1 //===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
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
7 //===----------------------------------------------------------------------===//
10 /// Defines the clang::FileManager interface and associated types.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
15 #define LLVM_CLANG_BASIC_FILEMANAGER_H
17 #include "clang/Basic/DirectoryEntry.h"
18 #include "clang/Basic/FileEntry.h"
19 #include "clang/Basic/FileSystemOptions.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"
40 } // end namespace llvm
44 class FileSystemStatCache;
46 /// Implements support for file system lookup, file system caching,
47 /// and directory search management.
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
53 class FileManager : public RefCountedBase<FileManager> {
54 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
55 FileSystemOptions FileSystemOpts;
56 llvm::SpecificBumpPtrAllocator<FileEntry> FilesAlloc;
57 llvm::SpecificBumpPtrAllocator<DirectoryEntry> DirsAlloc;
59 /// Cache for existing real directories.
60 llvm::DenseMap<llvm::sys::fs::UniqueID, DirectoryEntry *> UniqueRealDirs;
62 /// Cache for existing real files.
63 llvm::DenseMap<llvm::sys::fs::UniqueID, FileEntry *> UniqueRealFiles;
65 /// The virtual directories that we have allocated.
67 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
68 /// directories (foo/ and foo/bar/) here.
69 SmallVector<DirectoryEntry *, 4> VirtualDirectoryEntries;
70 /// The virtual files that we have allocated.
71 SmallVector<FileEntry *, 4> VirtualFileEntries;
73 /// A set of files that bypass the maps and uniquing. They can have
74 /// conflicting filenames.
75 SmallVector<FileEntry *, 0> BypassFileEntries;
77 /// A cache that maps paths to directory entries (either real or
78 /// virtual) we have looked up, or an error that occurred when we looked up
81 /// The actual Entries for real directories/files are
82 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
83 /// for virtual directories/files are owned by
84 /// VirtualDirectoryEntries/VirtualFileEntries above.
86 llvm::StringMap<llvm::ErrorOr<DirectoryEntry &>, llvm::BumpPtrAllocator>
89 /// A cache that maps paths to file entries (either real or
90 /// virtual) we have looked up, or an error that occurred when we looked up
93 /// \see SeenDirEntries
94 llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>, llvm::BumpPtrAllocator>
97 /// A mirror of SeenFileEntries to give fake answers for getBypassFile().
99 /// Don't bother hooking up a BumpPtrAllocator. This should be rarely used,
100 /// and only on error paths.
101 std::unique_ptr<llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>>>
102 SeenBypassFileEntries;
104 /// The file entry for stdin, if it has been accessed through the FileManager.
105 OptionalFileEntryRef STDIN;
107 /// The canonical names of files and directories .
108 llvm::DenseMap<const void *, llvm::StringRef> CanonicalNames;
110 /// Storage for canonical names that we have computed.
111 llvm::BumpPtrAllocator CanonicalNameStorage;
113 /// Each FileEntry we create is assigned a unique ID #.
115 unsigned NextFileUID;
118 std::unique_ptr<FileSystemStatCache> StatCache;
120 std::error_code getStatValue(StringRef Path, llvm::vfs::Status &Status,
122 std::unique_ptr<llvm::vfs::File> *F);
124 /// Add all ancestors of the given path (pointing to either a file
125 /// or a directory) as virtual directories.
126 void addAncestorsAsVirtualDirs(StringRef Path);
128 /// Fills the RealPathName in file entry.
129 void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName);
132 /// Construct a file manager, optionally with a custom VFS.
134 /// \param FS if non-null, the VFS to use. Otherwise uses
135 /// llvm::vfs::getRealFileSystem().
136 FileManager(const FileSystemOptions &FileSystemOpts,
137 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
140 /// Installs the provided FileSystemStatCache object within
143 /// Ownership of this object is transferred to the FileManager.
145 /// \param statCache the new stat cache to install. Ownership of this
146 /// object is transferred to the FileManager.
147 void setStatCache(std::unique_ptr<FileSystemStatCache> statCache);
149 /// Removes the FileSystemStatCache object from the manager.
150 void clearStatCache();
152 /// Returns the number of unique real file entries cached by the file manager.
153 size_t getNumUniqueRealFiles() const { return UniqueRealFiles.size(); }
155 /// Lookup, cache, and verify the specified directory (real or
158 /// This returns a \c std::error_code if there was an error reading the
159 /// directory. On success, returns the reference to the directory entry
160 /// together with the exact path that was used to access a file by a
161 /// particular call to getDirectoryRef.
163 /// \param CacheFailure If true and the file does not exist, we'll cache
164 /// the failure to find this file.
165 llvm::Expected<DirectoryEntryRef> getDirectoryRef(StringRef DirName,
166 bool CacheFailure = true);
168 /// Get a \c DirectoryEntryRef if it exists, without doing anything on error.
169 OptionalDirectoryEntryRef getOptionalDirectoryRef(StringRef DirName,
170 bool CacheFailure = true) {
171 return llvm::expectedToOptional(getDirectoryRef(DirName, CacheFailure));
174 /// Lookup, cache, and verify the specified directory (real or
177 /// This function is deprecated and will be removed at some point in the
178 /// future, new clients should use
179 /// \c getDirectoryRef.
181 /// This returns a \c std::error_code if there was an error reading the
182 /// directory. If there is no error, the DirectoryEntry is guaranteed to be
185 /// \param CacheFailure If true and the file does not exist, we'll cache
186 /// the failure to find this file.
