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/LLVM.h" 20 #include "clang/Basic/VirtualFileSystem.h" 21 #include "llvm/ADT/DenseMap.h" 22 #include "llvm/ADT/IntrusiveRefCntPtr.h" 23 #include "llvm/ADT/SmallVector.h" 24 #include "llvm/ADT/StringMap.h" 25 #include "llvm/ADT/StringRef.h" 26 #include "llvm/Support/Allocator.h" 27 #include <memory> 28 #include <map> 29 30 namespace llvm { 31 class MemoryBuffer; 32 } 33 34 namespace clang { 35 class FileManager; 36 class FileSystemStatCache; 37 38 /// \brief Cached information about one directory (either on disk or in 39 /// the virtual file system). 40 class DirectoryEntry { 41 const char *Name; // Name of the directory. 42 friend class FileManager; 43 public: 44 DirectoryEntry() : Name(nullptr) {} 45 const char *getName() const { return Name; } 46 }; 47 48 /// \brief Cached information about one file (either on disk 49 /// or in the virtual file system). 50 /// 51 /// If the 'File' member is valid, then this FileEntry has an open file 52 /// descriptor for the file. 53 class FileEntry { 54 const char *Name; // Name of the file. 55 std::string RealPathName; // Real path to the file; could be empty. 56 off_t Size; // File size in bytes. 57 time_t ModTime; // Modification time of file. 58 const DirectoryEntry *Dir; // Directory file lives in. 59 unsigned UID; // A unique (small) ID for the file. 60 llvm::sys::fs::UniqueID UniqueID; 61 bool IsNamedPipe; 62 bool InPCH; 63 bool IsValid; // Is this \c FileEntry initialized and valid? 64 65 /// \brief The open file, if it is owned by the \p FileEntry. 66 mutable std::unique_ptr<vfs::File> File; 67 friend class FileManager; 68 69 void operator=(const FileEntry &) = delete; 70 71 public: 72 FileEntry() 73 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false) 74 {} 75 76 // FIXME: this is here to allow putting FileEntry in std::map. Once we have 77 // emplace, we shouldn't need a copy constructor anymore. 78 /// Intentionally does not copy fields that are not set in an uninitialized 79 /// \c FileEntry. 80 FileEntry(const FileEntry &FE) : UniqueID(FE.UniqueID), 81 IsNamedPipe(FE.IsNamedPipe), InPCH(FE.InPCH), IsValid(FE.IsValid) { 82 assert(!isValid() && "Cannot copy an initialized FileEntry"); 83 } 84 85 const char *getName() const { return Name; } 86 StringRef tryGetRealPathName() const { return RealPathName; } 87 bool isValid() const { return IsValid; } 88 off_t getSize() const { return Size; } 89 unsigned getUID() const { return UID; } 90 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; } 91 bool isInPCH() const { return InPCH; } 92 time_t getModificationTime() const { return ModTime; } 93 94 /// \brief Return the directory the file lives in. 95 const DirectoryEntry *getDir() const { return Dir; } 96 97 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; } 98 99 /// \brief Check whether the file is a named pipe (and thus can't be opened by 100 /// the native FileManager methods). 101 bool isNamedPipe() const { return IsNamedPipe; } 102 103 void closeFile() const { 104 File.reset(); // rely on destructor to close File 105 } 106 }; 107 108 struct FileData; 109 110 /// \brief Implements support for file system lookup, file system caching, 111 /// and directory search management. 112 /// 113 /// This also handles more advanced properties, such as uniquing files based 114 /// on "inode", so that a file with two names (e.g. symlinked) will be treated 115 /// as a single file. 116 /// 117 class FileManager : public RefCountedBase<FileManager> { 118 IntrusiveRefCntPtr<vfs::FileSystem> FS; 119 FileSystemOptions FileSystemOpts; 120 121 /// \brief Cache for existing real directories. 122 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs; 123 124 /// \brief Cache for existing real files. 125 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles; 126 127 /// \brief The virtual directories that we have allocated. 128 /// 129 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent 130 /// directories (foo/ and foo/bar/) here. 131 SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries; 132 /// \brief The virtual files that we have allocated. 133 SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries; 134 135 /// \brief A cache that maps paths to directory entries (either real or 136 /// virtual) we have looked up 137 /// 138 /// The actual Entries for real directories/files are 139 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries 140 /// for virtual directories/files are owned by 141 /// VirtualDirectoryEntries/VirtualFileEntries above. 142 /// 143 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries; 144 145 /// \brief A cache that maps paths to file entries (either real or 146 /// virtual) we have looked up. 147 /// 148 /// \see SeenDirEntries 149 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries; 150 151 /// \brief The canonical names of directories. 152 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames; 153 154 /// \brief Storage for canonical names that we have computed. 