//! Circuit padding

//!

// TODO(DEDUP): we should eventually move client::circuit::padding here

#[cfg(feature = "circ-padding")]

use {crate::circuit::cell_sender::CircuitCellSender, crate::client::circuit::padding};

/// A possible way to handle a request to send padding.

#[derive(Copy, Clone, Debug)]

pub(crate) enum CircPaddingDisposition {

    /// Enqueue the padding normally.

    QueuePaddingNormally,

    /// Enqueue the padding, and allow one cell of data on our outbound queue

    /// to bypass the current block.

    QueuePaddingAndBypass,

    /// Do not take any actual padding action:

    /// existing data on our outbound queue will count as padding.

    TreatQueuedCellAsPadding,

}

/// Determine how exactly to handle a request to handle padding.

///

/// This is fairly complicated; see the maybenot documentation for more information.

///

// TODO(relay): relays use the same logic as clients here. Is that okay,

// or do they need to handle SendPadding differently??

#[cfg(feature = "circ-padding")]

    use CircPaddingDisposition::*;

    use padding::Bypass::*;

    use padding::Replace::*;

    // If true, and we are trying to send Replaceable padding,

    // we should let any data in the queue count as the queued padding instead,

    // if it is queued for our target hop (or any subsequent hop).

    //

    // TODO circpad: In addition to letting currently-queued data count as padding,

    // maybenot also permits us to send currently pending data from our streams

    // (or from our next hop, if we're a relay).  We don't have that implemented yet.

    //

    // TODO circpad: This will usually be false, since we try not to queue data

    // when there isn't space to write it.  If we someday add internal per-circuit

    // Buffers to chan_sender, this test is more likely to trigger.

            match (

            ) {

                (Replaceable, DoNotBypass) => {

                    } else {

                    }

                }

                (Replaceable, BypassBlocking) => {

                    } else {

                    }

                }

            }

        }

            Replaceable => {

                } else {

                }

            }

        },

    }