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: const Ci = Components.interfaces;
michael@0: const Cc = Components.classes;
michael@0: const Cu = Components.utils;
michael@0: const Cr = Components.results;
michael@0: 
michael@0: 
michael@0: const CLASS_MIMEINFO        = "mimetype";
michael@0: const CLASS_PROTOCOLINFO    = "scheme";
michael@0: 
michael@0: 
michael@0: // namespace prefix
michael@0: const NC_NS                 = "http://home.netscape.com/NC-rdf#";
michael@0: 
michael@0: // the most recent default handlers that have been injected.  Note that
michael@0: // this is used to construct an RDF resource, which needs to have NC_NS
michael@0: // prepended, since that hasn't been done yet
michael@0: const DEFAULT_HANDLERS_VERSION = "defaultHandlersVersion";
michael@0: 
michael@0: // type list properties
michael@0: 
michael@0: const NC_MIME_TYPES         = NC_NS + "MIME-types";
michael@0: const NC_PROTOCOL_SCHEMES   = NC_NS + "Protocol-Schemes";
michael@0: 
michael@0: // content type ("type") properties
michael@0: 
michael@0: // nsIHandlerInfo::type
michael@0: const NC_VALUE              = NC_NS + "value";
michael@0: const NC_DESCRIPTION        = NC_NS + "description";
michael@0: 
michael@0: // additional extensions
michael@0: const NC_FILE_EXTENSIONS    = NC_NS + "fileExtensions";
michael@0: 
michael@0: // references nsIHandlerInfo record
michael@0: const NC_HANDLER_INFO       = NC_NS + "handlerProp";
michael@0: 
michael@0: // handler info ("info") properties
michael@0: 
michael@0: // nsIHandlerInfo::preferredAction
michael@0: const NC_SAVE_TO_DISK       = NC_NS + "saveToDisk";
michael@0: const NC_HANDLE_INTERNALLY  = NC_NS + "handleInternal";
michael@0: const NC_USE_SYSTEM_DEFAULT = NC_NS + "useSystemDefault";
michael@0: 
michael@0: // nsIHandlerInfo::alwaysAskBeforeHandling
michael@0: const NC_ALWAYS_ASK         = NC_NS + "alwaysAsk";
michael@0: 
michael@0: // references nsIHandlerApp records
michael@0: const NC_PREFERRED_APP      = NC_NS + "externalApplication";
michael@0: const NC_POSSIBLE_APP       = NC_NS + "possibleApplication";
michael@0: 
michael@0: // handler app ("handler") properties
michael@0: 
michael@0: // nsIHandlerApp::name
michael@0: const NC_PRETTY_NAME        = NC_NS + "prettyName";
michael@0: 
michael@0: // nsILocalHandlerApp::executable
michael@0: const NC_PATH               = NC_NS + "path";
michael@0: 
michael@0: // nsIWebHandlerApp::uriTemplate
michael@0: const NC_URI_TEMPLATE       = NC_NS + "uriTemplate";
michael@0: 
michael@0: // nsIDBusHandlerApp::service
michael@0: const NC_SERVICE            = NC_NS + "service";
michael@0: 
michael@0: // nsIDBusHandlerApp::method
michael@0: const NC_METHOD             = NC_NS + "method";
michael@0: 
michael@0: // nsIDBusHandlerApp::objectPath
michael@0: const NC_OBJPATH            = NC_NS + "objectPath";
michael@0: 
michael@0: // nsIDBusHandlerApp::dbusInterface
michael@0: const NC_INTERFACE            = NC_NS + "dBusInterface";
michael@0: 
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: 
michael@0: 
michael@0: function HandlerService() {
michael@0:   this._init();
michael@0: }
michael@0: 
michael@0: const HandlerServiceFactory = {
michael@0:   _instance: null,
michael@0:   createInstance: function (outer, iid) {
michael@0:     if (this._instance)
michael@0:       return this._instance;
michael@0: 
michael@0:     let processType = Cc["@mozilla.org/xre/runtime;1"].
michael@0:       getService(Ci.nsIXULRuntime).processType;
michael@0:     if (processType != Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT)
michael@0:       return Cr.NS_ERROR_NOT_IMPLEMENTED;
michael@0: 
michael@0:     return (this._instance = new HandlerService());
michael@0:   }
michael@0: };
michael@0: 
michael@0: HandlerService.prototype = {
michael@0:   //**************************************************************************//
michael@0:   // XPCOM Plumbing
michael@0: 
michael@0:   classID:          Components.ID("{32314cc8-22f7-4f7f-a645-1a45453ba6a6}"),
michael@0:   QueryInterface:   XPCOMUtils.generateQI([Ci.nsIHandlerService]),
michael@0:   _xpcom_factory: HandlerServiceFactory,
michael@0: 
michael@0:   //**************************************************************************//
michael@0:   // Initialization & Destruction
michael@0:   
michael@0:   _init: function HS__init() {
michael@0:     // Observe profile-before-change so we can switch to the datasource
michael@0:     // in the new profile when the user changes profiles.
michael@0:     this._observerSvc.addObserver(this, "profile-before-change", false);
michael@0: 
michael@0:     // Observe xpcom-shutdown so we can remove these observers
michael@0:     // when the application shuts down.
michael@0:     this._observerSvc.addObserver(this, "xpcom-shutdown", false);
michael@0: 
michael@0:     // Observe profile-do-change so that non-default profiles get upgraded too
michael@0:     this._observerSvc.addObserver(this, "profile-do-change", false);
michael@0:     
michael@0:     // do any necessary updating of the datastore
michael@0:     this._updateDB();
michael@0:   },
michael@0: 
michael@0:   _updateDB: function HS__updateDB() {
michael@0:     try {
michael@0:       var defaultHandlersVersion = this._datastoreDefaultHandlersVersion;
michael@0:     } catch(ex) {
michael@0:       // accessing the datastore failed, we can't update anything
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     try {
michael@0:       // if we don't have the current version of the default prefs for
michael@0:       // this locale, inject any new default handers into the datastore
michael@0:       if (defaultHandlersVersion < this._prefsDefaultHandlersVersion) {
michael@0: 
michael@0:         // set the new version first so that if we recurse we don't
michael@0:         // call _injectNewDefaults several times
michael@0:         this._datastoreDefaultHandlersVersion =
michael@0:           this._prefsDefaultHandlersVersion;
michael@0:         this._injectNewDefaults();
michael@0:       } 
michael@0:     } catch (ex) {
michael@0:       // if injecting the defaults failed, set the version back to the
michael@0:       // previous value
michael@0:       this._datastoreDefaultHandlersVersion = defaultHandlersVersion;
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   get _currentLocale() {
michael@0:     var chromeRegistry = Cc["@mozilla.org/chrome/chrome-registry;1"].
michael@0:                          getService(Ci.nsIXULChromeRegistry);
michael@0:     var currentLocale = chromeRegistry.getSelectedLocale("global");
michael@0:     return currentLocale;
michael@0:   }, 
michael@0: 
michael@0:   _destroy: function HS__destroy() {
michael@0:     this._observerSvc.removeObserver(this, "profile-before-change");
michael@0:     this._observerSvc.removeObserver(this, "xpcom-shutdown");
michael@0:     this._observerSvc.removeObserver(this, "profile-do-change");
michael@0: 
michael@0:     // XXX Should we also null references to all the services that get stored
michael@0:     // by our memoizing getters in the Convenience Getters section?
michael@0:   },
michael@0: 
michael@0:   _onProfileChange: function HS__onProfileChange() {
michael@0:     // Lose our reference to the datasource so we reacquire it
michael@0:     // from the new profile the next time we need it.
