clang  14.0.0git
FileManager.h
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1 //===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// Defines the clang::FileManager interface and associated types.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
15 #define LLVM_CLANG_BASIC_FILEMANAGER_H
16 
18 #include "clang/Basic/FileEntry.h"
20 #include "clang/Basic/LLVM.h"
21 #include "llvm/ADT/DenseMap.h"
22 #include "llvm/ADT/IntrusiveRefCntPtr.h"
23 #include "llvm/ADT/PointerUnion.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/StringMap.h"
26 #include "llvm/ADT/StringRef.h"
27 #include "llvm/Support/Allocator.h"
28 #include "llvm/Support/ErrorOr.h"
29 #include "llvm/Support/FileSystem.h"
30 #include "llvm/Support/VirtualFileSystem.h"
31 #include <ctime>
32 #include <map>
33 #include <memory>
34 #include <string>
35 
36 namespace llvm {
37 
38 class MemoryBuffer;
39 
40 } // end namespace llvm
41 
42 namespace clang {
43 
44 class FileSystemStatCache;
45 
46 /// Implements support for file system lookup, file system caching,
47 /// and directory search management.
48 ///
49 /// This also handles more advanced properties, such as uniquing files based
50 /// on "inode", so that a file with two names (e.g. symlinked) will be treated
51 /// as a single file.
52 ///
53 class FileManager : public RefCountedBase<FileManager> {
55  FileSystemOptions FileSystemOpts;
56 
57  /// Cache for existing real directories.
58  std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
59 
60  /// Cache for existing real files.
61  std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
62 
63  /// The virtual directories that we have allocated.
64  ///
65  /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
66  /// directories (foo/ and foo/bar/) here.
67  SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries;
68  /// The virtual files that we have allocated.
69  SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries;
70 
71  /// A set of files that bypass the maps and uniquing. They can have
72  /// conflicting filenames.
73  SmallVector<std::unique_ptr<FileEntry>, 0> BypassFileEntries;
74 
75  /// A cache that maps paths to directory entries (either real or
76  /// virtual) we have looked up, or an error that occurred when we looked up
77  /// the directory.
78  ///
79  /// The actual Entries for real directories/files are
80  /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
81  /// for virtual directories/files are owned by
82  /// VirtualDirectoryEntries/VirtualFileEntries above.
83  ///
84  llvm::StringMap<llvm::ErrorOr<DirectoryEntry &>, llvm::BumpPtrAllocator>
85  SeenDirEntries;
86 
87  /// A cache that maps paths to file entries (either real or
88  /// virtual) we have looked up, or an error that occurred when we looked up
89  /// the file.
90  ///
91  /// \see SeenDirEntries
92  llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>, llvm::BumpPtrAllocator>
93  SeenFileEntries;
94 
95  /// A mirror of SeenFileEntries to give fake answers for getBypassFile().
96  ///
97  /// Don't bother hooking up a BumpPtrAllocator. This should be rarely used,
98  /// and only on error paths.
99  std::unique_ptr<llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>>>
100  SeenBypassFileEntries;
101 
102  /// The file entry for stdin, if it has been accessed through the FileManager.
104 
105  /// The canonical names of files and directories .
106  llvm::DenseMap<const void *, llvm::StringRef> CanonicalNames;
107 
108  /// Storage for canonical names that we have computed.
109  llvm::BumpPtrAllocator CanonicalNameStorage;
110 
111  /// Each FileEntry we create is assigned a unique ID #.
112  ///
113  unsigned NextFileUID;
114 
115  // Caching.
116  std::unique_ptr<FileSystemStatCache> StatCache;
117 
118  std::error_code getStatValue(StringRef Path, llvm::vfs::Status &Status,
119  bool isFile,
120  std::unique_ptr<llvm::vfs::File> *F);
121 
122  /// Add all ancestors of the given path (pointing to either a file
123  /// or a directory) as virtual directories.
124  void addAncestorsAsVirtualDirs(StringRef Path);
125 
126  /// Fills the RealPathName in file entry.
127  void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName);
128 
129 public:
130  /// Construct a file manager, optionally with a custom VFS.
131  ///
132  /// \param FS if non-null, the VFS to use. Otherwise uses
133  /// llvm::vfs::getRealFileSystem().
134  FileManager(const FileSystemOptions &FileSystemOpts,
136  ~FileManager();
137 
138  /// Installs the provided FileSystemStatCache object within
139  /// the FileManager.
140  ///
141  /// Ownership of this object is transferred to the FileManager.
142  ///
143  /// \param statCache the new stat cache to install. Ownership of this
144  /// object is transferred to the FileManager.