155 llvm::BumpPtrAllocator CanonicalNameStorage; 156 157 /// \brief Each FileEntry we create is assigned a unique ID #. 158 /// 159 unsigned NextFileUID; 160 161 // Statistics. 162 unsigned NumDirLookups, NumFileLookups; 163 unsigned NumDirCacheMisses, NumFileCacheMisses; 164 165 // Caching. 166 std::unique_ptr<FileSystemStatCache> StatCache; 167 168 bool getStatValue(const char *Path, FileData &Data, bool isFile, 169 std::unique_ptr<vfs::File> *F); 170 171 /// Add all ancestors of the given path (pointing to either a file 172 /// or a directory) as virtual directories. 173 void addAncestorsAsVirtualDirs(StringRef Path); 174 175 public: 176 FileManager(const FileSystemOptions &FileSystemOpts, 177 IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr); 178 ~FileManager(); 179 180 /// \brief Installs the provided FileSystemStatCache object within 181 /// the FileManager. 182 /// 183 /// Ownership of this object is transferred to the FileManager. 184 /// 185 /// \param statCache the new stat cache to install. Ownership of this 186 /// object is transferred to the FileManager. 187 /// 188 /// \param AtBeginning whether this new stat cache must be installed at the 189 /// beginning of the chain of stat caches. Otherwise, it will be added to 190 /// the end of the chain. 191 void addStatCache(std::unique_ptr<FileSystemStatCache> statCache, 192 bool AtBeginning = false); 193 194 /// \brief Removes the specified FileSystemStatCache object from the manager. 195 void removeStatCache(FileSystemStatCache *statCache); 196 197 /// \brief Removes all FileSystemStatCache objects from the manager. 198 void clearStatCaches(); 199 200 /// \brief Lookup, cache, and verify the specified directory (real or 201 /// virtual). 202 /// 203 /// This returns NULL if the directory doesn't exist. 204 /// 205 /// \param CacheFailure If true and the file does not exist, we'll cache 206 /// the failure to find this file. 207 const DirectoryEntry *getDirectory(StringRef DirName, 208 bool CacheFailure = true); 209 210 /// \brief Lookup, cache, and verify the specified file (real or 211 /// virtual). 212 /// 213 /// This returns NULL if the file doesn't exist. 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. 219 const FileEntry *getFile(StringRef Filename, bool OpenFile = false, 220 bool CacheFailure = true); 221 222 /// \brief Returns the current file system options 223 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; } 224 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; } 225 226 IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const { 227 return FS; 228 } 229 230 /// \brief Retrieve a file entry for a "virtual" file that acts as 231 /// if there were a file with the given name on disk. 232 /// 233 /// The file itself is not accessed. 234 const FileEntry *getVirtualFile(StringRef Filename, off_t Size, 235 time_t ModificationTime); 236 237 /// \brief Open the specified file as a MemoryBuffer, returning a new 238 /// MemoryBuffer if successful, otherwise returning null. 239 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 240 getBufferForFile(const FileEntry *Entry, bool isVolatile = false, 241 bool ShouldCloseOpenFile = true); 242 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 243 getBufferForFile(StringRef Filename); 244 245 /// \brief Get the 'stat' information for the given \p Path. 246 /// 247 /// If the path is relative, it will be resolved against the WorkingDir of the 248 /// FileManager's FileSystemOptions. 249 /// 250 /// \returns false on success, true on error. 251 bool getNoncachedStatValue(StringRef Path, 252 vfs::Status &Result); 253 254 /// \brief Remove the real file \p Entry from the cache. 255 void invalidateCache(const FileEntry *Entry); 256 257 /// \brief If path is not absolute and FileSystemOptions set the working 258 /// directory, the path is modified to be relative to the given 259 /// working directory. 260 /// \returns true if \c path changed. 261 bool FixupRelativePath(SmallVectorImpl<char> &path) const; 262 263 /// Makes \c Path absolute taking into account FileSystemOptions and the 264 /// working directory option. 265 /// \returns true if \c Path changed to absolute. 266 bool makeAbsolutePath(SmallVectorImpl<char> &Path) const; 267 268 /// \brief Produce an array mapping from the unique IDs assigned to each 269 /// file to the corresponding FileEntry pointer. 270 void GetUniqueIDMapping( 271 SmallVectorImpl<const FileEntry *> &UIDToFiles) const; 272 273 /// \brief Modifies the size and modification time of a previously created 274 /// FileEntry. Use with caution. 275 static void modifyFileEntry(FileEntry *File, off_t Size, 276 time_t ModificationTime); 277 278 /// \brief Retrieve the canonical name for a given directory. 279 /// 280 /// This is a very expensive operation, despite its results being cached, 281 /// and should only be used when the physical layout of the file system is 282 /// required, which is (almost) never. 283 StringRef getCanonicalName(const DirectoryEntry *Dir); 284 285 void PrintStats() const; 286 }; 287 288 } // end namespace clang 289 290 #endif 291
