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use crate::error::{Error, Result};
use crate::link::reconcile::StoredTransform;
use crate::protocol::command::transform_payload;
use crate::protocol::opcode::{Q_TRANSFORMS, TRANSFORM_MAX_ENTRIES};
use crate::protocol::{FrameType, Resp, parse_resp};
use crate::types::{Axis, LockTarget, Transform, Transforms};
use super::Device;
const SET: u8 = 1;
const REMOVE: u8 = 0;
impl Device {
/// `TRANSFORM` (§3.15): add or overwrite one field transform.
///
/// Moves a field the clone's descriptor declares into another, by swapping two axes or remapping
/// a source onto a destination. To weigh a field, or reverse it, use [`scale`](Device::scale),
/// which runs first and passes the transform what it kept. Every emitted report stays one the real
/// device could produce, so no [`allow_imperfect_clones`](Device::allow_imperfect_clones) needed.
///
/// Keyed by `(source, dest)`; setting an existing key overwrites its op in place, keeping its
/// position. Position is state: entries apply in installation order, and two writing one field do
/// not commute.
///
/// Transforms are session state, re-asserted after a reconnect, a device-chip restart or any
/// session release the box counts, and kept by the keepalive like a [`lock`](Device::lock). The
/// box clears them on control-PC silence, [`reset`](Device::reset), a device detach, a link drop
/// or a re-clone.
///
/// Fire-and-forget; [`query_transforms`](Device::query_transforms) confirms what the box holds,
/// and omits an entry naming a field the clone does not declare.
///
/// ```no_run
/// # use medius::{Axis, Device, Result, Transform};
/// # fn main() -> Result<()> {
/// let device = Device::find()?;
/// device.transform(&Transform::swap(Axis::X, Axis::Y))?; // X and Y exchanged
/// device.transform(&Transform::remap(Axis::Wheel, Axis::Y))?; // wheel moves Y
/// # Ok(()) }
/// ```
pub fn transform(&self, t: &Transform) -> Result<()> {
validate_transform(t)?;
// One guard over the capacity read and the send: it is not reentrant, and releasing it
// between them lets a concurrent set take the last slot.
let _serial = self.link.reassert_guard();
{
let d = self.link.desired().lock();
if !d.holds_transform(to_stored(t).key())
&& d.transform_count() >= TRANSFORM_MAX_ENTRIES
{
return Err(Error::TransformTableFull {
limit: TRANSFORM_MAX_ENTRIES,
});
}
}
self.transform_send_locked(t, SET)
}
pub(crate) fn transform_send(&self, t: &Transform, state: u8) -> Result<()> {
let _serial = self.link.reassert_guard();
self.transform_send_locked(t, state)
}
// Records the entry (or its removal) for replay before the write; rolled back if the frame never
// went out. The caller holds the re-assert guard.
fn transform_send_locked(&self, t: &Transform, state: u8) -> Result<()> {
let stored = to_stored(t);
let undo = if state == SET {
self.link.desired().lock().apply_transform(stored)
} else {
self.link.desired().lock().remove_transform(stored.key())
};
let (sclass, sid) = t.source.class_id();
let (dclass, did) = t.dest.class_id();
let sent = self.link.send(
FrameType::Transform,
&transform_payload(t.op.as_u8(), sclass, sid, dclass, did, state),
);
if sent.is_err() {
self.link.desired().lock().restore_transform(undo);
}
sent
}
/// `TRANSFORM` remove (§3.15): drop the transform with this entry's `(source, dest)`; the op is
/// ignored. A no-op on the box if no such entry is held.
pub fn untransform(&self, t: &Transform) -> Result<()> {
self.transform_send(t, REMOVE)
}
/// `TRANSFORM` clear (§3.15): drop the whole table (the `class 0xFF, id 0xFFFF, state 0`
/// blanket).
pub fn clear_transforms(&self) -> Result<()> {
// As `clear_rewrite`: the snapshot restores the entries if the send fails.
let _serial = self.link.reassert_guard();
let held = {
let mut d = self.link.desired().lock();
let held = d.held_transforms();
d.clear_transforms();
held
};
// Clear sentinel: op ignored, both classes 0xFF, both ids 0xFFFF, state 0.
let sent = self.link.send(
FrameType::Transform,
&transform_payload(0, 0xFF, 0xFFFF, 0xFF, 0xFFFF, REMOVE),
);
if sent.is_err() {
let mut d = self.link.desired().lock();
for t in held {
d.apply_transform(t);
}
}
sent
}
/// Exchange two axes: [`transform`](Device::transform) of [`Transform::swap`].
pub fn transform_swap(&self, a: Axis, b: Axis) -> Result<()> {
self.transform(&Transform::swap(a, b))
}
/// Move a source field into a destination: [`transform`](Device::transform) of
/// [`Transform::remap`].
pub fn transform_remap(
&self,
source: impl Into<LockTarget>,
dest: impl Into<LockTarget>,
) -> Result<()> {
self.transform(&Transform::remap(source, dest))
}
/// `QUERY(TRANSFORMS)` → [`Transforms`] (§4.18): the table as the entries that rebuild it, in
/// application order, and the table-full flag.
pub fn query_transforms(&self) -> Result<Transforms> {
let payload = self.link.query(Q_TRANSFORMS)?;
match parse_resp(&payload) {
Some(Resp::Transforms(t)) => Ok(t),
_ => Err(Error::NoReply),
}
}
}
pub(crate) fn to_stored(t: &Transform) -> StoredTransform {
let (sclass, sid) = t.source.class_id();
let (dclass, did) = t.dest.class_id();
StoredTransform {
op: t.op.as_u8(),
sclass,
sid,
dclass,
did,
}
}
// Mirrors the box's `transform_tab_set`: an op a class pair cannot take, including one field as both
// ends. Which fields the clone declares is for the box to check.
pub(crate) fn validate_transform(t: &Transform) -> Result<()> {
if !t.op.admits(t.source, t.dest) {
return Err(Error::TransformOpFields {
op: t.op,
src: t.source,
dst: t.dest,
});
}
Ok(())
}