`jupyter-channels.el` depends on the `jupyter-send` method defined in
`jupyter-messages.el` whereas `jupyter-messages.el` does not depend on any
functions in `jupyter-channels.el`.
* jupyter-channel.el: Require `jupyter-messages`
* jupyter-messages.el: Remove `jupyter-channels` require
* Handle the case of no time specification by defaulting to midnight when
decoding time
* Properly handle fractions in `jupyter--decode-time`
* Implement `jupyter--encode-time`
* Consider a time object to be a length 4 list of integers and encode the
object using `jupyter--encode-time` when encoding in `jupyter--encode`
* Add tests for time decoding/encoding
This introduces a way of keeping track of both the encoded and decoded parts of
a message, only decoding the parts of a message when needed, and only encoding
the parts of a message when needed.
If the objects passed to `jupyter--encode` or `jupyter--decode` are lists with
the first element being the symbol `message-part`, then the second element of
the list is interpreted as being the encoded message and the third element
being the decoded part of the message. If either the encoded or the decoded
part are nil, then `jupyter--encode` or `jupyter--decode` will fill those
message parts in and on subsequent calls, passing in the same list, no work
will need to be performed.
This avoids double encoding messages when relaying messages between the channel
subprocess and the browser displaying widgets. This speeds up the communication
process. The cost is storing two representations of the same message, i.e.
speed vs memory.
Fixes:
- Use `eq` instead of `equal` in message status predicates
- Fix time string decoding
- `parse-time-string` was returning all nil on Emacs 26
- Include validation for parent header in `jupyter--encode-message`
- Use `jupyter-message-header' to access the message header instead of `plist-get`
- Add missing namespace to sha256 function
- Any function defined should have a `jupyter-` prefix
- Remove `cl-lib` dependency in `jupyter-messages.el`
- Include `subr-x` in `jupyter-base.el`
- Use `tramp-file-name-user` instead of `tramp-file-name-real-user` since the
latter is missing in Emacs 26
- Allow specifying a msg-id before a call to `jupyter-send`
- This avoid sending a message to the browser displaying the widgets on every
message send to the kernel. The previous implementation generated a new ID
without allowing the caller to pass one in.
- Simplify message polling by sending received messages from the kernel to the
parent Emacs process at the moment of arrival.
