Optimize connecting to a server with many messages #664
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lmoureaux
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scrollToBottom() was called on the table widget once for every message, which triggered a new text layout every time, with O(n^2) complexity. Call it only after receiving a batch of messages for hopefully going down to O(n) complexity. Also use the opportunity to switch to a more lightweight QListWidget and adjust the themes accordingly. See longturn#584.
lmoureaux
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The code was still calling scrollToBottom() for every event because they are sent one by one, resulting in O(n^2) complexity. Instead of calling it directly, schedule a single call for when the server indicates that it's done processing. With this change, the layout of the message widget becomes invisible in profiles. See longturn#584.
When the server sends a message outside of any request (e.g. when a unit is killed by someone else in real time), there is no way to know when it will be done sending, thus scroll immediately. This shouldn't be a large performance hit since the server is unlikely to send hundreds of messages this way.
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This goes from O(n^3) complexity to mostly O(n). Layout of the message widget was the dominant contribution in profiles when connecting to LTEx24. After these changes, it becomes invisible.