xref: /llvm-project/clang/lib/Basic/FileManager.cpp (revision 48db39dc90c9cc6fbef608b6601d31b36e6c2f40)
1 ///===--- FileManager.cpp - File System Probing and Caching ----------------===//
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 //  This file implements the FileManager interface.
11 //
12 //===----------------------------------------------------------------------===//
13 //
14 // TODO: This should index all interesting directories with dirent calls.
15 //  getdirentries ?
16 //  opendir/readdir_r/closedir ?
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #include "clang/Basic/FileManager.h"
21 #include "llvm/ADT/SmallString.h"
22 #include "llvm/Support/Streams.h"
23 #include "llvm/Config/config.h"
24 using namespace clang;
25 
26 // FIXME: Enhance libsystem to support inode and other fields.
27 #include <sys/stat.h>
28 
29 #if defined(_MSC_VER)
30 #define S_ISDIR(s) (_S_IFDIR & s)
31 #endif
32 
33 /// NON_EXISTENT_DIR - A special value distinct from null that is used to
34 /// represent a dir name that doesn't exist on the disk.
35 #define NON_EXISTENT_DIR reinterpret_cast<DirectoryEntry*>((intptr_t)-1)
36 
37 //===----------------------------------------------------------------------===//
38 // Windows.
39 //===----------------------------------------------------------------------===//
40 
41 #ifdef LLVM_ON_WIN32
42 
43 #define IS_DIR_SEPARATOR_CHAR(x) ((x) == '/' || (x) == '\\')
44 
45 namespace {
46   static std::string GetFullPath(const char *relPath)
47   {
48     char *absPathStrPtr = _fullpath(NULL, relPath, 0);
49     assert(absPathStrPtr && "_fullpath() returned NULL!");
50 
51     std::string absPath(absPathStrPtr);
52 
53     free(absPathStrPtr);
54     return absPath;
55   }
56 }
57 
58 class FileManager::UniqueDirContainer {
59   /// UniqueDirs - Cache from full path to existing directories/files.
60   ///
61   llvm::StringMap<DirectoryEntry> UniqueDirs;
62 
63 public:
64   DirectoryEntry &getDirectory(const char *Name, struct stat &StatBuf) {
65     std::string FullPath(GetFullPath(Name));
66     return UniqueDirs.GetOrCreateValue(
67                               FullPath.c_str(),
68                               FullPath.c_str() + FullPath.size()
69                                                                 ).getValue();
70   }
71 
72   size_t size() { return UniqueDirs.size(); }
73 };
74 
75 class FileManager::UniqueFileContainer {
76   /// UniqueFiles - Cache from full path to existing directories/files.
77   ///
78   llvm::StringMap<FileEntry, llvm::BumpPtrAllocator> UniqueFiles;
79 
80 public:
81   FileEntry &getFile(const char *Name, struct stat &StatBuf) {
82     std::string FullPath(GetFullPath(Name));
83     return UniqueFiles.GetOrCreateValue(
84                                FullPath.c_str(),
85                                FullPath.c_str() + FullPath.size()
86                                                                  ).getValue();
87   }
88 
89   size_t size() { return UniqueFiles.size(); }
90 };
91 
92 //===----------------------------------------------------------------------===//
93 // Unix-like Systems.
94 //===----------------------------------------------------------------------===//
95 
96 #else
97 
98 #define IS_DIR_SEPARATOR_CHAR(x) ((x) == '/')
99 
100 class FileManager::UniqueDirContainer {
101   /// UniqueDirs - Cache from ID's to existing directories/files.
102   ///
103   std::map<std::pair<dev_t, ino_t>, DirectoryEntry> UniqueDirs;
104 
105 public:
106   DirectoryEntry &getDirectory(const char *Name, struct stat &StatBuf) {
107     return UniqueDirs[std::make_pair(StatBuf.st_dev, StatBuf.st_ino)];
108   }
109 
110   size_t size() { return UniqueDirs.size(); }
111 };
112 
113 class FileManager::UniqueFileContainer {
114   /// UniqueFiles - Cache from ID's to existing directories/files.
115   ///
116   std::set<FileEntry> UniqueFiles;
117 
118 public:
119   FileEntry &getFile(const char *Name, struct stat &StatBuf) {
120     return
121       const_cast<FileEntry&>(
122                     *UniqueFiles.insert(FileEntry(StatBuf.st_dev,
123                                                   StatBuf.st_ino,
124                                                   StatBuf.st_mode)).first);
125   }
126 
127   size_t size() { return UniqueFiles.size(); }
128 };
129 
130 #endif
131 
132 //===----------------------------------------------------------------------===//
133 // Common logic.
134 //===----------------------------------------------------------------------===//
135 
136 FileManager::FileManager()
137   : UniqueDirs(*new UniqueDirContainer),
138     UniqueFiles(*new UniqueFileContainer),
139     DirEntries(64), FileEntries(64), NextFileUID(0) {
140   NumDirLookups = NumFileLookups = 0;
141   NumDirCacheMisses = NumFileCacheMisses = 0;
142 }
143 
144 FileManager::~FileManager() {
145   delete &UniqueDirs;
146   delete &UniqueFiles;
147 }
148 
149 /// getDirectory - Lookup, cache, and verify the specified directory.  This
150 /// returns null if the directory doesn't exist.
151 ///
152 const DirectoryEntry *FileManager::getDirectory(const char *NameStart,
153                                                 const char *NameEnd) {
154   ++NumDirLookups;
155   llvm::StringMapEntry<DirectoryEntry *> &NamedDirEnt =
156     DirEntries.GetOrCreateValue(NameStart, NameEnd);
157 
158   // See if there is already an entry in the map.
