FileManager.cpp revision 4fed3f47f6b9e31d603c5c2d1f6d8ec2e1241e57 
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/System/Path.h"
23#include "llvm/Support/Streams.h"
24#include "llvm/Config/config.h"
25using namespace clang;
26
27// FIXME: Enhance libsystem to support inode and other fields.
28#include <sys/stat.h>
29
30#if defined(_MSC_VER)
31#define S_ISDIR(s) (_S_IFDIR & s)
32#endif
33
34/// NON_EXISTENT_DIR - A special value distinct from null that is used to
35/// represent a dir name that doesn't exist on the disk.
36#define NON_EXISTENT_DIR reinterpret_cast<DirectoryEntry*>((intptr_t)-1)
37
38//===----------------------------------------------------------------------===//
39// Windows.
40//===----------------------------------------------------------------------===//
41
42#ifdef LLVM_ON_WIN32
43
44#define IS_DIR_SEPARATOR_CHAR(x) ((x) == '/' || (x) == '\\')
45
46namespace {
47  static std::string GetFullPath(const char *relPath)
48  {
49    char *absPathStrPtr = _fullpath(NULL, relPath, 0);
50    assert(absPathStrPtr && "_fullpath() returned NULL!");
51
52    std::string absPath(absPathStrPtr);
53
54    free(absPathStrPtr);
55    return absPath;
56  }
57}
58
59class FileManager::UniqueDirContainer {
60  /// UniqueDirs - Cache from full path to existing directories/files.
61  ///
62  llvm::StringMap<DirectoryEntry> UniqueDirs;
63
64public:
65  DirectoryEntry &getDirectory(const char *Name, struct stat &StatBuf) {
66    std::string FullPath(GetFullPath(Name));
67    return UniqueDirs.GetOrCreateValue(
68                              FullPath.c_str(),
69                              FullPath.c_str() + FullPath.size()
70                                                                ).getValue();
71  }
72
73  size_t size() { return UniqueDirs.size(); }
74};
75
76class FileManager::UniqueFileContainer {
77  /// UniqueFiles - Cache from full path to existing directories/files.
78  ///
79  llvm::StringMap<FileEntry, llvm::BumpPtrAllocator> UniqueFiles;
80
81public:
82  FileEntry &getFile(const char *Name, struct stat &StatBuf) {
83    std::string FullPath(GetFullPath(Name));
84    return UniqueFiles.GetOrCreateValue(
85                               FullPath.c_str(),
86                               FullPath.c_str() + FullPath.size()
87                                                                 ).getValue();
88  }
89
90  size_t size() { return UniqueFiles.size(); }
91};
92
93//===----------------------------------------------------------------------===//
94// Unix-like Systems.
95//===----------------------------------------------------------------------===//
96
97#else
98
99#define IS_DIR_SEPARATOR_CHAR(x) ((x) == '/')
100
101class FileManager::UniqueDirContainer {
102  /// UniqueDirs - Cache from ID's to existing directories/files.
103  ///
104  std::map<std::pair<dev_t, ino_t>, DirectoryEntry> UniqueDirs;
105
106public:
107  DirectoryEntry &getDirectory(const char *Name, struct stat &StatBuf) {
108    return UniqueDirs[std::make_pair(StatBuf.st_dev, StatBuf.st_ino)];
109  }
110
111  size_t size() { return UniqueDirs.size(); }
112};
113
114class FileManager::UniqueFileContainer {
115  /// UniqueFiles - Cache from ID's to existing directories/files.
116  ///
117  std::set<FileEntry> UniqueFiles;
118
119public:
120  FileEntry &getFile(const char *Name, struct stat &StatBuf) {
121    return
122      const_cast<FileEntry&>(
123                    *UniqueFiles.insert(FileEntry(StatBuf.st_dev,
124                                                  StatBuf.st_ino,
125                                                  StatBuf.st_mode)).first);
126  }
127
128  size_t size() { return UniqueFiles.size(); }
129};
130
131#endif
132
133//===----------------------------------------------------------------------===//
134// Common logic.
135//===----------------------------------------------------------------------===//
136
137FileManager::FileManager()
138  : UniqueDirs(*new UniqueDirContainer),
139    UniqueFiles(*new UniqueFileContainer),
140    DirEntries(64), FileEntries(64), NextFileUID(0) {
141  NumDirLookups = NumFileLookups = 0;
142  NumDirCacheMisses = NumFileCacheMisses = 0;
143}
144
145FileManager::~FileManager() {
146  delete &UniqueDirs;
147  delete &UniqueFiles;
148}
149
150/// getDirectory - Lookup, cache, and verify the specified directory.  This
151/// returns null if the directory doesn't exist.
152///
153const DirectoryEntry *FileManager::getDirectory(const char *NameStart,
154                                                const char *NameEnd) {
155  ++NumDirLookups;
156  llvm::StringMapEntry<DirectoryEntry *> &NamedDirEnt =
157    DirEntries.GetOrCreateValue(NameStart, NameEnd);
158
159  // See if there is already an entry in the map.
160  if (NamedDirEnt.getValue())
161    return NamedDirEnt.getValue() == NON_EXISTENT_DIR
162              ? 0 : NamedDirEnt.getValue();
163
164  ++NumDirCacheMisses;
165
166  // By default, initialize it to invalid.
167  NamedDirEnt.setValue(NON_EXISTENT_DIR);
168
169  // Get the null-terminated directory name as stored as the key of the
170  // DirEntries map.
171  const char *InterndDirName = NamedDirEnt.getKeyData();
172
173  // Check to see if the directory exists.
