michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = [ "UserAgentOverrides" ];
michael@0: 
michael@0: const Ci = Components.interfaces;
michael@0: const Cc = Components.classes;
michael@0: 
michael@0: Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: Components.utils.import("resource://gre/modules/Services.jsm");
michael@0: Components.utils.import("resource://gre/modules/UserAgentUpdates.jsm");
michael@0: 
michael@0: const OVERRIDE_MESSAGE = "Useragent:GetOverride";
michael@0: const PREF_OVERRIDES_ENABLED = "general.useragent.site_specific_overrides";
michael@0: const DEFAULT_UA = Cc["@mozilla.org/network/protocol;1?name=http"]
michael@0:                      .getService(Ci.nsIHttpProtocolHandler)
michael@0:                      .userAgent;
michael@0: const MAX_OVERRIDE_FOR_HOST_CACHE_SIZE = 250;
michael@0: 
michael@0: XPCOMUtils.defineLazyServiceGetter(this, "ppmm",
michael@0:                                   "@mozilla.org/parentprocessmessagemanager;1",
michael@0:                                   "nsIMessageListenerManager");  // Might have to make this broadcast?
michael@0: 
michael@0: var gPrefBranch;
michael@0: var gOverrides = new Map;
michael@0: var gUpdatedOverrides;
michael@0: var gOverrideForHostCache = new Map;
michael@0: var gInitialized = false;
michael@0: var gOverrideFunctions = [
michael@0:   function (aHttpChannel) UserAgentOverrides.getOverrideForURI(aHttpChannel.URI)
michael@0: ];
michael@0: var gBuiltUAs = new Map;
michael@0: 
michael@0: this.UserAgentOverrides = {
michael@0:   init: function uao_init() {
michael@0:     if (gInitialized)
michael@0:       return;
michael@0: 
michael@0:     gPrefBranch = Services.prefs.getBranch("general.useragent.override.");
michael@0:     gPrefBranch.addObserver("", buildOverrides, false);
michael@0: 
michael@0:     ppmm.addMessageListener(OVERRIDE_MESSAGE, this);
michael@0:     Services.prefs.addObserver(PREF_OVERRIDES_ENABLED, buildOverrides, false);
michael@0: 
michael@0:     try {
michael@0:       Services.obs.addObserver(HTTP_on_modify_request, "http-on-modify-request", false);
michael@0:     } catch (x) {
michael@0:       // The http-on-modify-request notification is disallowed in content processes.
michael@0:     }
michael@0: 
michael@0:     UserAgentUpdates.init(function(overrides) {
michael@0:       gOverrideForHostCache.clear();
michael@0:       if (overrides) {
michael@0:         for (let domain in overrides) {
michael@0:           overrides[domain] = getUserAgentFromOverride(overrides[domain]);
michael@0:         }
michael@0:         overrides.get = function(key) this[key];
michael@0:       }
michael@0:       gUpdatedOverrides = overrides;
michael@0:     });
michael@0: 
michael@0:     buildOverrides();
michael@0:     gInitialized = true;
michael@0:   },
michael@0: 
michael@0:   addComplexOverride: function uao_addComplexOverride(callback) {
michael@0:     // Add to front of array so complex overrides have precedence
michael@0:     gOverrideFunctions.unshift(callback);
michael@0:   },
michael@0: 
michael@0:   getOverrideForURI: function uao_getOverrideForURI(aURI) {
michael@0:     let host = aURI.asciiHost;
michael@0:     if (!gInitialized ||
michael@0:         (!gOverrides.size && !gUpdatedOverrides) ||
michael@0:         !(host)) {
michael@0:       return null;
michael@0:     }
michael@0: 
michael@0:     let override = gOverrideForHostCache.get(host);
michael@0:     if (override !== undefined)
michael@0:       return override;
michael@0: 
michael@0:     function findOverride(overrides) {
