RECORD plugin can't work

[wenfer]

my code

package x11;

import com.github.moaxcp.x11client.X11Client;
import com.github.moaxcp.x11client.protocol.record.*;

import java.io.IOException;
import java.util.List;

public class X11Test {

    public static void main(String[] args) {
        try (X11Client client = X11Client.connect()) {
            int rc = client.nextResourceId();
            Range8 empty = Range8.builder().build();
            ExtRange emptyExtRange = ExtRange.builder()
                    .major(empty)
                    .minor(Range16.builder().build())
                    .build();
            Range range = Range.builder()
                    .deviceEvents(Range8.builder().first((byte) 2).last((byte) 6).build())
                    .coreRequests(empty)
                    .coreReplies(empty)
                    .extRequests(emptyExtRange)
                    .extReplies(emptyExtRange)
                    .deliveredEvents(empty)
                    .clientStarted(false)
                    .errors(empty)
                    .clientDied(false)
                    .build();

            CreateContext createContext = CreateContext.builder()
                    .context(rc)
                    .clientSpecs(List.of(Cs.ALL_CLIENTS.getValue()))
                    .elementHeader((byte) 0)
                    .ranges(List.of(range))
                    .build();
            client.send(createContext);

            EnableContext enableContext = EnableContext
                    .builder()
                    .context(rc)
                    .build();
            EnableContextReply enableContextReply = client.send(enableContext);
            if (enableContextReply.getCategory() == 0) {
                for (Byte datum : enableContextReply.getData()) {
                    System.out.println(datum);
                }
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

}

the code can't work, got this exception

Exception in thread "main" com.github.moaxcp.x11client.X11ErrorException: WindowError(firstErrorOffset=0, sequenceNumber=2, badValue=230686721, minorOpcode=0, majorOpcode=2)
    at com.github.moaxcp.x11client.XProtocolService.readReply(XProtocolService.java:87)
    at com.github.moaxcp.x11client.XProtocolService.send(XProtocolService.java:66)
    at com.github.moaxcp.x11client.X11Client.send(X11Client.java:238)
    at x11.X11Test.main(X11Test.java:51)

is somewhere wrong？

[moaxcp]

I would check the x11 server logs to see if there is anything helpful there. You can also compare the the java classes to the C library. There could be something it does differently before submitting the request.

[wenfer]

/the code is convert from rust(x11rb), that's work in rust,i show you code

fn main() {
    let (conn, screen_num) = x11rb::connect(None).unwrap();
    let rc = conn.generate_id().unwrap();
    let empty = Range8 { first: 0, last: 0 };
    let empty_ext = ExtRange {
        major: empty,
        minor: record::Range16 { first: 0, last: 0 },
    };
    let range = record::Range {
        core_requests: empty,
        core_replies: empty,
        ext_requests: empty_ext,
        ext_replies: empty_ext,
        delivered_events: empty,
        device_events: Range8 {
            // We want notification of core X11 events between key press and motion notify
            first: xproto::KEY_PRESS_EVENT,
            last: xproto::MOTION_NOTIFY_EVENT,
        },
        errors: empty,
        client_started: false,
        client_died: false,
    };
    let _ = conn.record_create_context(rc,
                                       0,
                                       &[CS::ALL_CLIENTS.into()],
                                       &[range]);
    for reply in conn.record_enable_context(rc).unwrap() {
        match reply {
            Ok(reply) => {
                //todo something
            }
            Err(err) => {
                println!("error:{}", err);
            }
        }
    }
  }```

[moaxcp]

The problem is with ProtocolPluginService

      if(plugin.getMajorVersion() != majorOpcode) {
        return false; //client must match server version
      }

I assumed this was a way to make sure the versions between the client and server matched.

What needs to happen is the plugin should send a QueryVersion request and return the major and minor versions so ProtocolPluginService can check they match.

[moaxcp]

I started working on this in the fix-plugins branch. Now I am getting a LengthError.

LengthError(firstErrorOffset=0, sequenceNumber=34, badValue=0, minorOpcode=0, majorOpcode=-109)
com.github.moaxcp.x11client.X11ErrorException: LengthError(firstErrorOffset=0, sequenceNumber=34, badValue=0, minorOpcode=0, majorOpcode=-109)
    at app//com.github.moaxcp.x11client.XProtocolService.readReply(XProtocolService.java:87)
    at app//com.github.moaxcp.x11client.XProtocolService.send(XProtocolService.java:66)
    at app//com.github.moaxcp.x11client.X11Client.send(X11Client.java:238)
    at app//com.github.moaxcp.x11client.RecordIT.test(RecordIT.java:43)

[moaxcp]

I added a sync after the CreateContext request and that is the request causing the failure. From there I logged the request. Can you tell if the length is correct?

