CommunicationStream

Abort CanConnect ClearAbort Connect Disconnect ReadWithCallback WriteWithCallback

Attributes

Aborted Connected

Fields

Define Class CommunicationStream;
    abstract;
    inherits from HardwareStream;
    inherits interface from Connectable;

    overrides CanConnect;
        // returns true if state is other than kConnected
        
    overrides Connect;
        // at this level just sets the state of the stream to kConnected
    overrides Connected;
        // return whether state is kConnected
        
    overrides Disconnect;
        // at this level just sets the state of the stream to kDisconnected

    overrides Abort;
        // at this level, sets the state of the stream to kAborted.  If have
        // CommunicationStream_ target, Abort is also called on it.     
    overrides Aborted;
        // if have CommunicationStream_ target, returns Aborted for the target.  
        // Otherwise returns whether state is kAborted.
    overrides ClearAbort;
        // at this level, sets the state of the stream back to kDisconnected.  If have
        // CommunicationStream_ target, ClearAbort is also called on it.

    // Serial streams are commonly data-link escaped, so per-character callbacks
    // are useful to avoid double buffering
    // The callback is called each byte, and returns false when there is no more data
    // Override these to allow subclass to call the callback function directly for speed
    operation WriteWithCallback(callback: EachByteFunction; params: Pointer);
        // while the callback function returns true, write the byte to self the callback returns
        // if the instance has a target then just delegate to it instead
    operation ReadWithCallback(callback: EachByteFunction; params: Pointer): Unsigned;
        // continue to read from self until callback returns false
        // if the instance has a target then just delegate to it instead
end class;