refactor: Extract a trait to make read_*_range fns more similar

src/storage/memdb.rs

@@ -402,7 +402,7 @@ impl MemDB {
         };
 
         let data = data.lock().unwrap();
-        let buff = match data.i64_series.get(&series_id) {
+        let buff = match FromSeries::from_series(&data, &series_id) {
             Some(b) => b,
             None => return Err(StorageError{description: format!("series {} not found", series_id)}),
         };
@@ -425,7 +425,7 @@ impl MemDB {
         };
 
         let data = data.lock().unwrap();
-        let buff = match data.f64_series.get(&series_id) {
+        let buff = match FromSeries::from_series(&data, &series_id) {
             Some(b) => b,
             None => return Err(StorageError{description: format!("series {} not found", series_id)}),
         };
@@ -435,6 +435,22 @@ impl MemDB {
     }
 }
 
+trait FromSeries: Clone {
+    fn from_series<'a>(data: &'a SeriesData, series_id: &u64) -> Option<&'a SeriesRingBuffer<Self>>;
+}
+
+impl FromSeries for i64 {
+    fn from_series<'a>(data: &'a SeriesData, series_id: &u64) -> Option<&'a SeriesRingBuffer<i64>> {
+        data.i64_series.get(series_id)
+    }
+}
+
+impl FromSeries for f64 {
+    fn from_series<'a>(data: &'a SeriesData, series_id: &u64) -> Option<&'a SeriesRingBuffer<f64>> {
+        data.f64_series.get(series_id)
+    }
+}
+
 struct PointsIterator<T: Clone> {
     values: Option<Vec<ReadPoint<T>>>,
     batch_size: usize,