introduce frame count base strategy

Author: MarinPostma

libsql-wal/src/swap_strategy/frame_count.rs

@@ -0,0 +1,22 @@
+use super::SwapStrategy;
+
+/// A swap strategy that swaps if the count of frames in the wal exceed some threshold
+pub struct FrameCountSwapStrategy {
+    max_frames_in_wal: usize,
+}
+
+impl FrameCountSwapStrategy {
+    pub fn new(max_frames_in_wal: usize) -> Self {
+        Self { max_frames_in_wal }
+    }
+}
+
+impl SwapStrategy for FrameCountSwapStrategy {
+    #[inline(always)]
+    fn should_swap(&self, frames_in_wal: usize) -> bool {
+        frames_in_wal >= self.max_frames_in_wal
+    }
+
+    #[inline(always)]
+    fn swapped(&self) { }
+}