Initial commit

codec/src/registry.rs

@@ -0,0 +1,67 @@
+use crate::{CodecError, DataValue, decode, encode};
+use std::collections::BTreeMap;
+use type_map::{TypeMap, Version};
+
+#[derive(Clone, Debug)]
+pub struct Registry {
+    versions: BTreeMap<Version, TypeMap>,
+}
+
+impl Registry {
+    pub fn new() -> Self {
+        Self {
+            versions: BTreeMap::new(),
+        }
+    }
+
+    pub fn register(&mut self, typemap: TypeMap) {
+        self.versions.insert(typemap.version.clone(), typemap);
+    }
+
+    pub fn get(&self, version: Version) -> Option<&TypeMap> {
+        self.versions.get(&version)
+    }
+
+    pub fn negotiate(&self, client_versions: &[Version]) -> Option<Version> {
+        client_versions
+            .iter()
+            .filter(|v| self.versions.contains_key(v))
+            .max()
+            .cloned()
+    }
+
+    pub fn latest(&self) -> Option<&TypeMap> {
+        self.versions.last_key_value().map(|(_, v)| v)
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct VersionedCodec {
+    registry: Registry,
+}
+
+impl VersionedCodec {
+    pub fn new(registry: Registry) -> Self {
+        Self { registry }
+    }
+
+    pub fn encode(&self, value: &DataValue, version: Version) -> Result<Vec<u8>, CodecError> {
+        let typemap = self
+            .registry
+            .get(version)
+            .ok_or(CodecError::UnknownVersion)?;
+        encode(value, typemap)
+    }
+
+    pub fn decode(&self, bytes: &[u8], version: Version) -> Result<DataValue, CodecError> {
+        let typemap = self
+            .registry
+            .get(version)
+            .ok_or(CodecError::UnknownVersion)?;
+        decode(bytes, typemap)
+    }
+
+    pub fn negotiate(&self, client_versions: &[Version]) -> Option<Version> {
+        self.registry.negotiate(client_versions)
+    }
+}