clang  8.0.0svn
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 /// 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 
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"
29 #include <ctime>
30 #include <map>
31 #include <memory>
32 #include <string>
33 
34 namespace llvm {
35 
36 class MemoryBuffer;
37 
38 } // end namespace llvm
39 
40 namespace clang {
41 
42 class FileSystemStatCache;
43 
44 /// Cached information about one directory (either on disk or in
45 /// the virtual file system).
47  friend class FileManager;
48 
49  StringRef Name; // Name of the directory.
50 
51 public:
52  StringRef getName() const { return Name; }
53 };
54 
55 /// Cached information about one file (either on disk
56 /// or in the virtual file system).
57 ///
58 /// If the 'File' member is valid, then this FileEntry has an open file
59 /// descriptor for the file.
60 class FileEntry {
61  friend class FileManager;
62 
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;
70  bool IsNamedPipe;
71  bool InPCH;
72  bool IsValid; // Is this \c FileEntry initialized and valid?
73  bool DeferredOpen; // Created by getFile(OpenFile=0); may open later.
74 
75  /// The open file, if it is owned by the \p FileEntry.
76  mutable std::unique_ptr<llvm::vfs::File> File;
77 
78 public:
80  : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false),
81  DeferredOpen(false) {}
82 
83  FileEntry(const FileEntry &) = delete;
84  FileEntry &operator=(const FileEntry &) = delete;
85 
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; }
94 
95  /// Return the directory the file lives in.
96  const DirectoryEntry *getDir() const { return Dir; }
97 
98  bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
99 
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; }
103 
104  void closeFile() const {
105  File.reset(); // rely on destructor to close File
106  }
107 
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; }
111 };
112 
113 struct FileData;
114 
115 /// Implements support for file system lookup, file system caching,
116 /// and directory search management.
117 ///
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.
121 ///
122 class FileManager : public RefCountedBase<FileManager> {
124  FileSystemOptions FileSystemOpts;
125 
126  /// Cache for existing real directories.
127  std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
128 
129  /// Cache for existing real files.
130  std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
131 
132  /// The virtual directories that we have allocated.
133  ///
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;
139 
140  /// A cache that maps paths to directory entries (either real or
141  /// virtual) we have looked up
142  ///
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.
147  ///
148  llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
149 
150  /// A cache that maps paths to file entries (either real or
151  /// virtual) we have looked up.
152  ///
153  /// \see SeenDirEntries
154  llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
155 
156  /// The canonical names of directories.
157  llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
158 
159  /// Storage for canonical names that we have computed.
160  llvm::BumpPtrAllocator CanonicalNameStorage;
161 
162  /// Each FileEntry we create is assigned a unique ID #.
163  ///
164  unsigned NextFileUID;
165 
166  // Statistics.
167  unsigned NumDirLookups, NumFileLookups;
168  unsigned NumDirCacheMisses, NumFileCacheMisses;
169 
170  // Caching.
171  std::unique_ptr<FileSystemStatCache> StatCache;
172 
173  bool getStatValue(StringRef Path, FileData &Data, bool isFile,
174  std::unique_ptr<llvm::vfs::File> *F);
175 
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);
179 
180  /// Fills the RealPathName in file entry.
181  void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName);
182 
183 public:
184  FileManager(const FileSystemOptions &FileSystemOpts,
186  ~FileManager();
187 
188  /// Installs the provided FileSystemStatCache object within
189  /// the FileManager.
190  ///
191  /// Ownership of this object is transferred to the FileManager.
192  ///
193  /// \param statCache the new stat cache to install. Ownership of this
194  /// object is transferred to the FileManager.
195  ///
196  /// \param AtBeginning whether this new stat cache must be installed at the
197  /// beginning of the chain of stat caches. Otherwise, it will be added to
198  /// the end of the chain.
199  void addStatCache(std::unique_ptr<FileSystemStatCache> statCache,
200  bool AtBeginning = false);
201 
202  /// Removes the specified FileSystemStatCache object from the manager.
203  void removeStatCache(FileSystemStatCache *statCache);
204 
205  /// Removes all FileSystemStatCache objects from the manager.
206  void clearStatCaches();
207 
208  /// Lookup, cache, and verify the specified directory (real or
209  /// virtual).
210  ///
211  /// This returns NULL if the directory doesn't exist.
212  ///
213  /// \param CacheFailure If true and the file does not exist, we'll cache
214  /// the failure to find this file.
