clang  8.0.0
FileManager.cpp
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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 = llvm::vfs::getRealFileSystem();
62 }
63 
64 FileManager::~FileManager() = default;
65 
66 void FileManager::setStatCache(std::unique_ptr<FileSystemStatCache> statCache) {
67  assert(statCache && "No stat cache provided?");
68  StatCache = std::move(statCache);
69 }
70 
71 void FileManager::clearStatCache() { StatCache.reset(); }
72 
73 /// Retrieve the directory that the given file name resides in.
74 /// Filename can point to either a real file or a virtual file.
76  StringRef Filename,
77  bool CacheFailure) {
78  if (Filename.empty())
79  return nullptr;
80 
81  if (llvm::sys::path::is_separator(Filename[Filename.size() - 1]))
82  return nullptr; // If Filename is a directory.
83 
84  StringRef DirName = llvm::sys::path::parent_path(Filename);
85  // Use the current directory if file has no path component.
86  if (DirName.empty())
87  DirName = ".";
88 
89  return FileMgr.getDirectory(DirName, CacheFailure);
90 }
91 
92 /// Add all ancestors of the given path (pointing to either a file or
93 /// a directory) as virtual directories.
94 void FileManager::addAncestorsAsVirtualDirs(StringRef Path) {
95  StringRef DirName = llvm::sys::path::parent_path(Path);
96  if (DirName.empty())
97  DirName = ".";
98 
99  auto &NamedDirEnt =
100  *SeenDirEntries.insert(std::make_pair(DirName, nullptr)).first;
101 
102  // When caching a virtual directory, we always cache its ancestors
103  // at the same time. Therefore, if DirName is already in the cache,
104  // we don't need to recurse as its ancestors must also already be in
105  // the cache.
106  if (NamedDirEnt.second && NamedDirEnt.second != NON_EXISTENT_DIR)
107  return;
108 
109  // Add the virtual directory to the cache.
110  auto UDE = llvm::make_unique<DirectoryEntry>();
111  UDE->Name = NamedDirEnt.first();
112  NamedDirEnt.second = UDE.get();
113  VirtualDirectoryEntries.push_back(std::move(UDE));
114 
115  // Recursively add the other ancestors.
116  addAncestorsAsVirtualDirs(DirName);
117 }
118 
119 const DirectoryEntry *FileManager::getDirectory(StringRef DirName,
120  bool CacheFailure) {
121  // stat doesn't like trailing separators except for root directory.
122  // At least, on Win32 MSVCRT, stat() cannot strip trailing '/'.
123  // (though it can strip '\\')
124  if (DirName.size() > 1 &&
125  DirName != llvm::sys::path::root_path(DirName) &&
126  llvm::sys::path::is_separator(DirName.back()))
127  DirName = DirName.substr(0, DirName.size()-1);
128 #ifdef _WIN32
129  // Fixing a problem with "clang C:test.c" on Windows.
130  // Stat("C:") does not recognize "C:" as a valid directory
131  std::string DirNameStr;
132  if (DirName.size() > 1 && DirName.back() == ':' &&
133  DirName.equals_lower(llvm::sys::path::root_name(DirName))) {
134  DirNameStr = DirName.str() + '.';
135  DirName = DirNameStr;
136  }
137 #endif
138 
139  ++NumDirLookups;
140  auto &NamedDirEnt =
141  *SeenDirEntries.insert(std::make_pair(DirName, nullptr)).first;
142 
143  // See if there was already an entry in the map. Note that the map
144  // contains both virtual and real directories.
145  if (NamedDirEnt.second)
146  return NamedDirEnt.second == NON_EXISTENT_DIR ? nullptr
147  : NamedDirEnt.second;
148 
149  ++NumDirCacheMisses;
150 
151  // By default, initialize it to invalid.
152  NamedDirEnt.second = NON_EXISTENT_DIR;
153 
154  // Get the null-terminated directory name as stored as the key of the
155  // SeenDirEntries map.
156  StringRef InterndDirName = NamedDirEnt.first();
157 
158  // Check to see if the directory exists.
159  FileData Data;
160  if (getStatValue(InterndDirName, Data, false, nullptr /*directory lookup*/)) {
161  // There's no real directory at the given path.
