More timeout checks in RegexOptions.NonBacktracking

[olsaarik]

This PR adds timeout checking into matching loops in all phases of RegexOptions.NonBacktracking, while previously only the first "find the end position" phase had the check. The second "find the start position by walking backwards" phase uses the same number of innermost loop iterations between cheks as the first one. However, the third phase for finding subcaptures uses a lower one to account for the phase being slower in general. I measured that the 100 characters per timeout check gives around a 15ms resolution in the third phase.

The constants configuring those numbers of iterations are moved into SymbolicRegexThresholds.

This PR includes the bug fix from #74525 to avoid a conflict after that one is merged.

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Issue Details

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This PR adds timeout checking into matching loops in all phases of RegexOptions.NonBacktracking, while previously only the first "find the end position" phase had the check. The second "find the start position by walking backwards" phase uses the same number of innermost loop iterations between cheks as the first one. However, the third phase for finding subcaptures uses a lower one to account for the phase being slower in general. I measured that the 100 characters per timeout check gives around a 15ms resolution in the third phase.

The constants configuring those numbers of iterations are moved into SymbolicRegexThresholds.

This PR includes the bug fix from #74525 to avoid a conflict after that one is merged.

Author:	olsaarik
Assignees:	-
Labels:	area-System.Text.RegularExpressions
Milestone:	-

[stephentoub]

@joperezr, are we trying to get this into 7?

@olsaarik, can this be rebased now that #74525 was merged?

[joperezr]

Hey @olsaarik sorry for missing this. Is this ready for review?

[joperezr]

friendly ping @olsaarik 😄 Are you waiting on a review for this?

[olsaarik]

Thanks for the ping. If I remember correctly I mostly finished this, but I'll give it a look and make sure all the tests pass. I'll let you know when it's ready for review

[ericstj]

@olsaarik, could you let us know if you had a chance to look at this? Thanks!

[buyaa-n]

@olsaarik, if the PR is not ready yet, should we convert it to draft?

[olsaarik]

This had dropped off my radar. Returned to draft now and I'll get back to it.

[ghost]

Draft Pull Request was automatically closed for 30 days of inactivity. Please let us know if you'd like to reopen it.

[ghost]

Draft Pull Request was automatically closed for 30 days of inactivity. Please let us know if you'd like to reopen it.