1 //===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \brief Defines the clang::FileManager interface and associated types.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
16 #define LLVM_CLANG_BASIC_FILEMANAGER_H
18 #include "clang/Basic/FileSystemOptions.h"
19 #include "clang/Basic/VirtualFileSystem.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/IntrusiveRefCntPtr.h"
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/ADT/StringMap.h"
24 #include "llvm/ADT/StringRef.h"
25 #include "llvm/Support/Allocator.h"
26 #include "llvm/Support/ErrorOr.h"
27 #include "llvm/Support/FileSystem.h"
37 } // end namespace llvm
41 class FileSystemStatCache;
43 /// \brief Cached information about one directory (either on disk or in
44 /// the virtual file system).
45 class DirectoryEntry {
46 friend class FileManager;
48 StringRef Name; // Name of the directory.
51 StringRef getName() const { return Name; }
54 /// \brief Cached information about one file (either on disk
55 /// or in the virtual file system).
57 /// If the 'File' member is valid, then this FileEntry has an open file
58 /// descriptor for the file.
60 friend class FileManager;
62 StringRef Name; // Name of the file.
63 std::string RealPathName; // Real path to the file; could be empty.
64 off_t Size; // File size in bytes.
65 time_t ModTime; // Modification time of file.
66 const DirectoryEntry *Dir; // Directory file lives in.
67 unsigned UID; // A unique (small) ID for the file.
68 llvm::sys::fs::UniqueID UniqueID;
71 bool IsValid; // Is this \c FileEntry initialized and valid?
73 /// \brief The open file, if it is owned by the \p FileEntry.
74 mutable std::unique_ptr<vfs::File> File;
78 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false)
81 FileEntry(const FileEntry &) = delete;
82 FileEntry &operator=(const FileEntry &) = delete;
84 StringRef getName() const { return Name; }
85 StringRef tryGetRealPathName() const { return RealPathName; }
86 bool isValid() const { return IsValid; }
87 off_t getSize() const { return Size; }
88 unsigned getUID() const { return UID; }
89 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
90 bool isInPCH() const { return InPCH; }
91 time_t getModificationTime() const { return ModTime; }
93 /// \brief Return the directory the file lives in.
94 const DirectoryEntry *getDir() const { return Dir; }
96 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
98 /// \brief Check whether the file is a named pipe (and thus can't be opened by
99 /// the native FileManager methods).
100 bool isNamedPipe() const { return IsNamedPipe; }
102 void closeFile() const {
103 File.reset(); // rely on destructor to close File
109 /// \brief Implements support for file system lookup, file system caching,
110 /// and directory search management.
112 /// This also handles more advanced properties, such as uniquing files based
113 /// on "inode", so that a file with two names (e.g. symlinked) will be treated
114 /// as a single file.
116 class FileManager : public RefCountedBase<FileManager> {
117 IntrusiveRefCntPtr<vfs::FileSystem> FS;
118 FileSystemOptions FileSystemOpts;
120 /// \brief Cache for existing real directories.
121 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
123 /// \brief Cache for existing real files.
124 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
126 /// \brief The virtual directories that we have allocated.
128 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
129 /// directories (foo/ and foo/bar/) here.
130 SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries;
131 /// \brief The virtual files that we have allocated.
132 SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries;
134 /// \brief A cache that maps paths to directory entries (either real or
135 /// virtual) we have looked up
137 /// The actual Entries for real directories/files are
138 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
139 /// for virtual directories/files are owned by
140 /// VirtualDirectoryEntries/VirtualFileEntries above.
142 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
144 /// \brief A cache that maps paths to file entries (either real or
145 /// virtual) we have looked up.
147 /// \see SeenDirEntries
148 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
150 /// \brief The canonical names of directories.
151 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
153 /// \brief Storage for canonical names that we have computed.
154 llvm::BumpPtrAllocator CanonicalNameStorage;
156 /// \brief Each FileEntry we create is assigned a unique ID #.
