Chris Lattner | 0f441ab | 2007-12-17 08:22:46 +0000 | [diff] [blame] | 1 | //===--- HeaderMap.cpp - A file that acts like dir of symlinks ------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file was developed by Chris Lattner and is distributed under |
| 6 | // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file implements the HeaderMap interface. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "clang/Lex/HeaderMap.h" |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 15 | #include "clang/Basic/FileManager.h" |
| 16 | #include "llvm/ADT/scoped_ptr.h" |
| 17 | #include "llvm/Support/DataTypes.h" |
| 18 | #include "llvm/Support/MathExtras.h" |
| 19 | #include "llvm/Support/MemoryBuffer.h" |
Chris Lattner | 0f441ab | 2007-12-17 08:22:46 +0000 | [diff] [blame] | 20 | using namespace clang; |
| 21 | |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 22 | enum { |
Chris Lattner | ba83265 | 2007-12-17 18:59:44 +0000 | [diff] [blame^] | 23 | HeaderMagicNumber = ('h' << 24) | ('m' << 16) | ('a' << 8) | 'p', |
| 24 | HeaderVersion = 1 |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 25 | }; |
| 26 | |
| 27 | struct HMapHeader { |
| 28 | uint32_t Magic; // Magic word, also indicates byte order. |
| 29 | uint16_t Version; // Version number -- currently 1. |
| 30 | uint16_t Reserved; // Reserved for future use - zero for now. |
| 31 | uint32_t StringsOffset; // Offset to start of string pool. |
| 32 | uint32_t Count; // Number of entries in the string table. |
| 33 | uint32_t Capacity; // Number of buckets (always a power of 2). |
| 34 | uint32_t MaxValueLength; // Length of longest result path (excluding nul). |
| 35 | // Strings follow the buckets, at StringsOffset. |
| 36 | }; |
| 37 | |
| 38 | |
| 39 | /// HeaderMap::Create - This attempts to load the specified file as a header |
| 40 | /// map. If it doesn't look like a HeaderMap, it gives up and returns null. |
| 41 | /// If it looks like a HeaderMap but is obviously corrupted, it puts a reason |
| 42 | /// into the string error argument and returns null. |
| 43 | const HeaderMap *HeaderMap::Create(const FileEntry *FE) { |
| 44 | // If the file is too small to be a header map, ignore it. |
| 45 | unsigned FileSize = FE->getSize(); |
| 46 | if (FileSize <= sizeof(HMapHeader)) return 0; |
| 47 | |
Chris Lattner | 9875131 | 2007-12-17 18:44:09 +0000 | [diff] [blame] | 48 | llvm::scoped_ptr<const llvm::MemoryBuffer> FileBuffer( |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 49 | llvm::MemoryBuffer::getFile(FE->getName(), strlen(FE->getName()), 0, |
| 50 | FE->getSize())); |
Chris Lattner | 9875131 | 2007-12-17 18:44:09 +0000 | [diff] [blame] | 51 | if (FileBuffer == 0) return 0; // Unreadable file? |
| 52 | const char *FileStart = FileBuffer->getBufferStart(); |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 53 | |
| 54 | // We know the file is at least as big as the header, check it now. |
| 55 | const HMapHeader *Header = reinterpret_cast<const HMapHeader*>(FileStart); |
| 56 | |
Chris Lattner | ba83265 | 2007-12-17 18:59:44 +0000 | [diff] [blame^] | 57 | // Sniff it to see if it's a headermap by checking the magic number and |
| 58 | // version. |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 59 | bool NeedsByteSwap; |
Chris Lattner | ba83265 | 2007-12-17 18:59:44 +0000 | [diff] [blame^] | 60 | if (Header->Magic == HeaderMagicNumber && Header->Version == HeaderVersion) |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 61 | NeedsByteSwap = false; |
Chris Lattner | ba83265 | 2007-12-17 18:59:44 +0000 | [diff] [blame^] | 62 | else if (Header->Magic == llvm::ByteSwap_32(HeaderMagicNumber) && |
| 63 | Header->Version == llvm::ByteSwap_16(HeaderVersion)) |
Chris Lattner | 1bfd4a6 | 2007-12-17 18:34:53 +0000 | [diff] [blame] | 64 | NeedsByteSwap = true; // Mixed endianness headermap. |
| 65 | else |
| 66 | return 0; // Not a header map. |
Chris Lattner | ba83265 | 2007-12-17 18:59:44 +0000 | [diff] [blame^] | 67 | |
| 68 | if (Header->Reserved != 0) return 0; |
Chris Lattner | 9875131 | 2007-12-17 18:44:09 +0000 | [diff] [blame] | 69 | |
| 70 | // Okay, everything looks good, create the header map. |
Chris Lattner | ba83265 | 2007-12-17 18:59:44 +0000 | [diff] [blame^] | 71 | return new HeaderMap(FileBuffer.take(), NeedsByteSwap); |
Chris Lattner | 9875131 | 2007-12-17 18:44:09 +0000 | [diff] [blame] | 72 | } |
| 73 | |
| 74 | HeaderMap::~HeaderMap() { |
| 75 | delete FileBuffer; |
| 76 | } |
| 77 | |
| 78 | |
| 79 | /// getFileName - Return the filename of the headermap. |
| 80 | const char *HeaderMap::getFileName() const { |
| 81 | return FileBuffer->getBufferIdentifier(); |
Chris Lattner | 0f441ab | 2007-12-17 08:22:46 +0000 | [diff] [blame] | 82 | } |
| 83 | |
| 84 | /// LookupFile - Check to see if the specified relative filename is located in |
| 85 | /// this HeaderMap. If so, open it and return its FileEntry. |
| 86 | const FileEntry *HeaderMap::LookupFile(const char *FilenameStart, |
| 87 | const char *FilenameEnd, |
| 88 | FileManager &FM) const { |
| 89 | // FIXME: this needs work. |
| 90 | return 0; |
| 91 | } |