162  if (!CacheFailure)
163  SeenDirEntries.erase(DirName);
164  return nullptr;
165  }
166 
167  // It exists. See if we have already opened a directory with the
168  // same inode (this occurs on Unix-like systems when one dir is
169  // symlinked to another, for example) or the same path (on
170  // Windows).
171  DirectoryEntry &UDE = UniqueRealDirs[Data.UniqueID];
172 
173  NamedDirEnt.second = &UDE;
174  if (UDE.getName().empty()) {
175  // We don't have this directory yet, add it. We use the string
176  // key from the SeenDirEntries map as the string.
177  UDE.Name = InterndDirName;
178  }
179 
180  return &UDE;
181 }
182 
183 const FileEntry *FileManager::getFile(StringRef Filename, bool openFile,
184  bool CacheFailure) {
185  ++NumFileLookups;
186 
187  // See if there is already an entry in the map.
188  auto &NamedFileEnt =
189  *SeenFileEntries.insert(std::make_pair(Filename, nullptr)).first;
190 
191  // See if there is already an entry in the map.
192  if (NamedFileEnt.second) {
193  if (NamedFileEnt.second == NON_EXISTENT_FILE)
194  return nullptr;
195  // Entry exists: return it *unless* it wasn't opened and open is requested.
196  if (!(NamedFileEnt.second->DeferredOpen && openFile))
197  return NamedFileEnt.second;
198  // We previously stat()ed the file, but didn't open it: do that below.
199  // FIXME: the below does other redundant work too (stats the dir and file).
200  } else {
201  // By default, initialize it to invalid.
202  NamedFileEnt.second = NON_EXISTENT_FILE;
203  }
204 
205  ++NumFileCacheMisses;
206 
207  // Get the null-terminated file name as stored as the key of the
208  // SeenFileEntries map.
209  StringRef InterndFileName = NamedFileEnt.first();
210 
211  // Look up the directory for the file. When looking up something like
212  // sys/foo.h we'll discover all of the search directories that have a 'sys'
213  // subdirectory. This will let us avoid having to waste time on known-to-fail
214  // searches when we go to find sys/bar.h, because all the search directories
215  // without a 'sys' subdir will get a cached failure result.
216  const DirectoryEntry *DirInfo = getDirectoryFromFile(*this, Filename,
217  CacheFailure);
218  if (DirInfo == nullptr) { // Directory doesn't exist, file can't exist.
219  if (!CacheFailure)
220  SeenFileEntries.erase(Filename);
221 
222  return nullptr;
223  }
224 
225  // FIXME: Use the directory info to prune this, before doing the stat syscall.
226  // FIXME: This will reduce the # syscalls.
227 
228  // Nope, there isn't. Check to see if the file exists.
229  std::unique_ptr<llvm::vfs::File> F;
230  FileData Data;
231  if (getStatValue(InterndFileName, Data, true, openFile ? &F : nullptr)) {
232  // There's no real file at the given path.
233  if (!CacheFailure)
234  SeenFileEntries.erase(Filename);
235 
236  return nullptr;
237  }
238 
239  assert((openFile || !F) && "undesired open file");
240 
241  // It exists. See if we have already opened a file with the same inode.
242  // This occurs when one dir is symlinked to another, for example.
243  FileEntry &UFE = UniqueRealFiles[Data.UniqueID];
244  UFE.DeferredOpen = !openFile;
245 
246  NamedFileEnt.second = &UFE;
247 
248  // If the name returned by getStatValue is different than Filename, re-intern
249  // the name.
250  if (Data.Name != Filename) {
251  auto &NamedFileEnt =
252  *SeenFileEntries.insert(std::make_pair(Data.Name, nullptr)).first;
253  if (!NamedFileEnt.second)
254  NamedFileEnt.second = &UFE;
255  else
256  assert(NamedFileEnt.second == &UFE &&
257  "filename from getStatValue() refers to wrong file");
258  InterndFileName = NamedFileEnt.first().data();
259  }
260 
261  // If we opened the file for the first time, record the resulting info.
262  // Do this even if the cache entry was valid, maybe we didn't previously open.
263  if (F && !UFE.File) {
264  if (auto PathName = F->getName())
265  fillRealPathName(&UFE, *PathName);
266  UFE.File = std::move(F);
267  assert(!UFE.DeferredOpen && "we just opened it!");
268  }
269 
270  if (UFE.isValid()) { // Already have an entry with this inode, return it.
