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 21 namespace llvm { 22 class MemoryBuffer; 23 } 24 namespace 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. 34 class 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 HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File,bool BSwap)41 HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File, bool BSwap) 42 : FileBuffer(std::move(File)), NeedsBSwap(BSwap) {} 43 public: 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 67 private: 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