145  void setStatCache(std::unique_ptr<FileSystemStatCache> statCache);
146 
147  /// Removes the FileSystemStatCache object from the manager.
148  void clearStatCache();
149 
150  /// Returns the number of unique real file entries cached by the file manager.
151  size_t getNumUniqueRealFiles() const { return UniqueRealFiles.size(); }
152 
153  /// Lookup, cache, and verify the specified directory (real or
154  /// virtual).
155  ///
156  /// This returns a \c std::error_code if there was an error reading the
157  /// directory. On success, returns the reference to the directory entry
158  /// together with the exact path that was used to access a file by a
159  /// particular call to getDirectoryRef.
160  ///
161  /// \param CacheFailure If true and the file does not exist, we'll cache
162  /// the failure to find this file.
164  bool CacheFailure = true);
165 
166  /// Get a \c DirectoryEntryRef if it exists, without doing anything on error.
168  getOptionalDirectoryRef(StringRef DirName, bool CacheFailure = true) {
169  return llvm::expectedToOptional(getDirectoryRef(DirName, CacheFailure));
170  }
171 
172  /// Lookup, cache, and verify the specified directory (real or
173  /// virtual).
174  ///
175  /// This function is deprecated and will be removed at some point in the
176  /// future, new clients should use
177  /// \c getDirectoryRef.
178  ///
179  /// This returns a \c std::error_code if there was an error reading the
180  /// directory. If there is no error, the DirectoryEntry is guaranteed to be
181  /// non-NULL.
182  ///
183  /// \param CacheFailure If true and the file does not exist, we'll cache
184  /// the failure to find this file.
185  llvm::ErrorOr<const DirectoryEntry *>
186  getDirectory(StringRef DirName, bool CacheFailure = true);
187 
188  /// Lookup, cache, and verify the specified file (real or
189  /// virtual).
190  ///
191  /// This function is deprecated and will be removed at some point in the
192  /// future, new clients should use
193  /// \c getFileRef.
194  ///
195  /// This returns a \c std::error_code if there was an error loading the file.
196  /// If there is no error, the FileEntry is guaranteed to be non-NULL.
197  ///
198  /// \param OpenFile if true and the file exists, it will be opened.
199  ///
200  /// \param CacheFailure If true and the file does not exist, we'll cache
201  /// the failure to find this file.
202  llvm::ErrorOr<const FileEntry *>
203  getFile(StringRef Filename, bool OpenFile = false, bool CacheFailure = true);
204 
205  /// Lookup, cache, and verify the specified file (real or virtual). Return the
206  /// reference to the file entry together with the exact path that was used to
207  /// access a file by a particular call to getFileRef. If the underlying VFS is
208  /// a redirecting VFS that uses external file names, the returned FileEntryRef
209  /// will use the external name instead of the filename that was passed to this
210  /// method.
211  ///
212  /// This returns a \c std::error_code if there was an error loading the file,
213  /// or a \c FileEntryRef otherwise.
214  ///
215  /// \param OpenFile if true and the file exists, it will be opened.
216  ///
217  /// \param CacheFailure If true and the file does not exist, we'll cache
218  /// the failure to find this file.
220  bool OpenFile = false,
221  bool CacheFailure = true);
222 
223  /// Get the FileEntryRef for stdin, returning an error if stdin cannot be
224  /// read.
225  ///
226  /// This reads and caches stdin before returning. Subsequent calls return the
227  /// same file entry, and a reference to the cached input is returned by calls
228  /// to getBufferForFile.
230 
231  /// Get a FileEntryRef if it exists, without doing anything on error.
233  bool OpenFile = false,
234  bool CacheFailure = true) {
235  return llvm::expectedToOptional(
236  getFileRef(Filename, OpenFile, CacheFailure));
237  }
238 
239  /// Returns the current file system options
240  FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
241  const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
242 
243  llvm::vfs::FileSystem &getVirtualFileSystem() const { return *FS; }
244 
246  this->FS = std::move(FS);
247  }
248 
249  /// Retrieve a file entry for a "virtual" file that acts as
250  /// if there were a file with the given name on disk.
251  ///
252  /// The file itself is not accessed.
253  FileEntryRef getVirtualFileRef(StringRef Filename, off_t Size,
254  time_t ModificationTime);
255 
256  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
257  time_t ModificationTime);
258 
259  /// Retrieve a FileEntry that bypasses VFE, which is expected to be a virtual
260  /// file entry, to access the real file. The returned FileEntry will have
261  /// the same filename as FE but a different identity and its own stat.
262  ///
263  /// This should be used only for rare error recovery paths because it
264  /// bypasses all mapping and uniquing, blindly creating a new FileEntry.