271 
272  // FIXME: this hack ensures that if we look up a file by a virtual path in
273  // the VFS that the getDir() will have the virtual path, even if we found
274  // the file by a 'real' path first. This is required in order to find a
275  // module's structure when its headers/module map are mapped in the VFS.
276  // We should remove this as soon as we can properly support a file having
277  // multiple names.
278  if (DirInfo != UFE.Dir && Data.IsVFSMapped)
279  UFE.Dir = DirInfo;
280 
281  // Always update the name to use the last name by which a file was accessed.
282  // FIXME: Neither this nor always using the first name is correct; we want
283  // to switch towards a design where we return a FileName object that
284  // encapsulates both the name by which the file was accessed and the
285  // corresponding FileEntry.
286  UFE.Name = InterndFileName;
287 
288  return &UFE;
289  }
290 
291  // Otherwise, we don't have this file yet, add it.
292  UFE.Name = InterndFileName;
293  UFE.Size = Data.Size;
294  UFE.ModTime = Data.ModTime;
295  UFE.Dir = DirInfo;
296  UFE.UID = NextFileUID++;
297  UFE.UniqueID = Data.UniqueID;
298  UFE.IsNamedPipe = Data.IsNamedPipe;
299  UFE.InPCH = Data.InPCH;
300  UFE.IsValid = true;
301  // Note File and DeferredOpen were initialized above.
302 
303  return &UFE;
304 }
305 
306 const FileEntry *
307 FileManager::getVirtualFile(StringRef Filename, off_t Size,
308  time_t ModificationTime) {
309  ++NumFileLookups;
310 
311  // See if there is already an entry in the map.
312  auto &NamedFileEnt =
313  *SeenFileEntries.insert(std::make_pair(Filename, nullptr)).first;
314 
315  // See if there is already an entry in the map.
316  if (NamedFileEnt.second && NamedFileEnt.second != NON_EXISTENT_FILE)
317  return NamedFileEnt.second;
318 
319  ++NumFileCacheMisses;
320 
321  // By default, initialize it to invalid.
322  NamedFileEnt.second = NON_EXISTENT_FILE;
323 
324  addAncestorsAsVirtualDirs(Filename);
325  FileEntry *UFE = nullptr;
326 
327  // Now that all ancestors of Filename are in the cache, the
328  // following call is guaranteed to find the DirectoryEntry from the
329  // cache.
330  const DirectoryEntry *DirInfo = getDirectoryFromFile(*this, Filename,
331  /*CacheFailure=*/true);
332  assert(DirInfo &&
333  "The directory of a virtual file should already be in the cache.");
334 
335  // Check to see if the file exists. If so, drop the virtual file
336  FileData Data;
337  const char *InterndFileName = NamedFileEnt.first().data();
338  if (getStatValue(InterndFileName, Data, true, nullptr) == 0) {
339  Data.Size = Size;
340  Data.ModTime = ModificationTime;
341  UFE = &UniqueRealFiles[Data.UniqueID];
342 
343  NamedFileEnt.second = UFE;
344 
345  // If we had already opened this file, close it now so we don't
346  // leak the descriptor. We're not going to use the file
347  // descriptor anyway, since this is a virtual file.
348  if (UFE->File)
349  UFE->closeFile();
350 
351  // If we already have an entry with this inode, return it.
352  if (UFE->isValid())
353  return UFE;
354 
355  UFE->UniqueID = Data.UniqueID;
356  UFE->IsNamedPipe = Data.IsNamedPipe;
357  UFE->InPCH = Data.InPCH;
358  fillRealPathName(UFE, Data.Name);
359  }
360 
361  if (!UFE) {
362  VirtualFileEntries.push_back(llvm::make_unique<FileEntry>());
363  UFE = VirtualFileEntries.back().get();
364  NamedFileEnt.second = UFE;
365  }
366 
367  UFE->Name = InterndFileName;
368  UFE->Size = Size;
369  UFE->ModTime = ModificationTime;
370  UFE->Dir = DirInfo;
371  UFE->UID = NextFileUID++;
372  UFE->IsValid = true;
373  UFE->File.reset();
374  UFE->DeferredOpen = false;
375  return UFE;
376 }
377 
379  StringRef pathRef(path.data(), path.size());
380 
381  if (FileSystemOpts.WorkingDir.empty()
382  || llvm::sys::path::is_absolute(pathRef))
383  return false;
384 
385  SmallString<128> NewPath(FileSystemOpts.WorkingDir);
386  llvm::sys::path::append(NewPath, pathRef);
387  path = NewPath;
388  return true;
389 }
390 
392  bool Changed = FixupRelativePath(Path);
393 
394  if (!llvm::sys::path::is_absolute(StringRef(Path.data(), Path.size()))) {
395  FS->makeAbsolute(Path);
396  Changed = true;
397  }
398 
399  return Changed;
400 }
401 
402 void FileManager::fillRealPathName(FileEntry *UFE, llvm::StringRef FileName) {
403  llvm::SmallString<128> AbsPath(FileName);
404  // This is not the same as `VFS::getRealPath()`, which resolves symlinks
405  // but can be very expensive on real file systems.
