1//===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// Defines the clang::FileManager interface and associated types.
11///
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
15#define LLVM_CLANG_BASIC_FILEMANAGER_H
16
17#include "clang/Basic/DirectoryEntry.h"
18#include "clang/Basic/FileEntry.h"
19#include "clang/Basic/FileSystemOptions.h"
20#include "clang/Basic/LLVM.h"
21#include "llvm/ADT/DenseMap.h"
22#include "llvm/ADT/IntrusiveRefCntPtr.h"
23#include "llvm/ADT/PointerUnion.h"
24#include "llvm/ADT/SmallVector.h"
25#include "llvm/ADT/StringMap.h"
26#include "llvm/ADT/StringRef.h"
27#include "llvm/Support/Allocator.h"
28#include "llvm/Support/ErrorOr.h"
29#include "llvm/Support/FileSystem.h"
30#include "llvm/Support/VirtualFileSystem.h"
31#include <ctime>
32#include <map>
33#include <memory>
34#include <string>
35
36namespace llvm {
37
38class MemoryBuffer;
39
40} // end namespace llvm
41
42namespace clang {
43
44class FileSystemStatCache;
45
46/// Implements support for file system lookup, file system caching,
47/// and directory search management.
48///
49/// This also handles more advanced properties, such as uniquing files based
50/// on "inode", so that a file with two names (e.g. symlinked) will be treated
51/// as a single file.
52///
53class FileManager : public RefCountedBase<FileManager> {
54 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
55 FileSystemOptions FileSystemOpts;
56 llvm::SpecificBumpPtrAllocator<FileEntry> FilesAlloc;
57 llvm::SpecificBumpPtrAllocator<DirectoryEntry> DirsAlloc;
58
59 /// Cache for existing real directories.
60 llvm::DenseMap<llvm::sys::fs::UniqueID, DirectoryEntry *> UniqueRealDirs;
61
62 /// Cache for existing real files.
63 llvm::DenseMap<llvm::sys::fs::UniqueID, FileEntry *> UniqueRealFiles;
64
65 /// The virtual directories that we have allocated.
66 ///
67 /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
68 /// directories (foo/ and foo/bar/) here.
69 SmallVector<DirectoryEntry *, 4> VirtualDirectoryEntries;
70 /// The virtual files that we have allocated.
71 SmallVector<FileEntry *, 4> VirtualFileEntries;
72
73 /// A set of files that bypass the maps and uniquing. They can have
74 /// conflicting filenames.
75 SmallVector<FileEntry *, 0> BypassFileEntries;
76
77 /// A cache that maps paths to directory entries (either real or
78 /// virtual) we have looked up, or an error that occurred when we looked up
79 /// the directory.
80 ///
81 /// The actual Entries for real directories/files are
82 /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
83 /// for virtual directories/files are owned by
84 /// VirtualDirectoryEntries/VirtualFileEntries above.
85 ///
86 llvm::StringMap<llvm::ErrorOr<DirectoryEntry &>, llvm::BumpPtrAllocator>
87 SeenDirEntries;
88
89 /// A cache that maps paths to file entries (either real or
90 /// virtual) we have looked up, or an error that occurred when we looked up
91 /// the file.
92 ///
93 /// \see SeenDirEntries
94 llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>, llvm::BumpPtrAllocator>
95 SeenFileEntries;
96
97 /// A mirror of SeenFileEntries to give fake answers for getBypassFile().
98 ///
99 /// Don't bother hooking up a BumpPtrAllocator. This should be rarely used,
100 /// and only on error paths.
101 std::unique_ptr<llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>>>
102 SeenBypassFileEntries;
103
104 /// The file entry for stdin, if it has been accessed through the FileManager.
105 OptionalFileEntryRef STDIN;
106
107 /// The canonical names of files and directories .
108 llvm::DenseMap<const void *, llvm::StringRef> CanonicalNames;
109
110 /// Storage for canonical names that we have computed.
111 llvm::BumpPtrAllocator CanonicalNameStorage;
112
113 /// Each FileEntry we create is assigned a unique ID #.
114 ///
115 unsigned NextFileUID;
116
117 // Caching.
118 std::unique_ptr<FileSystemStatCache> StatCache;
119
120 std::error_code getStatValue(StringRef Path, llvm::vfs::Status &Status,
121 bool isFile,
122 std::unique_ptr<llvm::vfs::File> *F);
123
124 /// Add all ancestors of the given path (pointing to either a file
125 /// or a directory) as virtual directories.
