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
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/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
34namespace llvm {
35
36class MemoryBuffer;
37
38} // end namespace llvm
39
40namespace clang {
41
42class FileSystemStatCache;
43
44/// Cached information about one directory (either on disk or in
45/// the virtual file system).
46class DirectoryEntry {
47 friend class FileManager;
48
49 StringRef Name; // Name of the directory.
50
51public:
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.
60class 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
74 /// The open file, if it is owned by the \p FileEntry.
75 mutable std::unique_ptr<llvm::vfs::File> File;
76
77public:
78 FileEntry()
79 : UniqueID(0, 0), IsNamedPipe(false), InPCH(false), IsValid(false)
80 {}
81
82 FileEntry(const FileEntry &) = delete;
83 FileEntry &operator=(const FileEntry &) = delete;
84
85 StringRef getName() const { return Name; }
86 StringRef tryGetRealPathName() const { return RealPathName; }
87 bool isValid() const { return IsValid; }
88 off_t getSize() const { return Size; }
89 unsigned getUID() const { return UID; }
90 const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
91 bool isInPCH() const { return InPCH; }
92 time_t getModificationTime() const { return ModTime; }
93
94 /// Return the directory the file lives in.
95 const DirectoryEntry *getDir() const { return Dir; }
96
97 bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
98
99 /// Check whether the file is a named pipe (and thus can't be opened by
100 /// the native FileManager methods).
101 bool isNamedPipe() const { return IsNamedPipe; }
102
103 void closeFile() const {
104 File.reset(); // rely on destructor to close File
105 }
106};
107
108struct FileData;
109
110/// Implements support for file system lookup, file system caching,
111/// and directory search management.
112///
113/// This also handles more advanced properties, such as uniquing files based
114/// on "inode", so that a file with two names (e.g. symlinked) will be treated
115/// as a single file.
116///
117class FileManager : public RefCountedBase<FileManager> {
118 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
119 FileSystemOptions FileSystemOpts;
120
121 /// Cache for existing real directories.
122 std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
123
124 /// Cache for existing real files.
125 std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
126
127 /// The virtual directories that we have allocated.
128 ///
129 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
130 /// directories (foo/ and foo/bar/) here.
131 SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries;
132 /// The virtual files that we have allocated.
133 SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries;
134
135 /// A cache that maps paths to directory entries (either real or
136 /// virtual) we have looked up
137 ///
138 /// The actual Entries for real directories/files are
139 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
140 /// for virtual directories/files are owned by
141 /// VirtualDirectoryEntries/VirtualFileEntries above.
142 ///
143 llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
144
145 /// A cache that maps paths to file entries (either real or
146 /// virtual) we have looked up.
147 ///
148 /// \see SeenDirEntries
149 llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
150
151 /// The canonical names of directories.
152 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
153
154 /// Storage for canonical names that we have computed.
155 llvm::BumpPtrAllocator CanonicalNameStorage;
156
157 /// Each FileEntry we create is assigned a unique ID #.
158 ///
159 unsigned NextFileUID;
160
161 // Statistics.
162 unsigned NumDirLookups, NumFileLookups;
163 unsigned NumDirCacheMisses, NumFileCacheMisses;
164
165 // Caching.
166 std::unique_ptr<FileSystemStatCache> StatCache;
167
168 bool getStatValue(StringRef Path, FileData &Data, bool isFile,
169 std::unique_ptr<llvm::vfs::File> *F);
170
171 /// Add all ancestors of the given path (pointing to either a file
172 /// or a directory) as virtual directories.
173 void addAncestorsAsVirtualDirs(StringRef Path);
174
175public:
176 FileManager(const FileSystemOptions &FileSystemOpts,
177 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
178 ~FileManager();
179
180 /// Installs the provided FileSystemStatCache object within
181 /// the FileManager.
182 ///
183 /// Ownership of this object is transferred to the FileManager.
184 ///
185 /// \param statCache the new stat cache to install. Ownership of this
186 /// object is transferred to the FileManager.
187 ///
188 /// \param AtBeginning whether this new stat cache must be installed at the
189 /// beginning of the chain of stat caches. Otherwise, it will be added to
190 /// the end of the chain.
191 void addStatCache(std::unique_ptr<FileSystemStatCache> statCache,
192 bool AtBeginning = false);
193
194 /// Removes the specified FileSystemStatCache object from the manager.
195 void removeStatCache(FileSystemStatCache *statCache);
196
197 /// Removes all FileSystemStatCache objects from the manager.
198 void clearStatCaches();
199
200 /// Lookup, cache, and verify the specified directory (real or
201 /// virtual).
202 ///
203 /// This returns NULL if the directory doesn't exist.
204 ///
205 /// \param CacheFailure If true and the file does not exist, we'll cache
206 /// the failure to find this file.
207 const DirectoryEntry *getDirectory(StringRef DirName,
208 bool CacheFailure = true);
209
210 /// Lookup, cache, and verify the specified file (real or
211 /// virtual).
212 ///
213 /// This returns NULL if the file doesn't exist.
214 ///
215 /// \param OpenFile if true and the file exists, it will be opened.
216 ///
217 /// \param CacheFailure If true and the file does not exist, we'll cache
218 /// the failure to find this file.
219 const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
220 bool CacheFailure = true);
221
222 /// Returns the current file system options
223 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
224 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
225
226 IntrusiveRefCntPtr<llvm::vfs::FileSystem> getVirtualFileSystem() const {
227 return FS;
228 }
229
230 /// Retrieve a file entry for a "virtual" file that acts as
231 /// if there were a file with the given name on disk.
232 ///
233 /// The file itself is not accessed.
234 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
235 time_t ModificationTime);
236
237 /// Open the specified file as a MemoryBuffer, returning a new
238 /// MemoryBuffer if successful, otherwise returning null.
239 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
240 getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
241 bool ShouldCloseOpenFile = true);
242 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
243 getBufferForFile(StringRef Filename, bool isVolatile = false);
244
245 /// Get the 'stat' information for the given \p Path.
246 ///
247 /// If the path is relative, it will be resolved against the WorkingDir of the
248 /// FileManager's FileSystemOptions.
249 ///
250 /// \returns false on success, true on error.
251 bool getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result);
252
253 /// Remove the real file \p Entry from the cache.
254 void invalidateCache(const FileEntry *Entry);
255
256 /// 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 /// 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 /// 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 /// 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
290