clang  6.0.0svn
FileManager.h
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1 //===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 ///
10 /// \file
11 /// \brief Defines the clang::FileManager interface and associated types.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
16 #define LLVM_CLANG_BASIC_FILEMANAGER_H
17 
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 <ctime>
29 #include <memory>
30 #include <map>
31 #include <string>
32 
33 namespace llvm {
34 
35 class MemoryBuffer;
36 
37 } // end namespace llvm
38 
39 namespace clang {
40 
41 class FileSystemStatCache;
42 
43 /// \brief Cached information about one directory (either on disk or in
44 /// the virtual file system).
46  friend class FileManager;
47 
48  StringRef Name; // Name of the directory.
49 
50 public:
51  StringRef getName() const { return Name; }
52 };
53 
54 /// \brief Cached information about one file (either on disk
55 /// or in the virtual file system).
56 ///
57 /// If the 'File' member is valid, then this FileEntry has an open file
58 /// descriptor for the file.
59 class FileEntry {
60  friend class FileManager;
61 
62  StringRef Name; // Name of the file.
63  std::string RealPathName; // Real path to the file; could be empty.
64  off_t Size; // File size in bytes.
65  time_t ModTime; // Modification time of file.
66  const DirectoryEntry *Dir; // Directory file lives in.
67  unsigned UID; // A unique (small) ID for the file.
68  llvm::sys::fs::UniqueID UniqueID;
69  bool IsNamedPipe;
70  bool InPCH;
71  bool IsValid; // Is this \c FileEntry initialized and valid?
72 
73  /// \brief The open file, if it is owned by the \p FileEntry.
74  mutable std::unique_ptr<vfs::File> File;
75 
76 public:
78  : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false)
79  {}
80 
81  FileEntry(const FileEntry &) = delete;
82  FileEntry &operator=(const FileEntry &) = delete;
83 
84  StringRef getName() const { return Name; }
85  StringRef tryGetRealPathName() const { return RealPathName; }
86  bool isValid() const { return IsValid; }
87  off_t getSize() const { return Size; }
88  unsigned getUID() const { return UID; }
89  const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
90  bool isInPCH() const { return InPCH; }
91  time_t getModificationTime() const { return ModTime; }
92 
93  /// \brief Return the directory the file lives in.
94  const DirectoryEntry *getDir() const { return Dir; }
95 
96  bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
97 
98  /// \brief Check whether the file is a named pipe (and thus can't be opened by
99  /// the native FileManager methods).
100  bool isNamedPipe() const { return IsNamedPipe; }
101 
102  void closeFile() const {
103  File.reset(); // rely on destructor to close File
104  }
105 };
106 
107 struct FileData;
108 
109 /// \brief Implements support for file system lookup, file system caching,
110 /// and directory search management.
111 ///
112 /// This also handles more advanced properties, such as uniquing files based
113 /// on "inode", so that a file with two names (e.g. symlinked) will be treated
114 /// as a single file.
115 ///
116 class FileManager : public RefCountedBase<FileManager> {
118  FileSystemOptions FileSystemOpts;
119 
120  /// \brief Cache for existing real directories.
121  std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
122 
123  /// \brief Cache for existing real files.
124  std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
125 
126  /// \brief The virtual directories that we have allocated.
127  ///
128  /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
129  /// directories (foo/ and foo/bar/) here.
130  SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries;
131  /// \brief The virtual files that we have allocated.
132  SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries;
133 
134  /// \brief A cache that maps paths to directory entries (either real or
135  /// virtual) we have looked up
136  ///
137  /// The actual Entries for real directories/files are
138  /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
139  /// for virtual directories/files are owned by
140  /// VirtualDirectoryEntries/VirtualFileEntries above.
141  ///
142  llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
143 
144  /// \brief A cache that maps paths to file entries (either real or
145  /// virtual) we have looked up.
146  ///
147  /// \see SeenDirEntries
148  llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
149 
150  /// \brief The canonical names of directories.
151  llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
152 
153  /// \brief Storage for canonical names that we have computed.
154  llvm::BumpPtrAllocator CanonicalNameStorage;
155 
156  /// \brief Each FileEntry we create is assigned a unique ID #.
157  ///
158  unsigned NextFileUID;
159 
160  // Statistics.
161  unsigned NumDirLookups, NumFileLookups;
162  unsigned NumDirCacheMisses, NumFileCacheMisses;
163 
164  // Caching.
165  std::unique_ptr<FileSystemStatCache> StatCache;
166 
167  bool getStatValue(StringRef Path, FileData &Data, bool isFile,
168  std::unique_ptr<vfs::File> *F);
169 
170  /// Add all ancestors of the given path (pointing to either a file
171  /// or a directory) as virtual directories.
