clang  6.0.0svn
FileManager.cpp
Go to the documentation of this file.
1 //===--- FileManager.cpp - File System Probing and Caching ----------------===//
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 //
10 // This file implements the FileManager interface.
11 //
12 //===----------------------------------------------------------------------===//
13 //
14 // TODO: This should index all interesting directories with dirent calls.
15 // getdirentries ?
16 // opendir/readdir_r/closedir ?
17 //
18 //===----------------------------------------------------------------------===//
19 
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/Config/llvm-config.h"
24 #include "llvm/ADT/STLExtras.h"
25 #include "llvm/Support/FileSystem.h"
26 #include "llvm/Support/MemoryBuffer.h"
27 #include "llvm/Support/Path.h"
28 #include "llvm/Support/raw_ostream.h"
29 #include <algorithm>
30 #include <cassert>
31 #include <climits>
32 #include <cstdint>
33 #include <cstdlib>
34 #include <string>
35 #include <utility>
36 
37 using namespace clang;
38 
39 /// NON_EXISTENT_DIR - A special value distinct from null that is used to
40 /// represent a dir name that doesn't exist on the disk.
41 #define NON_EXISTENT_DIR reinterpret_cast<DirectoryEntry*>((intptr_t)-1)
42 
43 /// NON_EXISTENT_FILE - A special value distinct from null that is used to
44 /// represent a filename that doesn't exist on the disk.
45 #define NON_EXISTENT_FILE reinterpret_cast<FileEntry*>((intptr_t)-1)
46 
47 //===----------------------------------------------------------------------===//
48 // Common logic.
49 //===----------------------------------------------------------------------===//
50 
53  : FS(std::move(FS)), FileSystemOpts(FSO), SeenDirEntries(64),
54  SeenFileEntries(64), NextFileUID(0) {
55  NumDirLookups = NumFileLookups = 0;
56  NumDirCacheMisses = NumFileCacheMisses = 0;
57 
58  // If the caller doesn't provide a virtual file system, just grab the real
59  // file system.
60  if (!this->FS)
61  this->FS = vfs::getRealFileSystem();
62 }
63 
64 FileManager::~FileManager() = default;
65 
66 void FileManager::addStatCache(std::unique_ptr<FileSystemStatCache> statCache,
67  bool AtBeginning) {
68  assert(statCache && "No stat cache provided?");
69  if (AtBeginning || !StatCache.get()) {
70  statCache->setNextStatCache(std::move(StatCache));
71  StatCache = std::move(statCache);
72  return;
73  }
74 
75  FileSystemStatCache *LastCache = StatCache.get();
76  while (LastCache->getNextStatCache())
77  LastCache = LastCache->getNextStatCache();
78 
79  LastCache->setNextStatCache(std::move(statCache));
80 }
81 
83  if (!statCache)
84  return;
85 
86  if (StatCache.get() == statCache) {
87  // This is the first stat cache.
88  StatCache = StatCache->takeNextStatCache();
89  return;
90  }
91 
92  // Find the stat cache in the list.
93  FileSystemStatCache *PrevCache = StatCache.get();
94  while (PrevCache && PrevCache->getNextStatCache() != statCache)
95  PrevCache = PrevCache->getNextStatCache();
96 
97  assert(PrevCache && "Stat cache not found for removal");
98  PrevCache->setNextStatCache(statCache->takeNextStatCache());
99 }
100 
102  StatCache.reset();
103 }
104 
105 /// \brief Retrieve the directory that the given file name resides in.
106 /// Filename can point to either a real file or a virtual file.
108  StringRef Filename,
109  bool CacheFailure) {
110  if (Filename.empty())
111  return nullptr;
112 
113  if (llvm::sys::path::is_separator(Filename[Filename.size() - 1]))
114  return nullptr; // If Filename is a directory.
115 
116  StringRef DirName = llvm::sys::path::parent_path(Filename);
117  // Use the current directory if file has no path component.