126 void addAncestorsAsVirtualDirs(StringRef Path);
127
128 /// Fills the RealPathName in file entry.
129 void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName);
130
131public:
132 /// Construct a file manager, optionally with a custom VFS.
133 ///
134 /// \param FS if non-null, the VFS to use. Otherwise uses
135 /// llvm::vfs::getRealFileSystem().
136 FileManager(const FileSystemOptions &FileSystemOpts,
137 IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
138 ~FileManager();
139
140 /// Installs the provided FileSystemStatCache object within
141 /// the FileManager.
142 ///
143 /// Ownership of this object is transferred to the FileManager.
144 ///
145 /// \param statCache the new stat cache to install. Ownership of this
146 /// object is transferred to the FileManager.
147 void setStatCache(std::unique_ptr<FileSystemStatCache> statCache);
148
149 /// Removes the FileSystemStatCache object from the manager.
150 void clearStatCache();
151
152 /// Returns the number of unique real file entries cached by the file manager.
153 size_t getNumUniqueRealFiles() const { return UniqueRealFiles.size(); }
154
155 /// Lookup, cache, and verify the specified directory (real or
156 /// virtual).
157 ///
158 /// This returns a \c std::error_code if there was an error reading the
159 /// directory. On success, returns the reference to the directory entry
160 /// together with the exact path that was used to access a file by a
161 /// particular call to getDirectoryRef.
162 ///
163 /// \param CacheFailure If true and the file does not exist, we'll cache
164 /// the failure to find this file.
165 llvm::Expected<DirectoryEntryRef> getDirectoryRef(StringRef DirName,
166 bool CacheFailure = true);
167
168 /// Get a \c DirectoryEntryRef if it exists, without doing anything on error.
169 OptionalDirectoryEntryRef getOptionalDirectoryRef(StringRef DirName,
170 bool CacheFailure = true) {
171 return llvm::expectedToOptional(E: getDirectoryRef(DirName, CacheFailure));
172 }
173
174 /// Lookup, cache, and verify the specified directory (real or
175 /// virtual).
176 ///
177 /// This function is deprecated and will be removed at some point in the
178 /// future, new clients should use
179 /// \c getDirectoryRef.
180 ///
181 /// This returns a \c std::error_code if there was an error reading the
182 /// directory. If there is no error, the DirectoryEntry is guaranteed to be
183 /// non-NULL.
184 ///
185 /// \param CacheFailure If true and the file does not exist, we'll cache
186 /// the failure to find this file.
187 llvm::ErrorOr<const DirectoryEntry *>
188 getDirectory(StringRef DirName, bool CacheFailure = true);
189
190 /// Lookup, cache, and verify the specified file (real or
191 /// virtual).
192 ///
193 /// This function is deprecated and will be removed at some point in the
194 /// future, new clients should use
195 /// \c getFileRef.
196 ///
197 /// This returns a \c std::error_code if there was an error loading the file.
198 /// If there is no error, the FileEntry is guaranteed to be non-NULL.
199 ///
200 /// \param OpenFile if true and the file exists, it will be opened.
201 ///
202 /// \param CacheFailure If true and the file does not exist, we'll cache
203 /// the failure to find this file.
204 llvm::ErrorOr<const FileEntry *>
205 getFile(StringRef Filename, bool OpenFile = false, bool CacheFailure = true);
206
207 /// Lookup, cache, and verify the specified file (real or virtual). Return the
208 /// reference to the file entry together with the exact path that was used to
209 /// access a file by a particular call to getFileRef. If the underlying VFS is
210 /// a redirecting VFS that uses external file names, the returned FileEntryRef
211 /// will use the external name instead of the filename that was passed to this
212 /// method.
213 ///
214 /// This returns a \c std::error_code if there was an error loading the file,
215 /// or a \c FileEntryRef otherwise.
216 ///
217 /// \param OpenFile if true and the file exists, it will be opened.
218 ///
219 /// \param CacheFailure If true and the file does not exist, we'll cache
220 /// the failure to find this file.
221 llvm::Expected<FileEntryRef> getFileRef(StringRef Filename,
222 bool OpenFile = false,
223 bool CacheFailure = true);
224
225 /// Get the FileEntryRef for stdin, returning an error if stdin cannot be
226 /// read.
227 ///
228 /// This reads and caches stdin before returning. Subsequent calls return the
229 /// same file entry, and a reference to the cached input is returned by calls
230 /// to getBufferForFile.
231 llvm::Expected<FileEntryRef> getSTDIN();
232
233 /// Get a FileEntryRef if it exists, without doing anything on error.
