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 // FIXME: Enhance libsystem to support inode and other fields in stat. 29 #include <sys/types.h> 30 #include <map> 31 32 #ifdef _MSC_VER 33 typedef unsigned short mode_t; 34 #endif 35 36 struct stat; 37 38 namespace llvm { 39 class MemoryBuffer; 40 } 41 42 namespace clang { 43 class FileManager; 44 class FileSystemStatCache; 45 46 /// \brief Cached information about one directory (either on disk or in 47 /// the virtual file system). 48 class DirectoryEntry { 49 const char *Name; // Name of the directory. 50 friend class FileManager; 51 public: 52 DirectoryEntry() : Name(nullptr) {} 53 const char *getName() const { return Name; } 54 }; 55 56 /// \brief Cached information about one file (either on disk 57 /// or in the virtual file system). 58 /// 59 /// If the 'File' member is valid, then this FileEntry has an open file 60 /// descriptor for the file. 61 class FileEntry { 62 const char *Name; // Name of the file. 63 off_t Size; // File size in bytes. 64 time_t ModTime; // Modification time of file. 65 const DirectoryEntry *Dir; // Directory file lives in. 66 unsigned UID; // A unique (small) ID for the file. 67 llvm::sys::fs::UniqueID UniqueID; 68 bool IsNamedPipe; 69 bool InPCH; 70 bool IsValid; // Is this \c FileEntry initialized and valid? 71 72 /// \brief The open file, if it is owned by the \p FileEntry. 73 mutable std::unique_ptr<vfs::File> File; 74 friend class FileManager; 75 76 void operator=(const FileEntry &) = delete; 77 78 public: 79 FileEntry() 80 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false) 81 {} 82 83 // FIXME: this is here to allow putting FileEntry in std::map. Once we have 84 // emplace, we shouldn't need a copy constructor anymore. 85 /// Intentionally does not copy fields that are not set in an uninitialized 86 /// \c FileEntry. 87 FileEntry(const FileEntry &FE) : UniqueID(FE.UniqueID), 88 IsNamedPipe(FE.IsNamedPipe), InPCH(FE.InPCH), IsValid(FE.IsValid) { 89 assert(!isValid() && "Cannot copy an initialized FileEntry"); 90 } 91 92 const char *getName() const { return Name; } 93 bool isValid() const { return IsValid; } 94 off_t getSize() const { return Size; } 95 unsigned getUID() const { return UID; } 96 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; } 97 bool isInPCH() const { return InPCH; } 98 time_t getModificationTime() const { return ModTime; } 99 100 /// \brief Return the directory the file lives in. 101 const DirectoryEntry *getDir() const { return Dir; } 102 103 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; } 104 105 /// \brief Check whether the file is a named pipe (and thus can't be opened by 106 /// the native FileManager methods). 107 bool isNamedPipe() const { return IsNamedPipe; } 108 109 void closeFile() const { 110 File.reset(); // rely on destructor to close File 111 } 112 }; 113 114 struct FileData; 115 116 /// \brief Implements support for file system lookup, file system caching, 117 /// and directory search management. 118 /// 119 /// This also handles more advanced properties, such as uniquing files based 120 /// on "inode", so that a file with two names (e.g. symlinked) will be treated 121 /// as a single file. 122 /// 123 class FileManager : public RefCountedBase<FileManager> { 124 IntrusiveRefCntPtr<vfs::FileSystem> FS; 125 FileSystemOptions FileSystemOpts; 126 127 /// \brief Cache for existing real directories. 128 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs; 129 130 /// \brief Cache for existing real files. 131 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles; 132 133 /// \brief The virtual directories that we have allocated. 134 /// 135 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent 136 /// directories (foo/ and foo/bar/) here. 137 SmallVector<DirectoryEntry*, 4> VirtualDirectoryEntries; 138 /// \brief The virtual files that we have allocated. 139 SmallVector<FileEntry*, 4> VirtualFileEntries; 140 141 /// \brief A cache that maps paths to directory entries (either real or 142 /// virtual) we have looked up 143 /// 144 /// The actual Entries for real directories/files are 145 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries 146 /// for virtual directories/files are owned by 147 /// VirtualDirectoryEntries/VirtualFileEntries above. 148 /// 149 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries; 150 151 /// \brief A cache that maps paths to file entries (either real or 152 /// virtual) we have looked up. 153 /// 154 /// \see SeenDirEntries 155 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries; 156 157 /// \brief The canonical names of directories. 