118  if (DirName.empty())
119  DirName = ".";
120 
121  return FileMgr.getDirectory(DirName, CacheFailure);
122 }
123 
124 /// Add all ancestors of the given path (pointing to either a file or
125 /// a directory) as virtual directories.
126 void FileManager::addAncestorsAsVirtualDirs(StringRef Path) {
127  StringRef DirName = llvm::sys::path::parent_path(Path);
128  if (DirName.empty())
129  DirName = ".";
130 
131  auto &NamedDirEnt =
132  *SeenDirEntries.insert(std::make_pair(DirName, nullptr)).first;
133 
134  // When caching a virtual directory, we always cache its ancestors
135  // at the same time. Therefore, if DirName is already in the cache,
136  // we don't need to recurse as its ancestors must also already be in
137  // the cache.
138  if (NamedDirEnt.second && NamedDirEnt.second != NON_EXISTENT_DIR)
139  return;
140 
141  // Add the virtual directory to the cache.
142  auto UDE = llvm::make_unique<DirectoryEntry>();
143  UDE->Name = NamedDirEnt.first();
144  NamedDirEnt.second = UDE.get();
145  VirtualDirectoryEntries.push_back(std::move(UDE));
146 
147  // Recursively add the other ancestors.
148  addAncestorsAsVirtualDirs(DirName);
149 }
150 
151 const DirectoryEntry *FileManager::getDirectory(StringRef DirName,
152  bool CacheFailure) {
153  // stat doesn't like trailing separators except for root directory.
154  // At least, on Win32 MSVCRT, stat() cannot strip trailing '/'.
155  // (though it can strip '\\')
156  if (DirName.size() > 1 &&
157  DirName != llvm::sys::path::root_path(DirName) &&
158  llvm::sys::path::is_separator(DirName.back()))
159  DirName = DirName.substr(0, DirName.size()-1);
160 #ifdef LLVM_ON_WIN32
161  // Fixing a problem with "clang C:test.c" on Windows.
162  // Stat("C:") does not recognize "C:" as a valid directory
163  std::string DirNameStr;
164  if (DirName.size() > 1 && DirName.back() == ':' &&
165  DirName.equals_lower(llvm::sys::path::root_name(DirName))) {
166  DirNameStr = DirName.str() + '.';
167  DirName = DirNameStr;
168  }
169 #endif
170 
171  ++NumDirLookups;
172  auto &NamedDirEnt =
173  *SeenDirEntries.insert(std::make_pair(DirName, nullptr)).first;
174 
175  // See if there was already an entry in the map. Note that the map
176  // contains both virtual and real directories.
177  if (NamedDirEnt.second)
178  return NamedDirEnt.second == NON_EXISTENT_DIR ? nullptr
179  : NamedDirEnt.second;
180 
181  ++NumDirCacheMisses;
182 
183  // By default, initialize it to invalid.
184  NamedDirEnt.second = NON_EXISTENT_DIR;
185 
186  // Get the null-terminated directory name as stored as the key of the
187  // SeenDirEntries map.
188  StringRef InterndDirName = NamedDirEnt.first();
189 
190  // Check to see if the directory exists.
191  FileData Data;
192  if (getStatValue(InterndDirName, Data, false, nullptr /*directory lookup*/)) {
193  // There's no real directory at the given path.
194  if (!CacheFailure)
195  SeenDirEntries.erase(DirName);
196  return nullptr;
197  }
198 
199  // It exists. See if we have already opened a directory with the
200  // same inode (this occurs on Unix-like systems when one dir is
201  // symlinked to another, for example) or the same path (on
202  // Windows).
203  DirectoryEntry &UDE = UniqueRealDirs[Data.UniqueID];
204 
205  NamedDirEnt.second = &UDE;
206  if (UDE.getName().empty()) {
207  // We don't have this directory yet, add it. We use the string
208  // key from the SeenDirEntries map as the string.