172  void addAncestorsAsVirtualDirs(StringRef Path);
173 
174 public:
175  FileManager(const FileSystemOptions &FileSystemOpts,
177  ~FileManager();
178 
179  /// \brief Installs the provided FileSystemStatCache object within
180  /// the FileManager.
181  ///
182  /// Ownership of this object is transferred to the FileManager.
183  ///
184  /// \param statCache the new stat cache to install. Ownership of this
185  /// object is transferred to the FileManager.
186  ///
187  /// \param AtBeginning whether this new stat cache must be installed at the
188  /// beginning of the chain of stat caches. Otherwise, it will be added to
189  /// the end of the chain.
190  void addStatCache(std::unique_ptr<FileSystemStatCache> statCache,
191  bool AtBeginning = false);
192 
193  /// \brief Removes the specified FileSystemStatCache object from the manager.
194  void removeStatCache(FileSystemStatCache *statCache);
195 
196  /// \brief Removes all FileSystemStatCache objects from the manager.
197  void clearStatCaches();
198 
199  /// \brief Lookup, cache, and verify the specified directory (real or
200  /// virtual).
201  ///
202  /// This returns NULL if the directory doesn't exist.
203  ///
204  /// \param CacheFailure If true and the file does not exist, we'll cache
205  /// the failure to find this file.
206  const DirectoryEntry *getDirectory(StringRef DirName,
207  bool CacheFailure = true);
208 
209  /// \brief Lookup, cache, and verify the specified file (real or
210  /// virtual).
211  ///
212  /// This returns NULL if the file doesn't exist.
213  ///
214  /// \param OpenFile if true and the file exists, it will be opened.
215  ///
216  /// \param CacheFailure If true and the file does not exist, we'll cache
217  /// the failure to find this file.
218  const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
219  bool CacheFailure = true);
220 
221  /// \brief Returns the current file system options
222  FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
223  const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
224 
226  return FS;
227  }
228 
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.
231  ///
232  /// The file itself is not accessed.
233  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
234  time_t ModificationTime);
235 
236  /// \brief Open the specified file as a MemoryBuffer, returning a new
237  /// MemoryBuffer if successful, otherwise returning null.
238  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
239  getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
240  bool ShouldCloseOpenFile = true);
241  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
242  getBufferForFile(StringRef Filename);
243 
244  /// \brief Get the 'stat' information for the given \p Path.
245  ///
246  /// If the path is relative, it will be resolved against the WorkingDir of the
247  /// FileManager's FileSystemOptions.
248  ///
249  /// \returns false on success, true on error.
250  bool getNoncachedStatValue(StringRef Path,
251  vfs::Status &Result);
252 
253  /// \brief Remove the real file \p Entry from the cache.
254  void invalidateCache(const FileEntry *Entry);
255 
256  /// \brief 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;
261 
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;
266 
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;
271 
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);
276 
277  /// \brief Retrieve the canonical name for a given directory.
278  ///
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);
283 
284  void PrintStats() const;
285 };
286 
287 } // end namespace clang
288 
289 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H
StringRef tryGetRealPathName() const
Definition: FileManager.h:85
Implements support for file system lookup, file system caching, and directory search management...
Definition: FileManager.h:116
time_t getModificationTime() const
Definition: FileManager.h:91
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:26
void closeFile() const
Definition: FileManager.h:102
const llvm::sys::fs::UniqueID & getUniqueID() const
Definition: FileManager.h:89
unsigned getUID() const
Definition: FileManager.h:88
Abstract interface for introducing a FileManager cache for &#39;stat&#39; system calls, which is used by prec...
The result of a status operation.
StringRef Filename
Definition: Format.cpp:1316
const DirectoryEntry * getDir() const
Return the directory the file lives in.
Definition: FileManager.h:94
#define false
Definition: stdbool.h:33
StringRef getName() const
Definition: FileManager.h:84
FileSystemOptions & getFileSystemOpts()
Returns the current file system options.
Definition: FileManager.h:222
bool isNamedPipe() const
Check whether the file is a named pipe (and thus can&#39;t be opened by the native FileManager methods)...
Definition: FileManager.h:100
bool operator<(const FileEntry &RHS) const
Definition: FileManager.h:96
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:59
const FileSystemOptions & getFileSystemOpts() const
Definition: FileManager.h:223
bool isValid() const
Definition: FileManager.h:86
Dataflow Directional Tag Classes.
bool isInPCH() const
Definition: FileManager.h:90
off_t getSize() const
Definition: FileManager.h:87
Defines the virtual file system interface vfs::FileSystem.
Defines the clang::FileSystemOptions interface.
Cached information about one directory (either on disk or in the virtual file system).
Definition: FileManager.h:45
Keeps track of options that affect how file operations are performed.
IntrusiveRefCntPtr< vfs::FileSystem > getVirtualFileSystem() const
Definition: FileManager.h:225
StringRef getName() const
Definition: FileManager.h:51