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 /// Defines the clang::FileManager interface and associated types.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
16 #define LLVM_CLANG_BASIC_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/SmallVector.h"
23 #include "llvm/ADT/StringMap.h"
24 #include "llvm/ADT/StringRef.h"
25 #include "llvm/Support/Allocator.h"
26 #include "llvm/Support/ErrorOr.h"
27 #include "llvm/Support/FileSystem.h"
28 #include "llvm/Support/VirtualFileSystem.h"
38 } // end namespace llvm
42 class FileSystemStatCache;
44 /// Cached information about one directory (either on disk or in
45 /// the virtual file system).
46 class DirectoryEntry {
47 friend class FileManager;
49 StringRef Name; // Name of the directory.
52 StringRef getName() const { return Name; }
55 /// Cached information about one file (either on disk
56 /// or in the virtual file system).
58 /// If the 'File' member is valid, then this FileEntry has an open file
59 /// descriptor for the file.
61 friend class FileManager;
63 StringRef Name; // Name of the file.
64 std::string RealPathName; // Real path to the file; could be empty.
65 off_t Size; // File size in bytes.
66 time_t ModTime; // Modification time of file.
67 const DirectoryEntry *Dir; // Directory file lives in.
68 unsigned UID; // A unique (small) ID for the file.
69 llvm::sys::fs::UniqueID UniqueID;
72 bool IsValid; // Is this \c FileEntry initialized and valid?
73 bool DeferredOpen; // Created by getFile(OpenFile=0); may open later.
75 /// The open file, if it is owned by the \p FileEntry.
76 mutable std::unique_ptr<llvm::vfs::File> File;
80 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false),
81 DeferredOpen(false) {}
83 FileEntry(const FileEntry &) = delete;
84 FileEntry &operator=(const FileEntry &) = delete;
86 StringRef getName() const { return Name; }
87 StringRef tryGetRealPathName() const { return RealPathName; }
88 bool isValid() const { return IsValid; }
89 off_t getSize() const { return Size; }
90 unsigned getUID() const { return UID; }
91 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
92 bool isInPCH() const { return InPCH; }
93 time_t getModificationTime() const { return ModTime; }
95 /// Return the directory the file lives in.
96 const DirectoryEntry *getDir() const { return Dir; }
98 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
100 /// Check whether the file is a named pipe (and thus can't be opened by
101 /// the native FileManager methods).
102 bool isNamedPipe() const { return IsNamedPipe; }
104 void closeFile() const {
105 File.reset(); // rely on destructor to close File
108 // Only for use in tests to see if deferred opens are happening, rather than
109 // relying on RealPathName being empty.
110 bool isOpenForTests() const { return File != nullptr; }
115 /// Implements support for file system lookup, file system caching,
116 /// and directory search management.
118 /// This also handles more advanced properties, such as uniquing files based
119 /// on "inode", so that a file with two names (e.g. symlinked) will be treated
120 /// as a single file.
122 class FileManager : public RefCountedBase<FileManager> {
123 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
124 FileSystemOptions FileSystemOpts;
126 /// Cache for existing real directories.
127 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
129 /// Cache for existing real files.
130 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
132 /// 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<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries;
137 /// The virtual files that we have allocated.
138 SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries;
140 /// 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 /// 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 /// The canonical names of directories.
157 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
159 /// Storage for canonical names that we have computed.
160 llvm::BumpPtrAllocator CanonicalNameStorage;
162 /// Each FileEntry we create is assigned a unique ID #.
164 unsigned NextFileUID;
167 unsigned NumDirLookups, NumFileLookups;
168 unsigned NumDirCacheMisses, NumFileCacheMisses;
171 std::unique_ptr<FileSystemStatCache> StatCache;
173 bool getStatValue(StringRef Path, FileData &Data, bool isFile,
174 std::unique_ptr<llvm::vfs::File> *F);
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);
180 /// Fills the RealPathName in file entry.
181 void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName);
184 FileManager(const FileSystemOptions &FileSystemOpts,
185 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
188 /// Installs the provided FileSystemStatCache object within
191 /// Ownership of this object is transferred to the FileManager.
193 /// \param statCache the new stat cache to install. Ownership of this
194 /// object is transferred to the FileManager.
195 void setStatCache(std::unique_ptr<FileSystemStatCache> statCache);
197 /// Removes the FileSystemStatCache object from the manager.
198 void clearStatCache();
200 /// Lookup, cache, and verify the specified directory (real or
203 /// This returns NULL if the directory doesn't exist.
205 /// \param CacheFailure If true and the file does not exist, we'll cache
206 /// the failure to find this file.
207 const DirectoryEntry *getDirectory(StringRef DirName,
208 bool CacheFailure = true);
210 /// Lookup, cache, and verify the specified file (real or
213 /// This returns NULL if the file doesn't exist.
215 /// \param OpenFile if true and the file exists, it will be opened.
217 /// \param CacheFailure If true and the file does not exist, we'll cache
218 /// the failure to find this file.
219 const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
220 bool CacheFailure = true);
222 /// Returns the current file system options
223 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
224 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
226 IntrusiveRefCntPtr<llvm::vfs::FileSystem> getVirtualFileSystem() const {
230 /// Retrieve a file entry for a "virtual" file that acts as
231 /// if there were a file with the given name on disk.
233 /// The file itself is not accessed.
234 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
235 time_t ModificationTime);
237 /// Open the specified file as a MemoryBuffer, returning a new
238 /// MemoryBuffer if successful, otherwise returning null.
239 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
240 getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
241 bool ShouldCloseOpenFile = true);
242 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
243 getBufferForFile(StringRef Filename, bool isVolatile = false);
245 /// Get the 'stat' information for the given \p Path.
247 /// If the path is relative, it will be resolved against the WorkingDir of the
248 /// FileManager's FileSystemOptions.
250 /// \returns false on success, true on error.
251 bool getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result);
253 /// Remove the real file \p Entry from the cache.
254 void invalidateCache(const FileEntry *Entry);
256 /// If path is not absolute and FileSystemOptions set the working
257 /// directory, the path is modified to be relative to the given
258 /// working directory.
259 /// \returns true if \c path changed.
260 bool FixupRelativePath(SmallVectorImpl<char> &path) const;
262 /// Makes \c Path absolute taking into account FileSystemOptions and the
263 /// working directory option.
264 /// \returns true if \c Path changed to absolute.
265 bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
267 /// 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;
272 /// 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);
277 /// Retrieve the canonical name for a given directory.
279 /// This is a very expensive operation, despite its results being cached,
280 /// and should only be used when the physical layout of the file system is
281 /// required, which is (almost) never.
282 StringRef getCanonicalName(const DirectoryEntry *Dir);
284 void PrintStats() const;
287 } // end namespace clang
289 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H