174  struct stat StatBuf;
175  if (stat_cached(InterndDirName, &StatBuf) ||   // Error stat'ing.
176      !S_ISDIR(StatBuf.st_mode))          // Not a directory?
177    return 0;
178
179  // It exists.  See if we have already opened a directory with the same inode.
180  // This occurs when one dir is symlinked to another, for example.
181  DirectoryEntry &UDE = UniqueDirs.getDirectory(InterndDirName, StatBuf);
182
183  NamedDirEnt.setValue(&UDE);
184  if (UDE.getName()) // Already have an entry with this inode, return it.
185    return &UDE;
186
187  // Otherwise, we don't have this directory yet, add it.  We use the string
188  // key from the DirEntries map as the string.
189  UDE.Name  = InterndDirName;
190  return &UDE;
191}
192
193/// NON_EXISTENT_FILE - A special value distinct from null that is used to
194/// represent a filename that doesn't exist on the disk.
195#define NON_EXISTENT_FILE reinterpret_cast<FileEntry*>((intptr_t)-1)
196
197/// getFile - Lookup, cache, and verify the specified file.  This returns null
198/// if the file doesn't exist.
199///
200const FileEntry *FileManager::getFile(const char *NameStart,
201                                      const char *NameEnd) {
202  ++NumFileLookups;
203
204  // See if there is already an entry in the map.
205  llvm::StringMapEntry<FileEntry *> &NamedFileEnt =
206    FileEntries.GetOrCreateValue(NameStart, NameEnd);
207
208  // See if there is already an entry in the map.
209  if (NamedFileEnt.getValue())
210    return NamedFileEnt.getValue() == NON_EXISTENT_FILE
211                 ? 0 : NamedFileEnt.getValue();
212
213  ++NumFileCacheMisses;
214
215  // By default, initialize it to invalid.
216  NamedFileEnt.setValue(NON_EXISTENT_FILE);
217
218  // Figure out what directory it is in.   If the string contains a / in it,
219  // strip off everything after it.
220  // FIXME: this logic should be in sys::Path.
221  const char *SlashPos = NameEnd-1;
222  while (SlashPos >= NameStart && !IS_DIR_SEPARATOR_CHAR(SlashPos[0]))
223    --SlashPos;
224
225  const DirectoryEntry *DirInfo;
226  if (SlashPos < NameStart) {
227    // Use the current directory if file has no path component.
228    const char *Name = ".";
229    DirInfo = getDirectory(Name, Name+1);
230  } else if (SlashPos == NameEnd-1)
231    return 0;       // If filename ends with a /, it's a directory.
232  else
233    DirInfo = getDirectory(NameStart, SlashPos);
234
235  if (DirInfo == 0)  // Directory doesn't exist, file can't exist.
236    return 0;
237
238  // Get the null-terminated file name as stored as the key of the
239  // FileEntries map.
240  const char *InterndFileName = NamedFileEnt.getKeyData();
241
242  // FIXME: Use the directory info to prune this, before doing the stat syscall.
243  // FIXME: This will reduce the # syscalls.
244
245  // Nope, there isn't.  Check to see if the file exists.
246  struct stat StatBuf;
247  //llvm::cerr << "STATING: " << Filename;
248  if (stat_cached(InterndFileName, &StatBuf) ||   // Error stat'ing.
249        S_ISDIR(StatBuf.st_mode)) {           // A directory?
250    // If this file doesn't exist, we leave a null in FileEntries for this path.
251    //llvm::cerr << ": Not existing\n";
252    return 0;
253  }
254  //llvm::cerr << ": exists\n";
255
256  // It exists.  See if we have already opened a file with the same inode.
257  // This occurs when one dir is symlinked to another, for example.
258  FileEntry &UFE = UniqueFiles.getFile(InterndFileName, StatBuf);
259
260  NamedFileEnt.setValue(&UFE);
261  if (UFE.getName())  // Already have an entry with this inode, return it.
262    return &UFE;
263
264  // Otherwise, we don't have this directory yet, add it.
265  // FIXME: Change the name to be a char* that points back to the 'FileEntries'
266  // key.
267  UFE.Name    = InterndFileName;
268  UFE.Size    = StatBuf.st_size;
269  UFE.ModTime = StatBuf.st_mtime;
270  UFE.Dir     = DirInfo;
271  UFE.UID     = NextFileUID++;
272  return &UFE;
273}
274
275void FileManager::PrintStats() const {
276  llvm::cerr << "\n*** File Manager Stats:\n";
277  llvm::cerr << UniqueFiles.size() << " files found, "
278             << UniqueDirs.size() << " dirs found.\n";
279  llvm::cerr << NumDirLookups << " dir lookups, "
280             << NumDirCacheMisses << " dir cache misses.\n";
281  llvm::cerr << NumFileLookups << " file lookups, "
282             << NumFileCacheMisses << " file cache misses.\n";
283
284  //llvm::cerr << PagesMapped << BytesOfPagesMapped << FSLookups;
285}
286
287int MemorizeStatCalls::stat(const char *path, struct stat *buf) {
288  int result = ::stat(path, buf);
289
290  if (result != 0) {
291    // Cache failed 'stat' results.
292    struct stat empty;
293    StatCalls[path] = StatResult(result, empty);
294  }
295  else if (!S_ISDIR(buf->st_mode) || llvm::sys::Path(path).isAbsolute()) {
296    // Cache file 'stat' results and directories with absolutely
297    // paths.
298    StatCalls[path] = StatResult(result, *buf);
299  }
300
301  return result;
302}
303