406  // FIXME: the semantic of RealPathName is unclear, and the name might be
407  // misleading. We need to clean up the interface here.
408  makeAbsolutePath(AbsPath);
409  llvm::sys::path::remove_dots(AbsPath, /*remove_dot_dot=*/true);
410  UFE->RealPathName = AbsPath.str();
411 }
412 
413 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
414 FileManager::getBufferForFile(const FileEntry *Entry, bool isVolatile,
415  bool ShouldCloseOpenFile) {
416  uint64_t FileSize = Entry->getSize();
417  // If there's a high enough chance that the file have changed since we
418  // got its size, force a stat before opening it.
419  if (isVolatile)
420  FileSize = -1;
421 
422  StringRef Filename = Entry->getName();
423  // If the file is already open, use the open file descriptor.
424  if (Entry->File) {
425  auto Result =
426  Entry->File->getBuffer(Filename, FileSize,
427  /*RequiresNullTerminator=*/true, isVolatile);
428  // FIXME: we need a set of APIs that can make guarantees about whether a
429  // FileEntry is open or not.
430  if (ShouldCloseOpenFile)
431  Entry->closeFile();
432  return Result;
433  }
434 
435  // Otherwise, open the file.
436 
437  if (FileSystemOpts.WorkingDir.empty())
438  return FS->getBufferForFile(Filename, FileSize,
439  /*RequiresNullTerminator=*/true, isVolatile);
440 
441  SmallString<128> FilePath(Entry->getName());
442  FixupRelativePath(FilePath);
443  return FS->getBufferForFile(FilePath, FileSize,
444  /*RequiresNullTerminator=*/true, isVolatile);
445 }
446 
447 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
448 FileManager::getBufferForFile(StringRef Filename, bool isVolatile) {
449  if (FileSystemOpts.WorkingDir.empty())
450  return FS->getBufferForFile(Filename, -1, true, isVolatile);
451 
452  SmallString<128> FilePath(Filename);
453  FixupRelativePath(FilePath);
454  return FS->getBufferForFile(FilePath.c_str(), -1, true, isVolatile);
455 }
456 
457 /// getStatValue - Get the 'stat' information for the specified path,
458 /// using the cache to accelerate it if possible. This returns true
459 /// if the path points to a virtual file or does not exist, or returns
460 /// false if it's an existent real file. If FileDescriptor is NULL,
461 /// do directory look-up instead of file look-up.
462 bool FileManager::getStatValue(StringRef Path, FileData &Data, bool isFile,
463  std::unique_ptr<llvm::vfs::File> *F) {
464  // FIXME: FileSystemOpts shouldn't be passed in here, all paths should be
465  // absolute!
466  if (FileSystemOpts.WorkingDir.empty())
467  return FileSystemStatCache::get(Path, Data, isFile, F,StatCache.get(), *FS);
468 
469  SmallString<128> FilePath(Path);
470  FixupRelativePath(FilePath);
471 
472  return FileSystemStatCache::get(FilePath.c_str(), Data, isFile, F,
473  StatCache.get(), *FS);
474 }
475 
477  llvm::vfs::Status &Result) {
478  SmallString<128> FilePath(Path);
479  FixupRelativePath(FilePath);
480 
481  llvm::ErrorOr<llvm::vfs::Status> S = FS->status(FilePath.c_str());
482  if (!S)
483  return true;
484  Result = *S;
485  return false;
486 }
487 
489  assert(Entry && "Cannot invalidate a NULL FileEntry");
490 
491  SeenFileEntries.erase(Entry->getName());
492 
493  // FileEntry invalidation should not block future optimizations in the file
494  // caches. Possible alternatives are cache truncation (invalidate last N) or
495  // invalidation of the whole cache.
