
414 
415 public:
InMemoryNode(Status Stat,InMemoryNodeKind Kind)416   InMemoryNode(Status Stat, InMemoryNodeKind Kind)
417       : Stat(std::move(Stat)), Kind(Kind) {}
~InMemoryNode()418   virtual ~InMemoryNode() {}
getStatus() const419   const Status &getStatus() const { return Stat; }
getKind() const420   InMemoryNodeKind getKind() const { return Kind; }
421   virtual std::string toString(unsigned Indent) const = 0;
422 };
423 
424 namespace {
425 class InMemoryFile : public InMemoryNode {
426   std::unique_ptr<llvm::MemoryBuffer> Buffer;
427 
428 public:
InMemoryFile(Status Stat,std::unique_ptr<llvm::MemoryBuffer> Buffer)429   InMemoryFile(Status Stat, std::unique_ptr<llvm::MemoryBuffer> Buffer)
430       : InMemoryNode(std::move(Stat), IME_File), Buffer(std::move(Buffer)) {}
431 
getBuffer()432   llvm::MemoryBuffer *getBuffer() { return Buffer.get(); }
toString(unsigned Indent) const433   std::string toString(unsigned Indent) const override {
434     return (std::string(Indent, ' ') + getStatus().getName() + "\n").str();
435   }
classof(const InMemoryNode * N)436   static bool classof(const InMemoryNode *N) {
437     return N->getKind() == IME_File;
438   }
439 };
440 
441 /// Adapt a InMemoryFile for VFS' File interface.
442 class InMemoryFileAdaptor : public File {
443   InMemoryFile &Node;
444 
445 public:
InMemoryFileAdaptor(InMemoryFile & Node)446   explicit InMemoryFileAdaptor(InMemoryFile &Node) : Node(Node) {}
447 
status()448   llvm::ErrorOr<Status> status() override { return Node.getStatus(); }
449   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBuffer(const Twine & Name,int64_t FileSize,bool RequiresNullTerminator,bool IsVolatile)450   getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
451             bool IsVolatile) override {
452     llvm::MemoryBuffer *Buf = Node.getBuffer();
453     return llvm::MemoryBuffer::getMemBuffer(
454         Buf->getBuffer(), Buf->getBufferIdentifier(), RequiresNullTerminator);
455   }
close()456   std::error_code close() override { return std::error_code(); }
457 };
458 } // end anonymous namespace
459 
460 class InMemoryDirectory : public InMemoryNode {
461   std::map<std::string, std::unique_ptr<InMemoryNode>> Entries;
462 
463 public:
InMemoryDirectory(Status Stat)464   InMemoryDirectory(Status Stat)
465       : InMemoryNode(std::move(Stat), IME_Directory) {}
getChild(StringRef Name)466   InMemoryNode *getChild(StringRef Name) {
467     auto I = Entries.find(Name);
468     if (I != Entries.end())
469       return I->second.get();
470     return nullptr;
471   }
addChild(StringRef Name,std::unique_ptr<InMemoryNode> Child)472   InMemoryNode *addChild(StringRef Name, std::unique_ptr<InMemoryNode> Child) {
473     return Entries.insert(make_pair(Name, std::move(Child)))
474         .first->second.get();
475   }
476 
477   typedef decltype(Entries)::const_iterator const_iterator;
begin() const478   const_iterator begin() const { return Entries.begin(); }
end() const479   const_iterator end() const { return Entries.end(); }
480 
toString(unsigned Indent) const481   std::string toString(unsigned Indent) const override {
482     std::string Result =
483         (std::string(Indent, ' ') + getStatus().getName() + "\n").str();
484     for (const auto &Entry : Entries) {
485       Result += Entry.second->toString(Indent + 2);
486     }
487     return Result;
488   }
classof(const InMemoryNode * N)489   static bool classof(const InMemoryNode *N) {
490     return N->getKind() == IME_Directory;
491   }
492 };
493 }
494 
InMemoryFileSystem(bool UseNormalizedPaths)495 InMemoryFileSystem::InMemoryFileSystem(bool UseNormalizedPaths)
496     : Root(new detail::InMemoryDirectory(
497           Status("", getNextVirtualUniqueID(), llvm::sys::TimeValue::MinTime(),
498                  0, 0, 0, llvm::sys::fs::file_type::directory_file,
499                  llvm::sys::fs::perms::all_all))),
500       UseNormalizedPaths(UseNormalizedPaths) {}
501 
~InMemoryFileSystem()502 InMemoryFileSystem::~InMemoryFileSystem() {}
503 
toString() const504 std::string InMemoryFileSystem::toString() const {
505   return Root->toString(/*Indent=*/0);
506 }
507 
addFile(const Twine & P,time_t ModificationTime,std::unique_ptr<llvm::MemoryBuffer> Buffer)508 bool InMemoryFileSystem::addFile(const Twine &P, time_t ModificationTime,
509                                  std::unique_ptr<llvm::MemoryBuffer> Buffer) {
510   SmallString<128> Path;
511   P.toVector(Path);
512 
513   // Fix up relative paths. This just prepends the current working directory.
514   std::error_code EC = makeAbsolute(Path);
515   assert(!EC);
516   (void)EC;
517 
518   if (useNormalizedPaths())
519     llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
520 
521   if (Path.empty())
522     return false;
523 
524   detail::InMemoryDirectory *Dir = Root.get();
525   auto I = llvm::sys::path::begin(Path), E = llvm::sys::path::end(Path);
526   while (true) {
527     StringRef Name = *I;
528     detail::InMemoryNode *Node = Dir->getChild(Name);
529     ++I;
530     if (!Node) {
531       if (I == E) {
532         // End of the path, create a new file.
533         // FIXME: expose the status details in the interface.
534         Status Stat(P.str(), getNextVirtualUniqueID(),
535                     llvm::sys::TimeValue(ModificationTime, 0), 0, 0,
536                     Buffer->getBufferSize(),
537                     llvm::sys::fs::file_type::regular_file,
538                     llvm::sys::fs::all_all);
539         Dir->addChild(Name, llvm::make_unique<detail::InMemoryFile>(
540                                 std::move(Stat), std::move(Buffer)));
541         return true;
542       }
543 
544       // Create a new directory. Use the path up to here.
545       // FIXME: expose the status details in the interface.
546       Status Stat(
547           StringRef(Path.str().begin(), Name.end() - Path.str().begin()),
548           getNextVirtualUniqueID(), llvm::sys::TimeValue(ModificationTime, 0),
549           0, 0, Buffer->getBufferSize(),
550           llvm::sys::fs::file_type::directory_file, llvm::sys::fs::all_all);
551       Dir = cast<detail::InMemoryDirectory>(Dir->addChild(
552           Name, llvm::make_unique<detail::InMemoryDirectory>(std::move(Stat))));
553       continue;
554     }
555 
556     if (auto *NewDir = dyn_cast<detail::InMemoryDirectory>(Node)) {
557       Dir = NewDir;
558     } else {
559       assert(isa<detail::InMemoryFile>(Node) &&
560              "Must be either file or directory!");
561 
562       // Trying to insert a directory in place of a file.
563       if (I != E)
564         return false;
565 
566       // Return false only if the new file is different from the existing one.