158 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames; 159 160 /// \brief Storage for canonical names that we have computed. 161 llvm::BumpPtrAllocator CanonicalNameStorage; 162 163 /// \brief Each FileEntry we create is assigned a unique ID #. 164 /// 165 unsigned NextFileUID; 166 167 // Statistics. 168 unsigned NumDirLookups, NumFileLookups; 169 unsigned NumDirCacheMisses, NumFileCacheMisses; 170 171 // Caching. 172 std::unique_ptr<FileSystemStatCache> StatCache; 173 174 bool getStatValue(const char *Path, FileData &Data, bool isFile, 175 std::unique_ptr<vfs::File> *F); 176 177 /// Add all ancestors of the given path (pointing to either a file 178 /// or a directory) as virtual directories. 179 void addAncestorsAsVirtualDirs(StringRef Path); 180 181 public: 182 FileManager(const FileSystemOptions &FileSystemOpts, 183 IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr); 184 ~FileManager(); 185 186 /// \brief Installs the provided FileSystemStatCache object within 187 /// the FileManager. 188 /// 189 /// Ownership of this object is transferred to the FileManager. 190 /// 191 /// \param statCache the new stat cache to install. Ownership of this 192 /// object is transferred to the FileManager. 193 /// 194 /// \param AtBeginning whether this new stat cache must be installed at the 195 /// beginning of the chain of stat caches. Otherwise, it will be added to 196 /// the end of the chain. 197 void addStatCache(std::unique_ptr<FileSystemStatCache> statCache, 198 bool AtBeginning = false); 199 200 /// \brief Removes the specified FileSystemStatCache object from the manager. 201 void removeStatCache(FileSystemStatCache *statCache); 202 203 /// \brief Removes all FileSystemStatCache objects from the manager. 204 void clearStatCaches(); 205 206 /// \brief Lookup, cache, and verify the specified directory (real or 207 /// virtual). 208 /// 209 /// This returns NULL if the directory doesn't exist. 210 /// 211 /// \param CacheFailure If true and the file does not exist, we'll cache 212 /// the failure to find this file. 213 const DirectoryEntry *getDirectory(StringRef DirName, 214 bool CacheFailure = true); 215 216 /// \brief Lookup, cache, and verify the specified file (real or 217 /// virtual). 218 /// 219 /// This returns NULL if the file doesn't exist. 220 /// 221 /// \param OpenFile if true and the file exists, it will be opened. 222 /// 223 /// \param CacheFailure If true and the file does not exist, we'll cache 224 /// the failure to find this file. 225 const FileEntry *getFile(StringRef Filename, bool OpenFile = false, 226 bool CacheFailure = true); 227 228 /// \brief Returns the current file system options 229 const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; } 230 231 IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const { 232 return FS; 233 } 234 235 /// \brief Retrieve a file entry for a "virtual" file that acts as 236 /// if there were a file with the given name on disk. 237 /// 238 /// The file itself is not accessed. 239 const FileEntry *getVirtualFile(StringRef Filename, off_t Size, 240 time_t ModificationTime); 241 242 /// \brief Open the specified file as a MemoryBuffer, returning a new 243 /// MemoryBuffer if successful, otherwise returning null. 244 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 245 getBufferForFile(const FileEntry *Entry, bool isVolatile = false, 246 bool ShouldCloseOpenFile = true); 247 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 248 getBufferForFile(StringRef Filename); 249 250 /// \brief Get the 'stat' information for the given \p Path. 251 /// 252 /// If the path is relative, it will be resolved against the WorkingDir of the 253 /// FileManager's FileSystemOptions. 254 /// 255 /// \returns false on success, true on error. 256 bool getNoncachedStatValue(StringRef Path, 257 vfs::Status &Result); 258 259 /// \brief Remove the real file \p Entry from the cache. 260 void invalidateCache(const FileEntry *Entry); 261 262 /// \brief If path is not absolute and FileSystemOptions set the working 263 /// directory, the path is modified to be relative to the given 264 /// working directory. 265 void FixupRelativePath(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 Remove any './' components from a path. 278 static bool removeDotPaths(SmallVectorImpl<char> &Path); 279 280 /// \brief Retrieve the canonical name for a given directory. 281 /// 282 /// This is a very expensive operation, despite its results being cached, 283 /// and should only be used when the physical layout of the file system is 284 /// required, which is (almost) never. 285 StringRef getCanonicalName(const DirectoryEntry *Dir); 286 287 void PrintStats() const; 288 }; 289 290 } // end namespace clang 291 292 #endif 293
