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_FILEMANAGER_H
16#define LLVM_CLANG_FILEMANAGER_H
17
18#include "clang/Basic/FileSystemOptions.h"
19#include "clang/Basic/LLVM.h"
20#include "llvm/ADT/IntrusiveRefCntPtr.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/ADT/StringMap.h"
23#include "llvm/ADT/StringRef.h"
24#include "llvm/ADT/OwningPtr.h"
25#include "llvm/Support/Allocator.h"
26// FIXME: Enhance libsystem to support inode and other fields in stat.
27#include <sys/types.h>
28
29#ifdef _MSC_VER
30typedef unsigned short mode_t;
31#endif
32
33struct stat;
34
35namespace llvm {
36class MemoryBuffer;
37namespace sys { class Path; }
38}
39
40namespace clang {
41class FileManager;
42class FileSystemStatCache;
43
44/// \brief Cached information about one directory (either on disk or in
45/// the virtual file system).
46class DirectoryEntry {
47  const char *Name;   // Name of the directory.
48  friend class FileManager;
49public:
50  DirectoryEntry() : Name(0) {}
51  const char *getName() const { return Name; }
52};
53
54/// \brief Cached information about one file (either on disk
55/// or in the virtual file system).
56///
57/// If the 'FD' member is valid, then this FileEntry has an open file
58/// descriptor for the file.
59class FileEntry {
60  const char *Name;           // Name of the file.
61  off_t Size;                 // File size in bytes.
62  time_t ModTime;             // Modification time of file.
63  const DirectoryEntry *Dir;  // Directory file lives in.
64  unsigned UID;               // A unique (small) ID for the file.
65  dev_t Device;               // ID for the device containing the file.
66  ino_t Inode;                // Inode number for the file.
67  mode_t FileMode;            // The file mode as returned by 'stat'.
68
69  /// FD - The file descriptor for the file entry if it is opened and owned
70  /// by the FileEntry.  If not, this is set to -1.
71  mutable int FD;
72  friend class FileManager;
73
74public:
75  FileEntry(dev_t device, ino_t inode, mode_t m)
76    : Name(0), Device(device), Inode(inode), FileMode(m), FD(-1) {}
77  // Add a default constructor for use with llvm::StringMap
78  FileEntry() : Name(0), Device(0), Inode(0), FileMode(0), FD(-1) {}
79
80  FileEntry(const FileEntry &FE) {
81    memcpy(this, &FE, sizeof(FE));
82    assert(FD == -1 && "Cannot copy a file-owning FileEntry");
83  }
84
85  void operator=(const FileEntry &FE) {
86    memcpy(this, &FE, sizeof(FE));
87    assert(FD == -1 && "Cannot assign a file-owning FileEntry");
88  }
89
90  ~FileEntry();
91
92  const char *getName() const { return Name; }
93  off_t getSize() const { return Size; }
94  unsigned getUID() const { return UID; }
95  ino_t getInode() const { return Inode; }
96  dev_t getDevice() const { return Device; }
97  time_t getModificationTime() const { return ModTime; }
98  mode_t getFileMode() const { return FileMode; }
99
100  /// \brief Return the directory the file lives in.
101  const DirectoryEntry *getDir() const { return Dir; }
102
103  bool operator<(const FileEntry &RHS) const {
104    return Device < RHS.Device || (Device == RHS.Device && Inode < RHS.Inode);
105  }
106};
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///
115class FileManager : public RefCountedBase<FileManager> {
116  FileSystemOptions FileSystemOpts;
117
118  class UniqueDirContainer;
119  class UniqueFileContainer;
120
121  /// \brief Cache for existing real directories.
122  UniqueDirContainer &UniqueRealDirs;
123
124  /// \brief Cache for existing real files.
125  UniqueFileContainer &UniqueRealFiles;
126
127  /// \brief The virtual directories that we have allocated.
128  ///
129  /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
130  /// directories (foo/ and foo/bar/) here.
131  SmallVector<DirectoryEntry*, 4> VirtualDirectoryEntries;
132  /// \brief The virtual files that we have allocated.
133  SmallVector<FileEntry*, 4> VirtualFileEntries;
134
135  /// \brief A cache that maps paths to directory entries (either real or
136  /// virtual) we have looked up
137  ///
138  /// The actual Entries for real directories/files are
139  /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
140  /// for virtual directories/files are owned by
141  /// VirtualDirectoryEntries/VirtualFileEntries above.
