Start reading the headermap header, drop the 'errorstr' argument to
the create method.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@45109 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Lex/HeaderMap.cpp b/Lex/HeaderMap.cpp
index 5b9c4b0..ebcbc17 100644
--- a/Lex/HeaderMap.cpp
+++ b/Lex/HeaderMap.cpp
@@ -12,10 +12,60 @@
//===----------------------------------------------------------------------===//
#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;
-const HeaderMap *HeaderMap::Create(const FileEntry *FE, std::string &ErrorInfo){
- // FIXME: woot!
+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;
}