Panama unresolved error when instantiating wayland struct...

[Mark Hammons]

Hi Maurizio,

No, wl_list is defined in wayland_utils.h while wl_listener is in 
wayland_server_core.h. I am currently looking through the issues on the 
openjdk tracker and seeing if there's a mitigation for this.

~Mark

On 2/15/19 12:30 AM, Maurizio Cimadamore wrote:
> Hi Mark,
> thanks for the report - from the looks of it, it seems an issue with 
> cross-header layout resolution, which is listed in the 'known issues' 
> in the EA page:
>
> "Dynamic layout resolution doesn't work across multiple headers."
>
> I will check in more details tomorrow, and confirm, one way or another.
>
> Quick check: are wl_list and wl_listener defined in the same header 
> file? If not that's likely the issue here.
>
> I think Pointer<?> is the correct type - jextract tries to insert as 
> more general types as possible when inserting Pointer in argument 
> position; if it generated Pointer<Void>, and that was an ordinary 
> function call, you could only call it with another Pointer<Void> - if 
> the argument type is Pointer<?> you can pass _any_ pointer - e.g. 
> Pointer<Byte>, Pointer<Integer> which is kind of close to what you can 
> do in C.
>
> Maurizio
>
> On 14/02/2019 22:23, Mark Hammons wrote:
>> Hi all,
>>
>> I decided to try to take the dive on project panama, starting with 
>> making a binding to linux's wayland server. I used the following 
>> command: ~/bin/jdk-13/bin/jextract 
>> /usr/include/wayland/wayland-server-core.h 
>> /usr/include/wayland/wayland-server.h 
>> /usr/include/wayland/wayland-util.h 
>> /usr/include/wayland/wayland-version.h 
>> /usr/include/wayland/wayland-server-protocol.h -I 
>> /usr/include/wayland -L /usr/lib64/ --record-library-path -l 
>> wayland-server -t wayland -o wayland_server.jar
>>
>>
>> When I try to allocate a wl_listener struct, I get the following error:
>>
>> [error] Exception in thread "main" 
>> java.lang.UnsupportedOperationException: bitsSize on Unresolved
>> [error]     at 
>> java.base/java.foreign.layout.Unresolved.bitsSize(Unresolved.java:76)
>> [error]     at 
>> java.base/java.util.stream.ReferencePipeline$5$1.accept(ReferencePipeline.java:229)
>> [error]     at 
>> java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
>> [error]     at 
>> java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
>> [error]     at 
>> java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
>> [error]     at 
>> java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
>> [error]     at 
>> java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
>> [error]     at 
>> java.base/java.util.stream.LongPipeline.reduce(LongPipeline.java:474)
>> [error]     at 
>> java.base/java.util.stream.LongPipeline.sum(LongPipeline.java:432)
>> [error]     at 
>> java.base/java.foreign.layout.Group.bitsSize(Group.java:119)
>> [error]     at 
>> java.base/java.foreign.memory.LayoutType.bytesSize(LayoutType.java:49)
>> [error]     at 
>> java.base/jdk.internal.foreign.ScopeImpl.allocateInternal(ScopeImpl.java:66)
>> [error]     at 
>> java.base/jdk.internal.foreign.ScopeImpl.allocate(ScopeImpl.java:92)
>> [error]     at 
>> java.base/jdk.internal.foreign.ScopeImpl.allocateStruct(ScopeImpl.java:98)
>> [error]     at TestApp$.delayedEndpoint$TestApp$1(TestApp.scala:22)
>> [error]     at TestApp$delayedInit$body.apply(TestApp.scala:13)
>> [error]     at scala.Function0.apply$mcV$sp(Function0.scala:39)
>> [error]     at scala.Function0.apply$mcV$sp$(Function0.scala:39)
>> [error]     at 
>> scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:17)
>> [error]     at scala.App.$anonfun$main$1$adapted(App.scala:80)
>> [error]     at scala.collection.immutable.List.foreach(List.scala:392)
>> [error]     at scala.App.main(App.scala:80)
>> [error]     at scala.App.main$(App.scala:78)
>> [error]     at TestApp$.main(TestApp.scala:13)
>> [error]     at TestApp.main(TestApp.scala)
>>
>> Looking at other bugs involving this kind of error message, it 
>> appears that unresolved is a type for when there's not enough layout 
>> information? In any case, here's the struct in question:
>>
>> struct wl_listener {
>>         struct wl_list link;
>>         wl_notify_func_t notify;
>> };
>>
>> and the definition of the elements:
>>
>> typedef void (*wl_notify_func_t)(struct wl_listener *listener, void 
>> *data);
>>
>> struct wl_list {
>>         /** Previous list element */
>>         struct wl_list *prev;
>>         /** Next list element */
>>         struct wl_list *next;
>> };
>>
>> I'm fairly certain the issue lies with the function pointer notify. 
>> When I looked at the decompiled source, wl_notify_func_t is defined as:
>>
>>     @FunctionalInterface
>>     @NativeCallback("(u64:${wl_listener}u64:v)v")
>>     public interface FI5 {
>>         void fn(Pointer<wayland_server_core.wl_listener> var1, 
>> Pointer<?> var2);
>>     }
>>
>>
>> which seems suspicious to me. var2 should be a Pointer<Void> I would 
>> think. It's a type I see elsewhere in the source for this file, so it 
>> seems suspect that var2 is a Pointer<?>.
>>
>>
>> Is this a bug? Am I just using jextract wrong?
>>
>> Thanks for your help,
>>
>> Mark Hammons
>>