265  /// There is no attempt to deduplicate these; if you bypass the same file
266  /// twice, you get two new file entries.
268 
269  /// Open the specified file as a MemoryBuffer, returning a new
270  /// MemoryBuffer if successful, otherwise returning null.
271  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
272  getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
273  bool RequiresNullTerminator = true);
274  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
275  getBufferForFile(StringRef Filename, bool isVolatile = false,
276  bool RequiresNullTerminator = true) {
277  return getBufferForFileImpl(Filename, /*FileSize=*/-1, isVolatile,
278  RequiresNullTerminator);
279  }
280 
281 private:
282  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
283  getBufferForFileImpl(StringRef Filename, int64_t FileSize, bool isVolatile,
284  bool RequiresNullTerminator);
285 
286 public:
287  /// Get the 'stat' information for the given \p Path.
288  ///
289  /// If the path is relative, it will be resolved against the WorkingDir of the
290  /// FileManager's FileSystemOptions.
291  ///
292  /// \returns a \c std::error_code describing an error, if there was one
293  std::error_code getNoncachedStatValue(StringRef Path,
294  llvm::vfs::Status &Result);
295 
296  /// If path is not absolute and FileSystemOptions set the working
297  /// directory, the path is modified to be relative to the given
298  /// working directory.
299  /// \returns true if \c path changed.
300  bool FixupRelativePath(SmallVectorImpl<char> &path) const;
301 
302  /// Makes \c Path absolute taking into account FileSystemOptions and the
303  /// working directory option.
304  /// \returns true if \c Path changed to absolute.
305  bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
306 
307  /// Produce an array mapping from the unique IDs assigned to each
308  /// file to the corresponding FileEntry pointer.
309  void GetUniqueIDMapping(
310  SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
311 
312  /// Retrieve the canonical name for a given directory.
313  ///
314  /// This is a very expensive operation, despite its results being cached,
315  /// and should only be used when the physical layout of the file system is
316  /// required, which is (almost) never.
317  StringRef getCanonicalName(const DirectoryEntry *Dir);
318 
319  /// Retrieve the canonical name for a given file.
320  ///
321  /// This is a very expensive operation, despite its results being cached,
322  /// and should only be used when the physical layout of the file system is
323  /// required, which is (almost) never.
324  StringRef getCanonicalName(const FileEntry *File);
325 
326  void PrintStats() const;
327 };
328 
329 } // end namespace clang
330 
331 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H
clang::FileManager::getNoncachedStatValue
std::error_code getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result)
Get the 'stat' information for the given Path.
Definition: FileManager.cpp:583
clang::FileManager::getOptionalFileRef
llvm::Optional< FileEntryRef > getOptionalFileRef(StringRef Filename, bool OpenFile=false, bool CacheFailure=true)
Get a FileEntryRef if it exists, without doing anything on error.
Definition: FileManager.h:232
llvm
Definition: Dominators.h:30
clang::FileManager::FileManager
FileManager(const FileSystemOptions &FileSystemOpts, IntrusiveRefCntPtr< llvm::vfs::FileSystem > FS=nullptr)
Construct a file manager, optionally with a custom VFS.
Definition: FileManager.cpp:51
clang::FileEntryRef
A reference to a FileEntry that includes the name of the file as it was accessed by the FileManager's...
Definition: FileEntry.h:60
clang::FileManager::GetUniqueIDMapping
void GetUniqueIDMapping(SmallVectorImpl< const FileEntry * > &UIDToFiles) const
Produce an array mapping from the unique IDs assigned to each file to the corresponding FileEntry poi...
Definition: FileManager.cpp:595
clang::FileManager::setStatCache
void setStatCache(std::unique_ptr< FileSystemStatCache > statCache)
Installs the provided FileSystemStatCache object within the FileManager.
Definition: FileManager.cpp:63
llvm::SmallVector
Definition: LLVM.h:38
clang::FileManager::clearStatCache
void clearStatCache()
Removes the FileSystemStatCache object from the manager.
Definition: FileManager.cpp:68
clang::FileManager::getFileRef
llvm::Expected< FileEntryRef > getFileRef(StringRef Filename, bool OpenFile=false, bool CacheFailure=true)
Lookup, cache, and verify the specified file (real or virtual).
Definition: FileManager.cpp:204
Filename
StringRef Filename
Definition: Format.cpp:2379
llvm::Optional< FileEntryRef >
DirectoryEntry.h
llvm::Expected
Definition: LLVM.h:41
clang::FileManager::getOptionalDirectoryRef
llvm::Optional< DirectoryEntryRef > getOptionalDirectoryRef(StringRef DirName, bool CacheFailure=true)
Get a DirectoryEntryRef if it exists, without doing anything on error.
