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_BASIC_FILEMANAGER_H
16 #define LLVM_CLANG_BASIC_FILEMANAGER_H
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"
36 class FileSystemStatCache;
38 /// \brief Cached information about one directory (either on disk or in
39 /// the virtual file system).
40 class DirectoryEntry {
41 const char *Name; // Name of the directory.
42 friend class FileManager;
44 DirectoryEntry() : Name(nullptr) {}
45 const char *getName() const { return Name; }
48 /// \brief Cached information about one file (either on disk
49 /// or in the virtual file system).
51 /// If the 'File' member is valid, then this FileEntry has an open file
52 /// descriptor for the file.
54 const char *Name; // Name of the file.
55 off_t Size; // File size in bytes.
56 time_t ModTime; // Modification time of file.
57 const DirectoryEntry *Dir; // Directory file lives in.
58 unsigned UID; // A unique (small) ID for the file.
59 llvm::sys::fs::UniqueID UniqueID;
62 bool IsValid; // Is this \c FileEntry initialized and valid?
64 /// \brief The open file, if it is owned by the \p FileEntry.
65 mutable std::unique_ptr<vfs::File> File;
66 friend class FileManager;
68 void operator=(const FileEntry &) = delete;
72 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false)
75 // FIXME: this is here to allow putting FileEntry in std::map. Once we have
76 // emplace, we shouldn't need a copy constructor anymore.
77 /// Intentionally does not copy fields that are not set in an uninitialized
79 FileEntry(const FileEntry &FE) : UniqueID(FE.UniqueID),
80 IsNamedPipe(FE.IsNamedPipe), InPCH(FE.InPCH), IsValid(FE.IsValid) {
81 assert(!isValid() && "Cannot copy an initialized FileEntry");
84 const char *getName() const { return Name; }
85 bool isValid() const { return IsValid; }
86 off_t getSize() const { return Size; }
87 unsigned getUID() const { return UID; }
88 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
89 bool isInPCH() const { return InPCH; }
90 time_t getModificationTime() const { return ModTime; }
92 /// \brief Return the directory the file lives in.
93 const DirectoryEntry *getDir() const { return Dir; }
95 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
97 /// \brief Check whether the file is a named pipe (and thus can't be opened by
98 /// the native FileManager methods).
99 bool isNamedPipe() const { return IsNamedPipe; }
101 void closeFile() const {
102 File.reset(); // rely on destructor to close File
108 /// \brief Implements support for file system lookup, file system caching,
109 /// and directory search management.
111 /// This also handles more advanced properties, such as uniquing files based
112 /// on "inode", so that a file with two names (e.g. symlinked) will be treated
113 /// as a single file.
115 class FileManager : public RefCountedBase<FileManager> {
116 IntrusiveRefCntPtr<vfs::FileSystem> FS;
117 FileSystemOptions FileSystemOpts;
119 /// \brief Cache for existing real directories.
120 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
122 /// \brief Cache for existing real files.
123 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
125 /// \brief The virtual directories that we have allocated.
127 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
128 /// directories (foo/ and foo/bar/) here.
129 SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries;
130 /// \brief The virtual files that we have allocated.
131 SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries;
133 /// \brief A cache that maps paths to directory entries (either real or
134 /// virtual) we have looked up
136 /// The actual Entries for real directories/files are
137 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
138 /// for virtual directories/files are owned by
139 /// VirtualDirectoryEntries/VirtualFileEntries above.
141 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
143 /// \brief A cache that maps paths to file entries (either real or
144 /// virtual) we have looked up.
146 /// \see SeenDirEntries
147 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
149 /// \brief The canonical names of directories.
150 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
152 /// \brief Storage for canonical names that we have computed.
153 llvm::BumpPtrAllocator CanonicalNameStorage;
155 /// \brief Each FileEntry we create is assigned a unique ID #.
157 unsigned NextFileUID;
160 unsigned NumDirLookups, NumFileLookups;
161 unsigned NumDirCacheMisses, NumFileCacheMisses;
164 std::unique_ptr<FileSystemStatCache> StatCache;
166 bool getStatValue(const char *Path, FileData &Data, bool isFile,
167 std::unique_ptr<vfs::File> *F);
169 /// Add all ancestors of the given path (pointing to either a file
170 /// or a directory) as virtual directories.
171 void addAncestorsAsVirtualDirs(StringRef Path);
174 FileManager(const FileSystemOptions &FileSystemOpts,
175 IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr);
178 /// \brief Installs the provided FileSystemStatCache object within
181 /// Ownership of this object is transferred to the FileManager.
183 /// \param statCache the new stat cache to install. Ownership of this
184 /// object is transferred to the FileManager.
186 /// \param AtBeginning whether this new stat cache must be installed at the
187 /// beginning of the chain of stat caches. Otherwise, it will be added to
188 /// the end of the chain.
189 void addStatCache(std::unique_ptr<FileSystemStatCache> statCache,
190 bool AtBeginning = false);
192 /// \brief Removes the specified FileSystemStatCache object from the manager.
193 void removeStatCache(FileSystemStatCache *statCache);
195 /// \brief Removes all FileSystemStatCache objects from the manager.
196 void clearStatCaches();
198 /// \brief Lookup, cache, and verify the specified directory (real or
201 /// This returns NULL if the directory doesn't exist.
203 /// \param CacheFailure If true and the file does not exist, we'll cache
204 /// the failure to find this file.
205 const DirectoryEntry *getDirectory(StringRef DirName,
206 bool CacheFailure = true);
208 /// \brief Lookup, cache, and verify the specified file (real or
211 /// This returns NULL if the file doesn't exist.
213 /// \param OpenFile if true and the file exists, it will be opened.
215 /// \param CacheFailure If true and the file does not exist, we'll cache
216 /// the failure to find this file.
217 const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
218 bool CacheFailure = true);
220 /// \brief Returns the current file system options
221 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
222 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
224 IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const {
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::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
238 getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
239 bool ShouldCloseOpenFile = true);
240 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
241 getBufferForFile(StringRef Filename);
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.
248 /// \returns false on success, true on error.
249 bool getNoncachedStatValue(StringRef Path,
250 vfs::Status &Result);
252 /// \brief Remove the real file \p Entry from the cache.
253 void invalidateCache(const FileEntry *Entry);
255 /// \brief If path is not absolute and FileSystemOptions set the working
256 /// directory, the path is modified to be relative to the given
257 /// working directory.
258 /// \returns true if \c path changed.
259 bool FixupRelativePath(SmallVectorImpl<char> &path) const;
261 /// Makes \c Path absolute taking into account FileSystemOptions and the
262 /// working directory option.
263 /// \returns true if \c Path changed to absolute.
264 bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
266 /// \brief Produce an array mapping from the unique IDs assigned to each
267 /// file to the corresponding FileEntry pointer.
268 void GetUniqueIDMapping(
269 SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
271 /// \brief Modifies the size and modification time of a previously created
272 /// FileEntry. Use with caution.
273 static void modifyFileEntry(FileEntry *File, off_t Size,
274 time_t ModificationTime);
276 /// \brief Retrieve the canonical name for a given directory.
278 /// This is a very expensive operation, despite its results being cached,
279 /// and should only be used when the physical layout of the file system is
280 /// required, which is (almost) never.
281 StringRef getCanonicalName(const DirectoryEntry *Dir);
283 void PrintStats() const;
286 } // end namespace clang