215  const DirectoryEntry *getDirectory(StringRef DirName,
216  bool CacheFailure = true);
217 
218  /// Lookup, cache, and verify the specified file (real or
219  /// virtual).
220  ///
221  /// This returns NULL if the file doesn't exist.
222  ///
223  /// \param OpenFile if true and the file exists, it will be opened.
224  ///
225  /// \param CacheFailure If true and the file does not exist, we'll cache
226  /// the failure to find this file.
227  const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
228  bool CacheFailure = true);
229 
230  /// Returns the current file system options
231  FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
232  const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
233 
235  return FS;
236  }
237 
238  /// Retrieve a file entry for a "virtual" file that acts as
239  /// if there were a file with the given name on disk.
240  ///
241  /// The file itself is not accessed.
242  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
243  time_t ModificationTime);
244 
245  /// Open the specified file as a MemoryBuffer, returning a new
246  /// MemoryBuffer if successful, otherwise returning null.
247  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
248  getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
249  bool ShouldCloseOpenFile = true);
250  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
251  getBufferForFile(StringRef Filename, bool isVolatile = false);
252 
253  /// Get the 'stat' information for the given \p Path.
254  ///
255  /// If the path is relative, it will be resolved against the WorkingDir of the
256  /// FileManager's FileSystemOptions.
257  ///
258  /// \returns false on success, true on error.
259  bool getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result);
260 
261  /// Remove the real file \p Entry from the cache.
262  void invalidateCache(const FileEntry *Entry);
263 
264  /// If path is not absolute and FileSystemOptions set the working
265  /// directory, the path is modified to be relative to the given
266  /// working directory.
267  /// \returns true if \c path changed.
268  bool FixupRelativePath(SmallVectorImpl<char> &path) const;
269 
270  /// Makes \c Path absolute taking into account FileSystemOptions and the
271  /// working directory option.
272  /// \returns true if \c Path changed to absolute.
273  bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
274 
275  /// Produce an array mapping from the unique IDs assigned to each
276  /// file to the corresponding FileEntry pointer.
277  void GetUniqueIDMapping(
278  SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
279 
280  /// Modifies the size and modification time of a previously created
281  /// FileEntry. Use with caution.
282  static void modifyFileEntry(FileEntry *File, off_t Size,
283  time_t ModificationTime);
284 
285  /// Retrieve the canonical name for a given directory.
286  ///
287  /// This is a very expensive operation, despite its results being cached,
288  /// and should only be used when the physical layout of the file system is
289  /// required, which is (almost) never.
290  StringRef getCanonicalName(const DirectoryEntry *Dir);
291 
292  void PrintStats() const;
293 };
294 
295 } // end namespace clang
296 
297 #endif // LLVM_CLANG_BASIC_FILEMANAGER_H
StringRef tryGetRealPathName() const
Definition: FileManager.h:87
Implements support for file system lookup, file system caching, and directory search management...
Definition: FileManager.h:122
time_t getModificationTime() const
Definition: FileManager.h:93
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:30
void closeFile() const
Definition: FileManager.h:104
const llvm::sys::fs::UniqueID & getUniqueID() const
Definition: FileManager.h:91
unsigned getUID() const
Definition: FileManager.h:90
Abstract interface for introducing a FileManager cache for &#39;stat&#39; system calls, which is used by prec...
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
StringRef Filename
Definition: Format.cpp:1629
const DirectoryEntry * getDir() const
Return the directory the file lives in.
Definition: FileManager.h:96
#define false
Definition: stdbool.h:33
StringRef getName() const
Definition: FileManager.h:86
FileSystemOptions & getFileSystemOpts()
Returns the current file system options.
Definition: FileManager.h:231
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:102
bool operator<(const FileEntry &RHS) const
Definition: FileManager.h:98
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:60
const FileSystemOptions & getFileSystemOpts() const
Definition: FileManager.h:232
bool isValid() const
Definition: FileManager.h:88
Dataflow Directional Tag Classes.
bool isInPCH() const
Definition: FileManager.h:92
off_t getSize() const
Definition: FileManager.h:89
bool isOpenForTests() const
Definition: FileManager.h:110
Defines the clang::FileSystemOptions interface.
Cached information about one directory (either on disk or in the virtual file system).
Definition: FileManager.h:46
Keeps track of options that affect how file operations are performed.
IntrusiveRefCntPtr< llvm::vfs::FileSystem > getVirtualFileSystem() const
Definition: FileManager.h:234
StringRef getName() const
Definition: FileManager.h:52