Cleanup

node_modules/mongodb/lib/operations/find.js

@@ -3,7 +3,9 @@
 const OperationBase = require('./operation').OperationBase;
 const Aspect = require('./operation').Aspect;
 const defineAspects = require('./operation').defineAspects;
-const resolveReadPreference = require('../utils').resolveReadPreference;
+const ReadPreference = require('../core').ReadPreference;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+const MongoError = require('../core/error').MongoError;
 
 class FindOperation extends OperationBase {
   constructor(collection, ns, command, options) {
@@ -11,16 +13,28 @@ class FindOperation extends OperationBase {
 
     this.ns = ns;
     this.cmd = command;
-    this.readPreference = resolveReadPreference(collection, this.options);
+    this.readPreference = ReadPreference.resolve(collection, this.options);
   }
 
   execute(server, callback) {
     // copied from `CommandOperationV2`, to be subclassed in the future
     this.server = server;
 
-    const cursorState = this.cursorState || {};
+    // updates readPreference if setReadPreference was called on the cursor
+    this.readPreference = ReadPreference.resolve(this, this.options);
+
+    if (typeof this.cmd.allowDiskUse !== 'undefined' && maxWireVersion(server) < 4) {
+      callback(new MongoError('The `allowDiskUse` option is not supported on MongoDB < 3.2'));
+      return;
+    }
+
+    if (this.explain) {
+      // We need to manually ensure explain is in the options.
+      this.options.explain = this.explain.verbosity;
+    }
 
     // TOOD: use `MongoDBNamespace` through and through
+    const cursorState = this.cursorState || {};
     server.query(this.ns.toString(), this.cmd, cursorState, this.options, callback);
   }
 }
@@ -28,7 +42,8 @@ class FindOperation extends OperationBase {
 defineAspects(FindOperation, [
   Aspect.READ_OPERATION,
   Aspect.RETRYABLE,
-  Aspect.EXECUTE_WITH_SELECTION
+  Aspect.EXECUTE_WITH_SELECTION,
+  Aspect.EXPLAINABLE
 ]);
 
 module.exports = FindOperation;