| //===--- HeaderMap.cpp - A file that acts like dir of symlinks ------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by Chris Lattner and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the HeaderMap interface. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Lex/HeaderMap.h" |
| #include "clang/Basic/FileManager.h" |
| #include "llvm/ADT/scoped_ptr.h" |
| #include "llvm/Support/DataTypes.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/Support/MemoryBuffer.h" |
| using namespace clang; |
| |
| enum { |
| HeaderMagicNumber = ('h' << 24) | ('m' << 16) | ('a' << 8) | 'p' |
| }; |
| |
| struct HMapHeader { |
| uint32_t Magic; // Magic word, also indicates byte order. |
| uint16_t Version; // Version number -- currently 1. |
| uint16_t Reserved; // Reserved for future use - zero for now. |
| uint32_t StringsOffset; // Offset to start of string pool. |
| uint32_t Count; // Number of entries in the string table. |
| uint32_t Capacity; // Number of buckets (always a power of 2). |
| uint32_t MaxValueLength; // Length of longest result path (excluding nul). |
| // Strings follow the buckets, at StringsOffset. |
| }; |
| |
| |
| /// HeaderMap::Create - This attempts to load the specified file as a header |
| /// map. If it doesn't look like a HeaderMap, it gives up and returns null. |
| /// If it looks like a HeaderMap but is obviously corrupted, it puts a reason |
| /// into the string error argument and returns null. |
| const HeaderMap *HeaderMap::Create(const FileEntry *FE) { |
| // If the file is too small to be a header map, ignore it. |
| unsigned FileSize = FE->getSize(); |
| if (FileSize <= sizeof(HMapHeader)) return 0; |
| |
| llvm::scoped_ptr<const llvm::MemoryBuffer> File( |
| llvm::MemoryBuffer::getFile(FE->getName(), strlen(FE->getName()), 0, |
| FE->getSize())); |
| if (File == 0) return 0; // Unreadable file? |
| const char *FileStart = File->getBufferStart(); |
| |
| // We know the file is at least as big as the header, check it now. |
| const HMapHeader *Header = reinterpret_cast<const HMapHeader*>(FileStart); |
| |
| // Sniff it to see if it's a headermap. |
| if (Header->Version != 1 || Header->Reserved != 0) |
| return 0; |
| |
| // Check the magic number. |
| bool NeedsByteSwap; |
| if (Header->Magic == HeaderMagicNumber) |
| NeedsByteSwap = false; |
| else if (Header->Magic == llvm::ByteSwap_32(HeaderMagicNumber)) |
| NeedsByteSwap = true; // Mixed endianness headermap. |
| else |
| return 0; // Not a header map. |
| |
| return 0; |
| } |
| |
| /// LookupFile - Check to see if the specified relative filename is located in |
| /// this HeaderMap. If so, open it and return its FileEntry. |
| const FileEntry *HeaderMap::LookupFile(const char *FilenameStart, |
| const char *FilenameEnd, |
| FileManager &FM) const { |
| // FIXME: this needs work. |
| return 0; |
| } |