Implement layer rules: opacity and block-out-from

1 files changed, 69 insertions, 0 deletions

diff --git a/src/layer/mod.rs b/src/layer/mod.rs
new file mode 100644
index 00000000..4d4d7819
--- /dev/null
+++ b/src/layer/mod.rs
@@ -0,0 +1,69 @@
+use niri_config::layer_rule::{LayerRule, Match};
+use niri_config::BlockOutFrom;
+use smithay::desktop::LayerSurface;
+
+pub mod mapped;
+pub use mapped::MappedLayer;
+
+/// Rules fully resolved for a layer-shell surface.
+#[derive(Debug, PartialEq)]
+pub struct ResolvedLayerRules {
+    /// Extra opacity to draw this window with.
+    pub opacity: Option<f32>,
+    /// Whether to block out this window from certain render targets.
+    pub block_out_from: Option<BlockOutFrom>,
+}
+
+impl ResolvedLayerRules {
+    pub const fn empty() -> Self {
+        Self {
+            opacity: None,
+            block_out_from: None,
+        }
+    }
+
+    pub fn compute(rules: &[LayerRule], surface: &LayerSurface, is_at_startup: bool) -> Self {
+        let _span = tracy_client::span!("ResolvedLayerRules::compute");
+
+        let mut resolved = ResolvedLayerRules::empty();
+
+        for rule in rules {
+            let matches = |m: &Match| {
+                if let Some(at_startup) = m.at_startup {
+                    if at_startup != is_at_startup {
+                        return false;
+                    }
+                }
+
+                surface_matches(surface, m)
+            };
+
+            if !(rule.matches.is_empty() || rule.matches.iter().any(matches)) {
+                continue;
+            }
+
+            if rule.excludes.iter().any(matches) {
+                continue;
+            }
+
+            if let Some(x) = rule.opacity {
+                resolved.opacity = Some(x);
+            }
+            if let Some(x) = rule.block_out_from {
+                resolved.block_out_from = Some(x);
+            }
+        }
+
+        resolved
+    }
+}
+
+fn surface_matches(surface: &LayerSurface, m: &Match) -> bool {
+    if let Some(namespace_re) = &m.namespace {
+        if !namespace_re.0.is_match(surface.namespace()) {
+            return false;
+        }
+    }
+
+    true
+}