Non-generic streams (make MsgStream a proper Stream) #71
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The original implementation of MsgStream (before it was a subclass of Stream) had `readStr` procs that raised an IOError if the entire string couldn't be read. This does not match the behavior of the standard Stream module, but the code here depends on it, and the lack of this check broke a unit test. (Note: This meant MsgPack had different behavior when using a regular stream than when using a MsgStream. In the former case, some truncated messages wouldn't be detected during unpacking, and bad data would be returned.) I created a Stream.readExactStr function that has the behavior the code here expects, and changed all the calls to `readStr` to `readExactStr`.
Now that MsgStream inherits from Stream, all procs that take a stream can just be regular procs with a `Stream` parameter, instead of generics.
This was referenced Feb 24, 2023
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I found a way to make MsgStream a proper subclass of Stream and initialize it correctly. It’s a bit of a kludge but it works; really it’s just a workaround of a design flaw in the
streamsmodule.That means the implementation of the stream API can be removed, since it’s all inherited now.
It also means that all the functions that operate on streams can be regular non-generic procs that take a
Streamparameter, instead of needing to make them generic over aByteStreamtype.In doing this I found a place where MsgStream had different semantics from a regular Stream: the
readStrfunction here would raise an IOError if it couldn’t read the entire string; the standard one doesn’t. I think raising an error is better behavior, but it’s nonstandard. I resolved this by defining a new functionreadExactString(Stream)that has the MsgStream behavior, and changing all calls toreadStringtoreadExactString.