567       return cast<detail::InMemoryFile>(Node)->getBuffer()->getBuffer() ==
568              Buffer->getBuffer();
569     }
570   }
571 }
572 
addFileNoOwn(const Twine & P,time_t ModificationTime,llvm::MemoryBuffer * Buffer)573 bool InMemoryFileSystem::addFileNoOwn(const Twine &P, time_t ModificationTime,
574                                       llvm::MemoryBuffer *Buffer) {
575   return addFile(P, ModificationTime,
576                  llvm::MemoryBuffer::getMemBuffer(
577                      Buffer->getBuffer(), Buffer->getBufferIdentifier()));
578 }
579 
580 static ErrorOr<detail::InMemoryNode *>
lookupInMemoryNode(const InMemoryFileSystem & FS,detail::InMemoryDirectory * Dir,const Twine & P)581 lookupInMemoryNode(const InMemoryFileSystem &FS, detail::InMemoryDirectory *Dir,
582                    const Twine &P) {
583   SmallString<128> Path;
584   P.toVector(Path);
585 
586   // Fix up relative paths. This just prepends the current working directory.
587   std::error_code EC = FS.makeAbsolute(Path);
588   assert(!EC);
589   (void)EC;
590 
591   if (FS.useNormalizedPaths())
592     llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
593 
594   if (Path.empty())
595     return Dir;
596 
597   auto I = llvm::sys::path::begin(Path), E = llvm::sys::path::end(Path);
598   while (true) {
599     detail::InMemoryNode *Node = Dir->getChild(*I);
600     ++I;
601     if (!Node)
602       return errc::no_such_file_or_directory;
603 
604     // Return the file if it's at the end of the path.
605     if (auto File = dyn_cast<detail::InMemoryFile>(Node)) {
606       if (I == E)
607         return File;
608       return errc::no_such_file_or_directory;
609     }
610 
611     // Traverse directories.
612     Dir = cast<detail::InMemoryDirectory>(Node);
613     if (I == E)
614       return Dir;
615   }
616 }
617 
status(const Twine & Path)618 llvm::ErrorOr<Status> InMemoryFileSystem::status(const Twine &Path) {
619   auto Node = lookupInMemoryNode(*this, Root.get(), Path);
620   if (Node)
621     return (*Node)->getStatus();
622   return Node.getError();
623 }
624 
625 llvm::ErrorOr<std::unique_ptr<File>>
openFileForRead(const Twine & Path)626 InMemoryFileSystem::openFileForRead(const Twine &Path) {
627   auto Node = lookupInMemoryNode(*this, Root.get(), Path);
628   if (!Node)
629     return Node.getError();
630 
631   // When we have a file provide a heap-allocated wrapper for the memory buffer
632   // to match the ownership semantics for File.
633   if (auto *F = dyn_cast<detail::InMemoryFile>(*Node))
634     return std::unique_ptr<File>(new detail::InMemoryFileAdaptor(*F));
635 
636   // FIXME: errc::not_a_file?
637   return make_error_code(llvm::errc::invalid_argument);
638 }
639 
640 namespace {
641 /// Adaptor from InMemoryDir::iterator to directory_iterator.
642 class InMemoryDirIterator : public clang::vfs::detail::DirIterImpl {
643   detail::InMemoryDirectory::const_iterator I;
644   detail::InMemoryDirectory::const_iterator E;
645 
646 public:
InMemoryDirIterator()647   InMemoryDirIterator() {}
InMemoryDirIterator(detail::InMemoryDirectory & Dir)648   explicit InMemoryDirIterator(detail::InMemoryDirectory &Dir)
649       : I(Dir.begin()), E(Dir.end()) {
650     if (I != E)
651       CurrentEntry = I->second->getStatus();
652   }
653 
increment()654   std::error_code increment() override {
655     ++I;
656     // When we're at the end, make CurrentEntry invalid and DirIterImpl will do
657     // the rest.
658     CurrentEntry = I != E ? I->second->getStatus() : Status();
659     return std::error_code();
660   }
661 };
662 } // end anonymous namespace
663 
dir_begin(const Twine & Dir,std::error_code & EC)664 directory_iterator InMemoryFileSystem::dir_begin(const Twine &Dir,
665                                                  std::error_code &EC) {
666   auto Node = lookupInMemoryNode(*this, Root.get(), Dir);
667   if (!Node) {
668     EC = Node.getError();
669     return directory_iterator(std::make_shared<InMemoryDirIterator>());
670   }
671 
672   if (auto *DirNode = dyn_cast<detail::InMemoryDirectory>(*Node))
673     return directory_iterator(std::make_shared<InMemoryDirIterator>(*DirNode));
674 
675   EC = make_error_code(llvm::errc::not_a_directory);
676   return directory_iterator(std::make_shared<InMemoryDirIterator>());
677 }
678 
setCurrentWorkingDirectory(const Twine & P)679 std::error_code InMemoryFileSystem::setCurrentWorkingDirectory(const Twine &P) {
680   SmallString<128> Path;
681   P.toVector(Path);
682 
683   // Fix up relative paths. This just prepends the current working directory.
684   std::error_code EC = makeAbsolute(Path);
685   assert(!EC);
686   (void)EC;
687 
688   if (useNormalizedPaths())
689     llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
690 
691   if (!Path.empty())
692     WorkingDirectory = Path.str();
693   return std::error_code();
694 }
695 }
696 }
697 
698 //===-----------------------------------------------------------------------===/
699 // RedirectingFileSystem implementation
700 //===-----------------------------------------------------------------------===/
701 
702 namespace {
703 
704 enum EntryKind {
705   EK_Directory,
706   EK_File
707 };
708 
709 /// \brief A single file or directory in the VFS.
710 class Entry {
711   EntryKind Kind;
712   std::string Name;
713 
714 public:
715   virtual ~Entry();
Entry(EntryKind K,StringRef Name)716   Entry(EntryKind K, StringRef Name) : Kind(K), Name(Name) {}
getName() const717   StringRef getName() const { return Name; }
getKind() const718   EntryKind getKind() const { return Kind; }
719 };
720 
721 class RedirectingDirectoryEntry : public Entry {
722   std::vector<std::unique_ptr<Entry>> Contents;
723   Status S;
724 
725 public:
RedirectingDirectoryEntry(StringRef Name,std::vector<std::unique_ptr<Entry>> Contents,Status S)726   RedirectingDirectoryEntry(StringRef Name,
727                             std::vector<std::unique_ptr<Entry>> Contents,
728                             Status S)
729       : Entry(EK_Directory, Name), Contents(std::move(Contents)),
730         S(std::move(S)) {}
RedirectingDirectoryEntry(StringRef Name,Status S)731   RedirectingDirectoryEntry(StringRef Name, Status S)
732       : Entry(EK_Directory, Name), S(std::move(S)) {}
getStatus()733   Status getStatus() { return S; }
addContent(std::unique_ptr<Entry> Content)734   void addContent(std::unique_ptr<Entry> Content) {
735     Contents.push_back(std::move(Content));
736   }
getLastContent() const737   Entry *getLastContent() const { return Contents.back().get(); }
738   typedef decltype(Contents)::iterator iterator;
contents_begin()739   iterator contents_begin() { return Contents.begin(); }
contents_end()740   iterator contents_end() { return Contents.end(); }
classof(const Entry * E)741   static bool classof(const Entry *E) { return E->getKind() == EK_Directory; }
742 };
743 
744 class RedirectingFileEntry : public Entry {
745 public:
746   enum NameKind {
747     NK_NotSet,
748     NK_External,
749     NK_Virtual
750   };
751 private:
752   std::string ExternalContentsPath;
753   NameKind UseName;
754 public:
RedirectingFileEntry(StringRef Name,StringRef ExternalContentsPath,NameKind UseName)755   RedirectingFileEntry(StringRef Name, StringRef ExternalContentsPath,
756                        NameKind UseName)
757       : Entry(EK_File, Name), ExternalContentsPath(ExternalContentsPath),
758         UseName(UseName) {}
getExternalContentsPath() const759   StringRef getExternalContentsPath() const { return ExternalContentsPath; }
760   /// \brief whether to use the external path as the name for this file.
useExternalName(bool GlobalUseExternalName) const761   bool useExternalName(bool GlobalUseExternalName) const {
762     return UseName == NK_NotSet ? GlobalUseExternalName
763                                 : (UseName == NK_External);
764   }
getUseName() const765   NameKind getUseName() const { return UseName; }
classof(const Entry * E)766   static bool classof(const Entry *E) { return E->getKind() == EK_File; }
767 };
768 
769 class RedirectingFileSystem;
770 
771 class VFSFromYamlDirIterImpl : public clang::vfs::detail::DirIterImpl {
772   std::string Dir;
773   RedirectingFileSystem &FS;
774   RedirectingDirectoryEntry::iterator Current, End;
775 
776 public:
777   VFSFromYamlDirIterImpl(const Twine &Path, RedirectingFileSystem &FS,
778                          RedirectingDirectoryEntry::iterator Begin,
779                          RedirectingDirectoryEntry::iterator End,
780                          std::error_code &EC);
781   std::error_code increment() override;
782 };
783 
784 /// \brief A virtual file system parsed from a YAML file.
