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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">I think our current Classfile.Option is already not so far from the proposed global context holder approach.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">The most significant use cases to persist (class hierarchy resolution and custom attributes) can be very well cached by keeping the Classfile.Option instances and re-using
them as many times as user needs.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">var options = List.of(Option.classHierarchyResolver(resolver),
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US"> Option.attributeMapper(mapper));<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">Classfile.build(clsDesc, options, handler);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">Classfile.parse(bytes, options); //here we have only vararg now<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">What I’m missing much much more than “global options holder” is per-transformation options (or even option change for transformed method).
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">For example I would like to use one class model to transform into multiple classes with different options, and I have to write:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">Classfile.parse(bytes, options1).transform(classTransform1);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">Classfile.parse(bytes, options2).transform(classTransform2);</span><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Instead of simple:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">var clm = Classfile.parse(bytes);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">clm.transform(classTransform1, options1);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">clm.transform(classTransform2, options2);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Or maybe:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">var clm = Classfile.parse(bytes, options1);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">clm.transform(classTransform1);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">clm.setOptions(options2);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US">clm.transform(classTransform2);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">However it raises the main question about what options are really tied to model parsing (I think it is only attributeMapper).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">And what options can be safely changed later. For example can I change processDebug, processLineNumbers or processUnknownAttributes on already parsed class model to
get different results of the following model traversal?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">And there are majority of options unrelated to the parsed class model but affecting only building and transformations (generateStackmap, constantPoolSharing, fixShortJumps,
patchDeadCode, classHierarchyResolver, filterDeadLabels).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">I think we should make more clear which options affect what actions (parsing, building, transformation) and give more flexibility to change them on the fly.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Adam<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">classfile-api-dev <classfile-api-dev-retn@openjdk.org> on behalf of Brian Goetz <brian.goetz@oracle.com><br>
<b>Date: </b>Thursday, 18 May 2023 16:16<br>
<b>To: </b>liangchenblue@gmail.com <liangchenblue@gmail.com>, classfile-api-dev <classfile-api-dev@openjdk.org><br>
<b>Subject: </b>Re: Planned features of a classfile context object<o:p></o:p></span></p>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:13.5pt;font-family:"Courier New"">Currently the ConstantPoolBuilder is another place we we attach options. This was more of a sin of convenience than anything else; the theory was that
if we are transforming a class, we'll parse it with a set of options, and then generate a new class which shares its CP, and the options came along for the ride.
<br>
<br>
Searching for a better name that ClassfileContext. The name Classfile is too good to waste, but it doesn't represent a classfile (that's ClassModel), so calling the new thing Classfile would likely be weird. Also ClassfileContext would make it harder to discover
the key entry points (build/parse). Classfile.Context is better in that it is more discoverable at least.
<br>
<br>
Classfile{Parser,Generator} are more discoverable but only tell half the story, and there's no obvious "first half" of the story. ClassfileReaderWriter is discoverable and honest but long. Classfile{Broker,Manager,Mediator} sound like parodies of the Design
Patterns era. <br>
<br>
A slightly cheeky but possibly viable option is "Classfiles"; while not a collection of classfiles, it is a collection of behaviors _about_ classfiles.
<br>
<br>
Classfiles.of(options).parse(bytes)<br>
Classfiles.of(options).generate(handler)<br>
<br>
<br>
<br>
<br>
</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt">On 5/17/2023 11:21 AM, Brian Goetz wrote:<o:p></o:p></span></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:13.5pt;font-family:"Courier New"">These are basically what is on my list, though I had in mind to move _all_ option information to the context, and leave it out of individual processing
decisions. </span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt">On 5/17/2023 9:59 AM, - wrote:<o:p></o:p></span></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<pre>Hi,<o:p></o:p></pre>
<pre>In the discussions a few weeks ago, we envisioned a Classfile context<o:p></o:p></pre>
<pre>object shared across multiple Classfile processing scenarios, mainly<o:p></o:p></pre>
<pre>for Class hierarchy information caching.<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>I want to confirm that these are contents of the object, mainly<o:p></o:p></pre>
<pre>promoted from individual options:<o:p></o:p></pre>
<pre> - Class Hierarchy information caching<o:p></o:p></pre>
<pre> - Custom attribute processing<o:p></o:p></pre>
<pre> - A set of default options, propagated to individual processing (may<o:p></o:p></pre>
<pre>be overridden classfile-wise)<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>What else is planned for the context object currently? Please don't<o:p></o:p></pre>
<pre>hesitate to propose. Thanks!<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>Chen Liang<o:p></o:p></pre>
</blockquote>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
</blockquote>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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