refactor(server): make common operation result handler

Author: mbroadst

lib/core/sdam/server.js

@@ -279,20 +279,7 @@ class Server extends EventEmitter {
 
     this.s.pool.withConnection((err, conn, cb) => {
       if (err) return cb(err);
-
-      conn.command(ns, cmd, options, (err, result) => {
-        if (err) {
-          if (options.session && err instanceof MongoNetworkError) {
-            options.session.serverSession.isDirty = true;
-          }
-
-          if (isSDAMUnrecoverableError(err)) {
-            this.emit('error', err);
-          }
-        }
-
-        cb(err, result);
-      });
+      conn.command(ns, cmd, options, makeOperationHandler(this, options, cb));
     }, callback);
   }
 
@@ -312,20 +299,7 @@ class Server extends EventEmitter {
 
     this.s.pool.withConnection((err, conn, cb) => {
       if (err) return cb(err);
-
-      conn.query(ns, cmd, cursorState, options, (err, result) => {
-        if (err) {
-          if (options.session && err instanceof MongoNetworkError) {
-            options.session.serverSession.isDirty = true;
-          }
-
-          if (isSDAMUnrecoverableError(err)) {
-            this.emit('error', err);
-          }
-        }
-
-        cb(err, result);
-      });
+      conn.query(ns, cmd, cursorState, options, makeOperationHandler(this, options, cb));
     }, callback);
   }
 
@@ -345,20 +319,7 @@ class Server extends EventEmitter {
 
     this.s.pool.withConnection((err, conn, cb) => {
       if (err) return cb(err);
-
-      conn.getMore(ns, cursorState, batchSize, options, (err, result) => {
-        if (err) {
-          if (options.session && err instanceof MongoNetworkError) {
-            options.session.serverSession.isDirty = true;
-          }
-
-          if (isSDAMUnrecoverableError(err)) {
-            this.emit('error', err);
-          }
-        }
-
-        cb(err, result);
-      });
+      conn.getMore(ns, cursorState, batchSize, options, makeOperationHandler(this, options, cb));
     }, callback);
   }
 
@@ -380,14 +341,7 @@ class Server extends EventEmitter {
 
     this.s.pool.withConnection((err, conn, cb) => {
       if (err) return cb(err);
-
-      conn.killCursors(ns, cursorState, (err, result) => {
-        if (err && isSDAMUnrecoverableError(err)) {
-          this.emit('error', err);
-        }
-
-        cb(err, result);
-      });
+      conn.killCursors(ns, cursorState, makeOperationHandler(this, null, cb));
     }, callback);
   }
 
@@ -482,21 +436,26 @@ function executeWriteOperation(args, options, callback) {
 
   server.s.pool.withConnection((err, conn, cb) => {
     if (err) return cb(err);
+    conn[op](ns, ops, options, makeOperationHandler(server, options, cb));
+  }, callback);
+}
 
-    conn[op](ns, ops, options, (err, result) => {
-      if (err) {
-        if (options.session && err instanceof MongoNetworkError) {
+function makeOperationHandler(server, options, callback) {
+  return function handleOperationResult(err, result) {
+    if (err) {
+      if (err instanceof MongoNetworkError) {
+        if (options && options.session) {
           options.session.serverSession.isDirty = true;
         }
+      }
 
-        if (isSDAMUnrecoverableError(err)) {
-          server.emit('error', err);
-        }
+      if (isSDAMUnrecoverableError(err)) {
+        server.emit('error', err);
       }
+    }
 
-      cb(err, result);
-    });
-  }, callback);
+    callback(err, result);
+  };
 }
 
 module.exports = {