michael@0:     this.__ds = null;
michael@0:   },
michael@0: 
michael@0:   _isInHandlerArray: function HS__isInHandlerArray(aArray, aHandler) {
michael@0:     var enumerator = aArray.enumerate();
michael@0:     while (enumerator.hasMoreElements()) {
michael@0:       let handler = enumerator.getNext();
michael@0:       handler.QueryInterface(Ci.nsIHandlerApp);
michael@0:       if (handler.equals(aHandler))
michael@0:         return true;
michael@0:     }
michael@0:     
michael@0:     return false;
michael@0:   },
michael@0: 
michael@0:   // note that this applies to the current locale only 
michael@0:   get _datastoreDefaultHandlersVersion() {
michael@0:     var version = this._getValue("urn:root", NC_NS + this._currentLocale +
michael@0:                                              "_" + DEFAULT_HANDLERS_VERSION);
michael@0:     
michael@0:     return version ? version : -1;
michael@0:   },
michael@0: 
michael@0:   set _datastoreDefaultHandlersVersion(aNewVersion) {
michael@0:     return this._setLiteral("urn:root", NC_NS + this._currentLocale + "_" + 
michael@0:                             DEFAULT_HANDLERS_VERSION, aNewVersion);
michael@0:   },
michael@0: 
michael@0:   get _prefsDefaultHandlersVersion() {
michael@0:     // get handler service pref branch
michael@0:     var prefSvc = Cc["@mozilla.org/preferences-service;1"].
michael@0:                   getService(Ci.nsIPrefService);
michael@0:     var handlerSvcBranch = prefSvc.getBranch("gecko.handlerService.");
michael@0: 
michael@0:     // get the version of the preferences for this locale
michael@0:     return Number(handlerSvcBranch.
michael@0:                   getComplexValue("defaultHandlersVersion", 
michael@0:                                   Ci.nsIPrefLocalizedString).data);
michael@0:   },
michael@0:   
michael@0:   _injectNewDefaults: function HS__injectNewDefaults() {
michael@0:     // get handler service pref branch
michael@0:     var prefSvc = Cc["@mozilla.org/preferences-service;1"].
michael@0:                   getService(Ci.nsIPrefService);
michael@0: 
michael@0:     let schemesPrefBranch = prefSvc.getBranch("gecko.handlerService.schemes.");
michael@0:     let schemePrefList = schemesPrefBranch.getChildList("");
michael@0: 
michael@0:     var schemes = {};
michael@0: 
michael@0:     // read all the scheme prefs into a hash
michael@0:     for each (var schemePrefName in schemePrefList) {
michael@0: 
michael@0:       let [scheme, handlerNumber, attribute] = schemePrefName.split(".");
michael@0: 
michael@0:       try {
michael@0:         var attrData =
michael@0:           schemesPrefBranch.getComplexValue(schemePrefName,
michael@0:                                             Ci.nsIPrefLocalizedString).data;
michael@0:         if (!(scheme in schemes))
michael@0:           schemes[scheme] = {};
michael@0:   
michael@0:         if (!(handlerNumber in schemes[scheme]))
michael@0:           schemes[scheme][handlerNumber] = {};
michael@0:         
michael@0:         schemes[scheme][handlerNumber][attribute] = attrData;
michael@0:       } catch (ex) {}
michael@0:     }
michael@0: 
michael@0:     let protoSvc = Cc["@mozilla.org/uriloader/external-protocol-service;1"].
michael@0:                    getService(Ci.nsIExternalProtocolService);
michael@0:     for (var scheme in schemes) {
michael@0: 
michael@0:       // This clause is essentially a reimplementation of 
michael@0:       // nsIExternalProtocolHandlerService.getProtocolHandlerInfo().
michael@0:       // Necessary because calling that from here would make XPConnect barf
michael@0:       // when getService tried to re-enter the constructor for this
michael@0:       // service.
michael@0:       let osDefaultHandlerFound = {};
michael@0:       let protoInfo = protoSvc.getProtocolHandlerInfoFromOS(scheme, 
michael@0:                                osDefaultHandlerFound);
michael@0:       
michael@0:       if (this.exists(protoInfo))
michael@0:         this.fillHandlerInfo(protoInfo, null);
michael@0:       else
michael@0:         protoSvc.setProtocolHandlerDefaults(protoInfo, 
michael@0:                                             osDefaultHandlerFound.value);
michael@0: 
michael@0:       // cache the possible handlers to avoid extra xpconnect traversals.      
michael@0:       let possibleHandlers = protoInfo.possibleApplicationHandlers;
michael@0: 
michael@0:       for each (var handlerPrefs in schemes[scheme]) {
michael@0: 
michael@0:         let handlerApp = Cc["@mozilla.org/uriloader/web-handler-app;1"].
michael@0:                          createInstance(Ci.nsIWebHandlerApp);
michael@0: 
michael@0:         handlerApp.uriTemplate = handlerPrefs.uriTemplate;
michael@0:         handlerApp.name = handlerPrefs.name;                
michael@0: 
michael@0:         if (!this._isInHandlerArray(possibleHandlers, handlerApp)) {
michael@0:           possibleHandlers.appendElement(handlerApp, false);
michael@0:         }
michael@0:       }
michael@0: 
michael@0:       this.store(protoInfo);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   //**************************************************************************//
michael@0:   // nsIObserver
michael@0:   
michael@0:   observe: function HS__observe(subject, topic, data) {
michael@0:     switch(topic) {
michael@0:       case "profile-before-change":
michael@0:         this._onProfileChange();
michael@0:         break;
michael@0:       case "xpcom-shutdown":
michael@0:         this._destroy();
michael@0:         break;
michael@0:       case "profile-do-change":
michael@0:         this._updateDB();
michael@0:         break;  
michael@0:     }
michael@0:   },
michael@0: 
michael@0: 
michael@0:   //**************************************************************************//
michael@0:   // nsIHandlerService
michael@0: 
michael@0:   enumerate: function HS_enumerate() {
michael@0:     var handlers = Cc["@mozilla.org/array;1"].
michael@0:                    createInstance(Ci.nsIMutableArray);
michael@0:     this._appendHandlers(handlers, CLASS_MIMEINFO);
michael@0:     this._appendHandlers(handlers, CLASS_PROTOCOLINFO);
michael@0:     return handlers.enumerate();
michael@0:   },
michael@0: 
michael@0:   fillHandlerInfo: function HS_fillHandlerInfo(aHandlerInfo, aOverrideType) {
michael@0:     var type = aOverrideType || aHandlerInfo.type;
michael@0:     var typeID = this._getTypeID(this._getClass(aHandlerInfo), type);
michael@0: 
michael@0:     // Determine whether or not information about this handler is available
michael@0:     // in the datastore by looking for its "value" property, which stores its
michael@0:     // type and should always be present.
michael@0:     if (!this._hasValue(typeID, NC_VALUE))
michael@0:       throw Cr.NS_ERROR_NOT_AVAILABLE;
michael@0: 
michael@0:     // Retrieve the human-readable description of the type.
michael@0:     if (this._hasValue(typeID, NC_DESCRIPTION))
michael@0:       aHandlerInfo.description = this._getValue(typeID, NC_DESCRIPTION);
michael@0: 
michael@0:     // Note: for historical reasons, we don't actually check that the type
michael@0:     // record has a "handlerProp" property referencing the info record.  It's
michael@0:     // unclear whether or not we should start doing this check; perhaps some
michael@0:     // legacy datasources don't have such references.
michael@0:     var infoID = this._getInfoID(this._getClass(aHandlerInfo), type);
michael@0: 
michael@0:     aHandlerInfo.preferredAction = this._retrievePreferredAction(infoID);
michael@0: 
michael@0:     var preferredHandlerID =
michael@0:       this._getPreferredHandlerID(this._getClass(aHandlerInfo), type);
michael@0: 
michael@0:     // Retrieve the preferred handler.
michael@0:     // Note: for historical reasons, we don't actually check that the info
michael@0:     // record has an "externalApplication" property referencing the preferred
michael@0:     // handler record.  It's unclear whether or not we should start doing
michael@0:     // this check; perhaps some legacy datasources don't have such references.
michael@0:     aHandlerInfo.preferredApplicationHandler =
michael@0:       this._retrieveHandlerApp(preferredHandlerID);
michael@0: 
michael@0:     // Fill the array of possible handlers with the ones in the datastore.
