nsStringKey/ and differences between plhash and pldhash

[Benjamin Smedberg]

What are the functional differences between nspr/lib/ds/plhash.h and xpcom/ds/pldhash.h. Is pldhash.h newer and more-efficient than plhash.h?

I have been completing a template-based hashtable for C++ objects based on plhash.h, because I found it first (similar to nsObjectHashtable, but automatically threadsafe). I have mostly gotten the code working... would it be worthwhile to think about recoding using pldhash.h instead?

I also see bug 119745, regarding nsStringKey. how often is nsStringKey actually used? Would it make sense to optimize nsStringKey to use shared buffers a la nsSharableString, to reduce memory usage? If there are many nsStringKey objects floating around, I would think you could obtain a sizable memory reduction, and reduce fragmentation on the heap. I just filed http://bugzilla.mozilla.org/show_bug.cgi?id=180264 on that issue.