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List:       kde-core-devel
Subject:    Re: Review Request 120202: [OS X] improvements to the kwallet/OSX keychain integration
From:       Thomas_Lübking <thomas.luebking () gmail ! com>
Date:       2014-09-21 11:38:50
Message-ID: 20140921113850.6970.74037 () probe ! kde ! org
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> On Sept. 18, 2014, 10:28 nachm., Albert Astals Cid wrote:
> > kdeui/util/kwallet.h, line 545
> > <https://git.reviewboard.kde.org/r/120202/diff/1/?file=312224#file312224line545>
> > 
> > This is bad, slots in an ifdef are a bad idea.
> > 
> > Is there any reason this slot has to be in KWallet and not some other object?
> 
> René J.V. Bertin wrote:
> May I ask why slots in an #ifdef are a bad idea, worse than any other kind of code? \
> I can see why platform-specific class members are not very elegant, but not why \
> that would be different for slots. 
> The slot has to have access to the Wallet instance, but it should be possible to \
> move it into the KWalletPrivate class since I already added a pointer to the \
> instance to that class. Would that be better? 
> Albert Astals Cid wrote:
> An ifdef in a public class is horrible.
> 
> As a user of the KWallet class when i should connect to it? Never? Then don't show \
> me to me it exists. 
> Thomas Lübking wrote:
> moc does not handle preprocessor statements.
> You'll likely get some error if the condition does not match because moc adds the \
> slot unconditionally, but the function isn't available. 
> That aside, #ifdef'ing functions in a public header (ie. exported API) is a bad \
> idea in general, because it causes different ABI (not that much a problem of an \
> architecure split) and usually confusion. 
> -> preattyplease #ifdef the implementation instead.
> 
> ```cpp
> void Foo::bar()
> {
> #if WANT_THIS
> fooBarFoo();
> #endif
> }
> ```
> 
> @Albert
> tbf, there're quite some present slots tagged "internal" in that class and since \
> they're all private slots, they're not available to user code anyway. The general \
> approach is ok, because they don't affect the vtable. 
> René J.V. Bertin wrote:
> Understood (and agreed). Not why moc doesn't take ifdefs into account, but that may \
> be a design choice, and isn't relevant here. 
> Albert Astals Cid wrote:
> @Thomas, i think last i checked you can still to connect to private slots, the only \
> thing is that you can't call them directly, but the metaobject doesn't know about \
> "private".

Indeed (jaws wide open) - so moc doesn't even care about that attribute.

Good to know, I foresee abuse >-)


- Thomas


-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://git.reviewboard.kde.org/r/120202/#review66894
-----------------------------------------------------------


