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 /// \brief 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/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" 28 #include <ctime> 29 #include <memory> 30 #include <map> 31 #include <string> 32 33 namespace llvm { 34 35 class MemoryBuffer; 36 37 } // end namespace llvm 38 39 namespace clang { 40 41 class FileSystemStatCache; 42 43 /// \brief Cached information about one directory (either on disk or in 44 /// the virtual file system). 45 class DirectoryEntry { 46 friend class FileManager; 47 48 StringRef Name; // Name of the directory. 49 50 public: 51 StringRef getName() const { return Name; } 52 }; 53 54 /// \brief Cached information about one file (either on disk 55 /// or in the virtual file system). 56 /// 57 /// If the 'File' member is valid, then this FileEntry has an open file 58 /// descriptor for the file. 59 class FileEntry { 60 friend class FileManager; 61 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; 69 bool IsNamedPipe; 70 bool InPCH; 71 bool IsValid; // Is this \c FileEntry initialized and valid? 72 73 /// \brief The open file, if it is owned by the \p FileEntry. 74 mutable std::unique_ptr<vfs::File> File; 75 76 public: 77 FileEntry() 78 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false) 79 {} 80 81 FileEntry(const FileEntry &) = delete; 82 FileEntry &operator=(const FileEntry &) = delete; 83 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; } 92 93 /// \brief Return the directory the file lives in. 94 const DirectoryEntry *getDir() const { return Dir; } 95 96 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; } 97 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; } 101 102 void closeFile() const { 103 File.reset(); // rely on destructor to close File 104 } 105 }; 106 107 struct FileData; 108 109 /// \brief Implements support for file system lookup, file system caching, 110 /// and directory search management. 111 /// 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. 115 /// 116 class FileManager : public RefCountedBase<FileManager> { 117 IntrusiveRefCntPtr<vfs::FileSystem> FS; 118 FileSystemOptions FileSystemOpts; 119 120 /// \brief Cache for existing real directories. 121 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs; 122 123 /// \brief Cache for existing real files. 124 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles; 125 126 /// \brief The virtual directories that we have allocated. 127 /// 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; 133 134 /// \brief A cache that maps paths to directory entries (either real or 135 /// virtual) we have looked up 136 /// 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. 141 /// 142 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries; 143 144 /// \brief A cache that maps paths to file entries (either real or 145 /// virtual) we have looked up. 146 /// 147 /// \see SeenDirEntries 148 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries; 149 150 /// \brief The canonical names of directories. 151 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames; 152 153 /// \brief Storage for canonical names that we have computed. 154 llvm::BumpPtrAllocator CanonicalNameStorage; 155 156 /// \brief Each FileEntry we create is assigned a unique ID #. 157 /// 158 unsigned NextFileUID; 159 160 // Statistics. 161 unsigned NumDirLookups, NumFileLookups; 162 unsigned NumDirCacheMisses, NumFileCacheMisses; 163 164 // Caching. 165 std::unique_ptr<FileSystemStatCache> StatCache; 166 167 bool getStatValue(StringRef Path, FileData &Data, bool isFile, 168 std::unique_ptr<vfs::File> *F); 169 170 /// Add all ancestors of the given path (pointing to either a file 171 /// or a directory) as virtual directories. 172 void addAncestorsAsVirtualDirs(StringRef Path); 173 174 public: 175 FileManager(const FileSystemOptions &FileSystemOpts, 176 IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr); 177 ~FileManager(); 178 179 /// \brief Installs the provided FileSystemStatCache object within 180 /// the FileManager. 181 /// 182 /// Ownership of this object is transferred to the FileManager. 183 /// 184 /// \param statCache the new stat cache to install. Ownership of this 185 /// object is transferred to the FileManager. 186 /// 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); 192 193 /// \brief Removes the specified FileSystemStatCache object from the manager. 194 void removeStatCache(FileSystemStatCache *statCache); 195 196 /// \brief Removes all FileSystemStatCache objects from the manager. 197 void clearStatCaches(); 198 199 /// \brief 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 /// \brief 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 /// \brief Returns the current file system options 222 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; } 223 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; } 224 225 IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const { 226 return FS; 227 } 228 229 /// \brief Retrieve a file entry for a "virtual" file that acts as 230 /// if there were a file with the given name on disk. 231 /// 232 /// The file itself is not accessed. 233 const FileEntry *getVirtualFile(StringRef Filename, off_t Size, 234 time_t ModificationTime); 235 236 /// \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); 243 244 /// \brief 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, 251 vfs::Status &Result); 252 253 /// \brief Remove the real file \p Entry from the cache. 254 void invalidateCache(const FileEntry *Entry); 255 256 /// \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; 261 262 /// 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; 266 267 /// \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; 271 272 /// \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); 276 277 /// \brief Retrieve the canonical name for a given directory. 278 /// 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); 283 284 void PrintStats() const; 285 }; 286 287 } // end namespace clang 288 289 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H 290