159   if (NamedDirEnt.getValue())
160     return NamedDirEnt.getValue() == NON_EXISTENT_DIR
161               ? 0 : NamedDirEnt.getValue();
162 
163   ++NumDirCacheMisses;
164 
165   // By default, initialize it to invalid.
166   NamedDirEnt.setValue(NON_EXISTENT_DIR);
167 
168   // Get the null-terminated directory name as stored as the key of the
169   // DirEntries map.
170   const char *InterndDirName = NamedDirEnt.getKeyData();
171 
172   // Check to see if the directory exists.
173   struct stat StatBuf;
174   if (stat_cached(InterndDirName, &StatBuf) ||   // Error stat'ing.
175       !S_ISDIR(StatBuf.st_mode))          // Not a directory?
176     return 0;
177 
178   // It exists.  See if we have already opened a directory with the same inode.
179   // This occurs when one dir is symlinked to another, for example.
180   DirectoryEntry &UDE = UniqueDirs.getDirectory(InterndDirName, StatBuf);
181 
182   NamedDirEnt.setValue(&UDE);
183   if (UDE.getName()) // Already have an entry with this inode, return it.
184     return &UDE;
185 
186   // Otherwise, we don't have this directory yet, add it.  We use the string
187   // key from the DirEntries map as the string.
188   UDE.Name  = InterndDirName;
189   return &UDE;
190 }
191 
192 /// NON_EXISTENT_FILE - A special value distinct from null that is used to
193 /// represent a filename that doesn't exist on the disk.
194 #define NON_EXISTENT_FILE reinterpret_cast<FileEntry*>((intptr_t)-1)
195 
196 /// getFile - Lookup, cache, and verify the specified file.  This returns null
197 /// if the file doesn't exist.
198 ///
199 const FileEntry *FileManager::getFile(const char *NameStart,
200                                       const char *NameEnd) {
201   ++NumFileLookups;
202 
203   // See if there is already an entry in the map.
204   llvm::StringMapEntry<FileEntry *> &NamedFileEnt =
205     FileEntries.GetOrCreateValue(NameStart, NameEnd);
206 
207   // See if there is already an entry in the map.
208   if (NamedFileEnt.getValue())
209     return NamedFileEnt.getValue() == NON_EXISTENT_FILE
210                  ? 0 : NamedFileEnt.getValue();
211 
212   ++NumFileCacheMisses;
213 
214   // By default, initialize it to invalid.
215   NamedFileEnt.setValue(NON_EXISTENT_FILE);
216 
217   // Figure out what directory it is in.   If the string contains a / in it,
218   // strip off everything after it.
219   // FIXME: this logic should be in sys::Path.
220   const char *SlashPos = NameEnd-1;
221   while (SlashPos >= NameStart && !IS_DIR_SEPARATOR_CHAR(SlashPos[0]))
222     --SlashPos;
223 
224   const DirectoryEntry *DirInfo;
225   if (SlashPos < NameStart) {
226     // Use the current directory if file has no path component.
227     const char *Name = ".";
228     DirInfo = getDirectory(Name, Name+1);
229   } else if (SlashPos == NameEnd-1)
230     return 0;       // If filename ends with a /, it's a directory.
231   else
232     DirInfo = getDirectory(NameStart, SlashPos);
233 
234   if (DirInfo == 0)  // Directory doesn't exist, file can't exist.
235     return 0;
236 
237   // Get the null-terminated file name as stored as the key of the
238   // FileEntries map.
239   const char *InterndFileName = NamedFileEnt.getKeyData();
240 
241   // FIXME: Use the directory info to prune this, before doing the stat syscall.
242   // FIXME: This will reduce the # syscalls.
243 
244   // Nope, there isn't.  Check to see if the file exists.
245   struct stat StatBuf;
246   //llvm::cerr << "STATING: " << Filename;
247   if (stat_cached(InterndFileName, &StatBuf) ||   // Error stat'ing.
248         S_ISDIR(StatBuf.st_mode)) {           // A directory?
249     // If this file doesn't exist, we leave a null in FileEntries for this path.
250     //llvm::cerr << ": Not existing\n";
251     return 0;
252   }
253   //llvm::cerr << ": exists\n";
254 
255   // It exists.  See if we have already opened a file with the same inode.
256   // This occurs when one dir is symlinked to another, for example.
257   FileEntry &UFE = UniqueFiles.getFile(InterndFileName, StatBuf);
258 
259   NamedFileEnt.setValue(&UFE);
260   if (UFE.getName())  // Already have an entry with this inode, return it.
261     return &UFE;
262 
263   // Otherwise, we don't have this directory yet, add it.
264   // FIXME: Change the name to be a char* that points back to the 'FileEntries'
265   // key.
266   UFE.Name    = InterndFileName;
267   UFE.Size    = StatBuf.st_size;
268   UFE.ModTime = StatBuf.st_mtime;
269   UFE.Dir     = DirInfo;
270   UFE.UID     = NextFileUID++;
271   return &UFE;
272 }
273 
274 void FileManager::PrintStats() const {
275   llvm::cerr << "\n*** File Manager Stats:\n";
276   llvm::cerr << UniqueFiles.size() << " files found, "
277              << UniqueDirs.size() << " dirs found.\n";
278   llvm::cerr << NumDirLookups << " dir lookups, "
279              << NumDirCacheMisses << " dir cache misses.\n";
280   llvm::cerr << NumFileLookups << " file lookups, "
281              << NumFileCacheMisses << " file cache misses.\n";
282 
283   //llvm::cerr << PagesMapped << BytesOfPagesMapped << FSLookups;
284 }
285