209  UDE.Name = InterndDirName;
210  }
211 
212  return &UDE;
213 }
214 
215 const FileEntry *FileManager::getFile(StringRef Filename, bool openFile,
216  bool CacheFailure) {
217  ++NumFileLookups;
218 
219  // See if there is already an entry in the map.
220  auto &NamedFileEnt =
221  *SeenFileEntries.insert(std::make_pair(Filename, nullptr)).first;
222 
223  // See if there is already an entry in the map.
224  if (NamedFileEnt.second)
225  return NamedFileEnt.second == NON_EXISTENT_FILE ? nullptr
226  : NamedFileEnt.second;
227 
228  ++NumFileCacheMisses;
229 
230  // By default, initialize it to invalid.
231  NamedFileEnt.second = NON_EXISTENT_FILE;
232 
233  // Get the null-terminated file name as stored as the key of the
234  // SeenFileEntries map.
235  StringRef InterndFileName = NamedFileEnt.first();
236 
237  // Look up the directory for the file. When looking up something like
238  // sys/foo.h we'll discover all of the search directories that have a 'sys'
239  // subdirectory. This will let us avoid having to waste time on known-to-fail
240  // searches when we go to find sys/bar.h, because all the search directories
241  // without a 'sys' subdir will get a cached failure result.
242  const DirectoryEntry *DirInfo = getDirectoryFromFile(*this, Filename,
243  CacheFailure);
244  if (DirInfo == nullptr) { // Directory doesn't exist, file can't exist.
245  if (!CacheFailure)
246  SeenFileEntries.erase(Filename);
247 
248  return nullptr;
249  }
250 
251  // FIXME: Use the directory info to prune this, before doing the stat syscall.
252  // FIXME: This will reduce the # syscalls.
253 
254  // Nope, there isn't. Check to see if the file exists.
255  std::unique_ptr<vfs::File> F;
256  FileData Data;
257  if (getStatValue(InterndFileName, Data, true, openFile ? &F : nullptr)) {
258  // There's no real file at the given path.
259  if (!CacheFailure)
260  SeenFileEntries.erase(Filename);
261 
262  return nullptr;
263  }
264 
265  assert((openFile || !F) && "undesired open file");
266 
267  // It exists. See if we have already opened a file with the same inode.
268  // This occurs when one dir is symlinked to another, for example.
269  FileEntry &UFE = UniqueRealFiles[Data.UniqueID];
270 
271  NamedFileEnt.second = &UFE;
272 
273  // If the name returned by getStatValue is different than Filename, re-intern
274  // the name.
275  if (Data.Name != Filename) {
276  auto &NamedFileEnt =
277  *SeenFileEntries.insert(std::make_pair(Data.Name, nullptr)).first;
278  if (!NamedFileEnt.second)
279  NamedFileEnt.second = &UFE;
280  else
281  assert(NamedFileEnt.second == &UFE &&
282  "filename from getStatValue() refers to wrong file");
283  InterndFileName = NamedFileEnt.first().data();
284  }
285 
286  if (UFE.isValid()) { // Already have an entry with this inode, return it.
287 
288  // FIXME: this hack ensures that if we look up a file by a virtual path in
289  // the VFS that the getDir() will have the virtual path, even if we found
290  // the file by a 'real' path first. This is required in order to find a
291  // module's structure when its headers/module map are mapped in the VFS.
292  // We should remove this as soon as we can properly support a file having
293  // multiple names.
294  if (DirInfo != UFE.Dir && Data.IsVFSMapped)
295  UFE.Dir = DirInfo;
296 
297  // Always update the name to use the last name by which a file was accessed.
298  // FIXME: Neither this nor always using the first name is correct; we want
299  // to switch towards a design where we return a FileName object that
300  // encapsulates both the name by which the file was accessed and the
301  // corresponding FileEntry.
