Closed Bug 14623 Opened 21 years ago Closed 21 years ago
editor strategy for batching/merging transactions needs some work
3) I've been overusing batching. Batching is evil. I used to think it was such a clear blue sky - being able to nest batches made a lot of stuff so much easier to write. But batching absolutely, positively breaks any kind of merging. You can't use it inside of any code that might be doing anything that is part of a mergable operation. Most things we do in response to typing is supposed to merge: hence, no batching in any of our typing execution path. The right solution here is the placeHolderTxn, which was Steve's original answer to the problem of merging together a bunch of disparate transactions under the auspices of one operation, while still allowing that overall operation to merge with a like one executed later. However, it's a pain to carry around a pointer to a placeHolderTxn everywhere the rules code goes and then fill it in the first time we discover that yes, this operation is going to have _some_ transactions in it and not be empty. There are a lot of places that can be the _first_ place to make actual content changes in response to typing. Deletion of the bogus node is one. Splitting of mailcites is one. Actual text insertion is one. Creating inline style nodes is one. I bet I'm forgetting some, and I bet there will be more later. Having all of these having to call some "check to see if the placeHolderTxn is null and if so make one" code (everyplace they might first make a content change) is pretty darn ugly. I would prefer that we create one of these placeHolderTxns at the start of a mergable operation (EditorKeyPress() would probably be the right place) and then at the end of the operation be able to detect whether anything actually got done. If nothing did, somehow the transaction should vanish. I assume we need an addition to the transaction manager here: something to say "hey, we know we told you to do that, and you did, and now it's on your undo stack, but we've since realized that transaction did _nothing_ and we want you to forget about it". Otherwise when the user does undo, there will be an "empty" undo operation. Although I've fixed a lot of undo problems this weekend without taking this step, it's going to be broken in places until we either do this, do something smarter that I havne't thought of but you hopefully will, or write lots of ugly code everywhere to check the status of any existing placeHolderTxn. [An example of broken undo still left is undoing typing that has returns in it. The results are pretty hideous right now.]
Summary: editor's use of GetChildNodes needs auditing → editor strategy for batching/merging transactions needs some work
accepting bug / m12
Status: ASSIGNED → RESOLVED
Closed: 21 years ago
Resolution: --- → FIXED
this is fixed - undo now works like you would expect. long live undo
I can't verify this one....jfrancis/buster, can you mark this verified-fixed.. thanks!
verified, per demo to rickg yesterday ;-)
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