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 off_t Size; // File size in bytes. 56 time_t ModTime; // Modification time of file. 57 const DirectoryEntry *Dir; // Directory file lives in. 58 unsigned UID; // A unique (small) ID for the file. 59 llvm::sys::fs::UniqueID UniqueID; 60 bool IsNamedPipe; 61 bool InPCH; 62 bool IsValid; // Is this \c FileEntry initialized and valid? 63 64 /// \brief The open file, if it is owned by the \p FileEntry. 65 mutable std::unique_ptr<vfs::File> File; 66 friend class FileManager; 67 68 void operator=(const FileEntry &) = delete; 69 70 public: 71 FileEntry() 72 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false) 73 {} 74 75 // FIXME: this is here to allow putting FileEntry in std::map. Once we have 76 // emplace, we shouldn't need a copy constructor anymore. 77 /// Intentionally does not copy fields that are not set in an uninitialized 78 /// \c FileEntry. 79 FileEntry(const FileEntry &FE) : UniqueID(FE.UniqueID), 80 IsNamedPipe(FE.IsNamedPipe), InPCH(FE.InPCH), IsValid(FE.IsValid) { 81 assert(!isValid() && "Cannot copy an initialized FileEntry"); 82 } 83 84 const char *getName() const { return Name; } 85 bool isValid() const { return IsValid; } 86 off_t getSize() const { return Size; } 87 unsigned getUID() const { return UID; } 88 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; } 89 bool isInPCH() const { return InPCH; } 90 time_t getModificationTime() const { return ModTime; } 91 92 /// \brief Return the directory the file lives in. 93 const DirectoryEntry *getDir() const { return Dir; } 94 95 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; } 96 97 /// \brief Check whether the file is a named pipe (and thus can't be opened by 98 /// the native FileManager methods). 99 bool isNamedPipe() const { return IsNamedPipe; } 100 101 void closeFile() const { 102 File.reset(); // rely on destructor to close File 103 } 104 }; 105 106 struct FileData; 107 108 /// \brief Implements support for file system lookup, file system caching, 109 /// and directory search management. 110 /// 111 /// This also handles more advanced properties, such as uniquing files based 112 /// on "inode", so that a file with two names (e.g. symlinked) will be treated 113 /// as a single file. 114 /// 115 class FileManager : public RefCountedBase<FileManager> { 116 IntrusiveRefCntPtr<vfs::FileSystem> FS; 117 FileSystemOptions FileSystemOpts; 118 119 /// \brief Cache for existing real directories. 120 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs; 121 122 /// \brief Cache for existing real files. 123 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles; 124 125 /// \brief The virtual directories that we have allocated. 126 /// 127 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent 128 /// directories (foo/ and foo/bar/) here. 129 SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries; 130 /// \brief The virtual files that we have allocated. 131 SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries; 132 133 /// \brief A cache that maps paths to directory entries (either real or 134 /// virtual) we have looked up 135 /// 136 /// The actual Entries for real directories/files are 137 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries 138 /// for virtual directories/files are owned by 139 /// VirtualDirectoryEntries/VirtualFileEntries above. 140 /// 141 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries; 142 143 /// \brief A cache that maps paths to file entries (either real or 144 /// virtual) we have looked up. 145 /// 146 /// \see SeenDirEntries 147 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries; 148 149 /// \brief The canonical names of directories. 150 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames; 151 152 /// \brief Storage for canonical names that we have computed. 153 llvm::BumpPtrAllocator CanonicalNameStorage; 154 155 /// \brief Each FileEntry we create is assigned a unique ID #. 156 /// 157 unsigned NextFileUID; 158 159 // Statistics. 160 unsigned NumDirLookups, NumFileLookups; 161 unsigned NumDirCacheMisses, NumFileCacheMisses; 162 163 // Caching. 164 std::unique_ptr<FileSystemStatCache> StatCache; 165 166 bool getStatValue(const char *Path, FileData &Data, bool isFile, 167 std::unique_ptr<vfs::File> *F); 168 169 /// Add all ancestors of the given path (pointing to either a file 170 /// or a directory) as virtual directories. 171 void addAncestorsAsVirtualDirs(StringRef Path); 172 173 public: 174 FileManager(const FileSystemOptions &FileSystemOpts, 175 IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr); 176 ~FileManager(); 177 178 /// \brief Installs the provided FileSystemStatCache object within 179 /// the FileManager. 180 /// 181 /// Ownership of this object is transferred to the FileManager. 182 /// 183 /// \param statCache the new stat cache to install. Ownership of this 184 /// object is transferred to the FileManager. 185 /// 186 /// \param AtBeginning whether this new stat cache must be installed at the 187 /// beginning of the chain of stat caches. Otherwise, it will be added to 188 /// the end of the chain. 189 void addStatCache(std::unique_ptr<FileSystemStatCache> statCache, 190 bool AtBeginning = false); 191 192 /// \brief Removes the specified FileSystemStatCache object from the manager. 193 void removeStatCache(FileSystemStatCache *statCache); 194 195 /// \brief Removes all FileSystemStatCache objects from the manager. 196 void clearStatCaches(); 197 198 /// \brief Lookup, cache, and verify the specified directory (real or 199 /// virtual). 200 /// 201 /// This returns NULL if the directory doesn't exist. 202 /// 203 /// \param CacheFailure If true and the file does not exist, we'll cache 204 /// the failure to find this file. 205 const DirectoryEntry *getDirectory(StringRef DirName, 206 bool CacheFailure = true); 207 208 /// \brief Lookup, cache, and verify the specified file (real or 209 /// virtual). 210 /// 211 /// This returns NULL if the file doesn't exist. 212 /// 213 /// \param OpenFile if true and the file exists, it will be opened. 214 /// 215 /// \param CacheFailure If true and the file does not exist, we'll cache 216 /// the failure to find this file. 217 const FileEntry *getFile(StringRef Filename, bool OpenFile = false, 218 bool CacheFailure = true); 219 220 /// \brief Returns the current file system options 221 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; } 222 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; } 223 224 IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const { 225 return FS; 226 } 227 228 /// \brief Retrieve a file entry for a "virtual" file that acts as 229 /// if there were a file with the given name on disk. 230 /// 231 /// The file itself is not accessed. 232 const FileEntry *getVirtualFile(StringRef Filename, off_t Size, 233 time_t ModificationTime); 234 235 /// \brief Open the specified file as a MemoryBuffer, returning a new 236 /// MemoryBuffer if successful, otherwise returning null. 237 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 238 getBufferForFile(const FileEntry *Entry, bool isVolatile = false, 239 bool ShouldCloseOpenFile = true); 240 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 241 getBufferForFile(StringRef Filename); 242 243 /// \brief Get the 'stat' information for the given \p Path. 244 /// 245 /// If the path is relative, it will be resolved against the WorkingDir of the 246 /// FileManager's FileSystemOptions. 247 /// 248 /// \returns false on success, true on error. 249 bool getNoncachedStatValue(StringRef Path, 250 vfs::Status &Result); 251 252 /// \brief Remove the real file \p Entry from the cache. 253 void invalidateCache(const FileEntry *Entry); 254 255 /// \brief 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 /// \brief 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 /// \brief 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 /// \brief 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 289
