XIChangeProperty missing a data parameter

[pascal-de-ladurantaye]

Hi, thanks for this python binding. As far as I've seen, it's a pretty good alternative to xpyb.

However, I think there's a problem with the binding generator for the XIChangeProperty function.

Here is the generated function:

def XIChangeProperty(self, deviceid, mode, format, property, type, num_items, is_checked=False):
        buf = six.BytesIO()
        buf.write(struct.pack("=xx2xHBBIII", deviceid, mode, format, property, type, num_items))
        return self.send_request(57, buf, is_checked=is_checked)

The problem is that there is no way for us to specify the new data for the property since there is no argument for it.

Here is the command line to disable the mouse (id=8) through a terminal: xinput set-prop 8 --type=int --format=8 136 0

(the 0 at the end is the new data)

This works perfectly, however we would like to have an all python solution through xcffib.

Do you think there's a way to do this through xcffib or do we need to use an os.system call instead?

[pascal-de-ladurantaye]

To clarify, here is the function call we are trying to make (equivalent to the command line call):

conn.xinput.XIChangeProperty(deviceid=8, mode=xcffib.xproto.PropMode.Replace, format=8, property=136, type=xcffib.xproto.Atom.INTEGER, num_items=1, data=0)

[tych0]

There isn't a way right now, mostly because I didn't know what switch meant when I wrote it:

https://github.com/tych0/xcffib/blob/master/generator/Data/XCB/Python/Parse.hs#L293

However, looking at the xml definition for XIChangeProperty, it's pretty clear what it means, so it should be easy enough to implement. Unfortunately, I'm not sure I'll have time for the next few weeks, but I'd be happy to help if you're interested in taking a crack at it.

[pascal-de-ladurantaye]

Would you be kind enough to tell me where I could find the xml definition for XIChangeProperty?

Thank you

[tych0]

On Wed, Jun 17, 2015 at 10:23:51AM -0700, Pascal de Ladurantaye wrote:

Would you be kind enough to tell me where I could find the xml definition for XIChangeProperty?

Sure, it is installed on most systems at /usr/share/xcb/xinput.xml, but the upstream repo is:

http://cgit.freedesktop.org/xcb/proto/

Tycho

Thank you

---

Reply to this email directly or view it on GitHub: https://github.com/tych0/xcffib/issues/49#issuecomment-112883558

[pascal-de-ladurantaye]

For reference purpose:

<request name="XIChangeProperty" opcode="57">
    <field type="DeviceId" name="deviceid" altenum="Device" />
    <field type="CARD8" name="mode" enum="PropMode" />
    <field type="CARD8" name="format" enum="PropertyFormat" />
    <field type="ATOM" name="property" />
    <field type="ATOM" name="type" />
    <field type="CARD32" name="num_items" />
    <switch name="items">
        <fieldref>format</fieldref>
        <!-- <bitcase> is not correct, this would need <cases>s.
                 It works in that case, because PropertyFormat items can be
                 distinguished exactly as their values don't have equal bits.
            -->
        <bitcase>
            <enumref ref="PropertyFormat">8Bits</enumref>
            <list type="CARD8" name="data8">
                <fieldref>num_items</fieldref>
            </list>
        </bitcase>
        <bitcase>
            <enumref ref="PropertyFormat">16Bits</enumref>
            <list type="CARD16" name="data16">
                <fieldref>num_items</fieldref>
            </list>
        </bitcase>
        <bitcase>
            <enumref ref="PropertyFormat">32Bits</enumref>
            <list type="CARD32" name="data32">
                <fieldref>num_items</fieldref>
            </list>
        </bitcase>
    </switch>
</request>

[pascal-de-ladurantaye]

After a look in the code, it seems I don't have the necessary skills to fix this (I've never written anything in Haskell). We have decided to go along with the command line option until this is fixed.

Hopefully, someone will eventually have time to fix this. All the necessary information is documented in this issue.

[flacjacket]

Haskell beginner incoming! So I took a crack at this:

@pascal-de-ladurantaye can you see if #50 does what you need?

@tych0 if you could take a look at it to see if I'm doing anything particularly bad with Haskell?

[padele]

@flacjacket I've built your branch but i was still unable to deactivate my mouse using either:

conn.xinput.XIChangeProperty(deviceid=deviceID, mode=xcffib.xproto.PropMode.Replace, format=8, property=136, type=xcffib.xproto.Atom.INTEGER, num_items=1, items=[0])

or

conn.xinput.XIChangeProperty(deviceid=deviceID, mode=xcffib.xproto.PropMode.Replace, format=8, property=136, type=xcffib.xproto.Atom.INTEGER, num_items=1, items=[False])

where deviceID is 8 as per this information: 8 Name is : PixArt HP USB Optical Mouse Type is : SlaveKeyboard Use is : ExtensionPointer Device is: ENABLED

were you able to deactivate or change any property of a device? Thanks for trying to help and fix this.

[pascal-de-ladurantaye]

Just realised i was logged in with the wrong account

[flacjacket]

I'm not sure exactly how to check if it works, or what I'd expect to happen.

You should try with format=xcffib.xinput.PropertyFormat._8Bits. The if-else block should look like:

if self.format == PropertyFormat._8Bits:
    unpacker.pad("B")
    self.items = xcffib.List(unpacker, "B", self.num_items)
elif self.format == PropertyFormat._16Bits:
    unpacker.pad("H")
    self.items = xcffib.List(unpacker, "H", self.num_items)
elif self.format == PropertyFormat._32Bits:
    unpacker.pad("I")
    self.items = xcffib.List(unpacker, "I", self.num_items)

it should probably have an else that raises an exception...

[pascal-de-ladurantaye]

PropertyFormat._8Bits == 8

this is the generated function:

def XIChangeProperty(self, deviceid, mode, format, property, type, num_items, items, is_checked=False):
        buf = six.BytesIO()
        buf.write(struct.pack("=xx2xHBBIII", deviceid, mode, format, property, type, num_items))
        if format == PropertyFormat._8Bits:
            buf.write(xcffib.pack_list(items, "B"))
        elif format == PropertyFormat._16Bits:
            buf.write(xcffib.pack_list(items, "H"))
        elif format == PropertyFormat._32Bits:
            buf.write(xcffib.pack_list(items, "I"))
        return self.send_request(57, buf, is_checked=is_checked)

[flacjacket]

Oh, yeah, that looks right (at least it was what I was thinking would work). I can see if I can get it working. What is the expected behavior when running that?

[pascal-de-ladurantaye]

you could try it yourself with the command line version:

xinput set-prop --type=int --format=8 136 0

property 136 is ENABLED 0 is for False

The expected behavior is, in my case, a total removal of the mouse pointer in the window manager. That's what i get with the command line interface.

[flacjacket]

So looking at the xcb generated C code, I noticed we aren't always packing things correctly, including this, see #51. I can try to address that and try again.

[tych0]

I believe this is also fixed with the merging of #50. Please re-open if it is not.