clang  3.8.0
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 
19 #include "clang/Basic/LLVM.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"
27 #include <memory>
28 #include <map>
29 
30 namespace llvm {
31 class MemoryBuffer;
32 }
33 
34 namespace clang {
35 class FileManager;
36 class FileSystemStatCache;
37 
38 /// \brief Cached information about one directory (either on disk or in
39 /// the virtual file system).
41  const char *Name; // Name of the directory.
42  friend class FileManager;
43 public:
44  DirectoryEntry() : Name(nullptr) {}
45  const char *getName() const { return Name; }
46 };
47 
48 /// \brief Cached information about one file (either on disk
49 /// or in the virtual file system).
50 ///
51 /// If the 'File' member is valid, then this FileEntry has an open file
52 /// descriptor for the file.
53 class FileEntry {
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;
60  bool IsNamedPipe;
61  bool InPCH;
62  bool IsValid; // Is this \c FileEntry initialized and valid?
63 
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;
67 
68  void operator=(const FileEntry &) = delete;
69 
70 public:
72  : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false)
73  {}
74 
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
78  /// \c FileEntry.
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");
82  }
83 
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; }
91 
92  /// \brief Return the directory the file lives in.
93  const DirectoryEntry *getDir() const { return Dir; }
94 
95  bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
96 
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; }
100 
101  void closeFile() const {
102  File.reset(); // rely on destructor to close File
103  }
104 };
105 
106 struct FileData;
107 
108 /// \brief Implements support for file system lookup, file system caching,
109 /// and directory search management.
110 ///
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.
114 ///
115 class FileManager : public RefCountedBase<FileManager> {
117  FileSystemOptions FileSystemOpts;
118 
119  /// \brief Cache for existing real directories.
120  std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
121 
122  /// \brief Cache for existing real files.
123  std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
124 
125  /// \brief The virtual directories that we have allocated.
126  ///
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;
132 
133  /// \brief A cache that maps paths to directory entries (either real or
134  /// virtual) we have looked up
135  ///
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.
140  ///
141  llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
142 
143  /// \brief A cache that maps paths to file entries (either real or
144  /// virtual) we have looked up.
145  ///
146  /// \see SeenDirEntries
147  llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
148 
149  /// \brief The canonical names of directories.
150  llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
151 
152  /// \brief Storage for canonical names that we have computed.
153  llvm::BumpPtrAllocator CanonicalNameStorage;
154 
155  /// \brief Each FileEntry we create is assigned a unique ID #.
156  ///
157  unsigned NextFileUID;
158 
159  // Statistics.
160  unsigned NumDirLookups, NumFileLookups;
161  unsigned NumDirCacheMisses, NumFileCacheMisses;
162 
163  // Caching.
164  std::unique_ptr<FileSystemStatCache> StatCache;
165 
166  bool getStatValue(const char *Path, FileData &Data, bool isFile,
167  std::unique_ptr<vfs::File> *F);
168 
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);
172 
173 public:
174  FileManager(const FileSystemOptions &FileSystemOpts,
176  ~FileManager();
177 
178  /// \brief Installs the provided FileSystemStatCache object within
179  /// the FileManager.
180  ///
181  /// Ownership of this object is transferred to the FileManager.
182  ///
183  /// \param statCache the new stat cache to install. Ownership of this
184  /// object is transferred to the FileManager.
185  ///
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);
191 
192  /// \brief Removes the specified FileSystemStatCache object from the manager.
193  void removeStatCache(FileSystemStatCache *statCache);
194 
195  /// \brief Removes all FileSystemStatCache objects from the manager.
196  void clearStatCaches();
197 
198  /// \brief Lookup, cache, and verify the specified directory (real or
199  /// virtual).
200  ///
201  /// This returns NULL if the directory doesn't exist.
202  ///
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);
207 
208  /// \brief Lookup, cache, and verify the specified file (real or
209  /// virtual).
210  ///
211  /// This returns NULL if the file doesn't exist.
212  ///
213  /// \param OpenFile if true and the file exists, it will be opened.
214  ///
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);
219 
220  /// \brief Returns the current file system options
221  FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
222  const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
223 
225  return FS;
226  }
227 
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.
230  ///
231  /// The file itself is not accessed.
232  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
233  time_t ModificationTime);
234 
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);
242 
243  /// \brief Get the 'stat' information for the given \p Path.
244  ///
245  /// If the path is relative, it will be resolved against the WorkingDir of the
246  /// FileManager's FileSystemOptions.
247  ///
248  /// \returns false on success, true on error.
249  bool getNoncachedStatValue(StringRef Path,
251 
252  /// \brief Remove the real file \p Entry from the cache.
253  void invalidateCache(const FileEntry *Entry);
254 
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;
260 
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;
265 
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;
270 
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);
275 
276  /// \brief Retrieve the canonical name for a given directory.
