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 #include "llvm/Support/FileSystem.h" 28 // FIXME: Enhance libsystem to support inode and other fields in stat. 29 #include <sys/types.h> 30 31 #ifdef _MSC_VER 32 typedef unsigned short mode_t; 33 #endif 34 35 struct stat; 36 37 namespace llvm { 38 class MemoryBuffer; 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 llvm::sys::fs::UniqueID UniqueID; 67 bool IsNamedPipe; 68 bool InPCH; 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(llvm::sys::fs::UniqueID UniqueID, bool IsNamedPipe, bool InPCH) 77 : Name(0), UniqueID(UniqueID), IsNamedPipe(IsNamedPipe), InPCH(InPCH), 78 FD(-1) {} 79 // Add a default constructor for use with llvm::StringMap 80 FileEntry() 81 : Name(0), UniqueID(0, 0), IsNamedPipe(false), InPCH(false), FD(-1) {} 82 83 FileEntry(const FileEntry &FE) { 84 memcpy(this, &FE, sizeof(FE)); 85 assert(FD == -1 && "Cannot copy a file-owning FileEntry"); 86 } 87 88 void operator=(const FileEntry &FE) { 89 memcpy(this, &FE, sizeof(FE)); 90 assert(FD == -1 && "Cannot assign a file-owning FileEntry"); 91 } 92 93 ~FileEntry(); 94 95 const char *getName() const { return Name; } 96 off_t getSize() const { return Size; } 97 unsigned getUID() const { return UID; } 98 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; } 99 bool isInPCH() const { return InPCH; } 100 time_t getModificationTime() const { return ModTime; } 101 102 /// \brief Return the directory the file lives in. 103 const DirectoryEntry *getDir() const { return Dir; } 104 105 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; } 106 107 /// \brief Check whether the file is a named pipe (and thus can't be opened by 108 /// the native FileManager methods). 109 bool isNamedPipe() const { return IsNamedPipe; } 110 }; 111 112 struct FileData; 113 114 /// \brief Implements support for file system lookup, file system caching, 115 /// and directory search management. 116 /// 117 /// This also handles more advanced properties, such as uniquing files based 118 /// on "inode", so that a file with two names (e.g. symlinked) will be treated 119 /// as a single file. 120 /// 121 class FileManager : public RefCountedBase<FileManager> { 122 FileSystemOptions FileSystemOpts; 123 124 class UniqueDirContainer; 125 class UniqueFileContainer; 126 127 /// \brief Cache for existing real directories. 128 UniqueDirContainer &UniqueRealDirs; 129 130 /// \brief Cache for existing real files. 131 UniqueFileContainer &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 OwningPtr<FileSystemStatCache> StatCache; 173 174 bool getStatValue(const char *Path, FileData &Data, bool isFile, 175 int *FileDescriptor); 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 ~FileManager(); 184 185 /// \brief Installs the provided FileSystemStatCache object within 186 /// the FileManager. 187 /// 188 /// Ownership of this object is transferred to the FileManager. 189 /// 190 /// \param statCache the new stat cache to install. Ownership of this 191 /// object is transferred to the FileManager. 192 /// 193 /// \param AtBeginning whether this new stat cache must be installed at the 194 /// beginning of the chain of stat caches. Otherwise, it will be added to 195 /// the end of the chain. 196 void addStatCache(FileSystemStatCache *statCache, bool AtBeginning = false); 197 198 /// \brief Removes the specified FileSystemStatCache object from the manager. 199 void removeStatCache(FileSystemStatCache *statCache); 200 201 /// \brief Removes all FileSystemStatCache objects from the manager. 202 void clearStatCaches(); 203 204 /// \brief Lookup, cache, and verify the specified directory (real or 205 /// virtual). 206 /// 207 /// This returns NULL if the directory doesn't exist. 208 /// 209 /// \param CacheFailure If true and the file does not exist, we'll cache 210 /// the failure to find this file. 211 const DirectoryEntry *getDirectory(StringRef DirName, 212 bool CacheFailure = true); 213 214 /// \brief Lookup, cache, and verify the specified file (real or 215 /// virtual). 216 /// 217 /// This returns NULL if the file doesn't exist. 218 /// 219 /// \param OpenFile if true and the file exists, it will be opened. 220 /// 221 /// \param CacheFailure If true and the file does not exist, we'll cache 222 /// the failure to find this file. 223 const FileEntry *getFile(StringRef Filename, bool OpenFile = false, 224 bool CacheFailure = true); 225 226 /// \brief Returns the current file system options 227 const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; } 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::MemoryBuffer *getBufferForFile(const FileEntry *Entry, 239 std::string *ErrorStr = 0, 240 bool isVolatile = false); 241 llvm::MemoryBuffer *getBufferForFile(StringRef Filename, 242 std::string *ErrorStr = 0); 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 bool getNoncachedStatValue(StringRef Path, 249 llvm::sys::fs::file_status &Result); 250 251 /// \brief Remove the real file \p Entry from the cache. 252 void invalidateCache(const FileEntry *Entry); 253 254 /// \brief If path is not absolute and FileSystemOptions set the working 255 /// directory, the path is modified to be relative to the given 256 /// working directory. 257 void FixupRelativePath(SmallVectorImpl<char> &path) const; 258 259 /// \brief Produce an array mapping from the unique IDs assigned to each 260 /// file to the corresponding FileEntry pointer. 261 void GetUniqueIDMapping( 262 SmallVectorImpl<const FileEntry *> &UIDToFiles) const; 263 264 /// \brief Modifies the size and modification time of a previously created 265 /// FileEntry. Use with caution. 266 static void modifyFileEntry(FileEntry *File, off_t Size, 267 time_t ModificationTime); 268 269 /// \brief Retrieve the canonical name for a given directory. 270 /// 271 /// This is a very expensive operation, despite its results being cached, 272 /// and should only be used when the physical layout of the file system is 273 /// required, which is (almost) never. 274 StringRef getCanonicalName(const DirectoryEntry *Dir); 275 276 void PrintStats() const; 277 }; 278 279 } // end namespace clang 280 281 #endif 282