michael@0:     this._fillPossibleHandlers(infoID,
michael@0:                                aHandlerInfo.possibleApplicationHandlers,
michael@0:                                aHandlerInfo.preferredApplicationHandler);
michael@0: 
michael@0:     // If we have an "always ask" flag stored in the RDF, always use its
michael@0:     // value. Otherwise, use the default value stored in the pref service.
michael@0:     var alwaysAsk;
michael@0:     if (this._hasValue(infoID, NC_ALWAYS_ASK)) {
michael@0:       alwaysAsk = (this._getValue(infoID, NC_ALWAYS_ASK) != "false");
michael@0:     } else {
michael@0:       var prefSvc = Cc["@mozilla.org/preferences-service;1"].
michael@0:                     getService(Ci.nsIPrefService);
michael@0:       var prefBranch = prefSvc.getBranch("network.protocol-handler.");
michael@0:       try {
michael@0:         alwaysAsk = prefBranch.getBoolPref("warn-external." + type);
michael@0:       } catch (e) {
michael@0:         // will throw if pref didn't exist.
michael@0:         try {
michael@0:           alwaysAsk = prefBranch.getBoolPref("warn-external-default");
michael@0:         } catch (e) {
michael@0:           // Nothing to tell us what to do, so be paranoid and prompt.
michael@0:           alwaysAsk = true;
michael@0:         }
michael@0:       }
michael@0:     }
michael@0:     aHandlerInfo.alwaysAskBeforeHandling = alwaysAsk;
michael@0: 
michael@0:     // If the object represents a MIME type handler, then also retrieve
michael@0:     // any file extensions.
michael@0:     if (aHandlerInfo instanceof Ci.nsIMIMEInfo)
michael@0:       for each (let fileExtension in this._retrieveFileExtensions(typeID))
michael@0:         aHandlerInfo.appendExtension(fileExtension);
michael@0:   },
michael@0: 
michael@0:   store: function HS_store(aHandlerInfo) {
michael@0:     // FIXME: when we switch from RDF to something with transactions (like
michael@0:     // SQLite), enclose the following changes in a transaction so they all
michael@0:     // get rolled back if any of them fail and we don't leave the datastore
michael@0:     // in an inconsistent state.
michael@0: 
michael@0:     this._ensureRecordsForType(aHandlerInfo);
michael@0:     this._storePreferredAction(aHandlerInfo);
michael@0:     this._storePreferredHandler(aHandlerInfo);
michael@0:     this._storePossibleHandlers(aHandlerInfo);
michael@0:     this._storeAlwaysAsk(aHandlerInfo);
michael@0: 
michael@0:     // Write the changes to the database immediately so we don't lose them
michael@0:     // if the application crashes.
michael@0:     if (this._ds instanceof Ci.nsIRDFRemoteDataSource)
michael@0:       this._ds.Flush();
michael@0:   },
michael@0: 
michael@0:   exists: function HS_exists(aHandlerInfo) {
michael@0:     var found;
michael@0: 
michael@0:     try {
michael@0:       var typeID = this._getTypeID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:       found = this._hasLiteralAssertion(typeID, NC_VALUE, aHandlerInfo.type);
michael@0:     } catch (e) {
michael@0:       // If the RDF threw (eg, corrupt file), treat as nonexistent.
michael@0:       found = false;
michael@0:     }
michael@0: 
michael@0:     return found;
michael@0:   },
michael@0: 
michael@0:   remove: function HS_remove(aHandlerInfo) {
michael@0:     var preferredHandlerID =
michael@0:       this._getPreferredHandlerID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:     this._removeAssertions(preferredHandlerID);
michael@0: 
michael@0:     var infoID = this._getInfoID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0: 
michael@0:     // Get a list of possible handlers.  After we have removed the info record,
michael@0:     // we'll check if any other info records reference these handlers, and we'll
michael@0:     // remove the handler records that aren't referenced by other info records.
michael@0:     var possibleHandlerIDs = [];
michael@0:     var possibleHandlerTargets = this._getTargets(infoID, NC_POSSIBLE_APP);
michael@0:     while (possibleHandlerTargets.hasMoreElements()) {
michael@0:       let possibleHandlerTarget = possibleHandlerTargets.getNext();
michael@0:       // Note: possibleHandlerTarget should always be an nsIRDFResource.
michael@0:       // The conditional is just here in case of a corrupt RDF datasource.
michael@0:       if (possibleHandlerTarget instanceof Ci.nsIRDFResource)
michael@0:         possibleHandlerIDs.push(possibleHandlerTarget.ValueUTF8);
michael@0:     }
michael@0: 
michael@0:     // Remove the info record.
michael@0:     this._removeAssertions(infoID);
michael@0: 
michael@0:     // Now that we've removed the info record, remove any possible handlers
michael@0:     // that aren't referenced by other info records.
michael@0:     for each (let possibleHandlerID in possibleHandlerIDs)
michael@0:       if (!this._existsResourceTarget(NC_POSSIBLE_APP, possibleHandlerID))
michael@0:         this._removeAssertions(possibleHandlerID);
michael@0: 
michael@0:     var typeID = this._getTypeID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:     this._removeAssertions(typeID);
michael@0: 
michael@0:     // Now that there's no longer a handler for this type, remove the type
michael@0:     // from the list of types for which there are known handlers.
michael@0:     var typeList = this._ensureAndGetTypeList(this._getClass(aHandlerInfo));
michael@0:     var type = this._rdf.GetResource(typeID);
michael@0:     var typeIndex = typeList.IndexOf(type);
michael@0:     if (typeIndex != -1)
michael@0:       typeList.RemoveElementAt(typeIndex, true);
michael@0: 
michael@0:     // Write the changes to the database immediately so we don't lose them
michael@0:     // if the application crashes.
michael@0:     // XXX If we're removing a bunch of handlers at once, will flushing
michael@0:     // after every removal cause a significant performance hit?
michael@0:     if (this._ds instanceof Ci.nsIRDFRemoteDataSource)
michael@0:       this._ds.Flush();
michael@0:   },
michael@0: 
michael@0:   getTypeFromExtension: function HS_getTypeFromExtension(aFileExtension) {
michael@0:     var fileExtension = aFileExtension.toLowerCase();
michael@0:     var typeID;
michael@0: 
michael@0:     if (this._existsLiteralTarget(NC_FILE_EXTENSIONS, fileExtension))
michael@0:       typeID = this._getSourceForLiteral(NC_FILE_EXTENSIONS, fileExtension);
michael@0: 
michael@0:     if (typeID && this._hasValue(typeID, NC_VALUE)) {
michael@0:       let type = this._getValue(typeID, NC_VALUE);
michael@0:       if (type == "")
michael@0:         throw Cr.NS_ERROR_FAILURE;
michael@0:       return type;
michael@0:     }
michael@0: 
michael@0:     return "";
michael@0:   },
michael@0: 
michael@0: 
michael@0:   //**************************************************************************//
michael@0:   // Retrieval Methods
michael@0: 
michael@0:   /**
michael@0:    * Retrieve the preferred action for the info record with the given ID.
michael@0:    *
michael@0:    * @param aInfoID  {string}  the info record ID
michael@0:    *
michael@0:    * @returns  {integer}  the preferred action enumeration value
michael@0:    */
michael@0:   _retrievePreferredAction: function HS__retrievePreferredAction(aInfoID) {
michael@0:     if (this._getValue(aInfoID, NC_SAVE_TO_DISK) == "true")
michael@0:       return Ci.nsIHandlerInfo.saveToDisk;
michael@0:     
michael@0:     if (this._getValue(aInfoID, NC_USE_SYSTEM_DEFAULT) == "true")
michael@0:       return Ci.nsIHandlerInfo.useSystemDefault;
michael@0:     
michael@0:     if (this._getValue(aInfoID, NC_HANDLE_INTERNALLY) == "true")
michael@0:       return Ci.nsIHandlerInfo.handleInternally;
michael@0: 
michael@0:     return Ci.nsIHandlerInfo.useHelperApp;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Fill an array of possible handlers with the handlers for the given info ID.
