1 files changed, 538 insertions, 0 deletions
diff --git a/remote/domains/content/runtime/ExecutionContext.jsm b/remote/domains/content/runtime/ExecutionContext.jsm
new file mode 100644
index 0000000000..7a04f3ae8f
--- /dev/null
+++ b/remote/domains/content/runtime/ExecutionContext.jsm
@@ -0,0 +1,538 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["ExecutionContext"];
+
+const uuidGen = Cc["@mozilla.org/uuid-generator;1"].getService(
+  Ci.nsIUUIDGenerator
+);
+
+const TYPED_ARRAY_CLASSES = [
+  "Uint8Array",
+  "Uint8ClampedArray",
+  "Uint16Array",
+  "Uint32Array",
+  "Int8Array",
+  "Int16Array",
+  "Int32Array",
+  "Float32Array",
+  "Float64Array",
+];
+
+function uuid() {
+  return uuidGen
+    .generateUUID()
+    .toString()
+    .slice(1, -1);
+}
+
+/**
+ * This class represent a debuggable context onto which we can evaluate Javascript.
+ * This is typically a document, but it could also be a worker, an add-on, ... or
+ * any kind of context involving JS scripts.
+ *
+ * @param {Debugger} dbg
+ *   A Debugger instance that we can use to inspect the given global.
+ * @param {GlobalObject} debuggee
+ *   The debuggable context's global object. This is typically the document window
+ *   object. But it can also be any global object, like a worker global scope object.
+ */
+class ExecutionContext {
+  constructor(dbg, debuggee, id, isDefault) {
+    this._debugger = dbg;
+    this._debuggee = this._debugger.addDebuggee(debuggee);
+
+    // Here, we assume that debuggee is a window object and we will propably have
+    // to adapt that once we cover workers or contexts that aren't a document.
+    this.window = debuggee;
+    this.windowId = this.window.windowGlobalChild.innerWindowId;
+    this.id = id;
+    this.frameId = this.window.browsingContext.id.toString();
+    this.isDefault = isDefault;
+
+    // objectId => Debugger.Object
+    this._remoteObjects = new Map();
+  }
+
+  destructor() {
+    this._debugger.removeDebuggee(this._debuggee);
+  }
+
+  get browsingContext() {
+    return this.window.browsingContext;
+  }
+
+  hasRemoteObject(objectId) {
+    return this._remoteObjects.has(objectId);
+  }
+
+  getRemoteObject(objectId) {
+    return this._remoteObjects.get(objectId);
+  }
+
+  getRemoteObjectByNodeId(nodeId) {
+    for (const value of this._remoteObjects.values()) {
+      if (value.nodeId == nodeId) {
+        return value;
+      }
+    }
+
+    return null;
+  }
+
+  releaseObject(objectId) {
+    return this._remoteObjects.delete(objectId);
+  }
+
+  /**
+   * Add a new debuggerObj to the object cache.
+   *
+   * Whenever an object is returned as reference, a new entry is added
+   * to the internal object cache. It means the same underlying object or node
+   * can be represented via multiple references.
+   */
+  setRemoteObject(debuggerObj) {
+    const objectId = uuid();
+
+    // TODO: Wrap Symbol into an object,
+    // which would allow us to set the objectId.
+    if (typeof debuggerObj == "object") {
+      debuggerObj.objectId = objectId;
+    }
+
+    // For node objects add an unique identifier.
+    if (
+      debuggerObj instanceof Debugger.Object &&
+      Node.isInstance(debuggerObj.unsafeDereference())
+    ) {
+      debuggerObj.nodeId = uuid();
+      // We do not differentiate between backendNodeId and nodeId (yet)
+      debuggerObj.backendNodeId = debuggerObj.nodeId;
+    }
+
+    this._remoteObjects.set(objectId, debuggerObj);
+
+    return objectId;
+  }
+
+  /**
+   * Evaluate a Javascript expression.
+   *
+   * @param {String} expression
+   *   The JS expression to evaluate against the JS context.
+   * @param {boolean} options.awaitPromise
+   *     Whether execution should `await` for resulting value
+   *     and return once awaited promise is resolved.
