|Summary:||[Qt] Make platform managing of OSAllocator better than r73106|
|Product:||WebKit||Reporter:||Csaba Osztrogonác <ossy>|
|Component:||Tools / Tests||Assignee:||Nobody <webkit-unassigned>|
|Severity:||Normal||CC:||commit-queue, ggaren, jturcotte, laszlo.gombos, paroga, yael|
|Version:||528+ (Nightly build)|
Description Csaba Osztrogonác 2010-12-02 07:26:21 PST
Comment 2 Csaba Osztrogonác 2010-12-02 07:38:44 PST
Patrick, Jocelyn, could you verify if the win case is good for all win/wince platform?
Comment 3 Geoffrey Garen 2010-12-02 10:28:20 PST
Comment on attachment 75375 [details] proposed fix EWS bots are green, so r=me. Thanks!
Comment 4 Laszlo Gombos 2010-12-02 10:31:11 PST
To me this seems like an opposite direction on where we want to go - this patch moves some logic from cross platform code into Qt specific build system; other ports would have to re-implement these guards now in their own port-specific mechanism.
Comment 5 Geoffrey Garen 2010-12-02 10:36:50 PST
This patch came out of a discussion I started by email, so I'll paste that here for context: > I ran into some trouble today with the Qt build system. I wanted to use separate files to separate concerns about different OS's like so: > > OSAllocator.h // cross-platform header > OSAllocatorPosix.cpp // used on POSIX OS's > OSAllocatorWin.cpp // used on Windows > > This fits the convention we use in WebCore, and it avoids cluttering files with #ifdefs and discordant implementations. > > It worked fine for most ports, but not for Qt, because Qt uses the same build project for both Linux and Windows. > > Is there any way to make portions of Qt's build project conditional based on OS, or to use different projects on different OS's?
Comment 6 Laszlo Gombos 2010-12-02 11:00:46 PST
(In reply to comment #5) > This patch came out of a discussion I started by email, so I'll paste that here for context: Thanks Geoffrey. > > This fits the convention we use in WebCore, and it avoids cluttering files with #ifdefs and discordant implementations. I think the convention you referring to in WebCore is different as that is relevant for files specific to a single port (e.g. Gtk or Qt). Files in this patch could be shared between ports. This was discussed in webkit-dev but I can not seems to find the thread anymore. The summary of the discussion is here - http://trac.webkit.org/wiki/Porting%20Macros%20plan.
Comment 7 Geoffrey Garen 2010-12-02 11:03:53 PST
> this patch moves some logic from cross platform code into Qt specific build system; The old code wasn't cross-platform -- it just put the burden of selecting different code for different platforms on the .cpp file, instead of the platform's build project file. > other ports would have to re-implement these guards now in their own port-specific mechanism For minor platform differences, one or two port-specific #ifdefs in a shared file is the most expedient solution, and I agree, it's nice not to have to rewrite the whole file for each port. However, in this case we have major platform differences -- for example, there is zero shared code between virtual memory allocation on Windows, POSIX, and Symbian. In such a case, I don't see much benefit to artificially merging platform-specific implementations, and I do see some disadvantages: * It doesn't match how major ports like Mac and Windows are organized. * It doesn't match how WebCore is organized. * It undermines the separation of concerns, and forces you to think about every permutation of ports for every line of port-specific code you write. * Having to write an "#if OS(WINDOWS)" guard inside OSAllocatorWin.cpp is very surprising. The whole point of OSAllocatorWin.cpp is that you should only build it on Windows. * It litters the code with #ifdefs, and often nested #ifdefs, which degrade readability. * It increases build times.
Comment 8 Patrick R. Gansterer 2010-12-02 11:12:37 PST
(In reply to comment #2) > Patrick, Jocelyn, could you verify if the win case is good for all win/wince platform? I didn't compile the new OSAllocatorWin.cpp with WinCE, but I don't think _this_ change will cause any troubles for WinCE.
Comment 9 WebKit Commit Bot 2010-12-02 12:09:40 PST
Comment on attachment 75375 [details] proposed fix Clearing flags on attachment: 75375 Committed r73179: <http://trac.webkit.org/changeset/73179>
Comment 10 WebKit Commit Bot 2010-12-02 12:09:45 PST
All reviewed patches have been landed. Closing bug.
Comment 11 Geoffrey Garen 2010-12-02 13:34:09 PST
I talked this over with some other folks, and the rough consensus was: - Separating completely different platform implementations into different .cpp files is good; - Surrounding a file like OSAllocatorWin.cpp with "#if OS(WINDOWS)" is not terribly harmful, so we're willing to do it if it makes some build systems simpler; - However, building more than one platform implementation file (for example, OSAllocatorWin.cpp and OSAllocatorPosix.cpp) in the same build system is not recommended practice. Ultimately, this probably argues against the #ifdef changes in r73179. I don't think there's an immediate need to roll them out, however, going forward, I think Laszlo is right that we should keep platform-specific implementation files #ifdef'd.