CreateContext(context=83886081, elementHeader=0, clientSpecs=[3], ranges=[Range(coreRequests=Range8(first=0, last=0), coreReplies=Range8(first=0, last=0), extRequests=ExtRange(major=Range8(first=0, last=0), minor=Range16(first=0, last=0)), extReplies=ExtRange(major=Range8(first=0, last=0), minor=Range16(first=0, last=0)), deliveredEvents=Range8(first=0, last=0), deviceEvents=Range8(first=2, last=6), errors=Range8(first=0, last=0), clientStarted=false, clientDied=false)]), size: 48, length: 12

Or maybe the write method is generated wrong?

  @Override
  public void write(byte offset, X11Output out) throws IOException {
    out.writeCard8((byte)(Byte.toUnsignedInt(OPCODE) + Byte.toUnsignedInt(offset)));
    out.writePad(1);
    out.writeCard16((short) getLength());
    out.writeCard32(context);
    out.writeCard8(elementHeader);
    out.writePad(3);
    int numClientSpecs = clientSpecs.size();
    out.writeCard32(numClientSpecs);
    int numRanges = ranges.size();
    out.writeCard32(numRanges);
    out.writeCard32(clientSpecs);
    for(Range t : ranges) {
      t.write(out);
    }
    out.writePadAlign(getSize());
  }

[wenfer]

i see release 0.13.0，it's fixed ？ i can't get from maven central , did pushed to nexus ?

[wenfer]

I added a sync after the CreateContext request and that is the request causing the failure. From there I logged the request. Can you tell if the length is correct?

CreateContext(context=83886081, elementHeader=0, clientSpecs=[3], ranges=[Range(coreRequests=Range8(first=0, last=0), coreReplies=Range8(first=0, last=0), extRequests=ExtRange(major=Range8(first=0, last=0), minor=Range16(first=0, last=0)), extReplies=ExtRange(major=Range8(first=0, last=0), minor=Range16(first=0, last=0)), deliveredEvents=Range8(first=0, last=0), deviceEvents=Range8(first=2, last=6), errors=Range8(first=0, last=0), clientStarted=false, clientDied=false)]), size: 48, length: 12

Or maybe the write method is generated wrong?

  @Override
  public void write(byte offset, X11Output out) throws IOException {
    out.writeCard8((byte)(Byte.toUnsignedInt(OPCODE) + Byte.toUnsignedInt(offset)));
    out.writePad(1);
    out.writeCard16((short) getLength());
    out.writeCard32(context);
    out.writeCard8(elementHeader);
    out.writePad(3);
    int numClientSpecs = clientSpecs.size();
    out.writeCard32(numClientSpecs);
    int numRanges = ranges.size();
    out.writeCard32(numRanges);
    out.writeCard32(clientSpecs);
    for(Range t : ranges) {
      t.write(out);
    }
    out.writePadAlign(getSize());
  }

sorry , i dont know x11 more , so i can't help you ,i just test record plugin in rust , that's all

[moaxcp]

Anything is possible but length is the error returned. I was just wondering what the length should be. Can you compare it to the length in rust? Or even compare the binary results? There are a few structs involved so it could be an issue with structs. I will have to look into it more.

[wenfer]

Now

which request lengtherror in ? show me the java code, i'll try help

[moaxcp]

I think I figured it out I just need to find some time to work on it. The problem is in writing the output. This is what CreateContext has.

  @Override
  public void write(byte offset, X11Output out) throws IOException {
    out.writeCard8((byte)(Byte.toUnsignedInt(OPCODE) + Byte.toUnsignedInt(offset)));
    out.writePad(1);
    out.writeCard16((short) getLength());
    out.writeCard32(context);
    out.writeCard8(elementHeader);
    out.writePad(3);
    int numClientSpecs = clientSpecs.size();
    out.writeCard32(numClientSpecs);
    int numRanges = ranges.size();
    out.writeCard32(numRanges);
    out.writeCard32(clientSpecs);
    for(Range t : ranges) {
      t.write(out);
    }
    out.writePadAlign(getSize());
  }

For the rust client this is what I found.

let mut request0 = vec![
            major_opcode,
            CREATE_CONTEXT_REQUEST,
            0,
            0,
            context_bytes[0],
            context_bytes[1],
            context_bytes[2],
            context_bytes[3],
            element_header_bytes[0],
            0,
            0,
            0,
            num_client_specs_bytes[0],
            num_client_specs_bytes[1],
            num_client_specs_bytes[2],
            num_client_specs_bytes[3],
            num_ranges_bytes[0],
            num_ranges_bytes[1],
            num_ranges_bytes[2],
            num_ranges_bytes[3],
        ];

The problem is here out.writeCard8((byte)(Byte.toUnsignedInt(OPCODE) + Byte.toUnsignedInt(offset)));. The first byte is the addition of the opcode and the offset or majorOpcode. When what should happen is the majorOpcode should be the first byte followed by OPCODE.

