1 files changed, 69 insertions, 0 deletions
diff --git a/devtools/shared/flags.js b/devtools/shared/flags.js
new file mode 100644
index 0000000000..1b0ec26472
--- /dev/null
+++ b/devtools/shared/flags.js
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+/* 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";
+
+/**
+ * This module controls various global flags that can be toggled on and off.
+ * These flags are generally used to change the behavior of the code during
+ * testing. They are tracked by preferences so that they are propagated
+ * between the parent and content processes. The flags are exposed via a module
+ * as a conveniene and to stop from littering preference names throughout the
+ * code ase.
+ *
+ * Each of the flags is documented where it is defined.
+ */
+
+/**
+ * We cannot make a normal property writeable on `exports` because
+ * the module system freezes it. This function observes a preference
+ * and provides the latest value through a getter.
+ */
+function makePrefTrackedFlag(exports, name, pref) {
+  let flag;
+  // We don't have access to pref in worker, so disable all logs by default
+  if (isWorker) {
+    flag = false;
+  } else {
+    flag = Services.prefs.getBoolPref(pref, false);
+    const prefObserver = () => {
+      flag = Services.prefs.getBoolPref(pref, false);
+    };
+    Services.prefs.addObserver(pref, prefObserver);
+
+    // Also listen for Loader unload to unregister the pref observer and prevent leaking
+    const unloadObserver = function (subject) {
+      if (subject.wrappedJSObject == require("@loader/unload")) {
+        Services.prefs.removeObserver(pref, prefObserver);
+        Services.obs.removeObserver(unloadObserver, "devtools:loader:destroy");
+      }
+    };
+    Services.obs.addObserver(unloadObserver, "devtools:loader:destroy");
+  }
+  Object.defineProperty(exports, name, {
+    get() {
+      return flag;
+    },
+  });
+}
+
+/**
+ * Setting the "devtools.debugger.log" preference to true will enable logging of
+ * the RDP calls to the devtools server.
+ */
+makePrefTrackedFlag(exports, "wantLogging", "devtools.debugger.log");
+
+/**
+ * Setting the "devtools.debugger.log.verbose" preference to true will enable a
+ * more verbose logging of the the RDP. The "devtools.debugger.log" preference
+ * must be set to true as well for this to have any effect.
+ */
+makePrefTrackedFlag(exports, "wantVerbose", "devtools.debugger.log.verbose");
+
+/**
+ * Setting the "devtools.testing" preference to true will toggle on certain
+ * behaviors that can differ from the production version of the code. These
+ * behaviors typically enable easier testing or enhanced debugging features.
+ */
+makePrefTrackedFlag(exports, "testing", "devtools.testing");