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_FILEMANAGER_H 16 #define LLVM_CLANG_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/OwningPtr.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 // FIXME: Enhance libsystem to support inode and other fields in stat. 28 #include <sys/types.h> 29 30 #ifdef _MSC_VER 31 typedef unsigned short mode_t; 32 #endif 33 34 struct stat; 35 36 namespace llvm { 37 class MemoryBuffer; 38 namespace sys { class Path; } 39 } 40 41 namespace clang { 42 class FileManager; 43 class FileSystemStatCache; 44 45 /// \brief Cached information about one directory (either on disk or in 46 /// the virtual file system). 47 class DirectoryEntry { 48 const char *Name; // Name of the directory. 49 friend class FileManager; 50 public: 51 DirectoryEntry() : Name(0) {} 52 const char *getName() const { return Name; } 53 }; 54 55 /// \brief Cached information about one file (either on disk 56 /// or in the virtual file system). 57 /// 58 /// If the 'FD' member is valid, then this FileEntry has an open file 59 /// descriptor for the file. 60 class FileEntry { 61 const char *Name; // Name of the file. 62 off_t Size; // File size in bytes. 63 time_t ModTime; // Modification time of file. 64 const DirectoryEntry *Dir; // Directory file lives in. 65 unsigned UID; // A unique (small) ID for the file. 66 dev_t Device; // ID for the device containing the file. 67 ino_t Inode; // Inode number for the file. 68 mode_t FileMode; // The file mode as returned by 'stat'. 69 70 /// FD - The file descriptor for the file entry if it is opened and owned 71 /// by the FileEntry. If not, this is set to -1. 72 mutable int FD; 73 friend class FileManager; 74 75 public: 76 FileEntry(dev_t device, ino_t inode, mode_t m) 77 : Name(0), Device(device), Inode(inode), FileMode(m), FD(-1) {} 78 // Add a default constructor for use with llvm::StringMap 79 FileEntry() : Name(0), Device(0), Inode(0), FileMode(0), FD(-1) {} 80 81 FileEntry(const FileEntry &FE) { 82 memcpy(this, &FE, sizeof(FE)); 83 assert(FD == -1 && "Cannot copy a file-owning FileEntry"); 84 } 85 86 void operator=(const FileEntry &FE) { 87 memcpy(this, &FE, sizeof(FE)); 88 assert(FD == -1 && "Cannot assign a file-owning FileEntry"); 89 } 90 91 ~FileEntry(); 92 93 const char *getName() const { return Name; } 94 off_t getSize() const { return Size; } 95 unsigned getUID() const { return UID; } 96 ino_t getInode() const { return Inode; } 97 dev_t getDevice() const { return Device; } 98 time_t getModificationTime() const { return ModTime; } 99 mode_t getFileMode() const { return FileMode; } 100 101 /// \brief Return the directory the file lives in. 102 const DirectoryEntry *getDir() const { return Dir; } 103 104 bool operator<(const FileEntry &RHS) const { 105 return Device < RHS.Device || (Device == RHS.Device && Inode < RHS.Inode); 106 } 107 108 /// \brief Check whether the file is a named pipe (and thus can't be opened by 109 /// the native FileManager methods). 110 bool isNamedPipe() const; 111 }; 112 113 /// \brief Implements support for file system lookup, file system caching, 114 /// and directory search management. 115 /// 116 /// This also handles more advanced properties, such as uniquing files based 117 /// on "inode", so that a file with two names (e.g. symlinked) will be treated 118 /// as a single file. 119 /// 120 class FileManager : public RefCountedBase<FileManager> { 121 FileSystemOptions FileSystemOpts; 122 123 class UniqueDirContainer; 124 class UniqueFileContainer; 125 126 /// \brief Cache for existing real directories. 127 UniqueDirContainer &UniqueRealDirs; 128 129 /// \brief Cache for existing real files. 130 UniqueFileContainer &UniqueRealFiles; 131 132 /// \brief The virtual directories that we have allocated. 133 /// 134 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent 135 /// directories (foo/ and foo/bar/) here. 136 SmallVector<DirectoryEntry*, 4> VirtualDirectoryEntries; 137 /// \brief The virtual files that we have allocated. 138 SmallVector<FileEntry*, 4> VirtualFileEntries; 139 140 /// \brief A cache that maps paths to directory entries (either real or 141 /// virtual) we have looked up 142 /// 143 /// The actual Entries for real directories/files are 144 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries 145 /// for virtual directories/files are owned by 146 /// VirtualDirectoryEntries/VirtualFileEntries above. 