785 ///
786 /// Currently, this class allows creating virtual directories and mapping
787 /// virtual file paths to existing external files, available in \c ExternalFS.
788 ///
789 /// The basic structure of the parsed file is:
790 /// \verbatim
791 /// {
792 ///   'version': <version number>,
793 ///   <optional configuration>
794 ///   'roots': [
795 ///              <directory entries>
796 ///            ]
797 /// }
798 /// \endverbatim
799 ///
800 /// All configuration options are optional.
801 ///   'case-sensitive': <boolean, default=true>
802 ///   'use-external-names': <boolean, default=true>
803 ///   'overlay-relative': <boolean, default=false>
804 ///
805 /// Virtual directories are represented as
806 /// \verbatim
807 /// {
808 ///   'type': 'directory',
809 ///   'name': <string>,
810 ///   'contents': [ <file or directory entries> ]
811 /// }
812 /// \endverbatim
813 ///
814 /// The default attributes for virtual directories are:
815 /// \verbatim
816 /// MTime = now() when created
817 /// Perms = 0777
818 /// User = Group = 0
819 /// Size = 0
820 /// UniqueID = unspecified unique value
821 /// \endverbatim
822 ///
823 /// Re-mapped files are represented as
824 /// \verbatim
825 /// {
826 ///   'type': 'file',
827 ///   'name': <string>,
828 ///   'use-external-name': <boolean> # Optional
829 ///   'external-contents': <path to external file>)
830 /// }
831 /// \endverbatim
832 ///
833 /// and inherit their attributes from the external contents.
834 ///
835 /// In both cases, the 'name' field may contain multiple path components (e.g.
836 /// /path/to/file). However, any directory that contains more than one child
837 /// must be uniquely represented by a directory entry.
838 class RedirectingFileSystem : public vfs::FileSystem {
839   /// The root(s) of the virtual file system.
840   std::vector<std::unique_ptr<Entry>> Roots;
841   /// \brief The file system to use for external references.
842   IntrusiveRefCntPtr<FileSystem> ExternalFS;
843   /// If IsRelativeOverlay is set, this represents the directory
844   /// path that should be prefixed to each 'external-contents' entry
845   /// when reading from YAML files.
846   std::string ExternalContentsPrefixDir;
847 
848   /// @name Configuration
849   /// @{
850 
851   /// \brief Whether to perform case-sensitive comparisons.
852   ///
853   /// Currently, case-insensitive matching only works correctly with ASCII.
854   bool CaseSensitive = true;
855 
856   /// IsRelativeOverlay marks whether a IsExternalContentsPrefixDir path must
857   /// be prefixed in every 'external-contents' when reading from YAML files.
858   bool IsRelativeOverlay = false;
859 
860   /// \brief Whether to use to use the value of 'external-contents' for the
861   /// names of files.  This global value is overridable on a per-file basis.
862   bool UseExternalNames = true;
863   /// @}
864 
865   /// Virtual file paths and external files could be canonicalized without "..",
866   /// "." and "./" in their paths. FIXME: some unittests currently fail on
867   /// win32 when using remove_dots and remove_leading_dotslash on paths.
868   bool UseCanonicalizedPaths =
869 #ifdef LLVM_ON_WIN32
870       false;
871 #else
872       true;
873 #endif
874 
875   friend class RedirectingFileSystemParser;
876 
877 private:
RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> ExternalFS)878   RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> ExternalFS)
879       : ExternalFS(std::move(ExternalFS)) {}
880 
881   /// \brief Looks up \p Path in \c Roots.
882   ErrorOr<Entry *> lookupPath(const Twine &Path);
883 
884   /// \brief Looks up the path <tt>[Start, End)</tt> in \p From, possibly
885   /// recursing into the contents of \p From if it is a directory.
886   ErrorOr<Entry *> lookupPath(sys::path::const_iterator Start,
887                               sys::path::const_iterator End, Entry *From);
888 
889   /// \brief Get the status of a given an \c Entry.
890   ErrorOr<Status> status(const Twine &Path, Entry *E);
891 
892 public:
893   /// \brief Parses \p Buffer, which is expected to be in YAML format and
894   /// returns a virtual file system representing its contents.
895   static RedirectingFileSystem *
896   create(std::unique_ptr<MemoryBuffer> Buffer,
897          SourceMgr::DiagHandlerTy DiagHandler, StringRef YAMLFilePath,
898          void *DiagContext, IntrusiveRefCntPtr<FileSystem> ExternalFS);
899 
900   ErrorOr<Status> status(const Twine &Path) override;
901   ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override;
902 
getCurrentWorkingDirectory() const903   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
904     return ExternalFS->getCurrentWorkingDirectory();
905   }
setCurrentWorkingDirectory(const Twine & Path)906   std::error_code setCurrentWorkingDirectory(const Twine &Path) override {
907     return ExternalFS->setCurrentWorkingDirectory(Path);
908   }
909 
dir_begin(const Twine & Dir,std::error_code & EC)910   directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override{
911     ErrorOr<Entry *> E = lookupPath(Dir);
912     if (!E) {
913       EC = E.getError();
914       return directory_iterator();
915     }
916     ErrorOr<Status> S = status(Dir, *E);
917     if (!S) {
918       EC = S.getError();
919       return directory_iterator();
920     }
921     if (!S->isDirectory()) {
922       EC = std::error_code(static_cast<int>(errc::not_a_directory),
923                            std::system_category());
924       return directory_iterator();
925     }
926 
927     auto *D = cast<RedirectingDirectoryEntry>(*E);
928     return directory_iterator(std::make_shared<VFSFromYamlDirIterImpl>(Dir,
929         *this, D->contents_begin(), D->contents_end(), EC));
930   }
931 
setExternalContentsPrefixDir(StringRef PrefixDir)932   void setExternalContentsPrefixDir(StringRef PrefixDir) {
933     ExternalContentsPrefixDir = PrefixDir.str();
934   }
935 
getExternalContentsPrefixDir() const936   StringRef getExternalContentsPrefixDir() const {
937     return ExternalContentsPrefixDir;
938   }
939 
940 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const941 LLVM_DUMP_METHOD void dump() const {
942     for (const std::unique_ptr<Entry> &Root : Roots)
943       dumpEntry(Root.get());
944   }
945 
dumpEntry(Entry * E,int NumSpaces=0) const946 LLVM_DUMP_METHOD void dumpEntry(Entry *E, int NumSpaces = 0) const {
947     StringRef Name = E->getName();
948     for (int i = 0, e = NumSpaces; i < e; ++i)
949       dbgs() << " ";
950     dbgs() << "'" << Name.str().c_str() << "'" << "\n";
951 
952     if (E->getKind() == EK_Directory) {
953       auto *DE = dyn_cast<RedirectingDirectoryEntry>(E);
954       assert(DE && "Should be a directory");
955 
956       for (std::unique_ptr<Entry> &SubEntry :
957            llvm::make_range(DE->contents_begin(), DE->contents_end()))
958         dumpEntry(SubEntry.get(), NumSpaces+2);
959     }
960   }
961 #endif
962 
963 };
964 
965 /// \brief A helper class to hold the common YAML parsing state.
