[Mono-dev] Win Patches for Datagrid (first here) then idle

Rob Wilkens robwilkens at gmail.com
Mon Jun 18 21:23:20 UTC 2012

Thanks for not blindly trusting me :-)

On 06/18/2012 05:20 PM, Stifu wrote:
> No, it's fine.
> Rob Wilkens wrote
>> Whoops a second problem with the one you posted in the commit you
>> mentioned, I think if we're checking >= then we want the results
>> reversed...
>> -Rob
>> On 06/18/2012 05:06 PM, Rob Wilkens wrote:
>>> I couldn't see it before you pushed it, and may have done it wrong
>>> myself (I don't recall now)..  :-)
>>> I'm sure in the case where this version you wrote would result in a zero
>>> result, the zero result is probably OK.
>>> The version below is probably good if you're ok with it.
>>> -Rob
>>> On 06/18/2012 04:58 PM, Stifu wrote:
>>>> Hah, that thought did cross my mind.
>>>> Did you just wait for me to push it before saying that? :p
>>>> We could go for:
>>>> 			int next_pixel_offset = pixel_offset;
>>>> 			if (CurrentColumn < CurrentTableStyle.GridColumnStyles.Count)	
>>>> 			{
>>>> 				next_pixel_offset +=
>>>> CurrentTableStyle.GridColumnStyles[CurrentColumn].Width;
>>>> 			}
>>>> Rob Wilkens wrote
>>>>> Slight issue which probably will never be a problem:
>>>>> I'd replace the "0" with "pixel_offset" since the normal condition for
>>>>> that is pixel_offset PLUS the current column (which may be invalid)
>>>>> width.. 
>>>>> I don't think it'll be a problem though and can probably stand as-is.
>>>>> -Rob
>>>>> On 06/18/2012 04:39 PM, Stifu wrote:
>>>>>> Alright, the first patch is in
>>>>>> (https://github.com/mono/mono/commit/42ebb31fc143a171a6a5930bc647627c557842ee).
>>>>>> I took the liberty to change the coding style.
>>>>>> Thanks.
>>>>>> Rob Wilkens wrote
>>>>>>> This is for Stifu:
>>>>>>> Please follow this sequence when applying or testing the patches
>>>>>>> listed
>>>>>>> below.  Doing in other order may break things.  If you want me to
>>>>>>> create
>>>>>>> a unit test for something you don't see a unit test for, let me know,
>>>>>>> but in some cases, clicks are required with a mouse and i'm not
>>>>>>> necessarily sure how to create a patch to do that.
>>>>>>> Ok, I've attached the patches i had queued as separate individual
>>>>>>> patches, i hope i did this right..  These are from ranges of git
>>>>>>> diffs..  Please let me know if there are issues, my feelings won't be
>>>>>>> hurt, i'd rather do this right than do it fast.
>>>>>>> The order to apply them in (then i'll get into what it fixes after):
>>>>>>> I'd suggest the DataGrid patches first because they are in the middle
>>>>>>> of
>>>>>>> everything and get in the way -- except don't apply the
>>>>>>> IdleAndDataGrid.Whitespace.Jun10.patch until you've applied ALL the
>>>>>>> patches prior to Jun 10 (including idle patches), those patches in
>>>>>>> the
>>>>>>> Whitespace patch don't fix anything other the prettying up the code,
>>>>>>> but
>>>>>>> they depend on both set of patches in sequence..
>>>>>>> So the sequence i'm suggesting they must be applied in if they are
>>>>>>> applied at all are:
>>>>>>> (1) DataGrid1.Jun3.patch first
>>>>>>> (2) DataGrid2.Jun4.patch second
>>>>>>> (3) DataGrid3.Novell322563.jun4.patch third
>>>>>>> (4) DataGrid4.Novell322154.jun6.patch
>>>>>>> -- but don't do the other one i said not to do at this point --
>>>>>>> now to the idle fixes, these next ones (5-9) are meant to all be
>>>>>>> applied
>>>>>>> as part of essentially one patch for it to work, but is broken up so
>>>>>>> you
>>>>>>> can see progression.
>>>>>>> (5) Idle1-3.Jun2 (sorry for forgetting patch extension), This
>>>>>>> contains 3
>>>>>>> commits in one but they were all related, and makes life easier by
>>>>>>> being
>>>>>>> summarized into one like this.
