fix: further layer A (per-app) glitches

crates/headroom-ipc/src/lib.rs

@@ -13,9 +13,9 @@ mod proto;
 pub use codec::{Codec, DEFAULT_MAX_FRAME_BYTES, MIN_MAX_FRAME_BYTES};
 pub use error::{Error, ErrorCode, ProtoError};
 pub use proto::{
-    DaemonEvent, Event, HelloData, LayerALevel, MeterTick, Op, ProfileEvent, ProfileInfo, Request,
-    Response, ResponsePayload, Route, RouteList, RouteRule, RouteRuleMatch, RoutingEvent,
-    ServerFrame, SinkInfo, Sinks, Status, StreamRoute, Topic,
+    DaemonEvent, Event, HelloData, LayerALevel, LayerASnapshot, MeterTick, Op, ProfileEvent,
+    ProfileInfo, Request, Response, ResponsePayload, Route, RouteList, RouteRule, RouteRuleMatch,
+    RoutingEvent, ServerFrame, SinkInfo, Sinks, Status, StreamRoute, Topic,
 };
 
 /// Wire-protocol version. Bumped only on incompatible changes.

crates/headroom-ipc/src/proto.rs

@@ -184,6 +184,36 @@ pub enum Op {
         enabled: bool,
     },
 
+    /// List per-app (Layer A) controller state for managed streams.
+    #[serde(rename = "per-app.list")]
+    LayerAList,
+
+    /// Enable or disable Layer A for a specific app (persistent
+    /// overlay override).
+    #[serde(rename = "per-app.set")]
+    PerAppSet {
+        /// Application identifier (process_binary or application_name).
+        app: String,
+        /// `true` to manage the app, `false` to leave it alone.
+        enabled: bool,
+    },
+
+    /// Enable or disable the Layer A master switch (persistent overlay
+    /// override).
+    #[serde(rename = "per-app.master")]
+    PerAppMaster {
+        /// `true` to enable Layer A globally.
+        enabled: bool,
+    },
+
+    /// Clear a managed stream's deference state (user-ceiling /
+    /// strict-mode lock) so the controller resumes normal control.
+    #[serde(rename = "per-app.reset")]
+    LayerAReset {
+        /// PipeWire node id of the managed stream.
+        node_id: u32,
+    },
+
     /// Subscribe to one or more event topics on this connection.
     #[serde(rename = "subscribe")]
     Subscribe {
@@ -217,6 +247,10 @@ impl Op {
             Op::SettingSet { .. } => "setting.set",
             Op::SettingList => "setting.list",
             Op::BypassSet { .. } => "bypass.set",
+            Op::LayerAList => "per-app.list",
+            Op::PerAppSet { .. } => "per-app.set",
+            Op::PerAppMaster { .. } => "per-app.master",
+            Op::LayerAReset { .. } => "per-app.reset",
             Op::Subscribe { .. } => "subscribe",
             Op::Unsubscribe { .. } => "unsubscribe",
         }
@@ -356,10 +390,20 @@ pub struct Status {
     pub profile: String,
     /// Global bypass flag.
     pub bypass: bool,
+    /// Layer A master switch (per-app level control enabled globally).
+    /// Older clients that don't understand the field treat it as
+    /// absent (serde `default`).
+    #[serde(default)]
+    pub per_app: bool,
     /// Sink status snapshot.
     pub sinks: Sinks,
     /// Currently-tracked playback streams.
     pub streams: Vec<StreamRoute>,
+    /// Per-app (Layer A) controller state for managed streams.
+    /// Empty when Layer A isn't managing anything. Older clients that
+    /// don't understand the field treat it as absent (serde `default`).
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub layer_a: Vec<LayerASnapshot>,
     /// Non-fatal warnings the daemon wants operators to see —
     /// typically from profile loading (TOML parse errors on a single
     /// file, the active profile name pointing at something not on
@@ -411,6 +455,29 @@ pub struct StreamRoute {
     pub route: Route,
 }
 
+/// Per-app (Layer A) controller state for one managed stream.
+/// Surfaced on `status` and `per-app.list`.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct LayerASnapshot {
+    /// Source PipeWire node id.
+    pub node_id: u32,
+    /// Application identifier.
+    pub app: String,
+    /// True while a tap + controller is actively managing the stream.
+    pub managed: bool,
+    /// Last linear volume the controller wrote (1.0 = unity).
+    pub volume_lin: f32,
+    /// Smoothed gain reduction the controller currently asserts, in dB
+    /// (`>= 0`; `0` means no cut).
+    pub reduction_db: f32,
+    /// User-set ceiling (linear) when ceiling-mode deference is active.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub user_ceiling_lin: Option<f32>,
+    /// True when strict-mode deference has locked the controller until
+    /// an explicit `per-app.reset`.
+    pub deferred: bool,
+}
+
 /// Summary entry returned by `profile.list`.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct ProfileInfo {