FileManager.h revision 6f42b62b6194f53bcbc349f5d17388e1936535d7 
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//  This file defines the FileManager interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_FILEMANAGER_H
15#define LLVM_CLANG_FILEMANAGER_H
16
17#include "clang/Basic/FileSystemOptions.h"
18#include "clang/Basic/LLVM.h"
19#include "llvm/ADT/IntrusiveRefCntPtr.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/ADT/StringMap.h"
22#include "llvm/ADT/StringRef.h"
23#include "llvm/ADT/OwningPtr.h"
24#include "llvm/Support/Allocator.h"
25// FIXME: Enhance libsystem to support inode and other fields in stat.
26#include <sys/types.h>
27
28#ifdef _MSC_VER
29typedef unsigned short mode_t;
30#endif
31
32struct stat;
33
34namespace llvm {
35class MemoryBuffer;
36namespace sys { class Path; }
37}
38
39namespace clang {
40class FileManager;
41class FileSystemStatCache;
42
43/// DirectoryEntry - Cached information about one directory (either on
44/// the disk or in the virtual file system).
45///
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/// FileEntry - Cached information about one file (either on the disk
55/// or in the virtual file system).  If the 'FD' member is valid, then
56/// this FileEntry has an open file descriptor for the file.
57///
58class FileEntry {
59  const char *Name;           // Name of the file.
60  off_t Size;                 // File size in bytes.
61  time_t ModTime;             // Modification time of file.
62  const DirectoryEntry *Dir;  // Directory file lives in.
63  unsigned UID;               // A unique (small) ID for the file.
64  dev_t Device;               // ID for the device containing the file.
65  ino_t Inode;                // Inode number for the file.
66  mode_t FileMode;            // The file mode as returned by 'stat'.
67
68  /// FD - The file descriptor for the file entry if it is opened and owned
69  /// by the FileEntry.  If not, this is set to -1.
70  mutable int FD;
71  friend class FileManager;
72
73public:
74  FileEntry(dev_t device, ino_t inode, mode_t m)
75    : Name(0), Device(device), Inode(inode), FileMode(m), FD(-1) {}
76  // Add a default constructor for use with llvm::StringMap
77  FileEntry() : Name(0), Device(0), Inode(0), FileMode(0), FD(-1) {}
78
79  FileEntry(const FileEntry &FE) {
80    memcpy(this, &FE, sizeof(FE));
81    assert(FD == -1 && "Cannot copy a file-owning FileEntry");
82  }
83
84  void operator=(const FileEntry &FE) {
85    memcpy(this, &FE, sizeof(FE));
86    assert(FD == -1 && "Cannot assign a file-owning FileEntry");
87  }
88
89  ~FileEntry();
90
91  const char *getName() const { return Name; }
92  off_t getSize() const { return Size; }
93  unsigned getUID() const { return UID; }
94  ino_t getInode() const { return Inode; }
95  dev_t getDevice() const { return Device; }
96  time_t getModificationTime() const { return ModTime; }
97  mode_t getFileMode() const { return FileMode; }
98
99  /// getDir - Return the directory the file lives in.
100  ///
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/// FileManager - Implements support for file system lookup, file system
109/// caching, and directory search management.  This also handles more advanced
110/// properties, such as uniquing files based on "inode", so that a file with two
111/// names (e.g. symlinked) will be treated as a single file.
112///
113class FileManager : public llvm::RefCountedBase<FileManager> {
114  FileSystemOptions FileSystemOpts;
115
116  class UniqueDirContainer;
117  class UniqueFileContainer;
118
119  /// UniqueRealDirs/UniqueRealFiles - Cache for existing real
120  /// directories/files.
121  ///
122  UniqueDirContainer &UniqueRealDirs;
123  UniqueFileContainer &UniqueRealFiles;
124
125  /// \brief The virtual directories that we have allocated.  For each
126  /// virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
127  /// directories (foo/ and foo/bar/) here.
128  SmallVector<DirectoryEntry*, 4> VirtualDirectoryEntries;
129  /// \brief The virtual files that we have allocated.