michael@0:       let searchHost = host;
michael@0:       let userAgent = overrides.get(searchHost);
michael@0: 
michael@0:       while (!userAgent) {
michael@0:         let dot = searchHost.indexOf('.');
michael@0:         if (dot === -1) {
michael@0:           return null;
michael@0:         }
michael@0:         searchHost = searchHost.slice(dot + 1);
michael@0:         userAgent = overrides.get(searchHost);
michael@0:       }
michael@0:       return userAgent;
michael@0:     }
michael@0: 
michael@0:     override = (gOverrides.size && findOverride(gOverrides))
michael@0:             || (gUpdatedOverrides && findOverride(gUpdatedOverrides));
michael@0: 
michael@0:     if (gOverrideForHostCache.size >= MAX_OVERRIDE_FOR_HOST_CACHE_SIZE) {
michael@0:       gOverrideForHostCache.clear();
michael@0:     }
michael@0:     gOverrideForHostCache.set(host, override);
michael@0: 
michael@0:     return override;
michael@0:   },
michael@0: 
michael@0:   uninit: function uao_uninit() {
michael@0:     if (!gInitialized)
michael@0:       return;
michael@0:     gInitialized = false;
michael@0: 
michael@0:     gPrefBranch.removeObserver("", buildOverrides);
michael@0: 
michael@0:     Services.prefs.removeObserver(PREF_OVERRIDES_ENABLED, buildOverrides);
michael@0: 
michael@0:     Services.obs.removeObserver(HTTP_on_modify_request, "http-on-modify-request");
michael@0:   },
michael@0: 
michael@0:   receiveMessage: function(aMessage) {
michael@0:     let name = aMessage.name;
michael@0:     switch (name) {
michael@0:       case OVERRIDE_MESSAGE:
michael@0:         let uri = aMessage.data.uri;
michael@0:         return this.getOverrideForURI(uri);
michael@0:       default:
michael@0:         throw("Wrong Message in UserAgentOverride: " + name);
michael@0:     }
michael@0:   }
michael@0: };
michael@0: 
michael@0: function getUserAgentFromOverride(override)
michael@0: {
michael@0:   let userAgent = gBuiltUAs.get(override);
michael@0:   if (userAgent !== undefined) {
michael@0:     return userAgent;
michael@0:   }
michael@0:   let [search, replace] = override.split("#", 2);
michael@0:   if (search && replace) {
michael@0:     userAgent = DEFAULT_UA.replace(new RegExp(search, "g"), replace);
michael@0:   } else {
michael@0:     userAgent = override;
michael@0:   }
michael@0:   gBuiltUAs.set(override, userAgent);
michael@0:   return userAgent;
michael@0: }
michael@0: 
michael@0: function buildOverrides() {
michael@0:   gOverrides.clear();
michael@0:   gOverrideForHostCache.clear();
michael@0: 
michael@0:   if (!Services.prefs.getBoolPref(PREF_OVERRIDES_ENABLED))
michael@0:     return;
michael@0: 
michael@0:   let builtUAs = new Map;
michael@0:   let domains = gPrefBranch.getChildList("");
michael@0: 
michael@0:   for (let domain of domains) {
michael@0:     let override = gPrefBranch.getCharPref(domain);
michael@0:     let userAgent = getUserAgentFromOverride(override);
michael@0: 
michael@0:     if (userAgent != DEFAULT_UA) {
michael@0:       gOverrides.set(domain, userAgent);
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: function HTTP_on_modify_request(aSubject, aTopic, aData) {
michael@0:   let channel = aSubject.QueryInterface(Ci.nsIHttpChannel);
michael@0: 
michael@0:   for (let callback of gOverrideFunctions) {
michael@0:     let modifiedUA = callback(channel, DEFAULT_UA);
michael@0:     if (modifiedUA) {
michael@0:       channel.setRequestHeader("User-Agent", modifiedUA, false);
michael@0:       return;
michael@0:     }
michael@0:   }
michael@0: }