[webkit-reviews] patch take 2 for webview bustage after trying to print invalid page range

[David Harrison]

John,

When _delayedEndPrintMode requeues, it needs to pass the  
initiatingOperation argument...

+        [self performSelector:@selector(_delayedEndPrintMode:)  
withObject:initiatingOperation afterDelay:0];

also, I would have _delayedEndPrintMode do nothing (just return) if  
the currentOperation is non-nil and not equal to initiatingOperation.

performSelector:withObject:afterDelay: retains the argument object  
until the message is sent.  Is it OK to do that with a  
printOperation?  You mentioned that printing is somewhat complex.

You could test this method by commenting out cancel in beginDocument.

Dave

On Jun 13, 2005, at 5:50 PM, John Sullivan wrote:

> 2005-06-13  John Sullivan  <sullivan at apple.com>
>
>         Reviewed by NOBODY (OOPS!).
>
>         * WebView.subproj/WebHTMLView.m:
>         (-[WebHTMLView _endPrintMode]):
>         new method, extracted from identical code in beginDocument  
> and endDocument. This method must be called
>         once to counterbalance the code called from knowsPageRange  
> that turns on "printing mode".
>         (-[WebHTMLView _delayedEndPrintMode:]):
>         new method, called from "perform after delay". Checks  
> whether the same print operation is still underway
>         and, if so, delays further. Otherwise calls _endPrintMode  
> directly.
>         (-[WebHTMLView knowsPageRange:]):
>         after turning on "printing mode", queue up a delayed call  
> to _delayedEndPrintMode:. If there's an early
>         error in the print mechanism such that beginDocument is  
> never called, this will cleanly end "printing
>         mode" and make the webview usable again.
>         (-[WebHTMLView beginDocument]):
>         cancel any delayed call to _delayedEndPrintMode:. If we get  
> this far along in printing, then we don't need
>         the failsafe call to _delayedEndPrintMode: that was set up  
> in knowsPageRange:. Also, call extracted method.
>         (-[WebHTMLView endDocument]):
>         call extracted method
>
> Index: WebView.subproj/WebHTMLView.m
> ===================================================================
> RCS file: /cvs/root/WebKit/WebView.subproj/WebHTMLView.m,v
> retrieving revision 1.449
> diff -u -r1.449 WebHTMLView.m
> --- WebView.subproj/WebHTMLView.m    13 Jun 2005 03:28:08 -0000     
> 1.449
> +++ WebView.subproj/WebHTMLView.m    14 Jun 2005 00:32:59 -0000
> @@ -3148,6 +3148,22 @@
>      [self _setPrinting:YES minimumPageWidth:pageWidth  
> maximumPageWidth:pageWidth adjustViewSize:YES];
> }
> +- (void)_endPrintMode
> +{
> +    [self _setPrinting:NO minimumPageWidth:0.0 maximumPageWidth: 
> 0.0 adjustViewSize:YES];
> +    [[self window] setAutodisplay:YES];
> +}
> +
> +- (void)_delayedEndPrintMode:(NSPrintOperation *)initiatingOperation
> +{
> +    ASSERT_ARG(initiatingOperation, initiatingOperation != nil);
> +    // If the operation that initiated this is still underway,  
> delay further
> +    if (initiatingOperation == [NSPrintOperation currentOperation]) {
> +        [self performSelector:@selector(_delayedEndPrintMode:)  
> withObject:nil afterDelay:0];
> +    } else {
> +        [self _endPrintMode];
> +    }
> +}
> // Return the number of pages available for printing
> - (BOOL)knowsPageRange:(NSRangePointer)range {
> @@ -3166,6 +3182,14 @@
>          maxLayoutWidth = paperWidth*PrintingMaximumShrinkFactor;
>      }
>      [self _setPrinting:YES minimumPageWidth:minLayoutWidth  
> maximumPageWidth:maxLayoutWidth adjustViewSize:YES]; // will relayout
> +    NSPrintOperation *printOperation = [NSPrintOperation  
> currentOperation];
> +    // Certain types of errors, including invalid page ranges, can  
> cause beginDocument and
> +    // endDocument to be skipped after we've put ourselves in  
> print mode (see 4145905). In those cases
> +    // we need to get out of print mode without relying on any  
> more callbacks from the printing mechanism.
> +    // If we get as far as beginDocument without trouble, then  
> this delayed request will be cancelled.
> +    // If not cancelled, this delayed call will be invoked in the  
> next pass through the main event loop,
> +    // which is after beginDocument and endDocument would be called.
> +    [self performSelector:@selector(_delayedEndPrintMode:)  
> withObject:printOperation afterDelay:0];
>      [[self _webView] _adjustPrintingMarginsForHeaderAndFooter];
>
>      // There is a theoretical chance that someone could do some  
> drawing between here and endDocument,
> @@ -3173,7 +3197,6 @@
>      // you'd simply see the printer fonts on screen. As of this  
> writing, this does not happen with Safari.
>      range->location = 1;
> -    NSPrintOperation *printOperation = [NSPrintOperation  
> currentOperation];
>      float totalScaleFactor = [self  
> _scaleFactorForPrintOperation:printOperation];
>      float userScaleFactor = [printOperation  
> _web_pageSetupScaleFactor];
>      [_private->pageRects release];
> @@ -3207,12 +3230,16 @@
> - (void)beginDocument
> {
>      NS_DURING
> +        // From now on we'll get a chance to call _endPrintMode in  
> either beginDocument or
> +        // endDocument, so we can cancel the "just in case"  
> pending call.
> +        [NSObject cancelPreviousPerformRequestsWithTarget:self
> +                                                 selector:@selector 
> (_delayedEndPrintMode:)
> +                                                   object: 
> [NSPrintOperation currentOperation]];
>          [super beginDocument];
>      NS_HANDLER
>          // Exception during [super beginDocument] means that  
> endDocument will not get called,
>          // so we need to clean up our "print mode" here.
> -        [self _setPrinting:NO minimumPageWidth:0.0  
> maximumPageWidth:0.0 adjustViewSize:YES];
> -        [[self window] setAutodisplay:YES];
> +        [self _endPrintMode];
>      NS_ENDHANDLER
> }
> @@ -3220,8 +3247,7 @@
> {
>      [super endDocument];
>      // Note sadly at this point [NSGraphicsContext  
> currentContextDrawingToScreen] is still NO
> -    [self _setPrinting:NO minimumPageWidth:0.0 maximumPageWidth: 
> 0.0 adjustViewSize:YES];
> -    [[self window] setAutodisplay:YES];
> +    [self _endPrintMode];
> }
> - (BOOL)_interceptEditingKeyEvent:(NSEvent *)event
> _______________________________________________
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