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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 :
18 : #include "clang/Basic/FileSystemOptions.h"
19 : #include "clang/Basic/LLVM.h"
20 : #include "clang/Basic/VirtualFileSystem.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).
40 : class DirectoryEntry {
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:
71 : FileEntry()
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 11 : 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> {
116 : IntrusiveRefCntPtr<vfs::FileSystem> FS;
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<DirectoryEntry*, 4> VirtualDirectoryEntries;
130 : /// \brief The virtual files that we have allocated.
131 : SmallVector<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,
175 : IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr);
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 : const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; }
222 :
223 : IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const {
224 : return FS;
225 : }
226 :
227 : /// \brief Retrieve a file entry for a "virtual" file that acts as
228 : /// if there were a file with the given name on disk.
229 : ///
230 : /// The file itself is not accessed.
231 : const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
232 : time_t ModificationTime);
233 :
234 : /// \brief Open the specified file as a MemoryBuffer, returning a new
235 : /// MemoryBuffer if successful, otherwise returning null.
236 : llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
237 : getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
238 : bool ShouldCloseOpenFile = true);
239 : llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
240 : getBufferForFile(StringRef Filename);
241 :
242 : /// \brief Get the 'stat' information for the given \p Path.
243 : ///
244 : /// If the path is relative, it will be resolved against the WorkingDir of the
245 : /// FileManager's FileSystemOptions.
246 : ///
247 : /// \returns false on success, true on error.
248 : bool getNoncachedStatValue(StringRef Path,
249 : vfs::Status &Result);
250 :
251 : /// \brief Remove the real file \p Entry from the cache.
252 : void invalidateCache(const FileEntry *Entry);
253 :
254 : /// \brief If path is not absolute and FileSystemOptions set the working
255 : /// directory, the path is modified to be relative to the given
256 : /// working directory.
257 : void FixupRelativePath(SmallVectorImpl<char> &path) const;
258 :
259 : /// \brief Produce an array mapping from the unique IDs assigned to each
260 : /// file to the corresponding FileEntry pointer.
261 : void GetUniqueIDMapping(
262 : SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
263 :
264 : /// \brief Modifies the size and modification time of a previously created
265 : /// FileEntry. Use with caution.
266 : static void modifyFileEntry(FileEntry *File, off_t Size,
267 : time_t ModificationTime);
268 :
269 : /// \brief Remove any './' components from a path.
270 : static bool removeDotPaths(SmallVectorImpl<char> &Path);
271 :
272 : /// \brief Retrieve the canonical name for a given directory.
273 : ///
274 : /// This is a very expensive operation, despite its results being cached,
275 : /// and should only be used when the physical layout of the file system is
276 : /// required, which is (almost) never.
277 : StringRef getCanonicalName(const DirectoryEntry *Dir);
278 :
279 : void PrintStats() const;
280 : };
281 :
282 : } // end namespace clang
283 :
284 : #endif
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