>>>>>>> (6) Now you should do IdleAndDataGrid.Whitespace.Jun10.patch
>>>>>>> (7) Next, do Idle-Win32IdleEnable.jun11.patch
>>>>>>> (8) Idle-RaceConditionFix-Jun12.patch is next
>>>>>>> (9) Idle-TestFixForIdle.jun12.patch is last
>>>>>>> There, I have 9 attachments, and above is the sequence to apply them
>>>>>>> in.
>>>>>>> The below numbering system matches the above patch order
>>>>>>> #1: from the commit message:
>>>>>>> The sample code in
>>>>>>> https://bugzilla.novell.com/show_bug.cgi?id=MONO79788 was crashing on
>>>>>>> me
>>>>>>> if I clicked on a row header (where the + was). I investigated and
>>>>>>> found
>>>>>>> that it was because, when the table had no data to display yet, and
>>>>>>> if
>>>>>>> you clicked on a row header (that's the area to the left of what
>>>>>>> would
>>>>>>> be the data), as part of assigning the current cell, it would call
>>>>>>> ensure cell visibility function, which would call
>>>>>>> ScrollToColumnInPixels
>>>>>>> which would try to get the next pixel offset by looking at
>>>>>>> CurrentTableStyle.GridColumnStyles[CurrentColumn].Width, but when no
>>>>>>> data was being displayed there were no columns. So while current
>>>>>>> column
>>>>>>> had a value of zero, there were no items in the GridColumnStyles
>>>>>>> Array/List, even at zero index. The fix for this was before indexing
>>>>>>> into GridColumnStyles to Check The Length to make sure we're not
>>>>>>> going
>>>>>>> beyond its bounds. It is probably perfectly acceptable if we're
>>>>>>> beyond
>>>>>>> the bounds to just leave this value at zero for the offset.
>>>>>>> #2 From the commit message:
>>>>>>> Xamaring bug 5511: This fixes this and some side issues..
>>>>>>> First, fixed the crash by creating two additional stacks for when
>>>>>>> navigating to and from other sub tables... Both were 'style' stacks
>>>>>>> which tracked per column styles. Those needed to be updated and reset
>>>>>>> on
>>>>>>> a per table basis. Second, When navigating forward or back, EndEdit
>>>>>>> needed to be called so that we don't leave an editing cell open when
>>>>>>> we
>>>>>>> navigate, otherwise there was the possibility and reality that the
>>>>>>> edited cell would still be visible and editing on the next table
>>>>>>> either
>>>>>>> forward or back. To recreate this on the sample code, presuming you
>>>>>>> can
>>>>>>> get past the initial crash which was fixed here, this could be
>>>>>>> illustrated without the endedits that were added as follows : Run: 1.
>>>>>>> click + 2. click pb 3. click + 4. click pb 3. click + 5. click pd 6.
>>>>>>> click back 6. click pc 7. See 0 highlighted in column header from
>>>>>>> previous table Finally, I modified some previous submissions on a
>>>>>>> related problem so that they had more "Love for Spaces" (whitespace)
>>>>>>> without changing the actual code other than that.
>>>>>>> The above may have fixed, i think it was 5510 too.
>>>>>>> #3: From the commit
>>>>>>> This solves PART of Novell Bugzilla Issue #322563
>>>>>>> https://bugzilla.novell.com/show_bug.cgi?id=322563 What this
>>>>>>> accomplishes is that it hides the non browsable columns (columns that
>>>>>>> were not part of the original dataset, in the test case) from view in
>>>>>>> the DataGrid. Unfortunately, i can't see an obvious way to hide
>>>>>>> the'parent rows' display of those non browsable columns value. That
>>>>>>> is
>>>>>>> if You viewed a subtable off hidden field pb_Id=0 it would show that
>>>>>>> value (pb_Id=0) on the top of the datagrid where it shows the
>>>>>>> previous
>>>>>>> rows. The remaining issue seems to be a non major issue since it is a
>>>>>>> non functional issue.
