JS implementation for Results from RPC

lib/lists.js

@@ -1,10 +1,11 @@
 'use strict';
 
 let rpc = require('./rpc');
+let util = require('./util');
 
 let idKey = Symbol();
 let realmKey = Symbol();
-let prototype = {};
+let prototype = util.createListPrototype(getterForLength, getterForIndex, setterForIndex);
 
 exports.create = create;
 
@@ -30,7 +31,7 @@ exports.create = create;
 
             // Since this method might have grown the list, ensure index properties are defined.
             if (growthMethod) {
-                defineIndexProperties(this.length);
+                prototype[util.growListPrototypeKey](this.length);
             }
 
             return result;
@@ -38,12 +39,6 @@ exports.create = create;
     });
 });
 
-Object.defineProperty(prototype, 'length', {
-    get() {
-        return rpc.getListSize(this[realmKey], this[idKey]);
-    }
-});
-
 function create(realmId, info) {
     let list = Object.create(prototype);
     let size = info.size;
@@ -51,27 +46,13 @@ function create(realmId, info) {
     list[realmKey] = realmId;
     list[idKey] = info.id;
 
-    defineIndexProperties(size);
+    list[util.growListPrototypeKey](size);
+
+    return list;
 }
 
-let maxSize = 0;
-function defineIndexProperties(size) {
-    if (size < maxSize) {
-        return;
-    }
-
-    let props = {};
-    for (let i = maxSize; i <= size; i++) {
-        props[i] = {
-            get: getterForIndex(i),
-            set: setterForIndex(i),
-        };
-    }
-
-    // TODO: Use ES6 Proxy once it's supported on Chrome!
-    Object.defineProperties(prototype, props);
-
-    maxSize = size + 1;
+function getterForLength() {
+    return rpc.getListSize(this[realmKey], this[idKey]);
 }
 
 function getterForIndex(index) {

lib/realm.js

@@ -2,6 +2,7 @@
 
 let lists = require('./lists');
 let objects = require('./objects');
+let results = require('./results');
 let rpc = require('./rpc');
 let types = require('./types');
 
@@ -51,8 +52,11 @@ class Realm {
         // TODO
     }
 
-    objects(type) {
-        // TODO
+    objects(type, predicate) {
+        let realmId = this[realmKey];
+        let info = rpc.getObjects(realmId, type, predicate);
+
+        return results.create(realmId, info);
     }
 
     write(callback) {

lib/results.js

@@ -0,0 +1,33 @@
+'use strict';
+
+let rpc = require('./rpc');
+let util = require('./util');
+
+let idKey = Symbol();
+let realmKey = Symbol();
+let prototype = util.createListPrototype(getterForLength, getterForIndex);
+
+exports.create = create;
+
+function create(realmId, info) {
+    let results = Object.create(prototype);
+    let size = info.size;
+
+    results[realmKey] = realmId;
+    results[idKey] = info.resultsId;
+
+    results[util.growListPrototypeKey](size);
+
+    return results;
+}
+
+function getterForLength() {
+    return rpc.getResultsSize(this[realmKey], this[idKey]);
+}
+
+function getterForIndex(index) {
+    return function() {
+        let realmId = this[realmKey];
+        return rpc.getResultsItem(realmId, this[idKey], index);
+    };
+}

lib/rpc.js

@@ -17,6 +17,7 @@ exports.registerTypeConverter = registerTypeConverter;
 
 exports.createRealm = createRealm;
 exports.createObject = createObject;
+exports.getObjects = getObjects;
 
 exports.getObjectProperty = getObjectProperty;
 exports.setObjectProperty = setObjectProperty;
@@ -26,6 +27,9 @@ exports.setListItem = setListItem;
 exports.getListSize = getListSize;
 exports.callListMethod = callListMethod;
 
+exports.getResultsItem = getResultsItem;
+exports.getResultsSize = getResultsSize;
+
 exports.beginTransaction = beginTransaction;
 exports.cancelTransaction = cancelTransaction;
 exports.commitTransaction = commitTransaction;
@@ -42,6 +46,10 @@ function createObject(realmId, type, values) {
     return sendRequest('create_object', {realmId, type, values});
 }
 
+function getObjects(realmId, type, predicate) {
+    return sendRequest('get_objects', {realmId, type, predicate});
+}
+
 function getObjectProperty(realmId, objectId, name) {
     let result = sendRequest('get_property', {realmId, objectId, name});
     return convert(result);
@@ -69,6 +77,15 @@ function callListMethod(realmId, listId, name, args) {
     return convert(result);
 }
 
+function getResultsItem(realmId, resultsId, index) {
+    let result = sendRequest('get_results_item', {realmId, resultsId, index});
+    return convert(result);
+}
+
+function getResultsSize(realmId, resultsId) {
+    return sendRequest('get_results_size', {realmId, resultsId});
+}
+
 function beginTransaction(realmId) {
     sendRequest('begin_transaction', {realmId});
 }

lib/util.js

@@ -0,0 +1,35 @@
+'use strict';
+
+let growListPrototypeKey = exports.growListPrototypeKey = Symbol();
+
+exports.createListPrototype = createListPrototype;
+
+function createListPrototype(getterForLength, getterForIndex, setterForIndex) {
+    let prototype = {};
+    let maxSize = 0;
+
+    Object.defineProperty(prototype, 'length', {
+        get: getterForLength
+    });
+
+    prototype[growListPrototypeKey] = function(size) {
+        if (size < maxSize) {
+            return;
+        }
+
+        let props = {};
+        for (let i = maxSize; i <= size; i++) {
+            props[i] = {
+                get: getterForIndex(i),
+                set: setterForIndex && setterForIndex(i),
+            };
+        }
+
+        // TODO: Use ES6 Proxy once it's supported on Chrome!
+        Object.defineProperties(prototype, props);
+
+        maxSize = size + 1;
+    }
+
+    return prototype;
+}