Definition: FileManager.h:168
llvm::RefCountedBase
Definition: LLVM.h:49
clang::FileSystemOptions
Keeps track of options that affect how file operations are performed.
Definition: FileSystemOptions.h:22
FileEntry.h
clang::FileManager::getBufferForFile
llvm::ErrorOr< std::unique_ptr< llvm::MemoryBuffer > > getBufferForFile(StringRef Filename, bool isVolatile=false, bool RequiresNullTerminator=true)
Definition: FileManager.h:275
clang::FileManager::getFileSystemOpts
const FileSystemOptions & getFileSystemOpts() const
Definition: FileManager.h:241
clang::FileManager::getVirtualFileSystem
llvm::vfs::FileSystem & getVirtualFileSystem() const
Definition: FileManager.h:243
clang::DirectoryEntry
Cached information about one directory (either on disk or in the virtual file system).
Definition: DirectoryEntry.h:33
clang::FileManager::setVirtualFileSystem
void setVirtualFileSystem(IntrusiveRefCntPtr< llvm::vfs::FileSystem > FS)
Definition: FileManager.h:245
clang::FileManager::getDirectoryRef
llvm::Expected< DirectoryEntryRef > getDirectoryRef(StringRef DirName, bool CacheFailure=true)
Lookup, cache, and verify the specified directory (real or virtual).
Definition: FileManager.cpp:118
clang::FileManager::FixupRelativePath
bool FixupRelativePath(SmallVectorImpl< char > &path) const
If path is not absolute and FileSystemOptions set the working directory, the path is modified to be r...
Definition: FileManager.cpp:485
clang::FileManager::getFileSystemOpts
FileSystemOptions & getFileSystemOpts()
Returns the current file system options.
Definition: FileManager.h:240
clang::FileEntry
Cached information about one file (either on disk or in the virtual file system).
Definition: FileEntry.h:331
clang::FileManager::PrintStats
void PrintStats() const
Definition: FileManager.cpp:648
clang::FileManager::getVirtualFileRef
FileEntryRef getVirtualFileRef(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...
Definition: FileManager.cpp:377
clang::FileManager::getBufferForFile
llvm::ErrorOr< std::unique_ptr< llvm::MemoryBuffer > > getBufferForFile(const FileEntry *Entry, bool isVolatile=false, bool RequiresNullTerminator=true)
Open the specified file as a MemoryBuffer, returning a new MemoryBuffer if successful,...
Definition: FileManager.cpp:521
clang::FileManager::getNumUniqueRealFiles
size_t getNumUniqueRealFiles() const
Returns the number of unique real file entries cached by the file manager.
Definition: FileManager.h:151
LLVM.h
clang::FileManager::~FileManager
~FileManager()
clang::FileManager::makeAbsolutePath
bool makeAbsolutePath(SmallVectorImpl< char > &Path) const
Makes Path absolute taking into account FileSystemOptions and the working directory option.
Definition: FileManager.cpp:498
clang
Definition: CalledOnceCheck.h:17
clang::FileManager
Implements support for file system lookup, file system caching, and directory search management.
Definition: FileManager.h:53
clang::FileManager::getCanonicalName
StringRef getCanonicalName(const DirectoryEntry *Dir)
Retrieve the canonical name for a given directory.
Definition: FileManager.cpp:616
clang::FileManager::getSTDIN
llvm::Expected< FileEntryRef > getSTDIN()
Get the FileEntryRef for stdin, returning an error if stdin cannot be read.
Definition: FileManager.cpp:353
clang::FileManager::getDirectory
llvm::ErrorOr< const DirectoryEntry * > getDirectory(StringRef DirName, bool CacheFailure=true)
Lookup, cache, and verify the specified directory (real or virtual).
Definition: FileManager.cpp:188
clang::FileManager::getFile
llvm::ErrorOr< const FileEntry * > getFile(StringRef Filename, bool OpenFile=false, bool CacheFailure=true)
Lookup, cache, and verify the specified file (real or virtual).
Definition: FileManager.cpp:196
FileSystemOptions.h
llvm::SmallVectorImpl< char >
clang::FileManager::getVirtualFile
const FileEntry * getVirtualFile(StringRef Filename, off_t Size, time_t ModificationTime)
Definition: FileManager.cpp:372
llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem >
clang::FileManager::getBypassFile
llvm::Optional< FileEntryRef > getBypassFile(FileEntryRef VFE)
Retrieve a FileEntry that bypasses VFE, which is expected to be a virtual file entry,...
Definition: FileManager.cpp:453