Code review comment for lp:~smspillaz/compiz-core/compiz-core.work_923683

Sam Spilsbury (smspillaz) wrote :

> 2. I'm not entirely sure about replacing geometry with serverGeometry. I
> thought it would be a good idea to do the opposite. There would be a slight
> performance penalty, but using just "geometry" would guarantee that compiz
> always agrees with the actual server geometry, instead of guessing/assuming
> that serverGeometry is accepted by the server (which does not always seem to
> be true, hence bug 886192).
>

serverGeometry will always be "accepted" by the server as long as the window is managed and the requested window geometry will not generate a BadValue error (eg, 0 < 1 < MAXINT) (eg, it is not override redirect and it is a child of a window for which we have a SubstructureRedirectMask.

Bug 886192 is not an example of this. In fact, the behaviour exhibited by bug 886192 is primarily /because/ we use the geometry last received from the server rather than geometry last sent, and the latency of which explains the reason why the window movement lags the cursor, because the server is "catching up".

The only case where you can't guaruntee that a similar update for geometry is going to be delivered by the server for serverGeometry as stored on XConfigureWindow is either in the case that A) Another client has SubstructureRedirectMask on the root window or a parent window owned by compiz and in that case compiz shouldn't even touch that window at all or B) override redirect windows, and as you can see in the code, we /always/ use geometry for override redirect windows in placement sensitive operations. Incidentally, override redirect windows are why getting window stacking right is such a nightmare, but thats a topic for another day.

> 3. There are two instances of double semicolons ";;" in this proposal.

Fix
>
> 4. I suspect this proposal will conflict just slightly with the proposal for
> bug 940139. But it should be minor.

Yes, fixable

>
> 5. NEW REGRESSION:
> 375 - XSynchronize (dpy, synchronousX ? True : False);
> 376 +// priv->connection = XGetXCBConnection (priv->dpy);

Please elaborate further on why this is a regression.

>
> 6. Why always two spaces before "* 2" ?

Most likely copy-and-paste errors

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