RFR: JDK-8176785 Add build support to generate PNG file from .dot file

[Magnus Ihse Bursie]

Here is an updated webrev:
http://cr.openjdk.java.net/~ihse/JDK-8176785-full-build-support-for-module-graphs/webrev.04/

This change does not stop requiring the full exploded image to be built 
first when building full docs. However, full-docs will no longer be 
automatically enabled, even when all prerequisites are present, so for 
normal uses (where the user does not give --enable-full-docs), this 
dependency will not be present.

The problem here is that if we do that, we will end up with broken 
Javadoc in the image/docs directory, since the generated HTML will 
contain an "<img src="$m-graph.png"..>" tag, but the png file itself 
will not exist. During an offline discussion, this was deemed acceptable.

I have changed the names of the targets to be more clear. Now we have 
"docs-jdk" and "docs-javase" as the "top level" javadoc targets. For 
these, we (currently) have the sub-targets "docs-jdk-javadoc" and 
"docs-javase-javadoc", but as part of JEP 299, more will soon follow. I 
have kept "docs-javadoc" as a legacy alias for "docs-jdk-javadoc".

I have also incorporated the fixes from Mandy's comment.

/Magnus


On 2017-04-07 13:02, Erik Joelsson wrote:
> Hello,
>
> This looks good in general. One thing I don't like about this is that 
> if full docs is enabled, the docs-javadoc target now requires the full 
> exploded image to be built first. I think that's unfortunate. Would it 
> be possible to introduce separate targets for the gengraphs parts so 
> that the main javadoc call can be run independently of most of the 
> rest of the build, using the existing docs-javadoc target (and the 
> newer docs-reference, even though I think that name is bit strange in 
> this context)?
>
> /Erik
>
>
> On 2017-04-07 10:40, Magnus Ihse Bursie wrote:
>> This bug is the continuation of JDK-8173303, in which Mandy added the 
>> generation of .dot files for @moduleGraph Javadoc tags.
>>
>> With this patch, the code is taken to it's completion, and the 
>> temporarily solutions left in place by JDK-8173303 has been replaced 
>> by properly integrated solutions.
>>
>> Summary of changes:
>> * A new option --enable-full-docs determines if module graphs should 
>> be created or not. (In the future, even more optional but "difficult" 
>> documentation work might be added to depend on this.) This is enabled 
>> by default is all prerequisites are present.
>> * It is not impossible to get to a state of the documentation with 
>> broken img links.
>> * I have re-introduced SetupJavadocGeneration to stop the code 
>> duplication between JDK and Java SE javadoc builds.
>> * I have fixed a bug in how the makefiles determines the dependencies 
>> of modules. This only affected a single module in nashorn, and no 
>> nashorn build code used these dependencies, so that's why it has gone 
>> unnoticed until now. I have verified that no other changes in module 
>> dependencies are introduced by this fix.
>> * Javadoc source code dependencies are now correct even for 
>> transitive modules
>> * Support added for the creation and use in jib of a "graphviz" module.
>>
>> This code is dependent on JDK-8172312. This webrev is done as a diff 
>> against the latest published webrev of JDK-8172312. JDK-8172312 is 
>> reviewed, but is currently awaiting the status for JEP 299 to be 
>> changed to Targeted before it can be pushed.
>>
>> This code only affects the build system and documentation. I intend 
>> to push it to jdk9 using the "noreg-doc" RDP2 exception.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8176785
>> WebRev: 
>> http://cr.openjdk.java.net/~ihse/JDK-8176785-full-build-support-for-module-graphs/webrev.01
>>
>