Channels

Portal Channels

Portal channels represent a bus (and permission to talk to it) on the computer. Portal channels are opened before the program starts (based on the daku custom section). Going in order of the portals, will allocate channels in ascending order starting from 1. Each portal allocates one channel. They can not and will not be closed until the WASM module exits.

Channel 0

Channel 0 is a special channel that allows you to send arbitrary bytes (Buffer) to the host from the guest. This is what a custom plugin API would use. Sending commands on a channel opened to portal 0 may also open "Device Channels". The buffer sent is re-written with received bytes, and the Command.channel field set to number of device channels opened.

Device Channels

Device channels represent something (physically or virtually) connected to a bus. Device channels are opened by sending commands to channels (this command is not allowed to fail if constructed properly, even if the data is stale - so you may open a channel to a disconnected device). They are allocated after the portal channels. When the device channel is closed it's number goes into a garbage list. The last ID is popped off the garbage list when opening a new device channel (if it exists).