Make string_util::WriteInto() DCHECK() that the supplied |length_with_null| > 1, meaning that the...

net/disk_cache/entry_impl.cc

Index: net/disk_cache/entry_impl.cc
===================================================================
--- net/disk_cache/entry_impl.cc	(revision 107404)
+++ net/disk_cache/entry_impl.cc	(working copy)
@@ -773,11 +773,11 @@
   File* key_file = const_cast<EntryImpl*>(this)->GetBackingFile(address,
                                                                 kKeyFileIndex);
 
-  if (!offset && key_file->GetLength() != static_cast<size_t>(key_len + 1))
+  ++key_len;  // We store a trailing \0 on disk that we read back below.

[joth, 2011/11/01 11:25:32]

My reading of line 432 is we don't write the trailing \0. So odds are we're
actually reading a spurious junk byte in here? (It's 'safely' ignored as it's
over the end of size; a subsequent c_str() call would overwrite it with \0
anyway)

[rvargas (doing something else), 2011/11/01 18:13:48]

The extra \0 on disk comes from lines 421 and 438.

[joth, 2011/11/01 19:14:51]

Ah yes, thanks.
Still - seems a bit funny this is intentionally reading off the end of
key_.size() one extra byte that is inaccessible by any conventional means be 
(both c_str() and resize(size()+1) will overwrite it)

[rvargas (doing something else), 2011/11/01 19:36:52]

yes, that looks like an oversight. I think the original intent was to double
check there was a \0 there... oh well.

+  if (!offset && key_file->GetLength() != static_cast<size_t>(key_len))
     return std::string();
 
-  if (!key_file ||
-      !key_file->Read(WriteInto(&key_, key_len + 1), key_len + 1, offset))
+  if (!key_file || !key_file->Read(WriteInto(&key_, key_len), key_len, offset))
     key_.clear();
   return key_;
 }