+   * @param {boolean} returnByValue
+   *     Whether the result is expected to be a JSON object
+   *     that should be sent by value.
+   *
+   * @return {Object} A multi-form object depending if the execution
+   *   succeed or failed. If the expression failed to evaluate,
+   *   it will return an object with an `exceptionDetails` attribute
+   *   matching the `ExceptionDetails` CDP type. Otherwise it will
+   *   return an object with `result` attribute whose type is
+   *   `RemoteObject` CDP type.
+   */
+  async evaluate(expression, awaitPromise, returnByValue) {
+    let rv = this._debuggee.executeInGlobal(expression);
+    if (!rv) {
+      return {
+        exceptionDetails: {
+          text: "Evaluation terminated!",
+        },
+      };
+    }
+
+    if (rv.throw) {
+      return this._returnError(rv.throw);
+    }
+
+    let result = rv.return;
+
+    if (result && result.isPromise && awaitPromise) {
+      if (result.promiseState === "fulfilled") {
+        result = result.promiseValue;
+      } else if (result.promiseState === "rejected") {
+        return this._returnError(result.promiseReason);
+      } else {
+        try {
+          const promiseResult = await result.unsafeDereference();
+          result = this._debuggee.makeDebuggeeValue(promiseResult);
+        } catch (e) {
+          // The promise has been rejected
+          return this._returnError(e);
+        }
+      }
+    }
+
+    if (returnByValue) {
+      result = this._toRemoteObjectByValue(result);
+    } else {
+      result = this._toRemoteObject(result);
+    }
+
+    return { result };
+  }
+
+  /**
+   * Given a Debugger.Object reference for an Exception, return a JSON object
+   * describing the exception by following CDP ExceptionDetails specification.
+   */
+  _returnError(exception) {
+    if (
+      this._debuggee.executeInGlobalWithBindings("exception instanceof Error", {
+        exception,
+      }).return
+    ) {
+      const text = this._debuggee.executeInGlobalWithBindings(
+        "exception.message",
+        { exception }
+      ).return;
+      return {
+        exceptionDetails: {
+          text,
+        },
+      };
+    }
+
+    // If that isn't an Error, consider the exception as a JS value
+    return {
+      exceptionDetails: {
+        exception: this._toRemoteObject(exception),
+      },
+    };
+  }
+
+  async callFunctionOn(
+    functionDeclaration,
+    callArguments = [],
+    returnByValue = false,
+    awaitPromise = false,
+    objectId = null
+  ) {
+    // Map the given objectId to a JS reference.
+    let thisArg = null;
+    if (objectId) {
+      thisArg = this.getRemoteObject(objectId);
+      if (!thisArg) {
+        throw new Error(`Unable to get target object with id: ${objectId}`);
+      }
+    }
+
+    // First evaluate the function
+    const fun = this._debuggee.executeInGlobal("(" + functionDeclaration + ")");
+    if (!fun) {
+      return {
+        exceptionDetails: {
+          text: "Evaluation terminated!",
+        },
+      };
+    }
+    if (fun.throw) {
+      return this._returnError(fun.throw);
+    }
+
+    // Then map all input arguments, which are matching CDP's CallArguments type,
+    // into JS values
+    const args = callArguments.map(arg => this._fromCallArgument(arg));
+
+    // Finally, call the function with these arguments
+    const rv = fun.return.apply(thisArg, args);
+    if (rv.throw) {
+      return this._returnError(rv.throw);
+    }
+
+    let result = rv.return;
+
+    if (result && result.isPromise && awaitPromise) {
+      if (result.promiseState === "fulfilled") {
+        result = result.promiseValue;
+      } else if (result.promiseState === "rejected") {
+        return this._returnError(result.promiseReason);
+      } else {
+        try {
+          const promiseResult = await result.unsafeDereference();
+          result = this._debuggee.makeDebuggeeValue(promiseResult);
+        } catch (e) {
+          // The promise has been rejected
+          return this._returnError(e);
+        }
+      }
+    }
+
+    if (returnByValue) {
+      result = this._toRemoteObjectByValue(result);
+    } else {
+      result = this._toRemoteObject(result);
+    }
+
+    return { result };
+  }
+
+  getProperties({ objectId, ownProperties }) {
+    let debuggerObj = this.getRemoteObject(objectId);
+    if (!debuggerObj) {
+      throw new Error("Could not find object with given id");
+    }
+
+    const result = [];
+    const serializeObject = (debuggerObj, isOwn) => {
+      for (const propertyName of debuggerObj.getOwnPropertyNames()) {
+        const descriptor = debuggerObj.getOwnPropertyDescriptor(propertyName);
+        result.push({
+          name: propertyName,
+
+          configurable: descriptor.configurable,
+          enumerable: descriptor.enumerable,
+          writable: descriptor.writable,
+          value: this._toRemoteObject(descriptor.value),
+          get: descriptor.get
+            ? this._toRemoteObject(descriptor.get)
+            : undefined,
+          set: descriptor.set
+            ? this._toRemoteObject(descriptor.set)
+            : undefined,
+
+          isOwn,
+        });
+      }
+    };
+
+    // When `ownProperties` is set to true, we only iterate over own properties.