michael@0:    *
michael@0:    * @param aInfoID            {string}           the ID of the info record
michael@0:    * @param aPossibleHandlers  {nsIMutableArray}  the array of possible handlers
michael@0:    * @param aPreferredHandler  {nsIHandlerApp}    the preferred handler, if any
michael@0:    */
michael@0:   _fillPossibleHandlers: function HS__fillPossibleHandlers(aInfoID,
michael@0:                                                            aPossibleHandlers,
michael@0:                                                            aPreferredHandler) {
michael@0:     // The set of possible handlers should include the preferred handler,
michael@0:     // but legacy datastores (from before we added possible handlers) won't
michael@0:     // include the preferred handler, so check if it's included as we build
michael@0:     // the list of handlers, and, if it's not included, add it to the list.
michael@0:     if (aPreferredHandler)
michael@0:       aPossibleHandlers.appendElement(aPreferredHandler, false);
michael@0: 
michael@0:     var possibleHandlerTargets = this._getTargets(aInfoID, NC_POSSIBLE_APP);
michael@0: 
michael@0:     while (possibleHandlerTargets.hasMoreElements()) {
michael@0:       let possibleHandlerTarget = possibleHandlerTargets.getNext();
michael@0:       if (!(possibleHandlerTarget instanceof Ci.nsIRDFResource))
michael@0:         continue;
michael@0: 
michael@0:       let possibleHandlerID = possibleHandlerTarget.ValueUTF8;
michael@0:       let possibleHandler = this._retrieveHandlerApp(possibleHandlerID);
michael@0:       if (possibleHandler && (!aPreferredHandler ||
michael@0:                               !possibleHandler.equals(aPreferredHandler)))
michael@0:         aPossibleHandlers.appendElement(possibleHandler, false);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Retrieve the handler app object with the given ID.
michael@0:    *
michael@0:    * @param aHandlerAppID  {string}  the ID of the handler app to retrieve
michael@0:    *
michael@0:    * @returns  {nsIHandlerApp}  the handler app, if any; otherwise null
michael@0:    */
michael@0:   _retrieveHandlerApp: function HS__retrieveHandlerApp(aHandlerAppID) {
michael@0:     var handlerApp;
michael@0: 
michael@0:     // If it has a path, it's a local handler; otherwise, it's a web handler.
michael@0:     if (this._hasValue(aHandlerAppID, NC_PATH)) {
michael@0:       let executable =
michael@0:         this._getFileWithPath(this._getValue(aHandlerAppID, NC_PATH));
michael@0:       if (!executable)
michael@0:         return null;
michael@0: 
michael@0:       handlerApp = Cc["@mozilla.org/uriloader/local-handler-app;1"].
michael@0:                    createInstance(Ci.nsILocalHandlerApp);
michael@0:       handlerApp.executable = executable;
michael@0:     }
michael@0:     else if (this._hasValue(aHandlerAppID, NC_URI_TEMPLATE)) {
michael@0:       let uriTemplate = this._getValue(aHandlerAppID, NC_URI_TEMPLATE);
michael@0:       if (!uriTemplate)
michael@0:         return null;
michael@0: 
michael@0:       handlerApp = Cc["@mozilla.org/uriloader/web-handler-app;1"].
michael@0:                    createInstance(Ci.nsIWebHandlerApp);
michael@0:       handlerApp.uriTemplate = uriTemplate;
michael@0:     }
michael@0:     else if (this._hasValue(aHandlerAppID, NC_SERVICE)) {
michael@0:       let service = this._getValue(aHandlerAppID, NC_SERVICE);
michael@0:       if (!service)
michael@0:         return null;
michael@0:       
michael@0:       let method = this._getValue(aHandlerAppID, NC_METHOD);
michael@0:       if (!method)
michael@0:         return null;
michael@0:       
michael@0:       let objpath = this._getValue(aHandlerAppID, NC_OBJPATH);
michael@0:       if (!objpath)
michael@0:         return null;
michael@0:       
michael@0:       let interface = this._getValue(aHandlerAppID, NC_INTERFACE);
michael@0:       if (!interface)
michael@0:         return null;
michael@0:       
michael@0:       handlerApp = Cc["@mozilla.org/uriloader/dbus-handler-app;1"].
michael@0:                    createInstance(Ci.nsIDBusHandlerApp);
michael@0:       handlerApp.service   = service;
michael@0:       handlerApp.method    = method;
michael@0:       handlerApp.objectPath   = objpath;
michael@0:       handlerApp.dBusInterface = interface;
michael@0:       
michael@0:     }
michael@0:     else
michael@0:       return null;
michael@0: 
michael@0:     handlerApp.name = this._getValue(aHandlerAppID, NC_PRETTY_NAME);
michael@0: 
michael@0:     return handlerApp;
michael@0:   },
michael@0: 
michael@0:   /*
michael@0:    * Retrieve file extensions, if any, for the MIME type with the given type ID.
michael@0:    *
michael@0:    * @param aTypeID  {string}  the type record ID
michael@0:    */
michael@0:   _retrieveFileExtensions: function HS__retrieveFileExtensions(aTypeID) {
michael@0:     var fileExtensions = [];
michael@0: 
michael@0:     var fileExtensionTargets = this._getTargets(aTypeID, NC_FILE_EXTENSIONS);
michael@0: 
michael@0:     while (fileExtensionTargets.hasMoreElements()) {
michael@0:       let fileExtensionTarget = fileExtensionTargets.getNext();
michael@0:       if (fileExtensionTarget instanceof Ci.nsIRDFLiteral &&
michael@0:           fileExtensionTarget.Value != "")
michael@0:         fileExtensions.push(fileExtensionTarget.Value);
michael@0:     }
michael@0: 
michael@0:     return fileExtensions;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Get the file with the given path.  This is not as simple as merely
michael@0:    * initializing a local file object with the path, because the path might be
michael@0:    * relative to the current process directory, in which case we have to
michael@0:    * construct a path starting from that directory.
michael@0:    *
michael@0:    * @param aPath  {string}  a path to a file
michael@0:    *
michael@0:    * @returns {nsILocalFile} the file, or null if the file does not exist
michael@0:    */
michael@0:   _getFileWithPath: function HS__getFileWithPath(aPath) {
michael@0:     var file = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);
michael@0: 
michael@0:     try {
michael@0:       file.initWithPath(aPath);
michael@0: 
michael@0:       if (file.exists())
michael@0:         return file;
michael@0:     }
michael@0:     catch(ex) {
michael@0:       // Note: for historical reasons, we don't actually check to see
michael@0:       // if the exception is NS_ERROR_FILE_UNRECOGNIZED_PATH, which is what
michael@0:       // nsILocalFile::initWithPath throws when a path is relative.
michael@0: 
michael@0:       file = this._dirSvc.get("XCurProcD", Ci.nsIFile);
michael@0: 
michael@0:       try {
michael@0:         file.append(aPath);
michael@0:         if (file.exists())
michael@0:           return file;
michael@0:       }
michael@0:       catch(ex) {}
michael@0:     }
michael@0: 
michael@0:     return null;
michael@0:   },
michael@0: 
michael@0: 
michael@0:   //**************************************************************************//
michael@0:   // Storage Methods
michael@0: 
michael@0:   _storePreferredAction: function HS__storePreferredAction(aHandlerInfo) {
michael@0:     var infoID = this._getInfoID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0: 
michael@0:     switch(aHandlerInfo.preferredAction) {
michael@0:       case Ci.nsIHandlerInfo.saveToDisk:
michael@0:         this._setLiteral(infoID, NC_SAVE_TO_DISK, "true");
michael@0:         this._removeTarget(infoID, NC_HANDLE_INTERNALLY);
michael@0:         this._removeTarget(infoID, NC_USE_SYSTEM_DEFAULT);
michael@0:         break;
michael@0: 
michael@0:       case Ci.nsIHandlerInfo.handleInternally:
michael@0:         this._setLiteral(infoID, NC_HANDLE_INTERNALLY, "true");
michael@0:         this._removeTarget(infoID, NC_SAVE_TO_DISK);
michael@0:         this._removeTarget(infoID, NC_USE_SYSTEM_DEFAULT);
michael@0:         break;
michael@0: 
michael@0:       case Ci.nsIHandlerInfo.useSystemDefault:
michael@0:         this._setLiteral(infoID, NC_USE_SYSTEM_DEFAULT, "true");
michael@0:         this._removeTarget(infoID, NC_SAVE_TO_DISK);
michael@0:         this._removeTarget(infoID, NC_HANDLE_INTERNALLY);
michael@0:         break;
michael@0: 
michael@0:       // This value is indicated in the datastore either by the absence of
michael@0:       // the three properties or by setting them all "false".  Of these two
michael@0:       // options, the former seems preferable, because it reduces the size
michael@0:       // of the RDF file and thus the amount of stuff we have to parse.