302  UFE.Name = InterndFileName;
303 
304  return &UFE;
305  }
306 
307  // Otherwise, we don't have this file yet, add it.
308  UFE.Name = InterndFileName;
309  UFE.Size = Data.Size;
310  UFE.ModTime = Data.ModTime;
311  UFE.Dir = DirInfo;
312  UFE.UID = NextFileUID++;
313  UFE.UniqueID = Data.UniqueID;
314  UFE.IsNamedPipe = Data.IsNamedPipe;
315  UFE.InPCH = Data.InPCH;
316  UFE.File = std::move(F);
317  UFE.IsValid = true;
318  if (UFE.File)
319  if (auto RealPathName = UFE.File->getName())
320  UFE.RealPathName = *RealPathName;
321  return &UFE;
322 }
323 
324 const FileEntry *
325 FileManager::getVirtualFile(StringRef Filename, off_t Size,
326  time_t ModificationTime) {
327  ++NumFileLookups;
328 
329  // See if there is already an entry in the map.
330  auto &NamedFileEnt =
331  *SeenFileEntries.insert(std::make_pair(Filename, nullptr)).first;
332 
333  // See if there is already an entry in the map.
334  if (NamedFileEnt.second && NamedFileEnt.second != NON_EXISTENT_FILE)
335  return NamedFileEnt.second;
336 
337  ++NumFileCacheMisses;
338 
339  // By default, initialize it to invalid.
340  NamedFileEnt.second = NON_EXISTENT_FILE;
341 
342  addAncestorsAsVirtualDirs(Filename);
343  FileEntry *UFE = nullptr;
344 
345  // Now that all ancestors of Filename are in the cache, the
346  // following call is guaranteed to find the DirectoryEntry from the
347  // cache.
348  const DirectoryEntry *DirInfo = getDirectoryFromFile(*this, Filename,
349  /*CacheFailure=*/true);
350  assert(DirInfo &&
351  "The directory of a virtual file should already be in the cache.");
352 
353  // Check to see if the file exists. If so, drop the virtual file
354  FileData Data;
355  const char *InterndFileName = NamedFileEnt.first().data();
356  if (getStatValue(InterndFileName, Data, true, nullptr) == 0) {
357  Data.Size = Size;
358  Data.ModTime = ModificationTime;
359  UFE = &UniqueRealFiles[Data.UniqueID];
360 
361  NamedFileEnt.second = UFE;
362 
363  // If we had already opened this file, close it now so we don't
364  // leak the descriptor. We're not going to use the file
365  // descriptor anyway, since this is a virtual file.
366  if (UFE->File)
367  UFE->closeFile();
368 
369  // If we already have an entry with this inode, return it.
370  if (UFE->isValid())
371  return UFE;
372 
373  UFE->UniqueID = Data.UniqueID;
374  UFE->IsNamedPipe = Data.IsNamedPipe;
375  UFE->InPCH = Data.InPCH;
376  }
377 
378  if (!UFE) {
379  VirtualFileEntries.push_back(llvm::make_unique<FileEntry>());
380  UFE = VirtualFileEntries.back().get();
381  NamedFileEnt.second = UFE;
382  }
383 
384  UFE->Name = InterndFileName;
385  UFE->Size = Size;
386  UFE->ModTime = ModificationTime;
387  UFE->Dir = DirInfo;
388  UFE->UID = NextFileUID++;
389  UFE->IsValid = true;
390  UFE->File.reset();
391  return UFE;
392 }
393 
395  StringRef pathRef(path.data(), path.size());
396 
397  if (FileSystemOpts.WorkingDir.empty()
398  || llvm::sys::path::is_absolute(pathRef))
399  return false;
400 
401  SmallString<128> NewPath(FileSystemOpts.WorkingDir);
402  llvm::sys::path::append(NewPath, pathRef);
403  path = NewPath;
404  return true;
405 }
406 
408  bool Changed = FixupRelativePath(Path);
409 
410  if (!llvm::sys::path::is_absolute(StringRef(Path.data(), Path.size()))) {
411  FS->makeAbsolute(Path);
412  Changed = true;
413  }
414 
415  return Changed;
416 }
417 
418 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
419 FileManager::getBufferForFile(const FileEntry *Entry, bool isVolatile,
420  bool ShouldCloseOpenFile) {
421  uint64_t FileSize = Entry->getSize();
422  // If there's a high enough chance that the file have changed since we
423  // got its size, force a stat before opening it.
