Import pref.js from idcounter-webext

akahuku/background/pref.js

@@ -0,0 +1,134 @@
+/**
+ * Extension preference background script
+ *
+ * DependsOn: Map, for...of, Map.prototype.keys (Firefox 20)
+ * DependsOn: browser.runtime.onMessage (Firefox 45)
+ * Permissions: storage
+ */
+
+"use strict";
+
+var Prefs = {
+  _defaultData: new Map(),
+  _userData: new Map(),
+
+  setDefault: function (name, defaultValue) {
+    this._defaultData.set(name, defaultValue);
+  },
+  checkDefault: function (name) {
+    return !(this._userData.has(name));
+  },
+
+  get: function (keys) {
+    var ret = {};
+    if (typeof keys === "string") {
+      if (keys) {
+        ret [keys] = this.getItem (keys);
+      }
+    }
+    else if (typeof keys == "object") {
+      if (keys === null) {
+        keys = this._defaultData.keys();
+      }
+      for (var key of keys) {
+        ret[key] = this.getItem(key);
+      }
+    }
+    else {
+      throw TypeError("keys must be a null, string, array of strings, or objects")
+    }
+    return ret;
+  },
+
+  set: function (keys) {
+    var ret = {};
+    for (var prop in keys) {
+      ret[prop] = {
+        oldValue: this.getItem(prop),
+        newValue: keys[prop],
+      };
+      this.setItem(prop, keys[prop]);
+    }
+    return ret;
+  },
+
+  restore: function (keys) {
+    for (var prop in keys) {
+      if (!this._defaultData.has(prop)) {
+        browser.storage.local.remove(prop);
+        console.log('remove invalid pref: "' + prop + '"');
+      }
+      else {
+        this.setItem(prop, keys[prop]);
+      }
+    }
+  },
+
+  getItem: function (name) {
+    if (this._userData.has(name)) {
+      return this._userData.get(name);
+    }
+    return this._defaultData.get(name);
+  },
+  setItem: function (name, value) {
+    if (!this._defaultData.has(name)) {
+      console.error("ignore invalid pref: '" + name
+          + '" ("' + value + '")');
+      return;
+    }
+    var dv = this._defaultData.get(name);
+    if (dv == value) {
+      this._userData.delete(name);
+      browser.storage.local.remove(name);
+    }
+    else {
+      this._userData.set(name, value);
+      var keys = {};
+      keys[name] = value;
+      browser.storage.local.set(keys);
+    }
+  },
+  hasItem: function (name) {
+    return this._defaultData.has(name) || this._userData.has(name);
+  },
+};
+
+
+/**
+ * Message handler from content scripts to this background script
+ */
+function handleMessage(message, sender, sendResponse) {
+  if ("target" in message && message.target === "pref.js") {
+    var args = message.args;
+    switch (message.command) {
+      case "get":
+        sendResponse (Prefs.get (args [0]));
+        break;
+      case "set":
+        sendResponse (Prefs.set (args [0]));
+        break;
+    }
+  }
+}
+browser.runtime.onMessage.addListener(handleMessage);
+
+/**
+ * declare pref entry with a default value
+ */
+function pref(name, defaultValue) {
+  Prefs.setDefault(name, defaultValue);
+}
+
+function prefEndDeclare() {
+  browser.storage.local.get(null).then (function (localPrefs) {
+    for (var prop in localPrefs) {
+      if (!Prefs.hasItem(prop)) {
+        // browser.storage.local.remove(prop);
+        console.log('remove invalid pref: "' + prop + '"');
+        delete localPrefs[prop];
+      }
+    }
+    Prefs.set (localPrefs);
+  });
+}
+