michael@0:       case Ci.nsIHandlerInfo.useHelperApp:
michael@0:       default:
michael@0:         this._removeTarget(infoID, NC_SAVE_TO_DISK);
michael@0:         this._removeTarget(infoID, NC_HANDLE_INTERNALLY);
michael@0:         this._removeTarget(infoID, NC_USE_SYSTEM_DEFAULT);
michael@0:         break;
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _storePreferredHandler: function HS__storePreferredHandler(aHandlerInfo) {
michael@0:     var infoID = this._getInfoID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:     var handlerID =
michael@0:       this._getPreferredHandlerID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0: 
michael@0:     var handler = aHandlerInfo.preferredApplicationHandler;
michael@0: 
michael@0:     if (handler) {
michael@0:       this._storeHandlerApp(handlerID, handler);
michael@0: 
michael@0:       // Make this app be the preferred app for the handler info.
michael@0:       //
michael@0:       // Note: nsExternalHelperAppService::FillContentHandlerProperties ignores
michael@0:       // this setting and instead identifies the preferred app as the resource
michael@0:       // whose URI follows the pattern urn:<class>:externalApplication:<type>.
michael@0:       // But the old downloadactions.js code used to set this property, so just
michael@0:       // in case there is still some code somewhere that relies on its presence,
michael@0:       // we set it here.
michael@0:       this._setResource(infoID, NC_PREFERRED_APP, handlerID);
michael@0:     }
michael@0:     else {
michael@0:       // There isn't a preferred handler.  Remove the existing record for it,
michael@0:       // if any.
michael@0:       this._removeTarget(infoID, NC_PREFERRED_APP);
michael@0:       this._removeAssertions(handlerID);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Store the list of possible handler apps for the content type represented
michael@0:    * by the given handler info object.
michael@0:    *
michael@0:    * @param aHandlerInfo  {nsIHandlerInfo}  the handler info object
michael@0:    */
michael@0:   _storePossibleHandlers: function HS__storePossibleHandlers(aHandlerInfo) {
michael@0:     var infoID = this._getInfoID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0: 
michael@0:     // First, retrieve the set of handler apps currently stored for the type,
michael@0:     // keeping track of their IDs in a hash that we'll use to determine which
michael@0:     // ones are no longer valid and should be removed.
michael@0:     var currentHandlerApps = {};
michael@0:     var currentHandlerTargets = this._getTargets(infoID, NC_POSSIBLE_APP);
michael@0:     while (currentHandlerTargets.hasMoreElements()) {
michael@0:       let handlerApp = currentHandlerTargets.getNext();
michael@0:       if (handlerApp instanceof Ci.nsIRDFResource) {
michael@0:         let handlerAppID = handlerApp.ValueUTF8;
michael@0:         currentHandlerApps[handlerAppID] = true;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     // Next, store any new handler apps.
michael@0:     var newHandlerApps =
michael@0:       aHandlerInfo.possibleApplicationHandlers.enumerate();
michael@0:     while (newHandlerApps.hasMoreElements()) {
michael@0:       let handlerApp =
michael@0:         newHandlerApps.getNext().QueryInterface(Ci.nsIHandlerApp);
michael@0:       let handlerAppID = this._getPossibleHandlerAppID(handlerApp);
michael@0:       if (!this._hasResourceAssertion(infoID, NC_POSSIBLE_APP, handlerAppID)) {
michael@0:         this._storeHandlerApp(handlerAppID, handlerApp);
michael@0:         this._addResourceAssertion(infoID, NC_POSSIBLE_APP, handlerAppID);
michael@0:       }
michael@0:       delete currentHandlerApps[handlerAppID];
michael@0:     }
michael@0: 
michael@0:     // Finally, remove any old handler apps that aren't being used anymore,
michael@0:     // and if those handler apps aren't being used by any other type either,
michael@0:     // then completely remove their record from the datastore so we don't
michael@0:     // leave it clogged up with information about handler apps we don't care
michael@0:     // about anymore.
michael@0:     for (let handlerAppID in currentHandlerApps) {
michael@0:       this._removeResourceAssertion(infoID, NC_POSSIBLE_APP, handlerAppID);
michael@0:       if (!this._existsResourceTarget(NC_POSSIBLE_APP, handlerAppID))
michael@0:         this._removeAssertions(handlerAppID);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Store the given handler app.
michael@0:    *
michael@0:    * Note: the reason this method takes the ID of the handler app in a param
michael@0:    * is that the ID is different than it usually is when the handler app
michael@0:    * in question is a preferred handler app, so this method can't just derive
michael@0:    * the ID of the handler app by calling _getPossibleHandlerAppID, its callers
michael@0:    * have to do that for it.
michael@0:    *
michael@0:    * @param aHandlerAppID {string}        the ID of the handler app to store
michael@0:    * @param aHandlerApp   {nsIHandlerApp} the handler app to store
michael@0:    */
michael@0:   _storeHandlerApp: function HS__storeHandlerApp(aHandlerAppID, aHandlerApp) {
michael@0:     aHandlerApp.QueryInterface(Ci.nsIHandlerApp);
michael@0:     this._setLiteral(aHandlerAppID, NC_PRETTY_NAME, aHandlerApp.name);
michael@0: 
michael@0:     // In the case of the preferred handler, the handler ID could have been
michael@0:     // used to refer to a different kind of handler in the past (i.e. either
michael@0:     // a local hander or a web handler), so if the new handler is a local
michael@0:     // handler, then we remove any web handler properties and vice versa.
michael@0:     // This is unnecessary but harmless for possible handlers.
michael@0: 
michael@0:     if (aHandlerApp instanceof Ci.nsILocalHandlerApp) {
michael@0:       this._setLiteral(aHandlerAppID, NC_PATH, aHandlerApp.executable.path);
michael@0:       this._removeTarget(aHandlerAppID, NC_URI_TEMPLATE);
michael@0:       this._removeTarget(aHandlerAppID, NC_METHOD);
michael@0:       this._removeTarget(aHandlerAppID, NC_SERVICE);
michael@0:       this._removeTarget(aHandlerAppID, NC_OBJPATH);
michael@0:       this._removeTarget(aHandlerAppID, NC_INTERFACE);
michael@0:     }
michael@0:     else if(aHandlerApp instanceof Ci.nsIWebHandlerApp){
michael@0:       aHandlerApp.QueryInterface(Ci.nsIWebHandlerApp);
michael@0:       this._setLiteral(aHandlerAppID, NC_URI_TEMPLATE, aHandlerApp.uriTemplate);
michael@0:       this._removeTarget(aHandlerAppID, NC_PATH);
michael@0:       this._removeTarget(aHandlerAppID, NC_METHOD);
michael@0:       this._removeTarget(aHandlerAppID, NC_SERVICE);
michael@0:       this._removeTarget(aHandlerAppID, NC_OBJPATH);
michael@0:       this._removeTarget(aHandlerAppID, NC_INTERFACE);
michael@0:     }
michael@0:     else if(aHandlerApp instanceof Ci.nsIDBusHandlerApp){
michael@0:       aHandlerApp.QueryInterface(Ci.nsIDBusHandlerApp);
michael@0:       this._setLiteral(aHandlerAppID, NC_SERVICE, aHandlerApp.service);
michael@0:       this._setLiteral(aHandlerAppID, NC_METHOD, aHandlerApp.method);
michael@0:       this._setLiteral(aHandlerAppID, NC_OBJPATH, aHandlerApp.objectPath);
michael@0:       this._setLiteral(aHandlerAppID, NC_INTERFACE, aHandlerApp.dBusInterface);
michael@0:       this._removeTarget(aHandlerAppID, NC_PATH);
michael@0:       this._removeTarget(aHandlerAppID, NC_URI_TEMPLATE);
michael@0:     }
michael@0:     else {
michael@0: 	throw "unknown handler type";
michael@0:     }
michael@0: 	
michael@0:   },
michael@0: 
michael@0:   _storeAlwaysAsk: function HS__storeAlwaysAsk(aHandlerInfo) {
michael@0:     var infoID = this._getInfoID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:     this._setLiteral(infoID,
michael@0:                      NC_ALWAYS_ASK,
michael@0:                      aHandlerInfo.alwaysAskBeforeHandling ? "true" : "false");
michael@0:   },
michael@0: 
michael@0: 
michael@0:   //**************************************************************************//
michael@0:   // Convenience Getters
michael@0: 
michael@0:   // Observer Service
michael@0:   __observerSvc: null,
michael@0:   get _observerSvc() {
michael@0:     if (!this.__observerSvc)
michael@0:       this.__observerSvc =
michael@0:         Cc["@mozilla.org/observer-service;1"].