158 unsigned NextFileUID;
161 unsigned NumDirLookups, NumFileLookups;
162 unsigned NumDirCacheMisses, NumFileCacheMisses;
165 std::unique_ptr<FileSystemStatCache> StatCache;
167 bool getStatValue(StringRef Path, FileData &Data, bool isFile,
168 std::unique_ptr<vfs::File> *F);
170 /// Add all ancestors of the given path (pointing to either a file
171 /// or a directory) as virtual directories.
172 void addAncestorsAsVirtualDirs(StringRef Path);
175 FileManager(const FileSystemOptions &FileSystemOpts,
176 IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr);
179 /// \brief Installs the provided FileSystemStatCache object within
182 /// Ownership of this object is transferred to the FileManager.
184 /// \param statCache the new stat cache to install. Ownership of this
185 /// object is transferred to the FileManager.
187 /// \param AtBeginning whether this new stat cache must be installed at the
188 /// beginning of the chain of stat caches. Otherwise, it will be added to
189 /// the end of the chain.
190 void addStatCache(std::unique_ptr<FileSystemStatCache> statCache,
191 bool AtBeginning = false);
193 /// \brief Removes the specified FileSystemStatCache object from the manager.
194 void removeStatCache(FileSystemStatCache *statCache);
196 /// \brief Removes all FileSystemStatCache objects from the manager.
197 void clearStatCaches();
199 /// \brief Lookup, cache, and verify the specified directory (real or
202 /// This returns NULL if the directory doesn't exist.
204 /// \param CacheFailure If true and the file does not exist, we'll cache
205 /// the failure to find this file.
206 const DirectoryEntry *getDirectory(StringRef DirName,
207 bool CacheFailure = true);
209 /// \brief Lookup, cache, and verify the specified file (real or
212 /// This returns NULL if the file doesn't exist.
214 /// \param OpenFile if true and the file exists, it will be opened.
216 /// \param CacheFailure If true and the file does not exist, we'll cache
217 /// the failure to find this file.
218 const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
219 bool CacheFailure = true);
221 /// \brief Returns the current file system options
222 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
223 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
225 IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const {
229 /// \brief Retrieve a file entry for a "virtual" file that acts as
230 /// if there were a file with the given name on disk.
232 /// The file itself is not accessed.
233 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
234 time_t ModificationTime);
236 /// \brief Open the specified file as a MemoryBuffer, returning a new
237 /// MemoryBuffer if successful, otherwise returning null.
238 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
239 getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
240 bool ShouldCloseOpenFile = true);
241 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
242 getBufferForFile(StringRef Filename);
244 /// \brief Get the 'stat' information for the given \p Path.
246 /// If the path is relative, it will be resolved against the WorkingDir of the
247 /// FileManager's FileSystemOptions.
249 /// \returns false on success, true on error.
250 bool getNoncachedStatValue(StringRef Path,
251 vfs::Status &Result);
253 /// \brief Remove the real file \p Entry from the cache.
254 void invalidateCache(const FileEntry *Entry);
256 /// \brief If path is not absolute and FileSystemOptions set the working
257 /// directory, the path is modified to be relative to the given
258 /// working directory.
259 /// \returns true if \c path changed.
260 bool FixupRelativePath(SmallVectorImpl<char> &path) const;
262 /// Makes \c Path absolute taking into account FileSystemOptions and the
263 /// working directory option.
264 /// \returns true if \c Path changed to absolute.
265 bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
267 /// \brief Produce an array mapping from the unique IDs assigned to each
268 /// file to the corresponding FileEntry pointer.
269 void GetUniqueIDMapping(
270 SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
272 /// \brief Modifies the size and modification time of a previously created
273 /// FileEntry. Use with caution.
274 static void modifyFileEntry(FileEntry *File, off_t Size,
275 time_t ModificationTime);
277 /// \brief Retrieve the canonical name for a given directory.
279 /// This is a very expensive operation, despite its results being cached,
280 /// and should only be used when the physical layout of the file system is
281 /// required, which is (almost) never.
282 StringRef getCanonicalName(const DirectoryEntry *Dir);
284 void PrintStats() const;
287 } // end namespace clang
289 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H