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 "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"
28 // FIXME: Enhance libsystem to support inode and other fields in stat.
29 #include <sys/types.h>
33 typedef unsigned short mode_t;
44 class FileSystemStatCache;
46 /// \brief Cached information about one directory (either on disk or in
47 /// the virtual file system).
48 class DirectoryEntry {
49 const char *Name; // Name of the directory.
50 friend class FileManager;
52 DirectoryEntry() : Name(nullptr) {}
53 const char *getName() const { return Name; }
56 /// \brief Cached information about one file (either on disk
57 /// or in the virtual file system).
59 /// If the 'File' member is valid, then this FileEntry has an open file
60 /// descriptor for the file.
62 std::string Name; // Name of the file.
63 off_t Size; // File size in bytes.
64 time_t ModTime; // Modification time of file.
65 const DirectoryEntry *Dir; // Directory file lives in.
66 unsigned UID; // A unique (small) ID for the file.
67 llvm::sys::fs::UniqueID UniqueID;
70 bool IsValid; // Is this \c FileEntry initialized and valid?
72 /// \brief The open file, if it is owned by the \p FileEntry.
73 mutable std::unique_ptr<vfs::File> File;
74 friend class FileManager;
76 void closeFile() const {
77 File.reset(nullptr); // rely on destructor to close File
80 void operator=(const FileEntry &) LLVM_DELETED_FUNCTION;
84 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false)
87 // FIXME: this is here to allow putting FileEntry in std::map. Once we have
88 // emplace, we shouldn't need a copy constructor anymore.
89 /// Intentionally does not copy fields that are not set in an uninitialized
91 FileEntry(const FileEntry &FE) : UniqueID(FE.UniqueID),
92 IsNamedPipe(FE.IsNamedPipe), InPCH(FE.InPCH), IsValid(FE.IsValid) {
93 assert(!isValid() && "Cannot copy an initialized FileEntry");
96 const char *getName() const { return Name.c_str(); }
97 bool isValid() const { return IsValid; }
98 off_t getSize() const { return Size; }
99 unsigned getUID() const { return UID; }
100 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
101 bool isInPCH() const { return InPCH; }
102 time_t getModificationTime() const { return ModTime; }
104 /// \brief Return the directory the file lives in.
105 const DirectoryEntry *getDir() const { return Dir; }
107 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
109 /// \brief Check whether the file is a named pipe (and thus can't be opened by
110 /// the native FileManager methods).
111 bool isNamedPipe() const { return IsNamedPipe; }
116 /// \brief Implements support for file system lookup, file system caching,
117 /// and directory search management.
119 /// This also handles more advanced properties, such as uniquing files based
120 /// on "inode", so that a file with two names (e.g. symlinked) will be treated
121 /// as a single file.
123 class FileManager : public RefCountedBase<FileManager> {
124 IntrusiveRefCntPtr<vfs::FileSystem> FS;
125 FileSystemOptions FileSystemOpts;
127 /// \brief Cache for existing real directories.
128 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
130 /// \brief Cache for existing real files.
131 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
133 /// \brief The virtual directories that we have allocated.
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;
141 /// \brief A cache that maps paths to directory entries (either real or
142 /// virtual) we have looked up
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.
149 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
151 /// \brief A cache that maps paths to file entries (either real or
152 /// virtual) we have looked up.
154 /// \see SeenDirEntries
155 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
157 /// \brief The canonical names of directories.
158 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
160 /// \brief Storage for canonical names that we have computed.
161 llvm::BumpPtrAllocator CanonicalNameStorage;
163 /// \brief Each FileEntry we create is assigned a unique ID #.
165 unsigned NextFileUID;
168 unsigned NumDirLookups, NumFileLookups;
169 unsigned NumDirCacheMisses, NumFileCacheMisses;
172 std::unique_ptr<FileSystemStatCache> StatCache;
174 bool getStatValue(const char *Path, FileData &Data, bool isFile,
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);
182 FileManager(const FileSystemOptions &FileSystemOpts,
183 IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr);
186 /// \brief Installs the provided FileSystemStatCache object within
189 /// Ownership of this object is transferred to the FileManager.
191 /// \param statCache the new stat cache to install. Ownership of this
192 /// object is transferred to the FileManager.
194 /// \param AtBeginning whether this new stat cache must be installed at the
195 /// beginning of the chain of stat caches. Otherwise, it will be added to
196 /// the end of the chain.
197 void addStatCache(FileSystemStatCache *statCache, bool AtBeginning = false);
199 /// \brief Removes the specified FileSystemStatCache object from the manager.
200 void removeStatCache(FileSystemStatCache *statCache);
202 /// \brief Removes all FileSystemStatCache objects from the manager.
203 void clearStatCaches();
205 /// \brief Lookup, cache, and verify the specified directory (real or
208 /// This returns NULL if the directory doesn't exist.
210 /// \param CacheFailure If true and the file does not exist, we'll cache
211 /// the failure to find this file.
212 const DirectoryEntry *getDirectory(StringRef DirName,
213 bool CacheFailure = true);
215 /// \brief Lookup, cache, and verify the specified file (real or
218 /// This returns NULL if the file doesn't exist.
220 /// \param OpenFile if true and the file exists, it will be opened.
222 /// \param CacheFailure If true and the file does not exist, we'll cache
223 /// the failure to find this file.
224 const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
225 bool CacheFailure = true);
227 /// \brief Returns the current file system options
228 const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; }
230 IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const {
234 /// \brief Retrieve a file entry for a "virtual" file that acts as
235 /// if there were a file with the given name on disk.
237 /// The file itself is not accessed.
238 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
239 time_t ModificationTime);
241 /// \brief Open the specified file as a MemoryBuffer, returning a new
242 /// MemoryBuffer if successful, otherwise returning null.
243 llvm::MemoryBuffer *getBufferForFile(const FileEntry *Entry,
244 std::string *ErrorStr = nullptr,
245 bool isVolatile = false,
246 bool ShouldCloseOpenFile = true);
247 llvm::MemoryBuffer *getBufferForFile(StringRef Filename,
248 std::string *ErrorStr = nullptr);
250 /// \brief Get the 'stat' information for the given \p Path.
252 /// If the path is relative, it will be resolved against the WorkingDir of the
253 /// FileManager's FileSystemOptions.
255 /// \returns false on success, true on error.
256 bool getNoncachedStatValue(StringRef Path,
257 vfs::Status &Result);
259 /// \brief Remove the real file \p Entry from the cache.
260 void invalidateCache(const FileEntry *Entry);
262 /// \brief If path is not absolute and FileSystemOptions set the working
263 /// directory, the path is modified to be relative to the given
264 /// working directory.
265 void FixupRelativePath(SmallVectorImpl<char> &path) const;
267 /// \brief 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 /// \brief 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 /// \brief 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