michael@0:         getService(Ci.nsIObserverService);
michael@0:     return this.__observerSvc;
michael@0:   },
michael@0: 
michael@0:   // Directory Service
michael@0:   __dirSvc: null,
michael@0:   get _dirSvc() {
michael@0:     if (!this.__dirSvc)
michael@0:       this.__dirSvc =
michael@0:         Cc["@mozilla.org/file/directory_service;1"].
michael@0:         getService(Ci.nsIProperties);
michael@0:     return this.__dirSvc;
michael@0:   },
michael@0: 
michael@0:   // MIME Service
michael@0:   __mimeSvc: null,
michael@0:   get _mimeSvc() {
michael@0:     if (!this.__mimeSvc)
michael@0:       this.__mimeSvc =
michael@0:         Cc["@mozilla.org/mime;1"].
michael@0:         getService(Ci.nsIMIMEService);
michael@0:     return this.__mimeSvc;
michael@0:   },
michael@0: 
michael@0:   // Protocol Service
michael@0:   __protocolSvc: null,
michael@0:   get _protocolSvc() {
michael@0:     if (!this.__protocolSvc)
michael@0:       this.__protocolSvc =
michael@0:         Cc["@mozilla.org/uriloader/external-protocol-service;1"].
michael@0:         getService(Ci.nsIExternalProtocolService);
michael@0:     return this.__protocolSvc;
michael@0:   },
michael@0: 
michael@0:   // RDF Service
michael@0:   __rdf: null,
michael@0:   get _rdf() {
michael@0:     if (!this.__rdf)
michael@0:       this.__rdf = Cc["@mozilla.org/rdf/rdf-service;1"].
michael@0:                    getService(Ci.nsIRDFService);
michael@0:     return this.__rdf;
michael@0:   },
michael@0: 
michael@0:   // RDF Container Utils
michael@0:   __containerUtils: null,
michael@0:   get _containerUtils() {
michael@0:     if (!this.__containerUtils)
michael@0:       this.__containerUtils = Cc["@mozilla.org/rdf/container-utils;1"].
michael@0:                               getService(Ci.nsIRDFContainerUtils);
michael@0:     return this.__containerUtils;
michael@0:   },
michael@0: 
michael@0:   // RDF datasource containing content handling config (i.e. mimeTypes.rdf)
michael@0:   __ds: null,
michael@0:   get _ds() {
michael@0:     if (!this.__ds) {
michael@0:       var file = this._dirSvc.get("UMimTyp", Ci.nsIFile);
michael@0:       // FIXME: make this a memoizing getter if we use it anywhere else.
michael@0:       var ioService = Cc["@mozilla.org/network/io-service;1"].
michael@0:                       getService(Ci.nsIIOService);
michael@0:       var fileHandler = ioService.getProtocolHandler("file").
michael@0:                         QueryInterface(Ci.nsIFileProtocolHandler);
michael@0:       this.__ds =
michael@0:         this._rdf.GetDataSourceBlocking(fileHandler.getURLSpecFromFile(file));
michael@0:     }
michael@0: 
michael@0:     return this.__ds;
michael@0:   },
michael@0: 
michael@0: 
michael@0:   //**************************************************************************//
michael@0:   // Datastore Utils
michael@0: 
michael@0:   /**
michael@0:    * Get the string identifying whether this is a MIME or a protocol handler.
michael@0:    * This string is used in the URI IDs of various RDF properties.
michael@0:    * 
michael@0:    * @param aHandlerInfo {nsIHandlerInfo} the handler for which to get the class
michael@0:    * 
michael@0:    * @returns {string} the class
michael@0:    */
michael@0:   _getClass: function HS__getClass(aHandlerInfo) {
michael@0:     if (aHandlerInfo instanceof Ci.nsIMIMEInfo)
michael@0:       return CLASS_MIMEINFO;
michael@0:     else
michael@0:       return CLASS_PROTOCOLINFO;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Return the unique identifier for a content type record, which stores
michael@0:    * the value field plus a reference to the content type's handler info record.
michael@0:    *
michael@0:    * |urn:<class>:<type>|
michael@0:    *
michael@0:    * XXX: should this be a property of nsIHandlerInfo?
michael@0:    *
michael@0:    * @param aClass {string} the class (CLASS_MIMEINFO or CLASS_PROTOCOLINFO)
michael@0:    * @param aType  {string} the type (a MIME type or protocol scheme)
michael@0:    *
michael@0:    * @returns {string} the ID
michael@0:    */
michael@0:   _getTypeID: function HS__getTypeID(aClass, aType) {
michael@0:     return "urn:" + aClass + ":" + aType;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Return the unique identifier for a handler info record, which stores
michael@0:    * the preferredAction and alwaysAsk fields plus a reference to the preferred
michael@0:    * handler app.  Roughly equivalent to the nsIHandlerInfo interface.
michael@0:    *
michael@0:    * |urn:<class>:handler:<type>|
michael@0:    *
michael@0:    * FIXME: the type info record should be merged into the type record,
michael@0:    * since there's a one to one relationship between them, and this record
michael@0:    * merely stores additional attributes of a content type.
michael@0:    *
michael@0:    * @param aClass {string} the class (CLASS_MIMEINFO or CLASS_PROTOCOLINFO)
michael@0:    * @param aType  {string} the type (a MIME type or protocol scheme)
michael@0:    *
michael@0:    * @returns {string} the ID
michael@0:    */
michael@0:   _getInfoID: function HS__getInfoID(aClass, aType) {
michael@0:     return "urn:" + aClass + ":handler:" + aType;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Return the unique identifier for a preferred handler record, which stores
michael@0:    * information about the preferred handler for a given content type, including
michael@0:    * its human-readable name and the path to its executable (for a local app)
michael@0:    * or its URI template (for a web app).
michael@0:    * 
michael@0:    * |urn:<class>:externalApplication:<type>|
michael@0:    *
michael@0:    * XXX: should this be a property of nsIHandlerApp?
michael@0:    *
michael@0:    * FIXME: this should be an arbitrary ID, and we should retrieve it from
michael@0:    * the datastore for a given content type via the NC:ExternalApplication
michael@0:    * property rather than looking for a specific ID, so a handler doesn't
michael@0:    * have to change IDs when it goes from being a possible handler to being
michael@0:    * the preferred one (once we support possible handlers).
