1 files changed, 109 insertions, 0 deletions
diff --git a/devtools/server/actors/object/symbol.js b/devtools/server/actors/object/symbol.js
new file mode 100644
index 0000000000..bd8bb97005
--- /dev/null
+++ b/devtools/server/actors/object/symbol.js
@@ -0,0 +1,109 @@
+/* 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";
+
+const { Actor } = require("resource://devtools/shared/protocol.js");
+const { symbolSpec } = require("resource://devtools/shared/specs/symbol.js");
+loader.lazyRequireGetter(
+  this,
+  "createValueGrip",
+  "resource://devtools/server/actors/object/utils.js",
+  true
+);
+
+/**
+ * Creates an actor for the specified symbol.
+ *
+ * @param {DevToolsServerConnection} conn: The connection to the client.
+ * @param {Symbol} symbol: The symbol we want to create an actor for.
+ */
+class SymbolActor extends Actor {
+  constructor(conn, symbol) {
+    super(conn, symbolSpec);
+    this.symbol = symbol;
+  }
+
+  rawValue() {
+    return this.symbol;
+  }
+
+  destroy() {
+    // Because symbolActors is not a weak map, we won't automatically leave
+    // it so we need to manually leave on destroy so that we don't leak
+    // memory.
+    this._releaseActor();
+    super.destroy();
+  }
+
+  /**
+   * Returns a grip for this actor for returning in a protocol message.
+   */
+  form() {
+    const form = {
+      type: this.typeName,
+      actor: this.actorID,
+    };
+    const name = getSymbolName(this.symbol);
+    if (name !== undefined) {
+      // Create a grip for the name because it might be a longString.
+      form.name = createValueGrip(name, this.getParent());
+    }
+    return form;
+  }
+
+  /**
+   * Handle a request to release this SymbolActor instance.
+   */
+  release() {
+    // TODO: also check if this.getParent() === threadActor.threadLifetimePool
+    // when the web console moves away from manually releasing pause-scoped
+    // actors.
+    this._releaseActor();
+    this.destroy();
+    return {};
+  }
+
+  _releaseActor() {
+    const parent = this.getParent();
+    if (parent && parent.symbolActors) {
+      delete parent.symbolActors[this.symbol];
+    }
+  }
+}
+
+const symbolProtoToString = Symbol.prototype.toString;
+
+function getSymbolName(symbol) {
+  const name = symbolProtoToString.call(symbol).slice("Symbol(".length, -1);
+  return name || undefined;
+}
+
+/**
+ * Create a grip for the given symbol.
+ *
+ * @param sym Symbol
+ *        The symbol we are creating a grip for.
+ * @param pool Pool
+ *        The actor pool where the new actor will be added.
+ */
+function symbolGrip(sym, pool) {
+  if (!pool.symbolActors) {
+    pool.symbolActors = Object.create(null);
+  }
+
+  if (sym in pool.symbolActors) {
+    return pool.symbolActors[sym].form();
+  }
+
+  const actor = new SymbolActor(pool.conn, sym);
+  pool.manage(actor);
+  pool.symbolActors[sym] = actor;
+  return actor.form();
+}
+
+module.exports = {
+  SymbolActor,
+  symbolGrip,
+};