On Sept. 14, 2014, 3:36 nachm., René J.V. Bertin wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/120202/
> -----------------------------------------------------------
> 
> (Updated Sept. 14, 2014, 3:36 nachm.)
> 
> 
> Review request for KDE Software on Mac OS X and kdelibs.
> 
> 
> Repository: kdelibs
> 
> 
> Description
> -------
> 
> I'm still working on (the KDE4-based version of) my OS X keychain backend for \
> kwallet. I'm at a point where I think I can present a work-in-progress in an RR \
> because at least one feature has been improved enough to be of interest for \
> everyone, and also because I could use feedback on how to proceed. I'm currently \
> focussing on 2 settings that are configured in the kwallet KCM (SystemSettings), \
> and for which I'm working on an implementation not requiring kwalletd and/or DBus. 
> - idle time closing of wallets. This feature was not supported in the commited \
> version presented in https://git.reviewboard.kde.org/r/119838/ The present patch \
> adds an idleTimer and a shared lastAccessTime member. The idleTimer is reset each \
> time a client performs one of a series of actions that I count as wallet accesses, \
> and before resetting I update the idle timeout value from KConfig. When the timer \
> fires, the elapsed time is compared to the shared last access time, and if it is >= \
> the timeout, the wallet is closed. This applies only to "KDE keychains", so \
> keychains used by OS X applications should not be affected. 
> - "close when last application exits". This requires maintaining a "user list" \
> which keeps track of what application has what wallet open. I've implemented an \
> "internal" version of such a registry, mapping wallet name to application names and \
> the list of wallets they have open (a list of wallet reference, pid per application \
> name). The registry is functional, but I have not yet decided (read: figured out) \
> how to make a distributed representation of it. 
> So the work-in-progress concerns the distributed user registry. The idea would be \
> to maintain the registry in shared memory, meaning it'd be reset (= disappear) when \
> the last application exits, contrary to a file which can go stale. This would be \
> simple if QSharedMemory objects could be resized, but apparently they cannot, so \
> I'll have to look at other solutions possibly involving OS X frameworks (NSData and \
> it's non-objectiveC version CFDataRef or CFMutableDataRef might be candidates). \
> Suggestions welcome. 
> Other work in progress concerns a less wheel-reinventing approach that builds on \
> kwalletd and DBus. I don't see why the code used in `kwallet.cpp` wouldn't work, \
> but I must still misunderstand its finer details. The present patch contains \
> outcommented code that does indeed cause kwalletd to be launched and slots and \
> signals to become visible e.g. in `qdbusviewer`. But they don't work, which in turn \
> makes the whole kwallet layer dysfunctional. Here too feedback is welcome on how \
> what I'm missing and/or how to get this to work. Once kwalletd works, wallet idle \
> timeout closing and closing when the last client exits should work out-of-the-box, \
> or at least I suppose. 
> 
> Diffs
> -----
> 
> kdeui/util/kwallet.h d7f703f 
> kdeui/util/kwallet_mac.cpp 8344ebb 
> kdeui/util/qosxkeychain.h d0934e6 
> kdeui/util/qosxkeychain.cpp 7cb9a22 
> 
> Diff: https://git.reviewboard.kde.org/r/120202/diff/
> 
> 
> Testing
> -------
> 
> OS X 10.6.8, kdelibs 4.14.1 git/master, KDE/MacPorts 4.12.5 .
> Once finalised, all changes should port easily to KF5's kwallet_mac.cpp .
> 
> 
> Thanks,
> 
> René J.V. Bertin
> 
> 


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      This is an automatically generated e-mail. To reply, visit:
      <a href="https://git.reviewboard.kde.org/r/120202/">https://git.reviewboard.kde.org/r/120202/</a>
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<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: \
10px;">  <p style="margin-top: 0;">On September 18th, 2014, 10:28 nachm. UTC, \
<b>Albert Astals Cid</b> wrote:</p>  <blockquote style="margin-left: 1em; \
border-left: 2px solid #d0d0d0; padding-left: 10px;">  


<table width="100%" border="0" bgcolor="white" style="border: 1px solid #C0C0C0; \
border-collapse: collapse; margin: 2px padding: 2px;">  <thead>
  <tr>
   <th colspan="4" bgcolor="#F0F0F0" style="border-bottom: 1px solid #C0C0C0; \
font-size: 9pt; padding: 4px 8px; text-align: left;">  <a \
href="https://git.reviewboard.kde.org/r/120202/diff/1/?file=312224#file312224line545" \
style="color: black; font-weight: bold; text-decoration: \
underline;">kdeui/util/kwallet.h</a>  <span style="font-weight: normal;">

     (Diff revision 1)

    </span>
   </th>
  </tr>
 </thead>

 <tbody style="background-color: #e4d9cb; padding: 4px 8px; text-align: center;">
  <tr>

   <td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">class \
KDEUI_EXPORT Wallet : public QObject</pre></td>

  </tr>
 </tbody>



 
 

 <tbody>

  <tr>
    <th bgcolor="#b1ebb0" style="border-right: 1px solid #C0C0C0;" \
align="right"><font size="2"></font></th>  <td bgcolor="#c5ffc4" width="50%"><pre \
style="font-size: 8pt; line-height: 140%; margin: 0; "></pre></td>  <th \
bgcolor="#b1ebb0" style="border-left: 1px solid #C0C0C0; border-right: 1px solid \
#C0C0C0;" align="right"><font size="2">544</font></th>  <td bgcolor="#c5ffc4" \
width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">        <span \
class="kt">void</span> <span class="nf">slotIdleTimedOut</span><span \
class="p">();</span></pre></td>  </tr>