michael@0:    * 
michael@0:    * @param aClass {string} the class (CLASS_MIMEINFO or CLASS_PROTOCOLINFO)
michael@0:    * @param aType  {string} the type (a MIME type or protocol scheme)
michael@0:    * 
michael@0:    * @returns {string} the ID
michael@0:    */
michael@0:   _getPreferredHandlerID: function HS__getPreferredHandlerID(aClass, aType) {
michael@0:     return "urn:" + aClass + ":externalApplication:" + aType;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Return the unique identifier for a handler app record, which stores
michael@0:    * information about a possible handler for one or more content types,
michael@0:    * including its human-readable name and the path to its executable (for a
michael@0:    * local app) or its URI template (for a web app).
michael@0:    *
michael@0:    * Note: handler app IDs for preferred handlers are different.  For those,
michael@0:    * see the _getPreferredHandlerID method.
michael@0:    *
michael@0:    * @param aHandlerApp  {nsIHandlerApp}   the handler app object
michael@0:    */
michael@0:   _getPossibleHandlerAppID: function HS__getPossibleHandlerAppID(aHandlerApp) {
michael@0:     var handlerAppID = "urn:handler:";
michael@0: 
michael@0:     if (aHandlerApp instanceof Ci.nsILocalHandlerApp)
michael@0:       handlerAppID += "local:" + aHandlerApp.executable.path;
michael@0:     else if(aHandlerApp instanceof Ci.nsIWebHandlerApp){
michael@0:       aHandlerApp.QueryInterface(Ci.nsIWebHandlerApp);
michael@0:       handlerAppID += "web:" + aHandlerApp.uriTemplate;
michael@0:     }
michael@0:     else if(aHandlerApp instanceof Ci.nsIDBusHandlerApp){
michael@0:       aHandlerApp.QueryInterface(Ci.nsIDBusHandlerApp);
michael@0:       handlerAppID += "dbus:" + aHandlerApp.service + " " + aHandlerApp.method + " " + aHandlerApp.uriTemplate;
michael@0:     }else{
michael@0: 	throw "unknown handler type";
michael@0:     }
michael@0:     
michael@0:     return handlerAppID;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Get the list of types for the given class, creating the list if it doesn't
michael@0:    * already exist. The class can be either CLASS_MIMEINFO or CLASS_PROTOCOLINFO
michael@0:    * (i.e. the result of a call to _getClass).
michael@0:    * 
michael@0:    * |urn:<class>s|
michael@0:    * |urn:<class>s:root|
michael@0:    * 
michael@0:    * @param aClass {string} the class for which to retrieve a list of types
michael@0:    *
michael@0:    * @returns {nsIRDFContainer} the list of types
michael@0:    */
michael@0:   _ensureAndGetTypeList: function HS__ensureAndGetTypeList(aClass) {
michael@0:     var source = this._rdf.GetResource("urn:" + aClass + "s");
michael@0:     var property =
michael@0:       this._rdf.GetResource(aClass == CLASS_MIMEINFO ? NC_MIME_TYPES
michael@0:                                                      : NC_PROTOCOL_SCHEMES);
michael@0:     var target = this._rdf.GetResource("urn:" + aClass + "s:root");
michael@0: 
michael@0:     // Make sure we have an arc from the source to the target.
michael@0:     if (!this._ds.HasAssertion(source, property, target, true))
michael@0:       this._ds.Assert(source, property, target, true);
michael@0: 
michael@0:     // Make sure the target is a container.
michael@0:     if (!this._containerUtils.IsContainer(this._ds, target))
michael@0:       this._containerUtils.MakeSeq(this._ds, target);
michael@0: 
michael@0:     // Get the type list as an RDF container.
michael@0:     var typeList = Cc["@mozilla.org/rdf/container;1"].
michael@0:                    createInstance(Ci.nsIRDFContainer);
michael@0:     typeList.Init(this._ds, target);
michael@0: 
michael@0:     return typeList;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Make sure there are records in the datasource for the given content type
michael@0:    * by creating them if they don't already exist.  We have to do this before
michael@0:    * storing any specific data, because we can't assume the presence
michael@0:    * of the records (the nsIHandlerInfo object might have been created
michael@0:    * from the OS), and the records have to all be there in order for the helper
michael@0:    * app service to properly construct an nsIHandlerInfo object for the type.
michael@0:    *
michael@0:    * Based on old downloadactions.js::_ensureMIMERegistryEntry.
michael@0:    *
michael@0:    * @param aHandlerInfo {nsIHandlerInfo} the type to make sure has a record
michael@0:    */
michael@0:   _ensureRecordsForType: function HS__ensureRecordsForType(aHandlerInfo) {
michael@0:     // Get the list of types.
michael@0:     var typeList = this._ensureAndGetTypeList(this._getClass(aHandlerInfo));
michael@0: 
michael@0:     // If there's already a record in the datastore for this type, then we
michael@0:     // don't need to do anything more.
michael@0:     var typeID = this._getTypeID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:     var type = this._rdf.GetResource(typeID);
michael@0:     if (typeList.IndexOf(type) != -1)
michael@0:       return;
michael@0: 
michael@0:     // Create a basic type record for this type.
michael@0:     typeList.AppendElement(type);
michael@0:     this._setLiteral(typeID, NC_VALUE, aHandlerInfo.type);
michael@0:     
michael@0:     // Create a basic info record for this type.
michael@0:     var infoID = this._getInfoID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:     this._setLiteral(infoID, NC_ALWAYS_ASK, "false");
michael@0:     this._setResource(typeID, NC_HANDLER_INFO, infoID);
michael@0:     // XXX Shouldn't we set preferredAction to useSystemDefault?
michael@0:     // That's what it is if there's no record in the datastore; why should it
michael@0:     // change to useHelperApp just because we add a record to the datastore?
michael@0:     
michael@0:     // Create a basic preferred handler record for this type.
michael@0:     // XXX Not sure this is necessary, since preferred handlers are optional,
michael@0:     // and nsExternalHelperAppService::FillHandlerInfoForTypeFromDS doesn't seem
michael@0:     // to require the record , but downloadactions.js::_ensureMIMERegistryEntry
michael@0:     // used to create it, so we'll do the same.
michael@0:     var preferredHandlerID =
michael@0:       this._getPreferredHandlerID(this._getClass(aHandlerInfo), aHandlerInfo.type);
michael@0:     this._setLiteral(preferredHandlerID, NC_PATH, "");
michael@0:     this._setResource(infoID, NC_PREFERRED_APP, preferredHandlerID);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Append known handlers of the given class to the given array.  The class
michael@0:    * can be either CLASS_MIMEINFO or CLASS_PROTOCOLINFO.
michael@0:    *
michael@0:    * @param aHandlers   {array} the array of handlers to append to
michael@0:    * @param aClass      {string} the class for which to append handlers
michael@0:    */
michael@0:   _appendHandlers: function HS__appendHandlers(aHandlers, aClass) {
michael@0:     var typeList = this._ensureAndGetTypeList(aClass);
michael@0:     var enumerator = typeList.GetElements();
michael@0: 
michael@0:     while (enumerator.hasMoreElements()) {
michael@0:       var element = enumerator.getNext();
michael@0:       
michael@0:       // This should never happen.  If it does, that means our datasource
michael@0:       // is corrupted with type list entries that point to literal values
michael@0:       // instead of resources.  If it does happen, let's just do our best
michael@0:       // to recover by ignoring this entry and moving on to the next one.
michael@0:       if (!(element instanceof Ci.nsIRDFResource))
michael@0:         continue;
michael@0: 
michael@0:       // Get the value of the element's NC:value property, which contains
michael@0:       // the MIME type or scheme for which we're retrieving a handler info.
michael@0:       var type = this._getValue(element.ValueUTF8, NC_VALUE);
michael@0:       if (!type)
michael@0:         continue;
michael@0: 
michael@0:       var handler;
michael@0:       if (typeList.Resource.ValueUTF8 == "urn:mimetypes:root")
michael@0:         handler = this._mimeSvc.getFromTypeAndExtension(type, null);
michael@0:       else
michael@0:         handler = this._protocolSvc.getProtocolHandlerInfo(type);
michael@0: 
michael@0:       aHandlers.appendElement(handler, false);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Whether or not a property of an RDF source has a value.