966 class RedirectingFileSystemParser {
967   yaml::Stream &Stream;
968 
error(yaml::Node * N,const Twine & Msg)969   void error(yaml::Node *N, const Twine &Msg) {
970     Stream.printError(N, Msg);
971   }
972 
973   // false on error
parseScalarString(yaml::Node * N,StringRef & Result,SmallVectorImpl<char> & Storage)974   bool parseScalarString(yaml::Node *N, StringRef &Result,
975                          SmallVectorImpl<char> &Storage) {
976     yaml::ScalarNode *S = dyn_cast<yaml::ScalarNode>(N);
977     if (!S) {
978       error(N, "expected string");
979       return false;
980     }
981     Result = S->getValue(Storage);
982     return true;
983   }
984 
985   // false on error
parseScalarBool(yaml::Node * N,bool & Result)986   bool parseScalarBool(yaml::Node *N, bool &Result) {
987     SmallString<5> Storage;
988     StringRef Value;
989     if (!parseScalarString(N, Value, Storage))
990       return false;
991 
992     if (Value.equals_lower("true") || Value.equals_lower("on") ||
993         Value.equals_lower("yes") || Value == "1") {
994       Result = true;
995       return true;
996     } else if (Value.equals_lower("false") || Value.equals_lower("off") ||
997                Value.equals_lower("no") || Value == "0") {
998       Result = false;
999       return true;
1000     }
1001 
1002     error(N, "expected boolean value");
1003     return false;
1004   }
1005 
1006   struct KeyStatus {
KeyStatus__anond43ed3180711::RedirectingFileSystemParser::KeyStatus1007     KeyStatus(bool Required=false) : Required(Required), Seen(false) {}
1008     bool Required;
1009     bool Seen;
1010   };
1011   typedef std::pair<StringRef, KeyStatus> KeyStatusPair;
1012 
1013   // false on error
checkDuplicateOrUnknownKey(yaml::Node * KeyNode,StringRef Key,DenseMap<StringRef,KeyStatus> & Keys)1014   bool checkDuplicateOrUnknownKey(yaml::Node *KeyNode, StringRef Key,
1015                                   DenseMap<StringRef, KeyStatus> &Keys) {
1016     if (!Keys.count(Key)) {
1017       error(KeyNode, "unknown key");
1018       return false;
1019     }
1020     KeyStatus &S = Keys[Key];
1021     if (S.Seen) {
1022       error(KeyNode, Twine("duplicate key '") + Key + "'");
1023       return false;
1024     }
1025     S.Seen = true;
1026     return true;
1027   }
1028 
1029   // false on error
checkMissingKeys(yaml::Node * Obj,DenseMap<StringRef,KeyStatus> & Keys)1030   bool checkMissingKeys(yaml::Node *Obj, DenseMap<StringRef, KeyStatus> &Keys) {
1031     for (DenseMap<StringRef, KeyStatus>::iterator I = Keys.begin(),
1032          E = Keys.end();
1033          I != E; ++I) {
1034       if (I->second.Required && !I->second.Seen) {
1035         error(Obj, Twine("missing key '") + I->first + "'");
1036         return false;
1037       }
1038     }
1039     return true;
1040   }
1041 
lookupOrCreateEntry(RedirectingFileSystem * FS,StringRef Name,Entry * ParentEntry=nullptr)1042   Entry *lookupOrCreateEntry(RedirectingFileSystem *FS, StringRef Name,
1043                              Entry *ParentEntry = nullptr) {
1044     if (!ParentEntry) { // Look for a existent root
1045       for (const std::unique_ptr<Entry> &Root : FS->Roots) {
1046         if (Name.equals(Root->getName())) {
1047           ParentEntry = Root.get();
1048           return ParentEntry;
1049         }
1050       }
1051     } else { // Advance to the next component
1052       auto *DE = dyn_cast<RedirectingDirectoryEntry>(ParentEntry);
1053       for (std::unique_ptr<Entry> &Content :
1054            llvm::make_range(DE->contents_begin(), DE->contents_end())) {
1055         auto *DirContent = dyn_cast<RedirectingDirectoryEntry>(Content.get());
1056         if (DirContent && Name.equals(Content->getName()))
1057           return DirContent;
1058       }
1059     }
1060 
1061     // ... or create a new one
1062     std::unique_ptr<Entry> E = llvm::make_unique<RedirectingDirectoryEntry>(
1063         Name, Status("", getNextVirtualUniqueID(), sys::TimeValue::now(), 0, 0,
1064                      0, file_type::directory_file, sys::fs::all_all));
1065 
1066     if (!ParentEntry) { // Add a new root to the overlay
1067       FS->Roots.push_back(std::move(E));
1068       ParentEntry = FS->Roots.back().get();
1069       return ParentEntry;
1070     }
1071 
1072     auto *DE = dyn_cast<RedirectingDirectoryEntry>(ParentEntry);
1073     DE->addContent(std::move(E));
1074     return DE->getLastContent();
1075   }
1076 
uniqueOverlayTree(RedirectingFileSystem * FS,Entry * SrcE,Entry * NewParentE=nullptr)1077   void uniqueOverlayTree(RedirectingFileSystem *FS, Entry *SrcE,
1078                          Entry *NewParentE = nullptr) {
1079     StringRef Name = SrcE->getName();
1080     switch (SrcE->getKind()) {
1081     case EK_Directory: {
1082       auto *DE = dyn_cast<RedirectingDirectoryEntry>(SrcE);
1083       assert(DE && "Must be a directory");
1084       // Empty directories could be present in the YAML as a way to
1085       // describe a file for a current directory after some of its subdir
1086       // is parsed. This only leads to redundant walks, ignore it.
1087       if (!Name.empty())
1088         NewParentE = lookupOrCreateEntry(FS, Name, NewParentE);
1089       for (std::unique_ptr<Entry> &SubEntry :
1090            llvm::make_range(DE->contents_begin(), DE->contents_end()))
1091         uniqueOverlayTree(FS, SubEntry.get(), NewParentE);
1092       break;
1093     }
1094     case EK_File: {
1095       auto *FE = dyn_cast<RedirectingFileEntry>(SrcE);
1096       assert(FE && "Must be a file");
1097       assert(NewParentE && "Parent entry must exist");
1098       auto *DE = dyn_cast<RedirectingDirectoryEntry>(NewParentE);
1099       DE->addContent(llvm::make_unique<RedirectingFileEntry>(
1100           Name, FE->getExternalContentsPath(), FE->getUseName()));
1101       break;
1102     }
1103     }
1104   }
1105 
parseEntry(yaml::Node * N,RedirectingFileSystem * FS)1106   std::unique_ptr<Entry> parseEntry(yaml::Node *N, RedirectingFileSystem *FS) {
1107     yaml::MappingNode *M = dyn_cast<yaml::MappingNode>(N);
1108     if (!M) {
1109       error(N, "expected mapping node for file or directory entry");
1110       return nullptr;
1111     }
1112 
1113     KeyStatusPair Fields[] = {
1114       KeyStatusPair("name", true),
1115       KeyStatusPair("type", true),
1116       KeyStatusPair("contents", false),
1117       KeyStatusPair("external-contents", false),
1118       KeyStatusPair("use-external-name", false),
1119     };
1120 
1121     DenseMap<StringRef, KeyStatus> Keys(std::begin(Fields), std::end(Fields));
1122 
1123     bool HasContents = false; // external or otherwise
1124     std::vector<std::unique_ptr<Entry>> EntryArrayContents;
1125     std::string ExternalContentsPath;
1126     std::string Name;
1127     auto UseExternalName = RedirectingFileEntry::NK_NotSet;
1128     EntryKind Kind;
1129 
1130     for (yaml::MappingNode::iterator I = M->begin(), E = M->end(); I != E;
1131          ++I) {
1132       StringRef Key;
1133       // Reuse the buffer for key and value, since we don't look at key after
1134       // parsing value.
