1//===--- HeaderMap.h - A file that acts like dir of symlinks ----*- 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 HeaderMap interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LEX_HEADERMAP_H
15#define LLVM_CLANG_LEX_HEADERMAP_H
16
17#include "clang/Basic/LLVM.h"
18#include "llvm/Support/Compiler.h"
19#include <memory>
20
21namespace llvm {
22  class MemoryBuffer;
23}
24namespace clang {
25  class FileEntry;
26  class FileManager;
27  struct HMapBucket;
28  struct HMapHeader;
29
30/// This class represents an Apple concept known as a 'header map'.  To the
31/// \#include file resolution process, it basically acts like a directory of
32/// symlinks to files.  Its advantages are that it is dense and more efficient
33/// to create and process than a directory of symlinks.
34class HeaderMap {
35  HeaderMap(const HeaderMap &) = delete;
36  void operator=(const HeaderMap &) = delete;
37
38  std::unique_ptr<const llvm::MemoryBuffer> FileBuffer;
39  bool NeedsBSwap;
40
41  HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File, bool BSwap)
42      : FileBuffer(std::move(File)), NeedsBSwap(BSwap) {}
43public:
44  /// HeaderMap::Create - This attempts to load the specified file as a header
45  /// map.  If it doesn't look like a HeaderMap, it gives up and returns null.
46  static const HeaderMap *Create(const FileEntry *FE, FileManager &FM);
47
48  /// LookupFile - Check to see if the specified relative filename is located in
49  /// this HeaderMap.  If so, open it and return its FileEntry.
50  /// If RawPath is not NULL and the file is found, RawPath will be set to the
51  /// raw path at which the file was found in the file system. For example,
52  /// for a search path ".." and a filename "../file.h" this would be
53  /// "../../file.h".
54  const FileEntry *LookupFile(StringRef Filename, FileManager &FM) const;
55
56  /// If the specified relative filename is located in this HeaderMap return
57  /// the filename it is mapped to, otherwise return an empty StringRef.
58  StringRef lookupFilename(StringRef Filename,
59                           SmallVectorImpl<char> &DestPath) const;
60
61  /// getFileName - Return the filename of the headermap.
62  const char *getFileName() const;
63
64  /// dump - Print the contents of this headermap to stderr.
65  void dump() const;
66
67private:
68  unsigned getEndianAdjustedWord(unsigned X) const;
69  const HMapHeader &getHeader() const;
70  HMapBucket getBucket(unsigned BucketNo) const;
71  const char *getString(unsigned StrTabIdx) const;
72};
73
74} // end namespace clang.
75
76#endif
77