496  UniqueRealFiles.erase(Entry->getUniqueID());
497 }
498 
500  SmallVectorImpl<const FileEntry *> &UIDToFiles) const {
501  UIDToFiles.clear();
502  UIDToFiles.resize(NextFileUID);
503 
504  // Map file entries
505  for (llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator>::const_iterator
506  FE = SeenFileEntries.begin(), FEEnd = SeenFileEntries.end();
507  FE != FEEnd; ++FE)
508  if (FE->getValue() && FE->getValue() != NON_EXISTENT_FILE)
509  UIDToFiles[FE->getValue()->getUID()] = FE->getValue();
510 
511  // Map virtual file entries
512  for (const auto &VFE : VirtualFileEntries)
513  if (VFE && VFE.get() != NON_EXISTENT_FILE)
514  UIDToFiles[VFE->getUID()] = VFE.get();
515 }
516 
518  off_t Size, time_t ModificationTime) {
519  File->Size = Size;
520  File->ModTime = ModificationTime;
521 }
522 
524  // FIXME: use llvm::sys::fs::canonical() when it gets implemented
525  llvm::DenseMap<const DirectoryEntry *, llvm::StringRef>::iterator Known
526  = CanonicalDirNames.find(Dir);
527  if (Known != CanonicalDirNames.end())
528  return Known->second;
529 
530  StringRef CanonicalName(Dir->getName());
531 
532  SmallString<4096> CanonicalNameBuf;
533  if (!FS->getRealPath(Dir->getName(), CanonicalNameBuf))
534  CanonicalName = StringRef(CanonicalNameBuf).copy(CanonicalNameStorage);
535 
536  CanonicalDirNames.insert(std::make_pair(Dir, CanonicalName));
537  return CanonicalName;
538 }
539 
541  llvm::errs() << "\n*** File Manager Stats:\n";
542  llvm::errs() << UniqueRealFiles.size() << " real files found, "
543  << UniqueRealDirs.size() << " real dirs found.\n";
544  llvm::errs() << VirtualFileEntries.size() << " virtual files found, "
545  << VirtualDirectoryEntries.size() << " virtual dirs found.\n";
546  llvm::errs() << NumDirLookups << " dir lookups, "
547  << NumDirCacheMisses << " dir cache misses.\n";
548  llvm::errs() << NumFileLookups << " file lookups, "
549  << NumFileCacheMisses << " file cache misses.\n";
550 
551  //llvm::errs() << PagesMapped << BytesOfPagesMapped << FSLookups;
552 }
Implements support for file system lookup, file system caching, and directory search management...
Definition: FileManager.h:122
Defines the clang::FileManager interface and associated types.
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:104
Defines the FileSystemStatCache interface.
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:91
#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
FileManager(const FileSystemOptions &FileSystemOpts, IntrusiveRefCntPtr< llvm::vfs::FileSystem > FS=nullptr)
Definition: FileManager.cpp:51
Definition: Format.h:2072
#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
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:1629
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.
Definition: FileManager.cpp:75
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.
static bool get(StringRef Path, FileData &Data, bool isFile, std::unique_ptr< llvm::vfs::File > *F, FileSystemStatCache *Cache, llvm::vfs::FileSystem &FS)
Get the &#39;stat&#39; information for the specified path, using the cache to accelerate it if possible...
llvm::sys::fs::UniqueID UniqueID
StringRef getName() const
Definition: FileManager.h:86
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:60
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:88
Dataflow Directional Tag Classes.
void clearStatCache()
Removes the FileSystemStatCache object from the manager.
Definition: FileManager.cpp:71
off_t getSize() const
Definition: FileManager.h:89
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.
bool getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result)
Get the &#39;stat&#39; information for the given Path.
Cached information about one directory (either on disk or in the virtual file system).
Definition: FileManager.h:46
void setStatCache(std::unique_ptr< FileSystemStatCache > statCache)
Installs the provided FileSystemStatCache object within the FileManager.
Definition: FileManager.cpp:66
Keeps track of options that affect how file operations are performed.
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.
StringRef getName() const
Definition: FileManager.h:52