424  if (isVolatile)
425  FileSize = -1;
426 
427  StringRef Filename = Entry->getName();
428  // If the file is already open, use the open file descriptor.
429  if (Entry->File) {
430  auto Result =
431  Entry->File->getBuffer(Filename, FileSize,
432  /*RequiresNullTerminator=*/true, isVolatile);
433  // FIXME: we need a set of APIs that can make guarantees about whether a
434  // FileEntry is open or not.
435  if (ShouldCloseOpenFile)
436  Entry->closeFile();
437  return Result;
438  }
439 
440  // Otherwise, open the file.
441 
442  if (FileSystemOpts.WorkingDir.empty())
443  return FS->getBufferForFile(Filename, FileSize,
444  /*RequiresNullTerminator=*/true, isVolatile);
445 
446  SmallString<128> FilePath(Entry->getName());
447  FixupRelativePath(FilePath);
448  return FS->getBufferForFile(FilePath, FileSize,
449  /*RequiresNullTerminator=*/true, isVolatile);
450 }
451 
452 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
454  if (FileSystemOpts.WorkingDir.empty())
455  return FS->getBufferForFile(Filename);
456 
457  SmallString<128> FilePath(Filename);
458  FixupRelativePath(FilePath);
459  return FS->getBufferForFile(FilePath.c_str());
460 }
461 
462 /// getStatValue - Get the 'stat' information for the specified path,
463 /// using the cache to accelerate it if possible. This returns true
464 /// if the path points to a virtual file or does not exist, or returns
465 /// false if it's an existent real file. If FileDescriptor is NULL,
466 /// do directory look-up instead of file look-up.
467 bool FileManager::getStatValue(StringRef Path, FileData &Data, bool isFile,
468  std::unique_ptr<vfs::File> *F) {
469  // FIXME: FileSystemOpts shouldn't be passed in here, all paths should be
470  // absolute!
471  if (FileSystemOpts.WorkingDir.empty())
472  return FileSystemStatCache::get(Path, Data, isFile, F,StatCache.get(), *FS);
473 
474  SmallString<128> FilePath(Path);
475  FixupRelativePath(FilePath);
476 
477  return FileSystemStatCache::get(FilePath.c_str(), Data, isFile, F,
478  StatCache.get(), *FS);
479 }
480 
482  vfs::Status &Result) {
483  SmallString<128> FilePath(Path);
484  FixupRelativePath(FilePath);
485 
486  llvm::ErrorOr<vfs::Status> S = FS->status(FilePath.c_str());
487  if (!S)
488  return true;
489  Result = *S;
490  return false;
491 }
492 
494  assert(Entry && "Cannot invalidate a NULL FileEntry");
495 
496  SeenFileEntries.erase(Entry->getName());
497 
498  // FileEntry invalidation should not block future optimizations in the file
499  // caches. Possible alternatives are cache truncation (invalidate last N) or
500  // invalidation of the whole cache.
