1 //===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===// 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 /// \file 11 /// Defines the clang::FileManager interface and associated types. 12 /// 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CLANG_BASIC_FILEMANAGER_H 16 #define LLVM_CLANG_BASIC_FILEMANAGER_H 17 18 #include "clang/Basic/FileSystemOptions.h" 19 #include "clang/Basic/LLVM.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" 28 #include "llvm/Support/VirtualFileSystem.h" 29 #include <ctime> 30 #include <map> 31 #include <memory> 32 #include <string> 33 34 namespace llvm { 35 36 class MemoryBuffer; 37 38 } // end namespace llvm 39 40 namespace clang { 41 42 class FileSystemStatCache; 43 44 /// Cached information about one directory (either on disk or in 45 /// the virtual file system). 46 class DirectoryEntry { 47 friend class FileManager; 48 49 StringRef Name; // Name of the directory. 50 51 public: getName()52 StringRef getName() const { return Name; } 53 }; 54 55 /// Cached information about one file (either on disk 56 /// or in the virtual file system). 57 /// 58 /// If the 'File' member is valid, then this FileEntry has an open file 59 /// descriptor for the file. 60 class FileEntry { 61 friend class FileManager; 62 63 StringRef Name; // Name of the file. 64 std::string RealPathName; // Real path to the file; could be empty. 65 off_t Size; // File size in bytes. 66 time_t ModTime; // Modification time of file. 67 const DirectoryEntry *Dir; // Directory file lives in. 68 unsigned UID; // A unique (small) ID for the file. 69 llvm::sys::fs::UniqueID UniqueID; 70 bool IsNamedPipe; 71 bool InPCH; 72 bool IsValid; // Is this \c FileEntry initialized and valid? 73 74 /// The open file, if it is owned by the \p FileEntry. 75 mutable std::unique_ptr<llvm::vfs::File> File; 76 77 public: FileEntry()78 FileEntry() 79 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false) 80 {} 81 82 FileEntry(const FileEntry &) = delete; 83 FileEntry &operator=(const FileEntry &) = delete; 84 getName()85 StringRef getName() const { return Name; } tryGetRealPathName()86 StringRef tryGetRealPathName() const { return RealPathName; } isValid()87 bool isValid() const { return IsValid; } getSize()88 off_t getSize() const { return Size; } getUID()89 unsigned getUID() const { return UID; } getUniqueID()90 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; } isInPCH()91 bool isInPCH() const { return InPCH; } getModificationTime()92 time_t getModificationTime() const { return ModTime; } 93 94 /// Return the directory the file lives in. getDir()95 const DirectoryEntry *getDir() const { return Dir; } 96 97 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; } 98 99 /// Check whether the file is a named pipe (and thus can't be opened by 100 /// the native FileManager methods). isNamedPipe()101 bool isNamedPipe() const { return IsNamedPipe; } 102 closeFile()103 void closeFile() const { 104 File.reset(); // rely on destructor to close File 105 } 106 107 // Only for use in tests to see if deferred opens are happening, rather than 108 // relying on RealPathName being empty. isOpenForTests()109 bool isOpenForTests() const { return File != nullptr; } 110 }; 111 112 struct FileData; 113 114 /// Implements support for file system lookup, file system caching, 115 /// and directory search management. 116 /// 117 /// This also handles more advanced properties, such as uniquing files based 118 /// on "inode", so that a file with two names (e.g. symlinked) will be treated 119 /// as a single file. 120 /// 121 class FileManager : public RefCountedBase<FileManager> { 122 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS; 123 FileSystemOptions FileSystemOpts; 124 125 /// Cache for existing real directories. 126 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs; 127 128 /// Cache for existing real files. 129 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles; 130 131 /// The virtual directories that we have allocated. 132 /// 133 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent 134 /// directories (foo/ and foo/bar/) here. 135 SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries; 136 /// The virtual files that we have allocated. 137 SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries; 138 139 /// A cache that maps paths to directory entries (either real or 140 /// virtual) we have looked up 141 /// 142 /// The actual Entries for real directories/files are 143 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries 144 /// for virtual directories/files are owned by 145 /// VirtualDirectoryEntries/VirtualFileEntries above. 