Add a MD5 checksum to the BDIC header....

third_party/hunspell/google/bdict_reader.cc

 // Copyright 2008 Google Inc. All Rights Reserved.
 
 #include "third_party/hunspell/google/bdict_reader.h"
 
 #include "base/logging.h"
 
 namespace hunspell {
 
 // Like the "Visitor" design pattern, this lightweight object provides an
 // interface around a serialized trie node at the given address in the memory.
@@ skipping 631 matching lines @@
       header_(NULL) {
 }
 
 bool BDictReader::Init(const unsigned char* bdict_data, size_t bdict_length) {
   if (bdict_length < sizeof(BDict::Header))
     return false;
 
   // Check header.
   header_ = reinterpret_cast<const BDict::Header*>(bdict_data);
   if (header_->signature != BDict::SIGNATURE ||
-      header_->major_version != 1 ||
-      header_->aff_offset > bdict_length ||
+      header_->major_version > BDict::MAJOR_VERSION ||
       header_->dic_offset > bdict_length)
     return false;
 
   // Get the affix header, make sure there is enough room for it.
   if (header_->aff_offset + sizeof(BDict::AffHeader) > bdict_length)
     return false;
   aff_header_ = reinterpret_cast<const BDict::AffHeader*>(
       &bdict_data[header_->aff_offset]);
 
   // Make sure there is enough room for the affix group count dword.
   if (aff_header_->affix_group_offset + sizeof(uint32) > bdict_length)
     return false;
 
+  // This function is called from SpellCheck::SpellCheckWord(), which blocks
+  // WebKit. To avoid blocking WebKit for a long time, we do not check the MD5
+  // digest here. Instead we check the MD5 digest when Chrome finishes
+  // downloading a dictionary.
+
   // Don't set these until the end. This way, NULL bdict_data_ will indicate
   // failure.
   bdict_data_ = bdict_data;
   bdict_length_ = bdict_length;
   return true;
 }
 
 int BDictReader::FindWord(
     const char* word,
     int affix_indices[BDict::MAX_AFFIXES_PER_WORD]) const {
@@ skipping 41 matching lines @@
                              aff_header_->rep_offset);
 }
 
 
 WordIterator BDictReader::GetAllWordIterator() const {
   NodeReader reader(bdict_data_, bdict_length_, header_->dic_offset, 0);
   return WordIterator(reader);
 }
 
 }  // namespace hunspell