1135       SmallString<256> Buffer;
1136       if (!parseScalarString(I->getKey(), Key, Buffer))
1137         return nullptr;
1138 
1139       if (!checkDuplicateOrUnknownKey(I->getKey(), Key, Keys))
1140         return nullptr;
1141 
1142       StringRef Value;
1143       if (Key == "name") {
1144         if (!parseScalarString(I->getValue(), Value, Buffer))
1145           return nullptr;
1146 
1147         if (FS->UseCanonicalizedPaths) {
1148           SmallString<256> Path(Value);
1149           // Guarantee that old YAML files containing paths with ".." and "."
1150           // are properly canonicalized before read into the VFS.
1151           Path = sys::path::remove_leading_dotslash(Path);
1152           sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
1153           Name = Path.str();
1154         } else {
1155           Name = Value;
1156         }
1157       } else if (Key == "type") {
1158         if (!parseScalarString(I->getValue(), Value, Buffer))
1159           return nullptr;
1160         if (Value == "file")
1161           Kind = EK_File;
1162         else if (Value == "directory")
1163           Kind = EK_Directory;
1164         else {
1165           error(I->getValue(), "unknown value for 'type'");
1166           return nullptr;
1167         }
1168       } else if (Key == "contents") {
1169         if (HasContents) {
1170           error(I->getKey(),
1171                 "entry already has 'contents' or 'external-contents'");
1172           return nullptr;
1173         }
1174         HasContents = true;
1175         yaml::SequenceNode *Contents =
1176             dyn_cast<yaml::SequenceNode>(I->getValue());
1177         if (!Contents) {
1178           // FIXME: this is only for directories, what about files?
1179           error(I->getValue(), "expected array");
1180           return nullptr;
1181         }
1182 
1183         for (yaml::SequenceNode::iterator I = Contents->begin(),
1184                                           E = Contents->end();
1185              I != E; ++I) {
1186           if (std::unique_ptr<Entry> E = parseEntry(&*I, FS))
1187             EntryArrayContents.push_back(std::move(E));
1188           else
1189             return nullptr;
1190         }
1191       } else if (Key == "external-contents") {
1192         if (HasContents) {
1193           error(I->getKey(),
1194                 "entry already has 'contents' or 'external-contents'");
1195           return nullptr;
1196         }
1197         HasContents = true;
1198         if (!parseScalarString(I->getValue(), Value, Buffer))
1199           return nullptr;
1200 
1201         SmallString<256> FullPath;
1202         if (FS->IsRelativeOverlay) {
1203           FullPath = FS->getExternalContentsPrefixDir();
1204           assert(!FullPath.empty() &&
1205                  "External contents prefix directory must exist");
1206           llvm::sys::path::append(FullPath, Value);
1207         } else {
1208           FullPath = Value;
1209         }
1210 
1211         if (FS->UseCanonicalizedPaths) {
1212           // Guarantee that old YAML files containing paths with ".." and "."
1213           // are properly canonicalized before read into the VFS.
1214           FullPath = sys::path::remove_leading_dotslash(FullPath);
1215           sys::path::remove_dots(FullPath, /*remove_dot_dot=*/true);
1216         }
1217         ExternalContentsPath = FullPath.str();
1218       } else if (Key == "use-external-name") {
1219         bool Val;
1220         if (!parseScalarBool(I->getValue(), Val))
1221           return nullptr;
1222         UseExternalName = Val ? RedirectingFileEntry::NK_External
1223                               : RedirectingFileEntry::NK_Virtual;
1224       } else {
1225         llvm_unreachable("key missing from Keys");
1226       }
1227     }
1228 
1229     if (Stream.failed())
1230       return nullptr;
1231 
1232     // check for missing keys
1233     if (!HasContents) {
1234       error(N, "missing key 'contents' or 'external-contents'");
1235       return nullptr;
1236     }
1237     if (!checkMissingKeys(N, Keys))
1238       return nullptr;
1239 
1240     // check invalid configuration
1241     if (Kind == EK_Directory &&
1242         UseExternalName != RedirectingFileEntry::NK_NotSet) {
1243       error(N, "'use-external-name' is not supported for directories");
1244       return nullptr;
1245     }
1246 
1247     // Remove trailing slash(es), being careful not to remove the root path
1248     StringRef Trimmed(Name);
1249     size_t RootPathLen = sys::path::root_path(Trimmed).size();
1250     while (Trimmed.size() > RootPathLen &&
1251            sys::path::is_separator(Trimmed.back()))
1252       Trimmed = Trimmed.slice(0, Trimmed.size()-1);
1253     // Get the last component
1254     StringRef LastComponent = sys::path::filename(Trimmed);
1255 
1256     std::unique_ptr<Entry> Result;
1257     switch (Kind) {
1258     case EK_File:
1259       Result = llvm::make_unique<RedirectingFileEntry>(
1260           LastComponent, std::move(ExternalContentsPath), UseExternalName);
1261       break;
1262     case EK_Directory:
1263       Result = llvm::make_unique<RedirectingDirectoryEntry>(
1264           LastComponent, std::move(EntryArrayContents),
1265           Status("", getNextVirtualUniqueID(), sys::TimeValue::now(), 0, 0, 0,
1266                  file_type::directory_file, sys::fs::all_all));
1267       break;
1268     }
1269 
1270     StringRef Parent = sys::path::parent_path(Trimmed);
1271     if (Parent.empty())
1272       return Result;
1273 
1274     // if 'name' contains multiple components, create implicit directory entries
1275     for (sys::path::reverse_iterator I = sys::path::rbegin(Parent),
1276                                      E = sys::path::rend(Parent);
1277          I != E; ++I) {
1278       std::vector<std::unique_ptr<Entry>> Entries;
1279       Entries.push_back(std::move(Result));
1280       Result = llvm::make_unique<RedirectingDirectoryEntry>(
1281           *I, std::move(Entries),
1282           Status("", getNextVirtualUniqueID(), sys::TimeValue::now(), 0, 0, 0,
1283                  file_type::directory_file, sys::fs::all_all));
1284     }
1285     return Result;
1286   }
1287 
1288 public:
RedirectingFileSystemParser(yaml::Stream & S)1289   RedirectingFileSystemParser(yaml::Stream &S) : Stream(S) {}
1290 
1291   // false on error
parse(yaml::Node * Root,RedirectingFileSystem * FS)1292   bool parse(yaml::Node *Root, RedirectingFileSystem *FS) {
1293     yaml::MappingNode *Top = dyn_cast<yaml::MappingNode>(Root);
1294     if (!Top) {
1295       error(Root, "expected mapping node");
1296       return false;
1297     }
1298 
1299     KeyStatusPair Fields[] = {
1300       KeyStatusPair("version", true),
1301       KeyStatusPair("case-sensitive", false),
1302       KeyStatusPair("use-external-names", false),
1303       KeyStatusPair("overlay-relative", false),
1304       KeyStatusPair("roots", true),
1305     };
1306 
1307     DenseMap<StringRef, KeyStatus> Keys(std::begin(Fields), std::end(Fields));
