FileManager.cpp revision 370187c8a3e96517c943329f2511737a04b85450 
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"
24using 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
45namespace {
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
58class FileManager::UniqueDirContainer {
59  /// UniqueDirs - Cache from full path to existing directories/files.
60  ///
61  llvm::StringMap<DirectoryEntry> UniqueDirs;
62
63public:
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
75class FileManager::UniqueFileContainer {
76  /// UniqueFiles - Cache from full path to existing directories/files.
77  ///
78  llvm::StringMap<FileEntry, llvm::BumpPtrAllocator> UniqueFiles;
79
80public:
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
100class 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
105public:
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
113class FileManager::UniqueFileContainer {
114  /// UniqueFiles - Cache from ID's to existing directories/files.
115  ///
116  std::set<FileEntry> UniqueFiles;
117
118public:
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
136FileManager::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
144FileManager::~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///
152const 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///
199const 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
274void 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