Add generic source wrapper for mixed mergers

diff --git a/src/source.rs b/src/source.rs
index e75f5c87b20065b3b32934b1e951977c1bab94a1..4672f9c945ca786d26f48e8b3cd9e57b49010302 100644 (file)
--- a/src/source.rs
+++ b/src/source.rs
@@ -117,6 +117,47 @@ impl<I: Iter> Iter for RangeIter<I> {
     }
 }
 
+struct WrapSource<'a, S: Source<'a> + Ranges<'a>>(S, PhantomData<&'a S>);
+impl<'a, S: Source<'a> + Ranges<'a>> Source<'a> for WrapSource<'a, S> {
+    type It = Box<dyn Iter + 'a>;
+    fn iter(&'a self) -> Self::It {
+        Box::new(self.0.iter())
+    }
+}
+impl<'a, S: Source<'a> + Ranges<'a>> Ranges<'a> for WrapSource<'a, S> {
+    type Get = Box<dyn Iter + 'a>;
+    type Prefix = Box<dyn Iter + 'a>;
+    type Range = Box<dyn Iter + 'a>;
+
+    fn get(&'a self, key: &[u8]) -> Self::Get {
+        Box::new(self.0.get(key))
+    }
+    fn get_prefix(&'a self, prefix: &[u8]) -> Self::Prefix {
+        Box::new(self.0.get_prefix(prefix))
+    }
+    fn get_range(&'a self, start: &[u8], end: &[u8]) -> Self::Range {
+        Box::new(self.0.get_range(start, end))
+    }
+}
+
+struct GenericSource<'a>(
+    Box<dyn Source<'a, It = Box<dyn Iter + 'a>> + 'a>,
+    PhantomData<&'a u8>,
+);
+impl<'a> GenericSource<'a> {
+    fn from<S: Source<'a> + Ranges<'a> + 'a>(source: S) -> Self {
+        GenericSource(Box::new(WrapSource(source, PhantomData)), PhantomData)
+    }
+}
+
+impl<'a> Source<'a> for GenericSource<'a> {
+    type It = Box<dyn Iter + 'a>;
+    fn iter(&'a self) -> Self::It {
+        self.0.iter()
+    }
+}
+impl<'a> DefaultRanges for GenericSource<'a> {}
+
 #[cfg(test)]
 pub mod test {
     use super::{DefaultRanges, Entry, Iter, Ranges, Source};