 </tbody>

</table>

  <pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">This \
is bad, slots in an ifdef are a bad idea.</p> <p style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: inherit;">Is there any reason \
this slot has to be in KWallet and not some other object?</p></pre>  </blockquote>



 <p>On September 21st, 2014, 10:35 vorm. UTC, <b>René J.V. Bertin</b> wrote:</p>
 <blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: \
10px;">  <pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">May I \
ask why slots in an #ifdef are a bad idea, worse than any other kind of code? I can \
see why platform-specific class members are not very elegant, but not why that would \
be different for slots.</p> <p style="padding: 0;text-rendering: inherit;margin: \
0;line-height: inherit;white-space: inherit;">The slot has to have access to the \
Wallet instance, but it should be possible to move it into the KWalletPrivate class \
since I already added a pointer to the instance to that class. Would that be \
better?</p></pre>  </blockquote>





 <p>On September 21st, 2014, 10:39 vorm. UTC, <b>Albert Astals Cid</b> wrote:</p>
 <blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: \
10px;">  <pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">An \
ifdef in a public class is horrible.</p> <p style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: inherit;">As a user of the \
KWallet class when i should connect to it? Never? Then don't show me to me it \
exists.</p></pre>  </blockquote>





 <p>On September 21st, 2014, 10:53 vorm. UTC, <b>Thomas Lübking</b> wrote:</p>
 <blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: \
10px;">  <pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">moc \
does not handle preprocessor statements.<br style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: normal;" /> You'll likely get \
some error if the condition does not match because moc adds the slot unconditionally, \
but the function isn't available.</p> <p style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: inherit;">That aside, #ifdef'ing \
functions in a public header (ie. exported API) is a bad idea in general, because it \
causes different ABI (not that much a problem of an architecure split) and usually \
confusion.</p> <p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">-&gt; preattyplease #ifdef the implementation \
instead.</p> <p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;"><div class="codehilite" style="background: \
#f8f8f8"><pre style="line-height: 125%"><span style="color: #B00040">void</span> \
Foo<span style="color: #666666">::</span>bar() {
<span style="color: #BC7A00">#if WANT_THIS</span>
   fooBarFoo();
<span style="color: #BC7A00">#endif</span>
}
</pre></div>
</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">@Albert<br style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: normal;" /> tbf, there're quite \
some present slots tagged "internal" in that class and since they're all private \
slots, they're not available to user code anyway. The general approach is ok, because \
they don't affect the vtable.</p></pre>  </blockquote>





 <p>On September 21st, 2014, 11:04 vorm. UTC, <b>René J.V. Bertin</b> wrote:</p>
 <blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: \
10px;">  <pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: \
inherit;">Understood (and agreed). Not why moc doesn't take ifdefs into account, but \
that may be a design choice, and isn't relevant here.</p></pre>  </blockquote>





 <p>On September 21st, 2014, 11:30 vorm. UTC, <b>Albert Astals Cid</b> wrote:</p>
 <blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: \
10px;">  <pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: \
-pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: \
inherit;">@Thomas, i think last i checked you can still to connect to private slots, \
the only thing is that you can't call them directly, but the metaobject doesn't know \
about "private".</p></pre>  </blockquote>







</blockquote>
<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; \
white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p \
style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: \
inherit;">Indeed (jaws wide open) - so moc doesn't even care about that \
attribute.</p> <p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">Good to know, I foresee abuse &gt;-)</p></pre> <br />




<p>- Thomas</p>


<br />
<p>On September 14th, 2014, 3:36 nachm. UTC, René J.V. Bertin wrote:</p>









<table bgcolor="#fefadf" width="100%" cellspacing="0" cellpadding="12" style="border: \
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  <td>

<div>Review request for KDE Software on Mac OS X and kdelibs.</div>
<div>By René J.V. Bertin.</div>


<p style="color: grey;"><i>Updated Sept. 14, 2014, 3:36 nachm.</i></p>









<div style="margin-top: 1.5em;">
 <b style="color: #575012; font-size: 10pt;">Repository: </b>
kdelibs
</div>