+    // Otherwise, we also iterate over propreties inherited from the prototype chain.
+    serializeObject(debuggerObj, true);
+
+    if (!ownProperties) {
+      while (true) {
+        debuggerObj = debuggerObj.proto;
+        if (!debuggerObj) {
+          break;
+        }
+        serializeObject(debuggerObj, false);
+      }
+    }
+
+    return {
+      result,
+    };
+  }
+
+  /**
+   * Given a CDP `CallArgument`, return a JS value that represent this argument.
+   * Note that `CallArgument` is actually very similar to `RemoteObject`
+   */
+  _fromCallArgument(arg) {
+    if (arg.objectId) {
+      if (!this.hasRemoteObject(arg.objectId)) {
+        throw new Error("Could not find object with given id");
+      }
+      return this.getRemoteObject(arg.objectId);
+    }
+
+    if (arg.unserializableValue) {
+      switch (arg.unserializableValue) {
+        case "-0":
+          return -0;
+        case "Infinity":
+          return Infinity;
+        case "-Infinity":
+          return -Infinity;
+        case "NaN":
+          return NaN;
+        default:
+          if (/^\d+n$/.test(arg.unserializableValue)) {
+            // eslint-disable-next-line no-undef
+            return BigInt(arg.unserializableValue.slice(0, -1));
+          }
+          throw new Error("Couldn't parse value object in call argument");
+      }
+    }
+
+    return this._deserialize(arg.value);
+  }
+
+  /**
+   * Given a JS value, create a copy of it within the debugee compartment.
+   */
+  _deserialize(obj) {
+    if (typeof obj !== "object") {
+      return obj;
+    }
+    const result = this._debuggee.executeInGlobalWithBindings(
+      "JSON.parse(obj)",
+      { obj: JSON.stringify(obj) }
+    );
+    if (result.throw) {
+      throw new Error("Unable to deserialize object");
+    }
+    return result.return;
+  }
+
+  /**
+   * Given a `Debugger.Object` object, return a JSON-serializable description of it
+   * matching `RemoteObject` CDP type.
+   *
+   * @param {Debugger.Object} debuggerObj
+   *  The object to serialize
+   * @return {RemoteObject}
+   *  The serialized description of the given object
+   */
+  _toRemoteObject(debuggerObj) {
+    const result = {};
+
+    // First handle all non-primitive values which are going to be wrapped by the
+    // Debugger API into Debugger.Object instances
+    if (debuggerObj instanceof Debugger.Object) {
+      const rawObj = debuggerObj.unsafeDereference();
+
+      result.objectId = this.setRemoteObject(debuggerObj);
+      result.type = typeof rawObj;
+
+      // Map the Debugger API `class` attribute to CDP `subtype`
+      const cls = debuggerObj.class;
+      if (debuggerObj.isProxy) {
+        result.subtype = "proxy";
+      } else if (cls == "Array") {
+        result.subtype = "array";
+      } else if (cls == "RegExp") {
+        result.subtype = "regexp";
+      } else if (cls == "Date") {
+        result.subtype = "date";
+      } else if (cls == "Map") {
+        result.subtype = "map";
+      } else if (cls == "Set") {
+        result.subtype = "set";
+      } else if (cls == "WeakMap") {
+        result.subtype = "weakmap";
+      } else if (cls == "WeakSet") {
+        result.subtype = "weakset";
+      } else if (cls == "Error") {
+        result.subtype = "error";
+      } else if (cls == "Promise") {
+        result.subtype = "promise";
+      } else if (TYPED_ARRAY_CLASSES.includes(cls)) {
+        result.subtype = "typedarray";
+      } else if (Node.isInstance(rawObj)) {
+        result.subtype = "node";
+        result.className = ChromeUtils.getClassName(rawObj);
+        result.description = rawObj.localName || rawObj.nodeName;
+        if (rawObj.id) {
+          result.description += `#${rawObj.id}`;
+        }
+      }
+      return result;
+    }
+
+    // Now, handle all values that Debugger API isn't wrapping into Debugger.API.