147 /// 148 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries; 149 150 /// \brief A cache that maps paths to file entries (either real or 151 /// virtual) we have looked up. 152 /// 153 /// \see SeenDirEntries 154 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries; 155 156 /// \brief The canonical names of directories. 157 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames; 158 159 /// \brief Storage for canonical names that we have computed. 160 llvm::BumpPtrAllocator CanonicalNameStorage; 161 162 /// \brief Each FileEntry we create is assigned a unique ID #. 163 /// 164 unsigned NextFileUID; 165 166 // Statistics. 167 unsigned NumDirLookups, NumFileLookups; 168 unsigned NumDirCacheMisses, NumFileCacheMisses; 169 170 // Caching. 171 OwningPtr<FileSystemStatCache> StatCache; 172 173 bool getStatValue(const char *Path, struct stat &StatBuf, 174 bool isFile, int *FileDescriptor); 175 176 /// Add all ancestors of the given path (pointing to either a file 177 /// or a directory) as virtual directories. 178 void addAncestorsAsVirtualDirs(StringRef Path); 179 180 public: 181 FileManager(const FileSystemOptions &FileSystemOpts); 182 ~FileManager(); 183 184 /// \brief Installs the provided FileSystemStatCache object within 185 /// the FileManager. 186 /// 187 /// Ownership of this object is transferred to the FileManager. 188 /// 189 /// \param statCache the new stat cache to install. Ownership of this 190 /// object is transferred to the FileManager. 191 /// 192 /// \param AtBeginning whether this new stat cache must be installed at the 193 /// beginning of the chain of stat caches. Otherwise, it will be added to 194 /// the end of the chain. 195 void addStatCache(FileSystemStatCache *statCache, bool AtBeginning = false); 196 197 /// \brief Removes the specified FileSystemStatCache object from the manager. 198 void removeStatCache(FileSystemStatCache *statCache); 199 200 /// \brief Removes all FileSystemStatCache objects from the manager. 201 void clearStatCaches(); 202 203 /// \brief Lookup, cache, and verify the specified directory (real or 204 /// virtual). 205 /// 206 /// This returns NULL if the directory doesn't exist. 207 /// 208 /// \param CacheFailure If true and the file does not exist, we'll cache 209 /// the failure to find this file. 210 const DirectoryEntry *getDirectory(StringRef DirName, 211 bool CacheFailure = true); 212 213 /// \brief Lookup, cache, and verify the specified file (real or 214 /// virtual). 215 /// 216 /// This returns NULL if the file doesn't exist. 217 /// 218 /// \param OpenFile if true and the file exists, it will be opened. 219 /// 220 /// \param CacheFailure If true and the file does not exist, we'll cache 221 /// the failure to find this file. 222 const FileEntry *getFile(StringRef Filename, bool OpenFile = false, 223 bool CacheFailure = true); 224 225 /// \brief Returns the current file system options 226 const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; } 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::MemoryBuffer *getBufferForFile(const FileEntry *Entry, 238 std::string *ErrorStr = 0, 239 bool isVolatile = false); 240 llvm::MemoryBuffer *getBufferForFile(StringRef Filename, 241 std::string *ErrorStr = 0); 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 bool getNoncachedStatValue(StringRef Path, struct stat &StatBuf); 248 249 /// \brief Remove the real file \p Entry from the cache. 250 void invalidateCache(const FileEntry *Entry); 251 252 /// \brief If path is not absolute and FileSystemOptions set the working 253 /// directory, the path is modified to be relative to the given 254 /// working directory. 255 void FixupRelativePath(SmallVectorImpl<char> &path) const; 256 257 /// \brief Produce an array mapping from the unique IDs assigned to each 258 /// file to the corresponding FileEntry pointer. 259 void GetUniqueIDMapping( 260 SmallVectorImpl<const FileEntry *> &UIDToFiles) const; 261 262 /// \brief Modifies the size and modification time of a previously created 263 /// FileEntry. Use with caution. 264 static void modifyFileEntry(FileEntry *File, off_t Size, 265 time_t ModificationTime); 266 267 /// \brief Retrieve the canonical name for a given directory. 268 /// 269 /// This is a very expensive operation, despite its results being cached, 270 /// and should only be used when the physical layout of the file system is 271 /// required, which is (almost) never. 272 StringRef getCanonicalName(const DirectoryEntry *Dir); 273 274 void PrintStats() const; 275 }; 276 277 } // end namespace clang 278 279 #endif 280