michael@0:    *
michael@0:    * @param sourceURI   {string}  the URI of the source
michael@0:    * @param propertyURI {string}  the URI of the property
michael@0:    * @returns           {boolean} whether or not the property has a value
michael@0:    */
michael@0:   _hasValue: function HS__hasValue(sourceURI, propertyURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     return this._ds.hasArcOut(source, property);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Get the value of a property of an RDF source.
michael@0:    *
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @returns           {string} the value of the property
michael@0:    */
michael@0:   _getValue: function HS__getValue(sourceURI, propertyURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0: 
michael@0:     var target = this._ds.GetTarget(source, property, true);
michael@0: 
michael@0:     if (!target)
michael@0:       return null;
michael@0:     
michael@0:     if (target instanceof Ci.nsIRDFResource)
michael@0:       return target.ValueUTF8;
michael@0: 
michael@0:     if (target instanceof Ci.nsIRDFLiteral)
michael@0:       return target.Value;
michael@0: 
michael@0:     return null;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Get all targets for the property of an RDF source.
michael@0:    *
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * 
michael@0:    * @returns {nsISimpleEnumerator} an enumerator of targets
michael@0:    */
michael@0:   _getTargets: function HS__getTargets(sourceURI, propertyURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0: 
michael@0:     return this._ds.GetTargets(source, property, true);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Set a property of an RDF source to a literal value.
michael@0:    *
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param value       {string} the literal value
michael@0:    */
michael@0:   _setLiteral: function HS__setLiteral(sourceURI, propertyURI, value) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetLiteral(value);
michael@0:     
michael@0:     this._setTarget(source, property, target);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Set a property of an RDF source to a resource target.
michael@0:    *
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param targetURI   {string} the URI of the target
michael@0:    */
michael@0:   _setResource: function HS__setResource(sourceURI, propertyURI, targetURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetResource(targetURI);
michael@0:     
michael@0:     this._setTarget(source, property, target);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Assert an arc into the RDF datasource if there is no arc with the given
michael@0:    * source and property; otherwise, if there is already an existing arc,
michael@0:    * change it to point to the given target. _setLiteral and _setResource
michael@0:    * call this after converting their string arguments into resources
michael@0:    * and literals, and most callers should call one of those two methods
michael@0:    * instead of this one.
michael@0:    *
michael@0:    * @param source    {nsIRDFResource}  the source
michael@0:    * @param property  {nsIRDFResource}  the property
michael@0:    * @param target    {nsIRDFNode}      the target
michael@0:    */
michael@0:   _setTarget: function HS__setTarget(source, property, target) {
michael@0:     if (this._ds.hasArcOut(source, property)) {
michael@0:       var oldTarget = this._ds.GetTarget(source, property, true);
michael@0:       this._ds.Change(source, property, oldTarget, target);
michael@0:     }
michael@0:     else
michael@0:       this._ds.Assert(source, property, target, true);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Assert that a property of an RDF source has a resource target.
michael@0:    * 
michael@0:    * The difference between this method and _setResource is that this one adds
michael@0:    * an assertion even if one already exists, which allows its callers to make
michael@0:    * sets of assertions (i.e. to set a property to multiple targets).
michael@0:    *
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param targetURI   {string} the URI of the target
michael@0:    */
michael@0:   _addResourceAssertion: function HS__addResourceAssertion(sourceURI,
michael@0:                                                            propertyURI,
michael@0:                                                            targetURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetResource(targetURI);
michael@0:     
michael@0:     this._ds.Assert(source, property, target, true);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Remove an assertion with a resource target.
michael@0:    *
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param targetURI   {string} the URI of the target
michael@0:    */
michael@0:   _removeResourceAssertion: function HS__removeResourceAssertion(sourceURI,
michael@0:                                                                  propertyURI,
michael@0:                                                                  targetURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetResource(targetURI);
michael@0: 
michael@0:     this._ds.Unassert(source, property, target);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Whether or not a property of an RDF source has a given resource target.
michael@0:    * 
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param targetURI   {string} the URI of the target
michael@0:    *
michael@0:    * @returns {boolean} whether or not there is such an assertion
michael@0:    */
michael@0:   _hasResourceAssertion: function HS__hasResourceAssertion(sourceURI,
michael@0:                                                            propertyURI,
michael@0:                                                            targetURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetResource(targetURI);
michael@0: 
michael@0:     return this._ds.HasAssertion(source, property, target, true);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Whether or not a property of an RDF source has a given literal value.
michael@0:    * 
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param value       {string} the literal value
michael@0:    *
michael@0:    * @returns {boolean} whether or not there is such an assertion
michael@0:    */
michael@0:   _hasLiteralAssertion: function HS__hasLiteralAssertion(sourceURI,
michael@0:                                                          propertyURI,
michael@0:                                                          value) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetLiteral(value);
michael@0: 
michael@0:     return this._ds.HasAssertion(source, property, target, true);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Whether or not there is an RDF source that has the given property set to
michael@0:    * the given literal value.
michael@0:    * 
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param value       {string} the literal value
michael@0:    *
michael@0:    * @returns {boolean} whether or not there is a source
michael@0:    */
michael@0:   _existsLiteralTarget: function HS__existsLiteralTarget(propertyURI, value) {
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetLiteral(value);
michael@0: 
michael@0:     return this._ds.hasArcIn(target, property);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Get the source for a property set to a given literal value.
michael@0:    *
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param value       {string} the literal value
michael@0:    */
michael@0:   _getSourceForLiteral: function HS__getSourceForLiteral(propertyURI, value) {
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetLiteral(value);
michael@0: 
michael@0:     var source = this._ds.GetSource(property, target, true);
michael@0:     if (source)
michael@0:       return source.ValueUTF8;
michael@0: 
michael@0:     return null;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Whether or not there is an RDF source that has the given property set to
michael@0:    * the given resource target.
michael@0:    * 
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    * @param targetURI   {string} the URI of the target
michael@0:    *
michael@0:    * @returns {boolean} whether or not there is a source
michael@0:    */
michael@0:   _existsResourceTarget: function HS__existsResourceTarget(propertyURI,
michael@0:                                                            targetURI) {
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0:     var target = this._rdf.GetResource(targetURI);
michael@0: 
michael@0:     return this._ds.hasArcIn(target, property);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Remove a property of an RDF source.
michael@0:    *
michael@0:    * @param sourceURI   {string} the URI of the source
michael@0:    * @param propertyURI {string} the URI of the property
michael@0:    */
michael@0:   _removeTarget: function HS__removeTarget(sourceURI, propertyURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var property = this._rdf.GetResource(propertyURI);
michael@0: 
michael@0:     if (this._ds.hasArcOut(source, property)) {
michael@0:       var target = this._ds.GetTarget(source, property, true);
michael@0:       this._ds.Unassert(source, property, target);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:  /**
michael@0:   * Remove all assertions about a given RDF source.
michael@0:   *
michael@0:   * Note: not recursive.  If some assertions point to other resources,
michael@0:   * and you want to remove assertions about those resources too, you need
michael@0:   * to do so manually.
michael@0:   *
michael@0:   * @param sourceURI {string} the URI of the source
michael@0:   */
michael@0:   _removeAssertions: function HS__removeAssertions(sourceURI) {
michael@0:     var source = this._rdf.GetResource(sourceURI);
michael@0:     var properties = this._ds.ArcLabelsOut(source);
michael@0:  
michael@0:     while (properties.hasMoreElements()) {
michael@0:       let property = properties.getNext();
michael@0:       let targets = this._ds.GetTargets(source, property, true);
michael@0:       while (targets.hasMoreElements()) {
michael@0:         let target = targets.getNext();
michael@0:         this._ds.Unassert(source, property, target);
michael@0:       }
michael@0:     }
michael@0:   }
michael@0: 
michael@0: };
michael@0: 
michael@0: //****************************************************************************//
michael@0: // More XPCOM Plumbing
michael@0: 
michael@0: this.NSGetFactory = XPCOMUtils.generateNSGetFactory([HandlerService]);