1308     std::vector<std::unique_ptr<Entry>> RootEntries;
1309 
1310     // Parse configuration and 'roots'
1311     for (yaml::MappingNode::iterator I = Top->begin(), E = Top->end(); I != E;
1312          ++I) {
1313       SmallString<10> KeyBuffer;
1314       StringRef Key;
1315       if (!parseScalarString(I->getKey(), Key, KeyBuffer))
1316         return false;
1317 
1318       if (!checkDuplicateOrUnknownKey(I->getKey(), Key, Keys))
1319         return false;
1320 
1321       if (Key == "roots") {
1322         yaml::SequenceNode *Roots = dyn_cast<yaml::SequenceNode>(I->getValue());
1323         if (!Roots) {
1324           error(I->getValue(), "expected array");
1325           return false;
1326         }
1327 
1328         for (yaml::SequenceNode::iterator I = Roots->begin(), E = Roots->end();
1329              I != E; ++I) {
1330           if (std::unique_ptr<Entry> E = parseEntry(&*I, FS))
1331             RootEntries.push_back(std::move(E));
1332           else
1333             return false;
1334         }
1335       } else if (Key == "version") {
1336         StringRef VersionString;
1337         SmallString<4> Storage;
1338         if (!parseScalarString(I->getValue(), VersionString, Storage))
1339           return false;
1340         int Version;
1341         if (VersionString.getAsInteger<int>(10, Version)) {
1342           error(I->getValue(), "expected integer");
1343           return false;
1344         }
1345         if (Version < 0) {
1346           error(I->getValue(), "invalid version number");
1347           return false;
1348         }
1349         if (Version != 0) {
1350           error(I->getValue(), "version mismatch, expected 0");
1351           return false;
1352         }
1353       } else if (Key == "case-sensitive") {
1354         if (!parseScalarBool(I->getValue(), FS->CaseSensitive))
1355           return false;
1356       } else if (Key == "overlay-relative") {
1357         if (!parseScalarBool(I->getValue(), FS->IsRelativeOverlay))
1358           return false;
1359       } else if (Key == "use-external-names") {
1360         if (!parseScalarBool(I->getValue(), FS->UseExternalNames))
1361           return false;
1362       } else {
1363         llvm_unreachable("key missing from Keys");
1364       }
1365     }
1366 
1367     if (Stream.failed())
1368       return false;
1369 
1370     if (!checkMissingKeys(Top, Keys))
1371       return false;
1372 
1373     // Now that we sucessefully parsed the YAML file, canonicalize the internal
1374     // representation to a proper directory tree so that we can search faster
1375     // inside the VFS.
1376     for (std::unique_ptr<Entry> &E : RootEntries)
1377       uniqueOverlayTree(FS, E.get());
1378 
1379     return true;
1380   }
1381 };
1382 } // end of anonymous namespace
1383 
1384 Entry::~Entry() = default;
1385 
1386 RedirectingFileSystem *
create(std::unique_ptr<MemoryBuffer> Buffer,SourceMgr::DiagHandlerTy DiagHandler,StringRef YAMLFilePath,void * DiagContext,IntrusiveRefCntPtr<FileSystem> ExternalFS)1387 RedirectingFileSystem::create(std::unique_ptr<MemoryBuffer> Buffer,
1388                               SourceMgr::DiagHandlerTy DiagHandler,
1389                               StringRef YAMLFilePath, void *DiagContext,
1390                               IntrusiveRefCntPtr<FileSystem> ExternalFS) {
1391 
1392   SourceMgr SM;
1393   yaml::Stream Stream(Buffer->getMemBufferRef(), SM);
1394 
1395   SM.setDiagHandler(DiagHandler, DiagContext);
1396   yaml::document_iterator DI = Stream.begin();
1397   yaml::Node *Root = DI->getRoot();
1398   if (DI == Stream.end() || !Root) {
1399     SM.PrintMessage(SMLoc(), SourceMgr::DK_Error, "expected root node");
1400     return nullptr;
1401   }
1402 
1403   RedirectingFileSystemParser P(Stream);
1404 
1405   std::unique_ptr<RedirectingFileSystem> FS(
1406       new RedirectingFileSystem(std::move(ExternalFS)));
1407 
1408   if (!YAMLFilePath.empty()) {
1409     // Use the YAML path from -ivfsoverlay to compute the dir to be prefixed
1410     // to each 'external-contents' path.
1411     //
1412     // Example:
1413     //    -ivfsoverlay dummy.cache/vfs/vfs.yaml
1414     // yields:
1415     //  FS->ExternalContentsPrefixDir => /<absolute_path_to>/dummy.cache/vfs
1416     //
1417     SmallString<256> OverlayAbsDir = sys::path::parent_path(YAMLFilePath);
1418     std::error_code EC = llvm::sys::fs::make_absolute(OverlayAbsDir);
1419     assert(!EC && "Overlay dir final path must be absolute");
1420     (void)EC;
1421     FS->setExternalContentsPrefixDir(OverlayAbsDir);
1422   }
1423 
1424   if (!P.parse(Root, FS.get()))
1425     return nullptr;
1426 
1427   return FS.release();
1428 }
1429 
lookupPath(const Twine & Path_)1430 ErrorOr<Entry *> RedirectingFileSystem::lookupPath(const Twine &Path_) {
1431   SmallString<256> Path;
1432   Path_.toVector(Path);
1433 
1434   // Handle relative paths
1435   if (std::error_code EC = makeAbsolute(Path))
1436     return EC;
1437 
1438   // Canonicalize path by removing ".", "..", "./", etc components. This is
1439   // a VFS request, do bot bother about symlinks in the path components
1440   // but canonicalize in order to perform the correct entry search.
1441   if (UseCanonicalizedPaths) {
1442     Path = sys::path::remove_leading_dotslash(Path);
1443     sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
1444   }
1445 
1446   if (Path.empty())
1447     return make_error_code(llvm::errc::invalid_argument);
1448 
1449   sys::path::const_iterator Start = sys::path::begin(Path);
1450   sys::path::const_iterator End = sys::path::end(Path);
1451   for (const std::unique_ptr<Entry> &Root : Roots) {
1452     ErrorOr<Entry *> Result = lookupPath(Start, End, Root.get());
1453     if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
1454       return Result;
1455   }
1456   return make_error_code(llvm::errc::no_such_file_or_directory);
1457 }
1458 
1459 ErrorOr<Entry *>
lookupPath(sys::path::const_iterator Start,sys::path::const_iterator End,Entry * From)1460 RedirectingFileSystem::lookupPath(sys::path::const_iterator Start,
1461                                   sys::path::const_iterator End, Entry *From) {
1462 #ifndef LLVM_ON_WIN32
1463   assert(!isTraversalComponent(*Start) &&
1464          !isTraversalComponent(From->getName()) &&
1465          "Paths should not contain traversal components");
1466 #else
1467   // FIXME: this is here to support windows, remove it once canonicalized
1468   // paths become globally default.
1469   if (Start->equals("."))
1470     ++Start;
1471 #endif
1472 
1473   StringRef FromName = From->getName();
1474 
1475   // Forward the search to the next component in case this is an empty one.
1476   if (!FromName.empty()) {
1477     if (CaseSensitive ? !Start->equals(FromName)
1478                       : !Start->equals_lower(FromName))
1479       // failure to match
1480       return make_error_code(llvm::errc::no_such_file_or_directory);
1481 
1482     ++Start;
1483 
1484     if (Start == End) {
1485       // Match!
