Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:27659
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain kromann.info designates 64.186.239.125 as permitted sender)
To: Andy Wharmby <andy.wharmby@googlemail.com>
Cc: PHP internals list <internals@lists.php.net>,
	Wez Furlong <kingwez@gmail.com>
Message-ID: <11697450594440000@9866357972520000.9866341568840000>
MIME-Version: 1.0
Reply-To: "Frank M. Kromann" <frank@kromann.info>
Date: Thu, 25 Jan 2007 09:10:59 -0800
Content-Type: text/plain;
	charset="us-ascii"
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] COM extension defects: Possible patch
	for defect 35464
From: frank@kromann.info ("Frank M. Kromann")

Hi Andy,

I think this code and your explanations look good. I'll give the patch a
run tonight when I get home but I do not see any problems with it.

- Frank

> Hi Internals
>     Attached is a suggested patch for  COM defect 35464 
> (http://bugs.php.net/bug.php?id=34564)  Any comments;  good or bad
welcome.
> Regards
>     Andy
> 
> Andy Wharmby
> IBM United Kingdom Limited
> Winchester, England SO21 2JN
> E-mail: andy_wharmby@uk.ibm.com
> 
> COM defect 35464
> ================
> 
> The following details 2 reasons why in/out parameters don't work; one 
> caused by a problem with tetscase another a defect in COM extension
code.
> The testcase supplied by the raiser implements the DWebBrowserEvents2 
> interface to register an handler for the BeforeNaviagte2 event. This
>  handler is passed  just one in/out parameter;  a VARIANT_BOOL which can

> be set to TRUE by the handler to cancel the navigation operation.
> Doing so  in PHP currently has no affect,  for the 2 reasons I will 
> describe below,  so the  navigation completes and the specified page is
> displayed by IE.
> 
> Issue 1
> ======
> The users code is attempting to modify the variant directly in PHP code

> as follows:
> 
>     $cancel = true;
> 
> rather than using the COM method variant_set as follows:
> 
>     variant_set($cancel, true);
> 
> With this correction to the PHP script in place the variant for $cancel

> is correctly changed to TRUE but IE still navigates to the requested
page
> so the modification is having no effect. The reason for this is the 
> subject of issue 2 below.
>  
> Issue 2
> ======
> When an event notification is received by the COM extension 
> disp_invokeex() processes the incoming parameters (variants)  by taking

> each one
> and wrapping it in a php_com_dotnet_object object. At this time a COPY 
> of the incoming variant is embedded into the php_com_dotnet_object so
we
> immediately have 2 copies of the variant  and it is this copy in the 
> php_com_dotnet_object which is processed (get and set) by the PHP code.
> I see no code that checks for modification to our copy in the 
> php_com_dotnet_object before returning to the caller (in this case IE) 
> so modification
> to in/out parameters by the PHP code has no affect.
> 
> Given that the code copies an incoming variant in php_com_wrap_variant()

> I would have expected to see some code prior to return in
disp_invokeex()
> which checks for  modifications to in/out  parameters and copies any 
> modified values back to the callers copy of the variant.
> 
> I have hacked some code as follows:     
>     com_wrapper.c: http://www.pastebin.ca/328026
>     com_variant.c:  http://www.pastebin.ca/328022
>     com_misc.c: http://www.pastebin.ca/328025
>     php_com_dotnet_internal.h: http://www.pastebin.ca/328027
>     
> The new code works as follows:
> (1) When a variant is modified by a call to variant_set() in 
> com_variant.c a new flag (obj->modified)  is set in the 
> php_com_dotnet_object.
> 
> (2) After a successful call to a event handler new code  in 
> com_wrapper.c function disp_invokeex() checks each of the event 
> handlers  arguments
>  (php_com_dotnet_object's ) to see if any of their embedded variants 
> have been modified. If so and the argument passed into the event handler
was
>  passed by reference then the value in the embedded variant is copied to

> the callers copy by a call to a new function  php_com_copy_variant()
> defined in com_variant.c.
> 
> With this patch applied when the supplied testcase is run the navigation

> is now cancelled as expected.
> 
> -- 
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>