I have to change the gradle-plugin to write the OPCODE instead of a padding for these extensions.

This explains why BigRequest works and all of the QueryVersion requests for the extensions because their OPCODE is 0 but everything else fails.

[wenfer]

The problem is here out.writeCard8((byte)(Byte.toUnsignedInt(OPCODE) + Byte.toUnsignedInt(offset)));. The first byte is the addition of the opcode and the offset or majorOpcode. When what should happen is the majorOpcode should be the first byte followed by OPCODE.

I have to change the gradle-plugin to write the OPCODE instead of a padding for these extensions.

This explains why BigRequest works and all of the QueryVersion requests for the extensions because their OPCODE is 0 but everything else fails.

you are hero !!!

[moaxcp]

This should be fixed now in 0.14.0

[wenfer]

i try in 0.14.0, the samples code return EnableContextReply field category is 4, in rust code category is 0, look like not fixed

[moaxcp]

One thing I noticed is you are supposed to use two clients for this. One for the control client and one for the data client. So I added a data client.

try (X11Client control = X11Client.connect()) {
            int rc = control.nextResourceId();
            Range8 empty = Range8.builder().build();
            ExtRange emptyExtRange = ExtRange.builder()
                    .major(empty)
                    .minor(Range16.builder().build())
                    .build();
            Range range = Range.builder()
                    .deviceEvents(Range8.builder().first(KeyPressEvent.NUMBER).last(MotionNotifyEvent.NUMBER).build())
                    .coreRequests(empty)
                    .coreReplies(empty)
                    .extRequests(emptyExtRange)
                    .extReplies(emptyExtRange)
                    .deliveredEvents(empty)
                    .clientStarted(false)
                    .errors(empty)
                    .clientDied(false)
                    .build();

            CreateContext createContext = CreateContext.builder()
                    .context(rc)
                    .clientSpecs(Collections.singletonList(Cs.ALL_CLIENTS.getValue()))
                    .elementHeader((byte) 0)
                    .ranges(Collections.singletonList(range))
                    .build();

            control.send(createContext);

            control.sync();

            EnableContext enableContext = EnableContext
                    .builder()
                    .context(rc)
                    .build();

            try (X11Client data = X11Client.connect()) {
                EnableContextReply enableContextReply = data.send(enableContext);
                log.info(String.format("enableContextReply: %s", enableContextReply));
            }
        }

I still get a category == 4 reply though.

The rust client shows an issue that I'm not sure my client is made to handle. It looks like it has mutliple replies.

for reply in data_conn.record_enable_context(rc)? {
        let reply = reply?;
        if reply.client_swapped {
            println!("Byte swapped clients are unsupported");
        } else if reply.category == RECORD_FROM_SERVER {
            let mut remaining = &reply.data[..];
            let mut should_exit = false;
            while !remaining.is_empty() {
                let (r, exit) = print_reply_data(&reply.data)?;
                remaining = r;
                if exit {
                    should_exit = true;
                }
            }
            if should_exit {
                break;
            }
        } else if reply.category == START_OF_DATA {
            println!("Press Escape to exit...");
        } else {
            println!("Got a reply with an unsupported category: {:?}", reply);
        }
    }

The current client does not support multiple replies for one request and I'm not sure it makes sense to me yet. Maybe these are events though. I'm just not sure.

[moaxcp]

To test multiple replies I added this.

            try (X11Client data = X11Client.connect()) {
                EnableContextReply enableContextReply = data.send(enableContext);
                log.info(String.format("enableContextReply: %s", enableContextReply));

                data.getNextEvent();
                data.getNextEvent();
            }

Then I get an error

com.github.moaxcp.x11client.X11ClientException: reply not expected when reading events
    at app//com.github.moaxcp.x11client.XProtocolService.getNextEvent(XProtocolService.java:138)
    at app//com.github.moaxcp.x11client.X11Client.getNextEvent(X11Client.java:251)
    at app//com.github.moaxcp.x11client.RecordIT.test(RecordIT.java:54)
    at java.base@17.0.7/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base@17.0.7/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)

It seems like a special case for the record extension and I'm not sure how to change the api for it.

[moaxcp]

I added this PR that seems to work. https://github.com/moaxcp/x11-client/pull/27

[moaxcp]

I updated the PR to help in reading the data in the record replies. Reading x11 replies is going to be tricky because I also need to track the sequence numbers of the requests to figure out what reply is being read.

[moaxcp]

I updated the PR with everything I have. I don't think it will work for reading requests and replies but it does work for most examples I have seen online.

[moaxcp]

I merged the PR and published the changes in 0.15.0. It should show up in maven soon.