<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
 <table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" \
style="border: 1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">I'm still working on (the KDE4-based version of) my OS \
X keychain backend for kwallet. I'm at a point where I think I can present a \
work-in-progress in an RR because at least one feature has been improved enough to be \
of interest for everyone, and also because I could use feedback on how to proceed.<br \
style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: \
normal;" /> I'm currently focussing on 2 settings that are configured in the kwallet \
KCM (SystemSettings), and for which I'm working on an implementation not requiring \
kwalletd and/or DBus.</p> <ul style="padding: 0;text-rendering: inherit;margin: 0 0 0 \
1em;line-height: inherit;white-space: normal;"> <li style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: normal;"> <p style="padding: \
0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">idle \
time closing of wallets. This feature was not supported in the commited version \
presented in https://git.reviewboard.kde.org/r/119838/ The present patch adds an \
idleTimer and a shared lastAccessTime member. The idleTimer is reset each time a \
client performs one of a series of actions that I count as wallet accesses, and \
before resetting I update the idle timeout value from KConfig. When the timer fires, \
the elapsed time is compared to the shared last access time, and if it is &gt;= the \
timeout, the wallet is closed. This applies only to "KDE keychains", so keychains \
used by OS X applications should not be affected.</p> </li>
<li style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: normal;"> <p style="padding: 0;text-rendering: inherit;margin: \
0;line-height: inherit;white-space: inherit;">"close when last application exits". \
This requires maintaining a "user list" which keeps track of what application has \
what wallet open. I've implemented an "internal" version of such a registry, mapping \
wallet name to application names and the list of wallets they have open (a list of \
wallet reference, pid per application name). The registry is functional, but I have \
not yet decided (read: figured out) how to make a distributed representation of \
it.</p> </li>
</ul>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">So the work-in-progress concerns the distributed user \
registry. The idea would be to maintain the registry in shared memory, meaning it'd \
be reset (= disappear) when the last application exits, contrary to a file which can \
go stale. This would be simple if QSharedMemory objects could be resized, but \
apparently they cannot, so I'll have to look at other solutions possibly involving OS \
X frameworks (NSData and it's non-objectiveC version CFDataRef or CFMutableDataRef \
might be candidates). Suggestions welcome.</p> <p style="padding: 0;text-rendering: \
inherit;margin: 0;line-height: inherit;white-space: inherit;">Other work in progress \
concerns a less wheel-reinventing approach that builds on kwalletd and DBus. I don't \
see why the code used in <code style="text-rendering: inherit;color: #4444cc;padding: \
0;white-space: normal;margin: 0;line-height: inherit;">kwallet.cpp</code> wouldn't \
work, but I must still misunderstand its finer details. The present patch contains \
outcommented code that does indeed cause kwalletd to be launched and slots and \
signals to become visible e.g. in <code style="text-rendering: inherit;color: \
#4444cc;padding: 0;white-space: normal;margin: 0;line-height: \
inherit;">qdbusviewer</code>. But they don't work, which in turn makes the whole \
kwallet layer dysfunctional. Here too feedback is welcome on how what I'm missing \
and/or how to get this to work.<br style="padding: 0;text-rendering: inherit;margin: \
0;line-height: inherit;white-space: normal;" /> Once kwalletd works, wallet idle \
timeout closing and closing when the last client exits should work out-of-the-box, or \
at least I suppose.</p></pre>  </td>
 </tr>
</table>


<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: \
1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: inherit;">OS X 10.6.8, kdelibs 4.14.1 git/master, KDE/MacPorts \
4.12.5 .<br style="padding: 0;text-rendering: inherit;margin: 0;line-height: \
inherit;white-space: normal;" /> Once finalised, all changes should port easily to \
KF5's kwallet_mac.cpp .</p></pre>  </td>
 </tr>
</table>


<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
<ul style="margin-left: 3em; padding-left: 0;">

 <li>kdeui/util/kwallet.h <span style="color: grey">(d7f703f)</span></li>

 <li>kdeui/util/kwallet_mac.cpp <span style="color: grey">(8344ebb)</span></li>

 <li>kdeui/util/qosxkeychain.h <span style="color: grey">(d0934e6)</span></li>

 <li>kdeui/util/qosxkeychain.cpp <span style="color: grey">(7cb9a22)</span></li>

</ul>

<p><a href="https://git.reviewboard.kde.org/r/120202/diff/" style="margin-left: \
3em;">View Diff</a></p>






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