501  UniqueRealFiles.erase(Entry->getUniqueID());
502 }
503 
505  SmallVectorImpl<const FileEntry *> &UIDToFiles) const {
506  UIDToFiles.clear();
507  UIDToFiles.resize(NextFileUID);
508 
509  // Map file entries
510  for (llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator>::const_iterator
511  FE = SeenFileEntries.begin(), FEEnd = SeenFileEntries.end();
512  FE != FEEnd; ++FE)
513  if (FE->getValue() && FE->getValue() != NON_EXISTENT_FILE)
514  UIDToFiles[FE->getValue()->getUID()] = FE->getValue();
515 
516  // Map virtual file entries
517  for (const auto &VFE : VirtualFileEntries)
518  if (VFE && VFE.get() != NON_EXISTENT_FILE)
519  UIDToFiles[VFE->getUID()] = VFE.get();
520 }
521 
523  off_t Size, time_t ModificationTime) {
524  File->Size = Size;
525  File->ModTime = ModificationTime;
526 }
527 
529  // FIXME: use llvm::sys::fs::canonical() when it gets implemented
530  llvm::DenseMap<const DirectoryEntry *, llvm::StringRef>::iterator Known
531  = CanonicalDirNames.find(Dir);
532  if (Known != CanonicalDirNames.end())
533  return Known->second;
534 
535  StringRef CanonicalName(Dir->getName());
536 
537 #ifdef LLVM_ON_UNIX
538  char CanonicalNameBuf[PATH_MAX];
539  if (realpath(Dir->getName().str().c_str(), CanonicalNameBuf))
540  CanonicalName = StringRef(CanonicalNameBuf).copy(CanonicalNameStorage);
541 #else
542  SmallString<256> CanonicalNameBuf(CanonicalName);
543  llvm::sys::fs::make_absolute(CanonicalNameBuf);
544  llvm::sys::path::native(CanonicalNameBuf);
545  // We've run into needing to remove '..' here in the wild though, so
546  // remove it.
547  // On Windows, symlinks are significantly less prevalent, so removing
548  // '..' is pretty safe.
549  // Ideally we'd have an equivalent of `realpath` and could implement
550  // sys::fs::canonical across all the platforms.
551  llvm::sys::path::remove_dots(CanonicalNameBuf, /* remove_dot_dot */ true);
552  CanonicalName = StringRef(CanonicalNameBuf).copy(CanonicalNameStorage);
553 #endif
554 
555  CanonicalDirNames.insert(std::make_pair(Dir, CanonicalName));
556  return CanonicalName;
557 }
558 
560  llvm::errs() << "\n*** File Manager Stats:\n";
561  llvm::errs() << UniqueRealFiles.size() << " real files found, "
562  << UniqueRealDirs.size() << " real dirs found.\n";
563  llvm::errs() << VirtualFileEntries.size() << " virtual files found, "
564  << VirtualDirectoryEntries.size() << " virtual dirs found.\n";
565  llvm::errs() << NumDirLookups << " dir lookups, "
566  << NumDirCacheMisses << " dir cache misses.\n";
567  llvm::errs() << NumFileLookups << " file lookups, "
568  << NumFileCacheMisses << " file cache misses.\n";
569 
570  //llvm::errs() << PagesMapped << BytesOfPagesMapped << FSLookups;
571 }
Implements support for file system lookup, file system caching, and directory search management...
Definition: FileManager.h:116
Defines the clang::FileManager interface and associated types.
IntrusiveRefCntPtr< FileSystem > getRealFileSystem()
Gets an vfs::FileSystem for the &#39;real&#39; file system, as seen by the operating system.
void GetUniqueIDMapping(SmallVectorImpl< const FileEntry *> &UIDToFiles) const
Produce an array mapping from the unique IDs assigned to each file to the corresponding FileEntry poi...
void closeFile() const
Definition: FileManager.h:102
Defines the FileSystemStatCache interface.
FileManager(const FileSystemOptions &FileSystemOpts, IntrusiveRefCntPtr< vfs::FileSystem > FS=nullptr)
Definition: FileManager.cpp:51
bool makeAbsolutePath(SmallVectorImpl< char > &Path) const
Makes Path absolute taking into account FileSystemOptions and the working directory option...
const llvm::sys::fs::UniqueID & getUniqueID() const
Definition: FileManager.h:89
#define NON_EXISTENT_DIR
NON_EXISTENT_DIR - A special value distinct from null that is used to represent a dir name that doesn...