1486       return From;
1487     }
1488   }
1489 
1490   auto *DE = dyn_cast<RedirectingDirectoryEntry>(From);
1491   if (!DE)
1492     return make_error_code(llvm::errc::not_a_directory);
1493 
1494   for (const std::unique_ptr<Entry> &DirEntry :
1495        llvm::make_range(DE->contents_begin(), DE->contents_end())) {
1496     ErrorOr<Entry *> Result = lookupPath(Start, End, DirEntry.get());
1497     if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
1498       return Result;
1499   }
1500   return make_error_code(llvm::errc::no_such_file_or_directory);
1501 }
1502 
getRedirectedFileStatus(const Twine & Path,bool UseExternalNames,Status ExternalStatus)1503 static Status getRedirectedFileStatus(const Twine &Path, bool UseExternalNames,
1504                                       Status ExternalStatus) {
1505   Status S = ExternalStatus;
1506   if (!UseExternalNames)
1507     S = Status::copyWithNewName(S, Path.str());
1508   S.IsVFSMapped = true;
1509   return S;
1510 }
1511 
status(const Twine & Path,Entry * E)1512 ErrorOr<Status> RedirectingFileSystem::status(const Twine &Path, Entry *E) {
1513   assert(E != nullptr);
1514   if (auto *F = dyn_cast<RedirectingFileEntry>(E)) {
1515     ErrorOr<Status> S = ExternalFS->status(F->getExternalContentsPath());
1516     assert(!S || S->getName() == F->getExternalContentsPath());
1517     if (S)
1518       return getRedirectedFileStatus(Path, F->useExternalName(UseExternalNames),
1519                                      *S);
1520     return S;
1521   } else { // directory
1522     auto *DE = cast<RedirectingDirectoryEntry>(E);
1523     return Status::copyWithNewName(DE->getStatus(), Path.str());
1524   }
1525 }
1526 
status(const Twine & Path)1527 ErrorOr<Status> RedirectingFileSystem::status(const Twine &Path) {
1528   ErrorOr<Entry *> Result = lookupPath(Path);
1529   if (!Result)
1530     return Result.getError();
1531   return status(Path, *Result);
1532 }
1533 
1534 namespace {
1535 /// Provide a file wrapper with an overriden status.
1536 class FileWithFixedStatus : public File {
1537   std::unique_ptr<File> InnerFile;
1538   Status S;
1539 
1540 public:
FileWithFixedStatus(std::unique_ptr<File> InnerFile,Status S)1541   FileWithFixedStatus(std::unique_ptr<File> InnerFile, Status S)
1542       : InnerFile(std::move(InnerFile)), S(std::move(S)) {}
1543 
status()1544   ErrorOr<Status> status() override { return S; }
1545   ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBuffer(const Twine & Name,int64_t FileSize,bool RequiresNullTerminator,bool IsVolatile)1546   getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
1547             bool IsVolatile) override {
1548     return InnerFile->getBuffer(Name, FileSize, RequiresNullTerminator,
1549                                 IsVolatile);
1550   }
close()1551   std::error_code close() override { return InnerFile->close(); }
1552 };
1553 } // end anonymous namespace
1554 
1555 ErrorOr<std::unique_ptr<File>>
openFileForRead(const Twine & Path)1556 RedirectingFileSystem::openFileForRead(const Twine &Path) {
1557   ErrorOr<Entry *> E = lookupPath(Path);
1558   if (!E)
1559     return E.getError();
1560 
1561   auto *F = dyn_cast<RedirectingFileEntry>(*E);
1562   if (!F) // FIXME: errc::not_a_file?
1563     return make_error_code(llvm::errc::invalid_argument);
1564 
1565   auto Result = ExternalFS->openFileForRead(F->getExternalContentsPath());
1566   if (!Result)
1567     return Result;
1568 
1569   auto ExternalStatus = (*Result)->status();
1570   if (!ExternalStatus)
1571     return ExternalStatus.getError();
1572 
1573   // FIXME: Update the status with the name and VFSMapped.
1574   Status S = getRedirectedFileStatus(Path, F->useExternalName(UseExternalNames),
1575                                      *ExternalStatus);
1576   return std::unique_ptr<File>(
1577       llvm::make_unique<FileWithFixedStatus>(std::move(*Result), S));
1578 }
1579 
1580 IntrusiveRefCntPtr<FileSystem>
getVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,SourceMgr::DiagHandlerTy DiagHandler,StringRef YAMLFilePath,void * DiagContext,IntrusiveRefCntPtr<FileSystem> ExternalFS)1581 vfs::getVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,
1582                     SourceMgr::DiagHandlerTy DiagHandler,
1583                     StringRef YAMLFilePath,
1584                     void *DiagContext,
1585                     IntrusiveRefCntPtr<FileSystem> ExternalFS) {
1586   return RedirectingFileSystem::create(std::move(Buffer), DiagHandler,
1587                                        YAMLFilePath, DiagContext,
1588                                        std::move(ExternalFS));
1589 }
1590 
getNextVirtualUniqueID()1591 UniqueID vfs::getNextVirtualUniqueID() {
1592   static std::atomic<unsigned> UID;
1593   unsigned ID = ++UID;
1594   // The following assumes that uint64_t max will never collide with a real
1595   // dev_t value from the OS.
1596   return UniqueID(std::numeric_limits<uint64_t>::max(), ID);
1597 }
1598 
addFileMapping(StringRef VirtualPath,StringRef RealPath)1599 void YAMLVFSWriter::addFileMapping(StringRef VirtualPath, StringRef RealPath) {
1600   assert(sys::path::is_absolute(VirtualPath) && "virtual path not absolute");
1601   assert(sys::path::is_absolute(RealPath) && "real path not absolute");
1602   assert(!pathHasTraversal(VirtualPath) && "path traversal is not supported");
1603   Mappings.emplace_back(VirtualPath, RealPath);
1604 }
1605 
1606 namespace {
1607 class JSONWriter {
1608   llvm::raw_ostream &OS;
1609   SmallVector<StringRef, 16> DirStack;
getDirIndent()1610   inline unsigned getDirIndent() { return 4 * DirStack.size(); }
getFileIndent()1611   inline unsigned getFileIndent() { return 4 * (DirStack.size() + 1); }
1612   bool containedIn(StringRef Parent, StringRef Path);
1613   StringRef containedPart(StringRef Parent, StringRef Path);
1614   void startDirectory(StringRef Path);
1615   void endDirectory();
1616   void writeEntry(StringRef VPath, StringRef RPath);
1617 
1618 public:
JSONWriter(llvm::raw_ostream & OS)1619   JSONWriter(llvm::raw_ostream &OS) : OS(OS) {}
1620   void write(ArrayRef<YAMLVFSEntry> Entries, Optional<bool> UseExternalNames,
1621              Optional<bool> IsCaseSensitive, Optional<bool> IsOverlayRelative,
1622              StringRef OverlayDir);
1623 };
1624 }
1625 
containedIn(StringRef Parent,StringRef Path)1626 bool JSONWriter::containedIn(StringRef Parent, StringRef Path) {
1627   using namespace llvm::sys;
1628   // Compare each path component.
1629   auto IParent = path::begin(Parent), EParent = path::end(Parent);
1630   for (auto IChild = path::begin(Path), EChild = path::end(Path);
1631        IParent != EParent && IChild != EChild; ++IParent, ++IChild) {
1632     if (*IParent != *IChild)
1633       return false;
1634   }
1635   // Have we exhausted the parent path?
