uriloader/exthandler/nsIHandlerService.idl

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "nsISupports.idl"
   6
   7 interface nsIHandlerInfo;
   8 interface nsISimpleEnumerator;
   9
  10 [scriptable, uuid(53f0ad17-ec62-46a1-adbc-efccc06babcd)]
  11 interface nsIHandlerService : nsISupports
  12 {
  13   /**
  14    * Asynchronously performs any IO that the nsIHandlerService needs to do
  15    * before it can be of use.
  16    */
  17   void asyncInit();
  18
  19   /**
  20    * Retrieve a list of all handlers in the datastore.  This list is not
  21    * guaranteed to be in any particular order, and callers should not assume
  22    * it will remain in the same order in the future.
  23    *
  24    * @returns a list of all handlers in the datastore
  25    */
  26   nsISimpleEnumerator enumerate();
  27
  28   /**
  29    * Fill a handler info object with information from the datastore.
  30    *
  31    * Note: because of the way the external helper app service currently mixes
  32    * OS and user handler info in the same handler info object, this method
  33    * takes an existing handler info object (probably retrieved from the OS)
  34    * and "fills it in" with information from the datastore, overriding any
  35    * existing properties on the object with properties from the datastore.
  36    *
  37    * Ultimately, however, we're going to separate OS and user handler info
  38    * into separate objects, at which point this method should be renamed to
  39    * something like "get" or "retrieve", take a class and type (or perhaps
  40    * a type whose class can be determined by querying the type, for example
  41    * an nsIContentType which is also an nsIMIMEType or an nsIProtocolScheme),
  42    * and return a handler info object representing only the user info.
  43    *
  44    * Note: if you specify an override type, then the service will fill in
  45    * the handler info object with information about that type instead of
  46    * the type specified by the object's nsIHandlerInfo::type attribute.
  47    *
  48    * This is useful when you are trying to retrieve information about a MIME
  49    * type that doesn't exist in the datastore, but you have a file extension
  50    * for that type, and nsIHandlerService::getTypeFromExtension returns another
  51    * MIME type that does exist in the datastore and can handle that extension.
  52    *
  53    * For example, the user clicks on a link, and the content has a MIME type
  54    * that isn't in the datastore, but the link has a file extension, and that
  55    * extension is associated with another MIME type in the datastore (perhaps
  56    * an unofficial MIME type preceded an official one, like with image/x-png
  57    * and image/png).
  58    *
  59    * In that situation, you can call this method to fill in the handler info
  60    * object with information about that other type by passing the other type
  61    * as the aOverrideType parameter.
  62    *
  63    * @param aHandlerInfo   the handler info object
  64    * @param aOverrideType  a type to use instead of aHandlerInfo::type
  65    *
  66    * Note: if there is no information in the datastore about this type,
  67    * this method throws NS_ERROR_NOT_AVAILABLE. Callers are encouraged to
  68    * check exists() before calling fillHandlerInfo(), to prevent spamming the
  69    * console with XPCOM exception errors.
  70    */
  71   void fillHandlerInfo(in nsIHandlerInfo aHandlerInfo,
  72                        in ACString aOverrideType);
  73
  74   /**
  75    * Save the preferred action, preferred handler, possible handlers, and
  76    * always ask properties of the given handler info object to the datastore.
  77    * Updates an existing record or creates a new one if necessary.
  78    *
  79    * Note: if preferred action is undefined or invalid, then we assume
  80    * the default value nsIHandlerInfo::useHelperApp.
  81    *
  82    * @param aHandlerInfo  the handler info object
  83    */
  84   void store(in nsIHandlerInfo aHandlerInfo);
  85
  86   /**
  87    * Whether or not a record for the given handler info object exists
  88    * in the datastore. If the datastore is corrupt (or some other error
  89    * is caught in the implementation), false will be returned.
  90    *
  91    * @param aHandlerInfo  a handler info object
  92    *
  93    * @returns whether or not a record exists
  94    */
  95   boolean exists(in nsIHandlerInfo aHandlerInfo);
  96
  97   /**
  98    * Remove the given handler info object from the datastore.  Deletes all
  99    * records associated with the object, including the preferred handler, info,
 100    * and type records plus the entry in the list of types, if they exist.
 101    * Otherwise, it does nothing and does not return an error.
 102    *
 103    * @param aHandlerInfo  the handler info object
 104    */
 105   void remove(in nsIHandlerInfo aHandlerInfo);
 106
 107   /**
 108    * Get the MIME type mapped to the given file extension in the datastore.
 109    *
 110    * XXX If we ever support extension -> protocol scheme mappings, then this
 111    * method should work for those as well.
 112    *
 113    * Note: in general, you should use nsIMIMEService::getTypeFromExtension
 114    * to get a MIME type from a file extension, as that method checks a variety
 115    * of other sources besides just the datastore.  Use this only when you want
 116    * to specifically get only the mapping available in the datastore.
 117    *
 118    * @param aFileExtension  the file extension
 119    *
 120    * @returns the MIME type, if any; otherwise returns an empty string ("").
 121    */
 122   ACString getTypeFromExtension(in ACString aFileExtension);
 123
 124   /**
 125    * Whether or not there is a handler known to the OS for the
 126    * specified protocol type.
 127    *
 128    * @param aProtocolScheme scheme to check for support
 129    *
 130    * @returns whether or not a handler exists
 131    */
 132   boolean existsForProtocolOS(in ACString aProtocolScheme);
 133
 134   /**
 135    * Whether or not there is a handler in the datastore or OS for
 136    * the specified protocol type. If there is no handler in the datastore,
 137    * falls back to a check for an OS handler.
 138    *
 139    * @param aProtocolScheme scheme to check for support
 140    *
 141    * @returns whether or not a handler exists
 142    */
 143   boolean existsForProtocol(in ACString aProtocolScheme);
 144
 145   /*
 146    * Fill in a handler info object using information from the OS, taking into
 147    * account the MIME type and file extension. When the OS handler
 148    * for the MIME type and extension match, |aFound| is returned as true. If
 149    * either the MIME type or extension is the empty string and a handler is
 150    * found, |aFound| is returned as true.
 151    */
 152   void getMIMEInfoFromOS(in nsIHandlerInfo aHandlerInfo,
 153                          in ACString aMIMEType,
 154                          in ACString aExtension,
 155                          out bool aFound);
 156
 157   /*
 158    * Get a description for the application responsible for handling
 159    * the provided protocol.
 160    */
 161   AString getApplicationDescription(in ACString aProtocolScheme);
 162 };