Definition: FileManager.cpp:41
Definition: Format.h:1900
#define NON_EXISTENT_FILE
NON_EXISTENT_FILE - A special value distinct from null that is used to represent a filename that does...
Definition: FileManager.cpp:45
Abstract interface for introducing a FileManager cache for &#39;stat&#39; system calls, which is used by prec...
std::unique_ptr< FileSystemStatCache > takeNextStatCache()
Retrieve the next stat call cache in the chain, transferring ownership of this cache (and...
The result of a status operation.
static bool get(StringRef Path, FileData &Data, bool isFile, std::unique_ptr< vfs::File > *F, FileSystemStatCache *Cache, vfs::FileSystem &FS)
Get the &#39;stat&#39; information for the specified path, using the cache to accelerate it if possible...
const FileEntry * getFile(StringRef Filename, bool OpenFile=false, bool CacheFailure=true)
Lookup, cache, and verify the specified file (real or virtual).
const DirectoryEntry * getDirectory(StringRef DirName, bool CacheFailure=true)
Lookup, cache, and verify the specified directory (real or virtual).
StringRef Filename
Definition: Format.cpp:1345
bool FixupRelativePath(SmallVectorImpl< char > &path) const
If path is not absolute and FileSystemOptions set the working directory, the path is modified to be r...
static const DirectoryEntry * getDirectoryFromFile(FileManager &FileMgr, StringRef Filename, bool CacheFailure)
Retrieve the directory that the given file name resides in.
void setNextStatCache(std::unique_ptr< FileSystemStatCache > Cache)
Sets the next stat call cache in the chain of stat caches.
std::string WorkingDir
If set, paths are resolved as if the working directory was set to the value of WorkingDir.
The result type of a method or function.
void addStatCache(std::unique_ptr< FileSystemStatCache > statCache, bool AtBeginning=false)
Installs the provided FileSystemStatCache object within the FileManager.
Definition: FileManager.cpp:66
llvm::sys::fs::UniqueID UniqueID
StringRef getName() const
Definition: FileManager.h:84
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:59
void clearStatCaches()
Removes all FileSystemStatCache objects from the manager.
void PrintStats() const
const FileEntry * getVirtualFile(StringRef Filename, off_t Size, time_t ModificationTime)
Retrieve a file entry for a "virtual" file that acts as if there were a file with the given name on d...
StringRef getCanonicalName(const DirectoryEntry *Dir)
Retrieve the canonical name for a given directory.
bool isValid() const
Definition: FileManager.h:86
Dataflow Directional Tag Classes.
off_t getSize() const
Definition: FileManager.h:87
void removeStatCache(FileSystemStatCache *statCache)
Removes the specified FileSystemStatCache object from the manager.
Definition: FileManager.cpp:82
llvm::ErrorOr< std::unique_ptr< llvm::MemoryBuffer > > getBufferForFile(const FileEntry *Entry, bool isVolatile=false, bool ShouldCloseOpenFile=true)
Open the specified file as a MemoryBuffer, returning a new MemoryBuffer if successful, otherwise returning null.
Cached information about one directory (either on disk or in the virtual file system).
Definition: FileManager.h:45
Keeps track of options that affect how file operations are performed.
bool getNoncachedStatValue(StringRef Path, vfs::Status &Result)
Get the &#39;stat&#39; information for the given Path.
static void modifyFileEntry(FileEntry *File, off_t Size, time_t ModificationTime)
Modifies the size and modification time of a previously created FileEntry.
void invalidateCache(const FileEntry *Entry)
Remove the real file Entry from the cache.
FileSystemStatCache * getNextStatCache()
Retrieve the next stat call cache in the chain.
StringRef getName() const
Definition: FileManager.h:51