234 OptionalFileEntryRef getOptionalFileRef(StringRef Filename,
235 bool OpenFile = false,
236 bool CacheFailure = true) {
237 return llvm::expectedToOptional(
238 E: getFileRef(Filename, OpenFile, CacheFailure));
239 }
240
241 /// Returns the current file system options
242 FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
243 const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
244
245 llvm::vfs::FileSystem &getVirtualFileSystem() const { return *FS; }
246 llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
247 getVirtualFileSystemPtr() const {
248 return FS;
249 }
250
251 /// Enable or disable tracking of VFS usage. Used to not track full header
252 /// search and implicit modulemap lookup.
253 void trackVFSUsage(bool Active);
254
255 void setVirtualFileSystem(IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
256 this->FS = std::move(FS);
257 }
258
259 /// Retrieve a file entry for a "virtual" file that acts as
260 /// if there were a file with the given name on disk.
261 ///
262 /// The file itself is not accessed.
263 FileEntryRef getVirtualFileRef(StringRef Filename, off_t Size,
264 time_t ModificationTime);
265
266 const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
267 time_t ModificationTime);
268
269 /// Retrieve a FileEntry that bypasses VFE, which is expected to be a virtual
270 /// file entry, to access the real file. The returned FileEntry will have
271 /// the same filename as FE but a different identity and its own stat.
272 ///
273 /// This should be used only for rare error recovery paths because it
274 /// bypasses all mapping and uniquing, blindly creating a new FileEntry.
275 /// There is no attempt to deduplicate these; if you bypass the same file
276 /// twice, you get two new file entries.
277 OptionalFileEntryRef getBypassFile(FileEntryRef VFE);
278
279 /// Open the specified file as a MemoryBuffer, returning a new
280 /// MemoryBuffer if successful, otherwise returning null.
281 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
282 getBufferForFile(FileEntryRef Entry, bool isVolatile = false,
283 bool RequiresNullTerminator = true);
284 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
285 getBufferForFile(StringRef Filename, bool isVolatile = false,
286 bool RequiresNullTerminator = true) const {
287 return getBufferForFileImpl(Filename, /*FileSize=*/FileSize: -1, isVolatile,
288 RequiresNullTerminator);
289 }
290
291private:
292 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
293 getBufferForFileImpl(StringRef Filename, int64_t FileSize, bool isVolatile,
294 bool RequiresNullTerminator) const;
295
296public:
297 /// Get the 'stat' information for the given \p Path.
298 ///
299 /// If the path is relative, it will be resolved against the WorkingDir of the
300 /// FileManager's FileSystemOptions.
301 ///
302 /// \returns a \c std::error_code describing an error, if there was one
303 std::error_code getNoncachedStatValue(StringRef Path,
304 llvm::vfs::Status &Result);
305
306 /// If path is not absolute and FileSystemOptions set the working
307 /// directory, the path is modified to be relative to the given
308 /// working directory.
309 /// \returns true if \c path changed.
310 bool FixupRelativePath(SmallVectorImpl<char> &path) const;
311
312 /// Makes \c Path absolute taking into account FileSystemOptions and the
313 /// working directory option.
314 /// \returns true if \c Path changed to absolute.
315 bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
316
317 /// Produce an array mapping from the unique IDs assigned to each
318 /// file to the corresponding FileEntryRef.
319 void
320 GetUniqueIDMapping(SmallVectorImpl<OptionalFileEntryRef> &UIDToFiles) const;
321
322 /// Retrieve the canonical name for a given directory.
323 ///
324 /// This is a very expensive operation, despite its results being cached,
325 /// and should only be used when the physical layout of the file system is
326 /// required, which is (almost) never.
327 StringRef getCanonicalName(DirectoryEntryRef Dir);
328
329 /// Retrieve the canonical name for a given file.
330 ///
331 /// This is a very expensive operation, despite its results being cached,
332 /// and should only be used when the physical layout of the file system is
333 /// required, which is (almost) never.
334 StringRef getCanonicalName(FileEntryRef File);
335
336private:
337 /// Retrieve the canonical name for a given file or directory.
338 ///
339 /// The first param is a key in the CanonicalNames array.
340 StringRef getCanonicalName(const void *Entry, StringRef Name);
341
342public:
343 void PrintStats() const;
344};
345
346} // end namespace clang
347
348#endif // LLVM_CLANG_BASIC_FILEMANAGER_H
349

source code of clang/include/clang/Basic/FileManager.h