+    // This is all the primitive JS types.
+    result.type = typeof debuggerObj;
+
+    // Symbol and BigInt are primitive values but aren't serializable.
+    // CDP expects them to be considered as objects, with an objectId to later inspect
+    // them.
+    if (result.type == "symbol") {
+      result.description = debuggerObj.toString();
+      result.objectId = this.setRemoteObject(debuggerObj);
+
+      return result;
+    }
+
+    // A few primitive type can't be serialized and CDP has special case for them
+    if (Object.is(debuggerObj, NaN)) {
+      result.unserializableValue = "NaN";
+    } else if (Object.is(debuggerObj, -0)) {
+      result.unserializableValue = "-0";
+    } else if (Object.is(debuggerObj, Infinity)) {
+      result.unserializableValue = "Infinity";
+    } else if (Object.is(debuggerObj, -Infinity)) {
+      result.unserializableValue = "-Infinity";
+    } else if (result.type == "bigint") {
+      result.unserializableValue = `${debuggerObj}n`;
+    }
+
+    if (result.unserializableValue) {
+      result.description = result.unserializableValue;
+      return result;
+    }
+
+    // Otherwise, we serialize the primitive values as-is via `value` attribute
+    result.value = debuggerObj;
+
+    // null is special as it has a dedicated subtype
+    if (debuggerObj === null) {
+      result.subtype = "null";
+    }
+
+    return result;
+  }
+
+  /**
+   * Given a `Debugger.Object` object, return a JSON-serializable description of it
+   * matching `RemoteObject` CDP type.
+   *
+   * @param {Debugger.Object} debuggerObj
+   *  The object to serialize
+   * @return {RemoteObject}
+   *  The serialized description of the given object
+   */
+  _toRemoteObjectByValue(debuggerObj) {
+    const type = typeof debuggerObj;
+
+    if (type == "undefined") {
+      return { type };
+    }
+
+    let unserializableValue = undefined;
+    if (Object.is(debuggerObj, -0)) {
+      unserializableValue = "-0";
+    } else if (Object.is(debuggerObj, NaN)) {
+      unserializableValue = "NaN";
+    } else if (Object.is(debuggerObj, Infinity)) {
+      unserializableValue = "Infinity";
+    } else if (Object.is(debuggerObj, -Infinity)) {
+      unserializableValue = "-Infinity";
+    } else if (typeof debuggerObj == "bigint") {
+      unserializableValue = `${debuggerObj}n`;
+    }
+
+    if (unserializableValue) {
+      return {
+        type,
+        unserializableValue,
+        description: unserializableValue,
+      };
+    }
+
+    const value = this._serialize(debuggerObj);
+    return {
+      type: typeof value,
+      value,
+      description: value != null ? value.toString() : value,
+    };
+  }
+
+  /**
+   * Convert a given `Debugger.Object` to an object.
+   *
+   * @param {Debugger.Object} obj
+   *  The object to convert
+   *
+   * @return {Object}
+   *  The converted object
+   */
+  _serialize(debuggerObj) {
+    const result = this._debuggee.executeInGlobalWithBindings(
+      "JSON.stringify(e)",
+      { e: debuggerObj }
+    );
+    if (result.throw) {
+      throw new Error("Object is not serializable");
+    }
+
+    return JSON.parse(result.return);
+  }
+}