1 files changed, 94 insertions, 0 deletions
diff --git a/devtools/platform/jsdebugger.sys.mjs b/devtools/platform/jsdebugger.sys.mjs
new file mode 100644
index 0000000000..a4af1fdbc3
--- /dev/null
+++ b/devtools/platform/jsdebugger.sys.mjs
@@ -0,0 +1,94 @@
+/* -*-  indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* 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/. */
+
+/*
+ * This is the js module for Debugger. Import it like so:
+ *   const { addDebuggerToGlobal } = ChromeUtils.importESModule(
+ *     "resource://gre/modules/jsdebugger.sys.mjs"
+ *   );
+ *   addDebuggerToGlobal(globalThis);
+ *
+ * This will create a 'Debugger' object, which provides an interface to debug
+ * JavaScript code running in other compartments in the same process, on the
+ * same thread.
+ *
+ * For documentation on the API, see:
+ *   https://developer.mozilla.org/en-US/docs/Tools/Debugger-API
+ */
+
+const init = Cc["@mozilla.org/jsdebugger;1"].createInstance(Ci.IJSDebugger);
+
+export function addDebuggerToGlobal(global) {
+  init.addClass(global);
+  initPromiseDebugging(global);
+}
+
+// Defines the Debugger in a sandbox global in a separate compartment. This
+// ensures the debugger and debuggee are in different compartments.
+export function addSandboxedDebuggerToGlobal(global) {
+  const sb = Cu.Sandbox(global, { freshCompartment: true });
+  addDebuggerToGlobal(sb);
+  global.Debugger = sb.Debugger;
+}
+
+function initPromiseDebugging(global) {
+  if (global.Debugger.Object.prototype.PromiseDebugging) {
+    return;
+  }
+
+  // If the PromiseDebugging object doesn't have all legacy functions, we're
+  // using the new accessors on Debugger.Object already.
+  if (!PromiseDebugging.getDependentPromises) {
+    return;
+  }
+
+  // Otherwise, polyfill them using PromiseDebugging.
+  global.Debugger.Object.prototype.PromiseDebugging = PromiseDebugging;
+  global.eval(polyfillSource);
+}
+
+const polyfillSource = `
+  Object.defineProperty(Debugger.Object.prototype, "promiseState", {
+    get() {
+      const state = this.PromiseDebugging.getState(this.unsafeDereference());
+      return {
+        state: state.state,
+        value: this.makeDebuggeeValue(state.value),
+        reason: this.makeDebuggeeValue(state.reason)
+      };
+    }
+  });
+  Object.defineProperty(Debugger.Object.prototype, "promiseLifetime", {
+    get() {
+      return this.PromiseDebugging.getPromiseLifetime(this.unsafeDereference());
+    }
+  });
+  Object.defineProperty(Debugger.Object.prototype, "promiseTimeToResolution", {
+    get() {
+      return this.PromiseDebugging.getTimeToSettle(this.unsafeDereference());
+    }
+  });
+  Object.defineProperty(Debugger.Object.prototype, "promiseDependentPromises", {
+    get() {
+      let promises = this.PromiseDebugging.getDependentPromises(this.unsafeDereference());
+      return promises.map(p => this.makeDebuggeeValue(p));
+    }
+  });
+  Object.defineProperty(Debugger.Object.prototype, "promiseAllocationSite", {
+    get() {
+      return this.PromiseDebugging.getAllocationStack(this.unsafeDereference());
+    }
+  });
+  Object.defineProperty(Debugger.Object.prototype, "promiseResolutionSite", {
+    get() {
+      let state = this.promiseState.state;
+      if (state === "fulfilled") {
+        return this.PromiseDebugging.getFullfillmentStack(this.unsafeDereference());
+      } else {
+        return this.PromiseDebugging.getRejectionStack(this.unsafeDereference());
+      }
+    }
+  });
+`;