1 files changed, 108 insertions, 0 deletions
diff --git a/devtools/server/actors/preference.js b/devtools/server/actors/preference.js
new file mode 100644
index 0000000000..3435fe9eb1
--- /dev/null
+++ b/devtools/server/actors/preference.js
@@ -0,0 +1,108 @@
+/* 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 {
+  preferenceSpec,
+} = require("resource://devtools/shared/specs/preference.js");
+
+const { PREF_STRING, PREF_INT, PREF_BOOL } = Services.prefs;
+
+function ensurePrefType(name, expectedType) {
+  const type = Services.prefs.getPrefType(name);
+  if (type !== expectedType) {
+    throw new Error(`preference is not of the right type: ${name}`);
+  }
+}
+
+/**
+ * Normally the preferences are set using Services.prefs, but this actor allows
+ * a devtools client to set preferences on the debuggee. This is particularly useful
+ * when remote debugging, and the preferences should persist to the remote target
+ * and not to the client. If used for a local target, it effectively behaves the same
+ * as using Services.prefs.
+ *
+ * This actor is used as a global-scoped actor, targeting the entire browser, not an
+ * individual tab.
+ */
+class PreferenceActor extends Actor {
+  constructor(conn) {
+    super(conn, preferenceSpec);
+  }
+  getTraits() {
+    // The *Pref traits are used to know if remote-debugging bugs related to
+    // specific preferences are fixed on the server or if the client should set
+    // default values for them. See the about:debugging module
+    // runtime-default-preferences.js
+    return {};
+  }
+
+  getBoolPref(name) {
+    ensurePrefType(name, PREF_BOOL);
+    return Services.prefs.getBoolPref(name);
+  }
+
+  getCharPref(name) {
+    ensurePrefType(name, PREF_STRING);
+    return Services.prefs.getCharPref(name);
+  }
+
+  getIntPref(name) {
+    ensurePrefType(name, PREF_INT);
+    return Services.prefs.getIntPref(name);
+  }
+
+  getAllPrefs() {
+    const prefs = {};
+    Services.prefs.getChildList("").forEach(function (name, index) {
+      // append all key/value pairs into a huge json object.
+      try {
+        let value;
+        switch (Services.prefs.getPrefType(name)) {
+          case PREF_STRING:
+            value = Services.prefs.getCharPref(name);
+            break;
+          case PREF_INT:
+            value = Services.prefs.getIntPref(name);
+            break;
+          case PREF_BOOL:
+            value = Services.prefs.getBoolPref(name);
+            break;
+          default:
+        }
+        prefs[name] = {
+          value,
+          hasUserValue: Services.prefs.prefHasUserValue(name),
+        };
+      } catch (e) {
+        // pref exists but has no user or default value
+      }
+    });
+    return prefs;
+  }
+
+  setBoolPref(name, value) {
+    Services.prefs.setBoolPref(name, value);
+    Services.prefs.savePrefFile(null);
+  }
+
+  setCharPref(name, value) {
+    Services.prefs.setCharPref(name, value);
+    Services.prefs.savePrefFile(null);
+  }
+
+  setIntPref(name, value) {
+    Services.prefs.setIntPref(name, value);
+    Services.prefs.savePrefFile(null);
+  }
+
+  clearUserPref(name) {
+    Services.prefs.clearUserPref(name);
+    Services.prefs.savePrefFile(null);
+  }
+}
+
+exports.PreferenceActor = PreferenceActor;