277  ///
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);
282 
283  void PrintStats() const;
284 };
285 
286 } // end namespace clang
287 
288 #endif
Implements support for file system lookup, file system caching, and directory search management...
Definition: FileManager.h:115
bool isValid() const
Definition: FileManager.h:85
FileManager(const FileSystemOptions &FileSystemOpts, IntrusiveRefCntPtr< vfs::FileSystem > FS=nullptr)
Definition: FileManager.cpp:49
off_t getSize() const
Definition: FileManager.h:86
class LLVM_ALIGNAS(8) DependentTemplateSpecializationType const IdentifierInfo * Name
Represents a template specialization type whose template cannot be resolved, e.g. ...
Definition: Type.h:4381
bool makeAbsolutePath(SmallVectorImpl< char > &Path) const
Makes Path absolute taking into account FileSystemOptions and the working directory option...
bool operator<(const FileEntry &RHS) const
Definition: FileManager.h:95
bool isInPCH() const
Definition: FileManager.h:89
Abstract interface for introducing a FileManager cache for 'stat' system calls, which is used by prec...
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
IntrusiveRefCntPtr< vfs::FileSystem > getVirtualFileSystem() const
Definition: FileManager.h:224
The result of a status operation.
const FileEntry * getFile(StringRef Filename, bool OpenFile=false, bool CacheFailure=true)
Lookup, cache, and verify the specified file (real or virtual).
const DirectoryEntry * getDirectory(StringRef DirName, bool CacheFailure=true)
Lookup, cache, and verify the specified directory (real or virtual).
StringRef Filename
Definition: Format.cpp:1723
const llvm::sys::fs::UniqueID & getUniqueID() const
Definition: FileManager.h:88
The result type of a method or function.
bool isNamedPipe() const
Check whether the file is a named pipe (and thus can't be opened by the native FileManager methods)...
Definition: FileManager.h:99
#define false
Definition: stdbool.h:33
void addStatCache(std::unique_ptr< FileSystemStatCache > statCache, bool AtBeginning=false)
Installs the provided FileSystemStatCache object within the FileManager.
Definition: FileManager.cpp:64
const char * getName() const
Definition: FileManager.h:84
FileSystemOptions & getFileSystemOpts()
Returns the current file system options.
Definition: FileManager.h:221
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:53
void clearStatCaches()
Removes all FileSystemStatCache objects from the manager.
Definition: FileManager.cpp:99
const FileEntry * getVirtualFile(StringRef Filename, off_t Size, time_t ModificationTime)
Retrieve a file entry for a "virtual" file that acts as if there were a file with the given name on d...
const char * getName() const
Definition: FileManager.h:45
StringRef getCanonicalName(const DirectoryEntry *Dir)
Retrieve the canonical name for a given directory.
unsigned getUID() const
Definition: FileManager.h:87
void removeStatCache(FileSystemStatCache *statCache)
Removes the specified FileSystemStatCache object from the manager.
Definition: FileManager.cpp:80
llvm::ErrorOr< std::unique_ptr< llvm::MemoryBuffer > > getBufferForFile(const FileEntry *Entry, bool isVolatile=false, bool ShouldCloseOpenFile=true)
Open the specified file as a MemoryBuffer, returning a new MemoryBuffer if successful, otherwise returning null.
Defines the virtual file system interface vfs::FileSystem.
void closeFile() const
Definition: FileManager.h:101
time_t getModificationTime() const
Definition: FileManager.h:90
Defines the clang::FileSystemOptions interface.
Cached information about one directory (either on disk or in the virtual file system).
Definition: FileManager.h:40
Keeps track of options that affect how file operations are performed.
bool getNoncachedStatValue(StringRef Path, vfs::Status &Result)
Get the 'stat' information for the given Path.
static void modifyFileEntry(FileEntry *File, off_t Size, time_t ModificationTime)
Modifies the size and modification time of a previously created FileEntry.
FileEntry(const FileEntry &FE)
Intentionally does not copy fields that are not set in an uninitialized FileEntry.
Definition: FileManager.h:79
void PrintStats() const
void invalidateCache(const FileEntry *Entry)
Remove the real file Entry from the cache.
const FileSystemOptions & getFileSystemOpts() const
Definition: FileManager.h:222
const DirectoryEntry * getDir() const
Return the directory the file lives in.
Definition: FileManager.h:93
bool FixupRelativePath(SmallVectorImpl< char > &path) const
If path is not absolute and FileSystemOptions set the working directory, the path is modified to be r...
void GetUniqueIDMapping(SmallVectorImpl< const FileEntry * > &UIDToFiles) const
Produce an array mapping from the unique IDs assigned to each file to the corresponding FileEntry poi...