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

Stifu stifu at free.fr
Mon Jun 18 20:56:14 UTC 2012


You can still submit a test later if you feel like it, and if you can find an
elegant-enough one. But considering it's a tricky part to test, I don't
require it.


Rob Wilkens wrote
> 
> Beautiful..
> 
> I was working on a unit test for this one, but i guess that is not needed
> 
> Here it is standalone test for that bug if you want it (attached)...
> 
> -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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