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 #include "llvm/Support/FileSystem.h"
28 // FIXME: Enhance libsystem to support inode and other fields in stat.
29 #include <sys/types.h>
32 typedef unsigned short mode_t;
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 llvm::sys::fs::UniqueID UniqueID;
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(llvm::sys::fs::UniqueID UniqueID, bool IsNamedPipe, bool InPCH)
77 : Name(0), UniqueID(UniqueID), IsNamedPipe(IsNamedPipe), InPCH(InPCH),
79 // Add a default constructor for use with llvm::StringMap
81 : Name(0), UniqueID(0, 0), IsNamedPipe(false), InPCH(false), FD(-1) {}
83 FileEntry(const FileEntry &FE) {
84 memcpy(this, &FE, sizeof(FE));
85 assert(FD == -1 && "Cannot copy a file-owning FileEntry");
88 void operator=(const FileEntry &FE) {
89 memcpy(this, &FE, sizeof(FE));
90 assert(FD == -1 && "Cannot assign a file-owning FileEntry");
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; }
102 /// \brief Return the directory the file lives in.
103 const DirectoryEntry *getDir() const { return Dir; }
105 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
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; }
114 /// \brief Implements support for file system lookup, file system caching,
115 /// and directory search management.
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.
121 class FileManager : public RefCountedBase<FileManager> {
122 FileSystemOptions FileSystemOpts;
124 class UniqueDirContainer;
125 class UniqueFileContainer;
127 /// \brief Cache for existing real directories.
128 UniqueDirContainer &UniqueRealDirs;
130 /// \brief Cache for existing real files.
131 UniqueFileContainer &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 OwningPtr<FileSystemStatCache> StatCache;
174 bool getStatValue(const char *Path, FileData &Data, bool isFile,
175 int *FileDescriptor);
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);
185 /// \brief Installs the provided FileSystemStatCache object within
188 /// Ownership of this object is transferred to the FileManager.
190 /// \param statCache the new stat cache to install. Ownership of this
191 /// object is transferred to the FileManager.
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);
198 /// \brief Removes the specified FileSystemStatCache object from the manager.
199 void removeStatCache(FileSystemStatCache *statCache);
201 /// \brief Removes all FileSystemStatCache objects from the manager.
202 void clearStatCaches();
204 /// \brief Lookup, cache, and verify the specified directory (real or
207 /// This returns NULL if the directory doesn't exist.
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);
214 /// \brief Lookup, cache, and verify the specified file (real or
217 /// This returns NULL if the file doesn't exist.
219 /// \param OpenFile if true and the file exists, it will be opened.
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);
226 /// \brief Returns the current file system options
227 const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; }
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.
232 /// The file itself is not accessed.
233 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
234 time_t ModificationTime);
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);
244 /// \brief Get the 'stat' information for the given \p Path.
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);
251 /// \brief Remove the real file \p Entry from the cache.
252 void invalidateCache(const FileEntry *Entry);
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;
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;
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);
269 /// \brief Retrieve the canonical name for a given directory.
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);
276 void PrintStats() const;
279 } // end namespace clang