>>>>>>> #4: From the commit
>>>>>>> Novell #323154
>>>>>>> Decided to include this in same branch (same pull request) as earlier
>>>>>>> changes due to it affecting the same DataGrid.cs -- i didn't want any
>>>>>>> conflicts. Here's a copy of what i wrote up earlier about this: the
>>>>>>> problem report is here:
>>>>>>> https://bugzilla.novell.com/show_bug.cgi?id=323154 I found by
>>>>>>> deduction
>>>>>>> that the repaint wasn't cancelling the active edit box after the row
>>>>>>> was
>>>>>>> deleted .. So while the table updated, the edit box with the old
>>>>>>> value
>>>>>>> didn't go away... The repaint was initiated from an Invalidate call
>>>>>>> which stack trace looked something like this:
>>>>>>> System.Windows.Forms.DataGrid.CalcAreasAndInvalidate() at
>>>>>>> System.Windows.Forms.DataGrid.RecreateDataGridRows(Boolean recalc) at
>>>>>>> System.Windows.Forms.DataGrid.OnListManagerItemChanged(System.Object
>>>>>>> sender, System.Windows.Forms.ItemChangedEventArgs e) at
>>>>>>> System.Windows.Forms.CurrencyManager.OnItemChanged(System.Windows.Forms.ItemChangedEventArgs
>>>>>>> e) at System.Windows.Forms.CurrencyManager.UpdateIsBinding() at
>>>>>>> System.Windows.Forms.CurrencyManager.ListChangedHandler(System.Object
>>>>>>> sender, System.ComponentModel.ListChangedEventArgs e) at
>>>>>>> System.Data.DataView.OnListChanged(System.ComponentModel.ListChangedEventArgs
>>>>>>> e) at System.Data.DataView.OnRowDeleted(System.Object sender,
>>>>>>> System.Data.DataRowChangeEventArgs args) at
>>>>>>> System.Data.DataTable.OnRowDeleted(System.Data.DataRowChangeEventArgs
>>>>>>> e)
>>>>>>> at System.Data.DataTable.DeletedDataRow(System.Data.DataRow dr,
>>>>>>> DataRowAction action) at System.Data.DataRow.Delete() at
>>>>>>> System.Data.DataView.Delete(Int32 index) at
>>>>>>> System.Data.DataRowView.Delete() at grid.ProcessCmdKey(Message ByRef
>>>>>>> msg, Keys keyData) (etc) ProcessCmdKey is from user code in sample in
>>>>>>> bug report... After the delete (as seen above), the first thing the
>>>>>>> DataGrid gets back is an OnListManagerItemChanged... Before that
>>>>>>> would
>>>>>>> call RecreateDataGridRows(), if it was going to do that, i inserted a
>>>>>>> check to see if we're editing, and if so, i cancel the edit (because
>>>>>>> we're reloading dataset), here is a summary of what my patch will
>>>>>>> look
>>>>>>> like in ONListManagerItemChanged in DataGrid.cs in
>>>>>>> System.Windows.Forms
>>>>>>> directory: if (rows == null || RowsCount != rows.Length -
>>>>>>> (ShowEditRow ?
>>>>>>> 1 : 0)) + { + if (is_editing) + CancelEditing ();
>>>>>>> RecreateDataGridRows
>>>>>>> (true); + } This solved the problem reported. It is now identical to
>>>>>>> windows .net behavior from what i can see, as far as this problem
>>>>>>> report
>>>>>>> goes anyway. MS .NET Crashes as well as mono in the sample code if
>>>>>>> you
>>>>>>> press a key twice to delete two rows when there was only one row to
>>>>>>> delete (index out of range). This is not necessarily a good thing,
>>>>>>> but
>>>>>>> it's user code from the bug report which causes that, not anything
>>>>>>> inherently different in mono.
>>>>>>> #5-#9 are all about fixing bug From Novell #321541 which if i have
>>>>>>> the
>>>>>>> right number is adding the ability to have the idle event handler
>>>>>>> only
>>>>>>> send idle events to the thread the idle handler was assigned in.  So
>>>>>>> if
>>>>>>> you have 2 threads, and they each assigned an idle event handler,
>>>>>>> they
>>>>>>> would each get their own idle event handler called when that thread
>>>>>>> went
>>>>>>> idle.  Or if only one thread had an idle event handler assigned that
>>>>>>> same idle handler wouldn't be called for EVERY thread, it would only
>>>>>>> be
>>>>>>> called on the thread it was assigned on.  This is so it more closely
>>>>>>> matches the windows .net behavior.
>>>>>>> I'll include each of the individual commit messages though they were
>>>>>>> all
>>>>>>> towards the same goal
>>>>>>> #5 had three commits:
>>>>>>> This addresses a 6-year old Novell bugzilla issue: 321541...