142  ///
143  llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
144
145  /// \brief A cache that maps paths to file entries (either real or
146  /// virtual) we have looked up.
147  ///
148  /// \see SeenDirEntries
149  llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
150
151  /// \brief Each FileEntry we create is assigned a unique ID #.
152  ///
153  unsigned NextFileUID;
154
155  // Statistics.
156  unsigned NumDirLookups, NumFileLookups;
157  unsigned NumDirCacheMisses, NumFileCacheMisses;
158
159  // Caching.
160  OwningPtr<FileSystemStatCache> StatCache;
161
162  bool getStatValue(const char *Path, struct stat &StatBuf,
163                    int *FileDescriptor);
164
165  /// Add all ancestors of the given path (pointing to either a file
166  /// or a directory) as virtual directories.
167  void addAncestorsAsVirtualDirs(StringRef Path);
168
169public:
170  FileManager(const FileSystemOptions &FileSystemOpts);
171  ~FileManager();
172
173  /// \brief Installs the provided FileSystemStatCache object within
174  /// the FileManager.
175  ///
176  /// Ownership of this object is transferred to the FileManager.
177  ///
178  /// \param statCache the new stat cache to install. Ownership of this
179  /// object is transferred to the FileManager.
180  ///
181  /// \param AtBeginning whether this new stat cache must be installed at the
182  /// beginning of the chain of stat caches. Otherwise, it will be added to
183  /// the end of the chain.
184  void addStatCache(FileSystemStatCache *statCache, bool AtBeginning = false);
185
186  /// \brief Removes the specified FileSystemStatCache object from the manager.
187  void removeStatCache(FileSystemStatCache *statCache);
188
189  /// \brief Removes all FileSystemStatCache objects from the manager.
190  void clearStatCaches();
191
192  /// \brief Lookup, cache, and verify the specified directory (real or
193  /// virtual).
194  ///
195  /// This returns NULL if the directory doesn't exist.
196  ///
197  /// \param CacheFailure If true and the file does not exist, we'll cache
198  /// the failure to find this file.
199  const DirectoryEntry *getDirectory(StringRef DirName,
200                                     bool CacheFailure = true);
201
202  /// \brief Lookup, cache, and verify the specified file (real or
203  /// virtual).
204  ///
205  /// This returns NULL if the file doesn't exist.
206  ///
207  /// \param OpenFile if true and the file exists, it will be opened.
208  ///
209  /// \param CacheFailure If true and the file does not exist, we'll cache
210  /// the failure to find this file.
211  const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
212                           bool CacheFailure = true);
213
214  /// \brief Returns the current file system options
215  const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; }
216
217  /// \brief Retrieve a file entry for a "virtual" file that acts as
218  /// if there were a file with the given name on disk.
219  ///
220  /// The file itself is not accessed.
221  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
222                                  time_t ModificationTime);
223
224  /// \brief Open the specified file as a MemoryBuffer, returning a new
225  /// MemoryBuffer if successful, otherwise returning null.
226  llvm::MemoryBuffer *getBufferForFile(const FileEntry *Entry,
227                                       std::string *ErrorStr = 0,
228                                       bool isVolatile = false);
229  llvm::MemoryBuffer *getBufferForFile(StringRef Filename,
230                                       std::string *ErrorStr = 0);
231
232  /// \brief Get the 'stat' information for the given \p Path.
233  ///
234  /// If the path is relative, it will be resolved against the WorkingDir of the
235  /// FileManager's FileSystemOptions.
236  bool getNoncachedStatValue(StringRef Path, struct stat &StatBuf);
237
238  /// \brief Remove the real file \p Entry from the cache.
239  void invalidateCache(const FileEntry *Entry);
240
241  /// \brief If path is not absolute and FileSystemOptions set the working
242  /// directory, the path is modified to be relative to the given
243  /// working directory.
244  void FixupRelativePath(SmallVectorImpl<char> &path) const;
245
246  /// \brief Produce an array mapping from the unique IDs assigned to each
247  /// file to the corresponding FileEntry pointer.
248  void GetUniqueIDMapping(
249                    SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
250
251  /// \brief Modifies the size and modification time of a previously created
252  /// FileEntry. Use with caution.
253  static void modifyFileEntry(FileEntry *File, off_t Size,
254                              time_t ModificationTime);
255
256  void PrintStats() const;
257};
258
259}  // end namespace clang
260
261#endif
262