Clone function (#624)

* Add clone function

* Replace utilIsolate with clone

* Replace JsonSchema.isolate with clone function

* Include core.js for tests which use json-schema.js

* Update visisted set

4 files changed, 75 insertions, 37 deletions

diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index 344706d1..59a3de45 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -38,7 +38,6 @@
  * profileConditionsDescriptorPromise
  * requestJson
  * requestText
- * utilIsolate
  */
 
 class Backend {
@@ -875,7 +874,7 @@ class Backend {
         for (const target of targets) {
             try {
                 const result = this._modifySetting(target);
-                results.push({result: utilIsolate(result)});
+                results.push({result: clone(result)});
             } catch (e) {
                 results.push({error: errorToJson(e)});
             }
@@ -889,7 +888,7 @@ class Backend {
         for (const target of targets) {
             try {
                 const result = this._getSetting(target);
-                results.push({result: utilIsolate(result)});
+                results.push({result: clone(result)});
             } catch (e) {
                 results.push({error: errorToJson(e)});
             }
diff --git a/ext/bg/js/json-schema.js b/ext/bg/js/json-schema.js
index f62402f9..2e009a7a 100644
--- a/ext/bg/js/json-schema.js
+++ b/ext/bg/js/json-schema.js
@@ -90,7 +90,7 @@ class JsonSchemaProxyHandler {
             throw new Error(`Property ${property} not supported`);
         }
 
-        value = JsonSchema.isolate(value);
+        value = JsonSchema.clone(value);
 
         JsonSchemaProxyHandler.validate(value, propertySchema, new JsonSchemaTraversalInfo(value, propertySchema));
 
@@ -515,7 +515,7 @@ class JsonSchemaProxyHandler {
 
             const schemaDefault = schema.default;
             if (typeof schemaDefault !== 'undefined') {
-                value = JsonSchema.isolate(schemaDefault);
+                value = JsonSchema.clone(schemaDefault);
                 type = JsonSchemaProxyHandler.getValueType(value);
                 assignDefault = !JsonSchemaProxyHandler.isValueTypeAny(value, type, schemaType);
             }
@@ -628,19 +628,7 @@ class JsonSchema {
         return JsonSchemaProxyHandler.getValidValueOrDefault(schema, value);
     }
 
-    static isolate(value) {
-        if (value === null) { return null; }
-
-        switch (typeof value) {
-            case 'boolean':
-            case 'number':
-            case 'string':
-            case 'bigint':
-            case 'symbol':
-                return value;
-        }
-
-        const stringValue = JSON.stringify(value);
-        return typeof stringValue === 'string' ? JSON.parse(stringValue) : null;
+    static clone(value) {
+        return clone(value);
     }
 }
diff --git a/ext/bg/js/util.js b/ext/bg/js/util.js
index edc19c6e..fa31b0d8 100644
--- a/ext/bg/js/util.js
+++ b/ext/bg/js/util.js
@@ -15,26 +15,10 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-function utilIsolate(value) {
-    if (value === null) { return null; }
-
-    switch (typeof value) {
-        case 'boolean':
-        case 'number':
-        case 'string':
-        case 'bigint':
-        case 'symbol':
-            return value;
-    }
-
-    const stringValue = JSON.stringify(value);
-    return typeof stringValue === 'string' ? JSON.parse(stringValue) : null;
-}
-
 function utilFunctionIsolate(func) {
     return function isolatedFunction(...args) {
         try {
-            args = args.map((v) => utilIsolate(v));
+            args = args.map((v) => clone(v));
             return func.call(this, ...args);
         } catch (e) {
             try {
@@ -50,7 +34,7 @@ function utilFunctionIsolate(func) {
 
 function utilBackgroundIsolate(data) {
     const backgroundPage = chrome.extension.getBackgroundPage();
-    return backgroundPage.utilIsolate(data);
+    return backgroundPage.clone(data);
 }
 
 function utilBackgroundFunctionIsolate(func) {
diff --git a/ext/mixed/js/core.js b/ext/mixed/js/core.js
index 21b7bf5e..9b3ea3e2 100644
--- a/ext/mixed/js/core.js
+++ b/ext/mixed/js/core.js
@@ -157,6 +157,73 @@ function getSetDifference(set1, set2) {
     );
 }
 
+const clone = (() => {
+    // eslint-disable-next-line no-shadow
+    function clone(value) {
+        if (value === null) { return null; }
+        switch (typeof value) {
+            case 'boolean':
+            case 'number':
+            case 'string':
+            case 'bigint':
+            case 'symbol':
+            case 'undefined':
+                return value;
+            default:
+                return cloneInternal(value, new Set());
+        }
+    }
+
+    function cloneInternal(value, visited) {
+        if (value === null) { return null; }
+        switch (typeof value) {
+            case 'boolean':
+            case 'number':
+            case 'string':
+            case 'bigint':
+            case 'symbol':
+            case 'undefined':
+                return value;
+            case 'function':
+                return cloneObject(value, visited);
+            case 'object':
+                return Array.isArray(value) ? cloneArray(value, visited) : cloneObject(value, visited);
+        }
+    }
+
+    function cloneArray(value, visited) {
+        if (visited.has(value)) { throw new Error('Circular'); }
+        try {
+            visited.add(value);
+            const result = [];
+            for (const item of value) {
+                result.push(cloneInternal(item, visited));
+            }
+            return result;
+        } finally {
+            visited.delete(value);
+        }
+    }
+
+    function cloneObject(value, visited) {
+        if (visited.has(value)) { throw new Error('Circular'); }
+        try {
+            visited.add(value);
+            const result = {};
+            for (const key in value) {
+                if (Object.prototype.hasOwnProperty.call(value, key)) {
+                    result[key] = cloneInternal(value[key], visited);
+                }
+            }
+            return result;
+        } finally {
+            visited.delete(value);
+        }
+    }
+
+    return clone;
+})();
+
 
 /*
  * Async utilities