146 /// 147 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries; 148 149 /// A cache that maps paths to file entries (either real or 150 /// virtual) we have looked up. 151 /// 152 /// \see SeenDirEntries 153 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries; 154 155 /// The canonical names of directories. 156 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames; 157 158 /// Storage for canonical names that we have computed. 159 llvm::BumpPtrAllocator CanonicalNameStorage; 160 161 /// Each FileEntry we create is assigned a unique ID #. 162 /// 163 unsigned NextFileUID; 164 165 // Statistics. 166 unsigned NumDirLookups, NumFileLookups; 167 unsigned NumDirCacheMisses, NumFileCacheMisses; 168 169 // Caching. 170 std::unique_ptr<FileSystemStatCache> StatCache; 171 172 bool getStatValue(StringRef Path, FileData &Data, bool isFile, 173 std::unique_ptr<llvm::vfs::File> *F); 174 175 /// Add all ancestors of the given path (pointing to either a file 176 /// or a directory) as virtual directories. 177 void addAncestorsAsVirtualDirs(StringRef Path); 178 179 /// Fills the RealPathName in file entry. 180 void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName); 181 182 public: 183 FileManager(const FileSystemOptions &FileSystemOpts, 184 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr); 185 ~FileManager(); 186 187 /// Installs the provided FileSystemStatCache object within 188 /// the FileManager. 189 /// 190 /// Ownership of this object is transferred to the FileManager. 191 /// 192 /// \param statCache the new stat cache to install. Ownership of this 193 /// object is transferred to the FileManager. 194 void setStatCache(std::unique_ptr<FileSystemStatCache> statCache); 195 196 /// Removes the FileSystemStatCache object from the manager. 197 void clearStatCache(); 198 199 /// Lookup, cache, and verify the specified directory (real or 200 /// virtual). 201 /// 202 /// This returns NULL if the directory doesn't exist. 203 /// 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); 208 209 /// Lookup, cache, and verify the specified file (real or 210 /// virtual). 211 /// 212 /// This returns NULL if the file doesn't exist. 213 /// 214 /// \param OpenFile if true and the file exists, it will be opened. 215 /// 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); 220 221 /// Returns the current file system options getFileSystemOpts()222 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; } getFileSystemOpts()223 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; } 224 getVirtualFileSystem()225 IntrusiveRefCntPtr<llvm::vfs::FileSystem> getVirtualFileSystem() const { 226 return FS; 227 } 228 229 /// Retrieve a file entry for a "virtual" file that acts as 230 /// if there were a file with the given name on disk. 231 /// 232 /// The file itself is not accessed. 233 const FileEntry *getVirtualFile(StringRef Filename, off_t Size, 234 time_t ModificationTime); 235 236 /// 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, bool isVolatile = false); 243 244 /// Get the 'stat' information for the given \p Path. 245 /// 246 /// If the path is relative, it will be resolved against the WorkingDir of the 247 /// FileManager's FileSystemOptions. 248 /// 249 /// \returns false on success, true on error. 250 bool getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result); 251 252 /// Remove the real file \p Entry from the cache. 253 void invalidateCache(const FileEntry *Entry); 254 255 /// If path is not absolute and FileSystemOptions set the working 256 /// directory, the path is modified to be relative to the given 257 /// working directory. 258 /// \returns true if \c path changed. 259 bool FixupRelativePath(SmallVectorImpl<char> &path) const; 260 261 /// Makes \c Path absolute taking into account FileSystemOptions and the 262 /// working directory option. 263 /// \returns true if \c Path changed to absolute. 264 bool makeAbsolutePath(SmallVectorImpl<char> &Path) const; 265 266 /// Produce an array mapping from the unique IDs assigned to each 267 /// file to the corresponding FileEntry pointer. 268 void GetUniqueIDMapping( 269 SmallVectorImpl<const FileEntry *> &UIDToFiles) const; 270 271 /// Modifies the size and modification time of a previously created 272 /// FileEntry. Use with caution. 273 static void modifyFileEntry(FileEntry *File, off_t Size, 274 time_t ModificationTime); 275 276 /// Retrieve the canonical name for a given directory. 277 /// 278 /// This is a very expensive operation, despite its results being cached, 279 /// and should only be used when the physical layout of the file system is 280 /// required, which is (almost) never. 281 StringRef getCanonicalName(const DirectoryEntry *Dir); 282 283 void PrintStats() const; 284 }; 285 286 } // end namespace clang 287 288 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H 289