1636   return IParent == EParent;
1637 }
1638 
containedPart(StringRef Parent,StringRef Path)1639 StringRef JSONWriter::containedPart(StringRef Parent, StringRef Path) {
1640   assert(!Parent.empty());
1641   assert(containedIn(Parent, Path));
1642   return Path.slice(Parent.size() + 1, StringRef::npos);
1643 }
1644 
startDirectory(StringRef Path)1645 void JSONWriter::startDirectory(StringRef Path) {
1646   StringRef Name =
1647       DirStack.empty() ? Path : containedPart(DirStack.back(), Path);
1648   DirStack.push_back(Path);
1649   unsigned Indent = getDirIndent();
1650   OS.indent(Indent) << "{\n";
1651   OS.indent(Indent + 2) << "'type': 'directory',\n";
1652   OS.indent(Indent + 2) << "'name': \"" << llvm::yaml::escape(Name) << "\",\n";
1653   OS.indent(Indent + 2) << "'contents': [\n";
1654 }
1655 
endDirectory()1656 void JSONWriter::endDirectory() {
1657   unsigned Indent = getDirIndent();
1658   OS.indent(Indent + 2) << "]\n";
1659   OS.indent(Indent) << "}";
1660 
1661   DirStack.pop_back();
1662 }
1663 
writeEntry(StringRef VPath,StringRef RPath)1664 void JSONWriter::writeEntry(StringRef VPath, StringRef RPath) {
1665   unsigned Indent = getFileIndent();
1666   OS.indent(Indent) << "{\n";
1667   OS.indent(Indent + 2) << "'type': 'file',\n";
1668   OS.indent(Indent + 2) << "'name': \"" << llvm::yaml::escape(VPath) << "\",\n";
1669   OS.indent(Indent + 2) << "'external-contents': \""
1670                         << llvm::yaml::escape(RPath) << "\"\n";
1671   OS.indent(Indent) << "}";
1672 }
1673 
write(ArrayRef<YAMLVFSEntry> Entries,Optional<bool> UseExternalNames,Optional<bool> IsCaseSensitive,Optional<bool> IsOverlayRelative,StringRef OverlayDir)1674 void JSONWriter::write(ArrayRef<YAMLVFSEntry> Entries,
1675                        Optional<bool> UseExternalNames,
1676                        Optional<bool> IsCaseSensitive,
1677                        Optional<bool> IsOverlayRelative,
1678                        StringRef OverlayDir) {
1679   using namespace llvm::sys;
1680 
1681   OS << "{\n"
1682         "  'version': 0,\n";
1683   if (IsCaseSensitive.hasValue())
1684     OS << "  'case-sensitive': '"
1685        << (IsCaseSensitive.getValue() ? "true" : "false") << "',\n";
1686   if (UseExternalNames.hasValue())
1687     OS << "  'use-external-names': '"
1688        << (UseExternalNames.getValue() ? "true" : "false") << "',\n";
1689   bool UseOverlayRelative = false;
1690   if (IsOverlayRelative.hasValue()) {
1691     UseOverlayRelative = IsOverlayRelative.getValue();
1692     OS << "  'overlay-relative': '"
1693        << (UseOverlayRelative ? "true" : "false") << "',\n";
1694   }
1695   OS << "  'roots': [\n";
1696 
1697   if (!Entries.empty()) {
1698     const YAMLVFSEntry &Entry = Entries.front();
1699     startDirectory(path::parent_path(Entry.VPath));
1700 
1701     StringRef RPath = Entry.RPath;
1702     if (UseOverlayRelative) {
1703       unsigned OverlayDirLen = OverlayDir.size();
1704       assert(RPath.substr(0, OverlayDirLen) == OverlayDir &&
1705              "Overlay dir must be contained in RPath");
1706       RPath = RPath.slice(OverlayDirLen, RPath.size());
1707     }
1708 
1709     writeEntry(path::filename(Entry.VPath), RPath);
1710 
1711     for (const auto &Entry : Entries.slice(1)) {
1712       StringRef Dir = path::parent_path(Entry.VPath);
1713       if (Dir == DirStack.back())
1714         OS << ",\n";
1715       else {
1716         while (!DirStack.empty() && !containedIn(DirStack.back(), Dir)) {
1717           OS << "\n";
1718           endDirectory();
1719         }
1720         OS << ",\n";
1721         startDirectory(Dir);
1722       }
1723       StringRef RPath = Entry.RPath;
1724       if (UseOverlayRelative) {
1725         unsigned OverlayDirLen = OverlayDir.size();
1726         assert(RPath.substr(0, OverlayDirLen) == OverlayDir &&
1727                "Overlay dir must be contained in RPath");
1728         RPath = RPath.slice(OverlayDirLen, RPath.size());
1729       }
1730       writeEntry(path::filename(Entry.VPath), RPath);
1731     }
1732 
1733     while (!DirStack.empty()) {
1734       OS << "\n";
1735       endDirectory();
1736     }
1737     OS << "\n";
1738   }
1739 
1740   OS << "  ]\n"
1741      << "}\n";
1742 }
1743 
write(llvm::raw_ostream & OS)1744 void YAMLVFSWriter::write(llvm::raw_ostream &OS) {
1745   std::sort(Mappings.begin(), Mappings.end(),
1746             [](const YAMLVFSEntry &LHS, const YAMLVFSEntry &RHS) {
1747     return LHS.VPath < RHS.VPath;
1748   });
1749 
1750   JSONWriter(OS).write(Mappings, UseExternalNames, IsCaseSensitive,
1751                        IsOverlayRelative, OverlayDir);
1752 }
1753 
VFSFromYamlDirIterImpl(const Twine & _Path,RedirectingFileSystem & FS,RedirectingDirectoryEntry::iterator Begin,RedirectingDirectoryEntry::iterator End,std::error_code & EC)1754 VFSFromYamlDirIterImpl::VFSFromYamlDirIterImpl(
1755     const Twine &_Path, RedirectingFileSystem &FS,
1756     RedirectingDirectoryEntry::iterator Begin,
1757     RedirectingDirectoryEntry::iterator End, std::error_code &EC)
1758     : Dir(_Path.str()), FS(FS), Current(Begin), End(End) {
1759   if (Current != End) {
1760     SmallString<128> PathStr(Dir);
1761     llvm::sys::path::append(PathStr, (*Current)->getName());
1762     llvm::ErrorOr<vfs::Status> S = FS.status(PathStr);
1763     if (S)
1764       CurrentEntry = *S;
1765     else
1766       EC = S.getError();
1767   }
1768 }
1769 
increment()1770 std::error_code VFSFromYamlDirIterImpl::increment() {
1771   assert(Current != End && "cannot iterate past end");
1772   if (++Current != End) {
1773     SmallString<128> PathStr(Dir);
1774     llvm::sys::path::append(PathStr, (*Current)->getName());
1775     llvm::ErrorOr<vfs::Status> S = FS.status(PathStr);
1776     if (!S)
1777       return S.getError();
1778     CurrentEntry = *S;
1779   } else {
1780     CurrentEntry = Status();
1781   }
1782   return std::error_code();
1783 }
1784 
recursive_directory_iterator(FileSystem & FS_,const Twine & Path,std::error_code & EC)1785 vfs::recursive_directory_iterator::recursive_directory_iterator(FileSystem &FS_,
1786                                                            const Twine &Path,
1787                                                            std::error_code &EC)
1788     : FS(&FS_) {
1789   directory_iterator I = FS->dir_begin(Path, EC);
1790   if (!EC && I != directory_iterator()) {
1791     State = std::make_shared<IterState>();
1792     State->push(I);
1793   }
1794 }
1795 
1796 vfs::recursive_directory_iterator &
increment(std::error_code & EC)1797 recursive_directory_iterator::increment(std::error_code &EC) {
1798   assert(FS && State && !State->empty() && "incrementing past end");
1799   assert(State->top()->isStatusKnown() && "non-canonical end iterator");
1800   vfs::directory_iterator End;
1801   if (State->top()->isDirectory()) {
1802     vfs::directory_iterator I = FS->dir_begin(State->top()->getName(), EC);
1803     if (EC)
1804       return *this;
1805     if (I != End) {
1806       State->push(I);
1807       return *this;
1808     }
1809   }
1810 
1811   while (!State->empty() && State->top().increment(EC) == End)
1812     State->pop();
1813 
1814   if (State->empty())
1815     State.reset(); // end iterator
1816 
1817   return *this;
1818 }
1819