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/ADT/Optional.h" 19 #include "llvm/Support/Compiler.h" 20 #include "llvm/Support/MemoryBuffer.h" 21 #include <memory> 22 23 namespace clang { 24 25 class FileEntry; 26 class FileManager; 27 struct HMapBucket; 28 struct HMapHeader; 29 30 /// Implementation for \a HeaderMap that doesn't depend on \a FileManager. 31 class HeaderMapImpl { 32 std::unique_ptr<const llvm::MemoryBuffer> FileBuffer; 33 bool NeedsBSwap; 34 35 public: HeaderMapImpl(std::unique_ptr<const llvm::MemoryBuffer> File,bool NeedsBSwap)36 HeaderMapImpl(std::unique_ptr<const llvm::MemoryBuffer> File, bool NeedsBSwap) 37 : FileBuffer(std::move(File)), NeedsBSwap(NeedsBSwap) {} 38 39 // Check for a valid header and extract the byte swap. 40 static bool checkHeader(const llvm::MemoryBuffer &File, bool &NeedsByteSwap); 41 42 /// If the specified relative filename is located in this HeaderMap return 43 /// the filename it is mapped to, otherwise return an empty StringRef. 44 StringRef lookupFilename(StringRef Filename, 45 SmallVectorImpl<char> &DestPath) const; 46 47 /// Return the filename of the headermap. 48 const char *getFileName() const; 49 50 /// Print the contents of this headermap to stderr. 51 void dump() const; 52 53 private: 54 unsigned getEndianAdjustedWord(unsigned X) const; 55 const HMapHeader &getHeader() const; 56 HMapBucket getBucket(unsigned BucketNo) const; 57 58 /// Look up the specified string in the string table. If the string index is 59 /// not valid, return None. 60 Optional<StringRef> getString(unsigned StrTabIdx) const; 61 }; 62 63 /// This class represents an Apple concept known as a 'header map'. To the 64 /// \#include file resolution process, it basically acts like a directory of 65 /// symlinks to files. Its advantages are that it is dense and more efficient 66 /// to create and process than a directory of symlinks. 67 class HeaderMap : private HeaderMapImpl { HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File,bool BSwap)68 HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File, bool BSwap) 69 : HeaderMapImpl(std::move(File), BSwap) {} 70 71 public: 72 /// This attempts to load the specified file as a header map. If it doesn't 73 /// look like a HeaderMap, it gives up and returns null. 74 static const HeaderMap *Create(const FileEntry *FE, FileManager &FM); 75 76 /// Check to see if the specified relative filename is located in this 77 /// HeaderMap. If so, open it and return its FileEntry. If RawPath is not 78 /// NULL and the file is found, RawPath will be set to the raw path at which 79 /// the file was found in the file system. For example, for a search path 80 /// ".." and a filename "../file.h" this would be "../../file.h". 81 const FileEntry *LookupFile(StringRef Filename, FileManager &FM) const; 82 83 using HeaderMapImpl::lookupFilename; 84 using HeaderMapImpl::getFileName; 85 using HeaderMapImpl::dump; 86 }; 87 88 } // end namespace clang. 89 90 #endif 91