>>>>>>> Created a hashtable of per-thread event handlers for idle.. Assigned
>>>>>>> in
>>>>>>> to that hashtable when the regular Idle eventhandler was assigned by
>>>>>>> mapping it by ManagedThreadId. The hashtable had to use a separate
>>>>>>> object (different class) rather than an EventHandler directly,
>>>>>>> because
>>>>>>> an eventhandler apparently cannot be assigned to another object, it
>>>>>>> can
>>>>>>> only be a part of a class. It also couldn't be checked for null or
>>>>>>> called from outside the class so i handled that as appropriate (by
>>>>>>> secondary callers). This has been checked against the code in 321541
>>>>>>> and
>>>>>>> the code appears to work fine now. I have also confirmed no new unit
>>>>>>> test failures have been introduced by this change. There were 3
>>>>>>> failures
>>>>>>> before, and are three failures now. Also, This includes a unit test,
>>>>>>> which will fail without this patch. Here's a shortcut to the Novell
>>>>>>> bug:
>>>>>>> https://bugzilla.novell.com/show_bug.cgi?id=321541
>>>>>>> Per suggestion, Changed a Hashtable to a generic dictionary.
>>>>>>> This change is to properly use the GenericDictionary to use
>>>>>>> the EventHandler type directly rather than the temporary class that
>>>>>>> was
>>>>>>> being used in my first attempt at this.
>>>>>>> (so some of the changes from the first commit you don't see here
>>>>>>> because
>>>>>>> they were thrown away by the second and third in a rewrite)
>>>>>>> #6 is a bunch of whitespace fixes for Datagrid and idle which has to
>>>>>>> be
>>>>>>> applied at this point in sequence.
>>>>>>> #7 Enables the idle message to work on Win32.  When i tested on Win32
>>>>>>> i
>>>>>>> realized the Idle event handler was never called, so i fixed that so
>>>>>>> when it went idle it would call it.
>>>>>>> Here's the commit from #7:
>>>>>>> This patch will enable the idle event to be called when the
>>>>>>> applicati...
>>>>>>> ...on is idle on Win32. This was necessary to make an earlier unit
>>>>>>> test
>>>>>>> from the same set of patches work on win32. Plus, it's a good idea.
>>>>>>> #8 This is important, essentially this had a lock set to stop a race
>>>>>>> condition that was happening with the test. There was an 'if
>>>>>>> something
>>>>>>> == null assign something to something new... And two threads were
>>>>>>> hitting this code at the same time and this was causing one thread to
>>>>>>> assign it, and before it would start working with it, thread 2 would
>>>>>>> reassign it, and this resulted in a stack dump (exception) in
>>>>>>> add_Idle,
>>>>>>> this fix seemed to stop that.
>>>>>>> Here's the commit message
>>>>>>> This code fixes a possible race condition which during my testing
>>>>>>> seemed
>>>>>>> to be hit about once every twenty runs or so. Sometimes if two
>>>>>>> threads
>>>>>>> were assigning the idle handler at the same time, and it's the first
>>>>>>> assignment, they will both try to assign a new dictionary. This
>>>>>>> resulted
>>>>>>> in funny behavior, such as immediately after an add, the item
>>>>>>> wouldn't
>>>>>>> be found. After applying this fix, a lock around that particular
>>>>>>> check/assignment, I reran the tests about 50-75 times and never ran
>>>>>>> into
>>>>>>> this race condition again.
>>>>>>> #9 the last one is just some test changes after what i was told about
>>>>>>> mono requiring that all threads create the forms in the same thread.
>>>>>>> This only seemed to be a problem on windows, from what i recall, and
>>>>>>> only occasionally.
>>>>>>> The commit message reads:
>>>>>>> Due to a WinForms requriement (which only seems to occasionally be a
>>>>>>> problem on Windows), where all Controls (including Forms) must be
>>>>>>> created on One Thread, and then to do work on them from other threads
>>>>>>> only by use of invoke ( According to :
>>>>>>> http://www.mono-project.com/FAQ:_Winforms ), I modified my unit test
>>>>>>> accordingly to be in compliance.
>>>>>>> _______________________________________________
>>>>>>> Mono-devel-list mailing list
>>>>>>> Mono-devel-list at .ximian
>>>>>>> http://lists.ximian.com/mailman/listinfo/mono-devel-list
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