187 llvm::ErrorOr<const DirectoryEntry *>
188 getDirectory(StringRef DirName, bool CacheFailure = true);
190 /// Lookup, cache, and verify the specified file (real or
193 /// This function is deprecated and will be removed at some point in the
194 /// future, new clients should use
197 /// This returns a \c std::error_code if there was an error loading the file.
198 /// If there is no error, the FileEntry is guaranteed to be non-NULL.
200 /// \param OpenFile if true and the file exists, it will be opened.
202 /// \param CacheFailure If true and the file does not exist, we'll cache
203 /// the failure to find this file.
204 llvm::ErrorOr<const FileEntry *>
205 getFile(StringRef Filename, bool OpenFile = false, bool CacheFailure = true);
207 /// Lookup, cache, and verify the specified file (real or virtual). Return the
208 /// reference to the file entry together with the exact path that was used to
209 /// access a file by a particular call to getFileRef. If the underlying VFS is
210 /// a redirecting VFS that uses external file names, the returned FileEntryRef
211 /// will use the external name instead of the filename that was passed to this
214 /// This returns a \c std::error_code if there was an error loading the file,
215 /// or a \c FileEntryRef otherwise.
217 /// \param OpenFile if true and the file exists, it will be opened.
219 /// \param CacheFailure If true and the file does not exist, we'll cache
220 /// the failure to find this file.
221 llvm::Expected<FileEntryRef> getFileRef(StringRef Filename,
222 bool OpenFile = false,
223 bool CacheFailure = true);
225 /// Get the FileEntryRef for stdin, returning an error if stdin cannot be
228 /// This reads and caches stdin before returning. Subsequent calls return the
229 /// same file entry, and a reference to the cached input is returned by calls
230 /// to getBufferForFile.
231 llvm::Expected<FileEntryRef> getSTDIN();
233 /// Get a FileEntryRef if it exists, without doing anything on error.
234 OptionalFileEntryRef getOptionalFileRef(StringRef Filename,
235 bool OpenFile = false,
236 bool CacheFailure = true) {
237 return llvm::expectedToOptional(
238 getFileRef(Filename, OpenFile, CacheFailure));
241 /// Returns the current file system options
242 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
243 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
245 llvm::vfs::FileSystem &getVirtualFileSystem() const { return *FS; }
246 llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
247 getVirtualFileSystemPtr() const {
251 void setVirtualFileSystem(IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
252 this->FS = std::move(FS);
255 /// Retrieve a file entry for a "virtual" file that acts as
256 /// if there were a file with the given name on disk.
258 /// The file itself is not accessed.
259 FileEntryRef getVirtualFileRef(StringRef Filename, off_t Size,
260 time_t ModificationTime);
262 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
263 time_t ModificationTime);
265 /// Retrieve a FileEntry that bypasses VFE, which is expected to be a virtual
266 /// file entry, to access the real file. The returned FileEntry will have
267 /// the same filename as FE but a different identity and its own stat.
269 /// This should be used only for rare error recovery paths because it
270 /// bypasses all mapping and uniquing, blindly creating a new FileEntry.
271 /// There is no attempt to deduplicate these; if you bypass the same file
272 /// twice, you get two new file entries.
273 OptionalFileEntryRef getBypassFile(FileEntryRef VFE);
275 /// Open the specified file as a MemoryBuffer, returning a new
276 /// MemoryBuffer if successful, otherwise returning null.
277 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
278 getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
279 bool RequiresNullTerminator = true);
280 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
281 getBufferForFile(StringRef Filename, bool isVolatile = false,
282 bool RequiresNullTerminator = true) {
283 return getBufferForFileImpl(Filename, /*FileSize=*/-1, isVolatile,
284 RequiresNullTerminator);
288 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
289 getBufferForFileImpl(StringRef Filename, int64_t FileSize, bool isVolatile,
290 bool RequiresNullTerminator);
293 /// Get the 'stat' information for the given \p Path.
295 /// If the path is relative, it will be resolved against the WorkingDir of the
296 /// FileManager's FileSystemOptions.
298 /// \returns a \c std::error_code describing an error, if there was one
299 std::error_code getNoncachedStatValue(StringRef Path,
300 llvm::vfs::Status &Result);
302 /// If path is not absolute and FileSystemOptions set the working
303 /// directory, the path is modified to be relative to the given
304 /// working directory.
305 /// \returns true if \c path changed.
306 bool FixupRelativePath(SmallVectorImpl<char> &path) const;
308 /// Makes \c Path absolute taking into account FileSystemOptions and the
309 /// working directory option.
310 /// \returns true if \c Path changed to absolute.
311 bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
313 /// Produce an array mapping from the unique IDs assigned to each
314 /// file to the corresponding FileEntry pointer.
315 void GetUniqueIDMapping(
316 SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
318 /// Retrieve the canonical name for a given directory.
320 /// This is a very expensive operation, despite its results being cached,
321 /// and should only be used when the physical layout of the file system is
322 /// required, which is (almost) never.
323 StringRef getCanonicalName(const DirectoryEntry *Dir);
325 /// Retrieve the canonical name for a given file.
327 /// This is a very expensive operation, despite its results being cached,
328 /// and should only be used when the physical layout of the file system is
329 /// required, which is (almost) never.
330 StringRef getCanonicalName(const FileEntry *File);
332 void PrintStats() const;
335 } // end namespace clang
337 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H