refactor: add all wire protocol methods to the connection class

Author: mbroadst

lib/cmap/connection.js

@@ -19,10 +19,6 @@ class Connection extends EventEmitter {
   constructor(stream, options) {
     super(options);
 
-    if (typeof options.generation === 'undefined') {
-      throw new TypeError('connection requires a pool generation');
-    }
-
     this.id = options.id;
     this.address = streamIdentifier(stream);
     this.bson = options.bson;
@@ -61,7 +57,7 @@ class Connection extends EventEmitter {
   }
 
   get generation() {
-    return this[kGeneration];
+    return this[kGeneration] || 0;
   }
 
   get idleTime() {
@@ -102,19 +98,47 @@ class Connection extends EventEmitter {
     });
   }
 
+  // Wire protocol methods
   command(ns, cmd, options, callback) {
-    // NOTE: The wire protocol methods will eventually be migrated to this class, but for now
-    //       we need to pretend we _are_ a server.
-    const server = {
-      description: this.description,
-      s: {
-        bson: this.bson,
-        pool: { write: write.bind(this) }
-      }
-    };
+    wp.command(makeServerTrampoline(this), ns, cmd, options, callback);
+  }
 
-    wp.command(server, ns, cmd, options, callback);
+  query(ns, cmd, cursorState, options, callback) {
+    wp.query(makeServerTrampoline(this), ns, cmd, cursorState, options, callback);
   }
+
+  getMore(ns, cursorState, batchSize, options, callback) {
+    wp.getMore(makeServerTrampoline(this), ns, cursorState, batchSize, options, callback);
+  }
+
+  killCursors(ns, cursorState, callback) {
+    wp.killCursors(makeServerTrampoline(this), ns, cursorState, callback);
+  }
+
+  insert(ns, ops, options, callback) {
+    wp.insert(makeServerTrampoline(this), ns, ops, options, callback);
+  }
+
+  update(ns, ops, options, callback) {
+    wp.update(makeServerTrampoline(this), ns, ops, options, callback);
+  }
+
+  remove(ns, ops, options, callback) {
+    wp.remove(makeServerTrampoline(this), ns, ops, options, callback);
+  }
+}
+
+/// This lets us emulate a legacy `Server` instance so we can work with the existing wire
+/// protocol methods. Eventually, the operation executor will return a `Connection` to execute
+/// against.
+function makeServerTrampoline(server) {
+  return {
+    description: server.description,
+    s: {
+      bson: server.bson,
+      pool: { write: write.bind(server) }
+    }
+  };
 }
 
 function messageHandler(conn) {