130  SmallVector<FileEntry*, 4> VirtualFileEntries;
131
132  /// SeenDirEntries/SeenFileEntries - This is a cache that maps paths
133  /// to directory/file entries (either real or virtual) we have
134  /// looked up.  The actual Entries for real directories/files are
135  /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
136  /// for virtual directories/files are owned by
137  /// VirtualDirectoryEntries/VirtualFileEntries above.
138  ///
139  llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
140  llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
141
142  /// NextFileUID - Each FileEntry we create is assigned a unique ID #.
143  ///
144  unsigned NextFileUID;
145
146  // Statistics.
147  unsigned NumDirLookups, NumFileLookups;
148  unsigned NumDirCacheMisses, NumFileCacheMisses;
149
150  // Caching.
151  OwningPtr<FileSystemStatCache> StatCache;
152
153  bool getStatValue(const char *Path, struct stat &StatBuf,
154                    int *FileDescriptor);
155
156  /// Add all ancestors of the given path (pointing to either a file
157  /// or a directory) as virtual directories.
158  void addAncestorsAsVirtualDirs(StringRef Path);
159
160public:
161  FileManager(const FileSystemOptions &FileSystemOpts);
162  ~FileManager();
163
164  /// \brief Installs the provided FileSystemStatCache object within
165  /// the FileManager.
166  ///
167  /// Ownership of this object is transferred to the FileManager.
168  ///
169  /// \param statCache the new stat cache to install. Ownership of this
170  /// object is transferred to the FileManager.
171  ///
172  /// \param AtBeginning whether this new stat cache must be installed at the
173  /// beginning of the chain of stat caches. Otherwise, it will be added to
174  /// the end of the chain.
175  void addStatCache(FileSystemStatCache *statCache, bool AtBeginning = false);
176
177  /// \brief Removes the specified FileSystemStatCache object from the manager.
178  void removeStatCache(FileSystemStatCache *statCache);
179
180  /// getDirectory - Lookup, cache, and verify the specified directory
181  /// (real or virtual).  This returns NULL if the directory doesn't exist.
182  ///
183  /// \param CacheFailure If true and the file does not exist, we'll cache
184  /// the failure to find this file.
185  const DirectoryEntry *getDirectory(StringRef DirName,
186                                     bool CacheFailure = true);
187
188  /// \brief Lookup, cache, and verify the specified file (real or
189  /// virtual).  This returns NULL if the file doesn't exist.
190  ///
191  /// \param OpenFile if true and the file exists, it will be opened.
192  ///
193  /// \param CacheFailure If true and the file does not exist, we'll cache
194  /// the failure to find this file.
195  const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
196                           bool CacheFailure = true);
197
198  /// \brief Returns the current file system options
199  const FileSystemOptions &getFileSystemOptions() { return FileSystemOpts; }
200
201  /// \brief Retrieve a file entry for a "virtual" file that acts as
202  /// if there were a file with the given name on disk. The file
203  /// itself is not accessed.
204  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
205                                  time_t ModificationTime);
206
207  /// \brief Open the specified file as a MemoryBuffer, returning a new
208  /// MemoryBuffer if successful, otherwise returning null.
209  llvm::MemoryBuffer *getBufferForFile(const FileEntry *Entry,
210                                       std::string *ErrorStr = 0);
211  llvm::MemoryBuffer *getBufferForFile(StringRef Filename,
212                                       std::string *ErrorStr = 0);
213
214  // getNoncachedStatValue - Will get the 'stat' information for the given path.
215  // If the path is relative, it will be resolved against the WorkingDir of the
216  // FileManager's FileSystemOptions.
217  bool getNoncachedStatValue(StringRef Path, struct stat &StatBuf);
218
219  /// \brief If path is not absolute and FileSystemOptions set the working
220  /// directory, the path is modified to be relative to the given
221  /// working directory.
222  void FixupRelativePath(SmallVectorImpl<char> &path) const;
223
224  /// \brief Produce an array mapping from the unique IDs assigned to each
225  /// file to the corresponding FileEntry pointer.
226  void GetUniqueIDMapping(
227                    SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
228
229  void PrintStats() const;
230};
231
232}  // end namespace clang
233
234#endif
235