Review Request: Enforce parse-jobs to be processed in order of their priorities

[Sven Brauch]

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This is an automatically generated e-mail. To reply, visit:
http://git.reviewboard.kde.org/r/104019/
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(Updated Feb. 25, 2012, 5:48 p.m.)


Review request for KDevelop, Milian Wolff and David Nolden.


Description
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As recently discussed on the mailing list, it is currently unnecessarily difficult to handle the following scenario:
File A does something like "import B"; you want A to be parsed with the top-context for B available.
Various language plugins have various solutions for this problem, but none of them were considered optimal by their creators (as far as I understood).

This patch aims to adress that problem. It changes the parsejob creation algorithm by enforcing it to wait with creating a job with a worse priority as long as jobs with a better priority are still running. Example: Three documents A, B and C are scheduled for parsing, A and B with priority 0 and C with priority -1. Assuming two parse jobs are available, the old function would create two parsejobs for C and A or B (let's say A), then wait for one of them to finish, then create a third job for B. The new function will create a parsejob for C and wait until that one is finished, and then create two jobs for A and B (still simultaneously, because they have the same priority). In other words: It's guaranteed that all parse jobs running at any specific time have the same priority. (*)

Why is that useful? Because parsejob priorities can be used to adress the above problem now: Let priority(x) be the priority of the parse-job for document x. You can then parse A, and as soon as you encounter the "import B", you can schedule B with priority(A)-1 and schedule A (again) with priority(A). That's now guaranteed to first parse B and then re-parse A with the top-context for B being available.
Oh, this patch also adds a function to get a parseJobs ownPriority(), that wasn't available before.

Please tell me what you think.

Greetings,
Sven
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(*) I'm aware of the fact that this will decrease performance by a little bit. However, I'm pretty sure it's not relevant. If the general concept of this is accepted, I'll test it.


Diffs (updated)
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  language/backgroundparser/backgroundparser.h 954ee17 
  language/backgroundparser/backgroundparser.cpp 7210254 
  language/backgroundparser/parsejob.h 135319c 
  language/backgroundparser/parsejob.cpp 552ef68 

Diff: http://git.reviewboard.kde.org/r/104019/diff/


Testing
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Thanks,

Sven Brauch

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