1 //===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \brief Defines the clang::FileManager interface and associated types.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_FILEMANAGER_H
16 #define LLVM_CLANG_FILEMANAGER_H
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>
31 typedef unsigned short mode_t;
38 namespace sys { class Path; }
43 class FileSystemStatCache;
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;
51 DirectoryEntry() : Name(0) {}
52 const char *getName() const { return Name; }
55 /// \brief Cached information about one file (either on disk
56 /// or in the virtual file system).
58 /// If the 'FD' member is valid, then this FileEntry has an open file
59 /// descriptor for the file.
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'.
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.
73 friend class FileManager;
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) {}
81 FileEntry(const FileEntry &FE) {
82 memcpy(this, &FE, sizeof(FE));
83 assert(FD == -1 && "Cannot copy a file-owning FileEntry");
86 void operator=(const FileEntry &FE) {
87 memcpy(this, &FE, sizeof(FE));
88 assert(FD == -1 && "Cannot assign a file-owning FileEntry");
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; }
101 /// \brief Return the directory the file lives in.
102 const DirectoryEntry *getDir() const { return Dir; }
104 bool operator<(const FileEntry &RHS) const {
105 return Device < RHS.Device || (Device == RHS.Device && Inode < RHS.Inode);
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;
113 /// \brief Implements support for file system lookup, file system caching,
114 /// and directory search management.
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.
120 class FileManager : public RefCountedBase<FileManager> {
121 FileSystemOptions FileSystemOpts;
123 class UniqueDirContainer;
124 class UniqueFileContainer;
126 /// \brief Cache for existing real directories.
127 UniqueDirContainer &UniqueRealDirs;
129 /// \brief Cache for existing real files.
130 UniqueFileContainer &UniqueRealFiles;
132 /// \brief The virtual directories that we have allocated.
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;
140 /// \brief A cache that maps paths to directory entries (either real or
141 /// virtual) we have looked up
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.
148 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
150 /// \brief A cache that maps paths to file entries (either real or
151 /// virtual) we have looked up.
153 /// \see SeenDirEntries
154 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
156 /// \brief The canonical names of directories.
157 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
159 /// \brief Storage for canonical names that we have computed.
160 llvm::BumpPtrAllocator CanonicalNameStorage;
162 /// \brief Each FileEntry we create is assigned a unique ID #.
164 unsigned NextFileUID;
167 unsigned NumDirLookups, NumFileLookups;
168 unsigned NumDirCacheMisses, NumFileCacheMisses;
171 OwningPtr<FileSystemStatCache> StatCache;
173 bool getStatValue(const char *Path, struct stat &StatBuf,
174 bool isFile, int *FileDescriptor);
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);
181 FileManager(const FileSystemOptions &FileSystemOpts);
184 /// \brief Installs the provided FileSystemStatCache object within
187 /// Ownership of this object is transferred to the FileManager.
189 /// \param statCache the new stat cache to install. Ownership of this
190 /// object is transferred to the FileManager.
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);
197 /// \brief Removes the specified FileSystemStatCache object from the manager.
198 void removeStatCache(FileSystemStatCache *statCache);
200 /// \brief Removes all FileSystemStatCache objects from the manager.
201 void clearStatCaches();
203 /// \brief Lookup, cache, and verify the specified directory (real or
206 /// This returns NULL if the directory doesn't exist.
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);
213 /// \brief Lookup, cache, and verify the specified file (real or
216 /// This returns NULL if the file doesn't exist.
218 /// \param OpenFile if true and the file exists, it will be opened.
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);
225 /// \brief Returns the current file system options
226 const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; }
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.
231 /// The file itself is not accessed.
232 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
233 time_t ModificationTime);
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);
243 /// \brief Get the 'stat' information for the given \p Path.
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);
249 /// \brief Remove the real file \p Entry from the cache.
250 void invalidateCache(const FileEntry *Entry);
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;
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;
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);
267 /// \brief Retrieve the canonical name for a given directory.
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);
274 void PrintStats() const;
277 } // end namespace clang