Add a cache for unchanged layouts

Co-Authored-By: Laurenz <laurmaedje@gmail.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/cache.rs b/src/cache.rs
new file mode 100644
index 00000000..4cf97ba6
--- /dev/null
+++ b/src/cache.rs
@@ -0,0 +1,34 @@
+//! Caching for incremental compilation.
+
+use std::collections::HashMap;
+
+use crate::layout::{Frame, Regions};
+
+/// A cache for incremental compilation.
+#[derive(Default, Debug, Clone)]
+pub struct Cache {
+    /// A map that holds the layouted nodes from past compilations.
+    pub frames: HashMap<u64, FramesEntry>,
+}
+
+impl Cache {
+    /// Create a new, empty cache.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Clear the cache.
+    pub fn clear(&mut self) {
+        self.frames.clear();
+    }
+}
+
+/// Frames from past compilations and checks for their validity in future
+/// compilations.
+#[derive(Debug, Clone)]
+pub struct FramesEntry {
+    /// The regions in which these frames are valid.
+    pub regions: Regions,
+    /// Cached frames for a node.
+    pub frames: Vec<Frame>,
+}