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    * Retrieve a list of all handlers in the datastore.  This list is not
  15    * guaranteed to be in any particular order, and callers should not assume
  16    * it will remain in the same order in the future.
  17    *
  18    * @returns a list of all handlers in the datastore
  19    */
  20   nsISimpleEnumerator enumerate();
  21
  22   /**
  23    * Fill a handler info object with information from the datastore.
  24    *
  25    * Note: because of the way the external helper app service currently mixes
  26    * OS and user handler info in the same handler info object, this method
  27    * takes an existing handler info object (probably retrieved from the OS)
  28    * and "fills it in" with information from the datastore, overriding any
  29    * existing properties on the object with properties from the datastore.
  30    *
  31    * Ultimately, however, we're going to separate OS and user handler info
  32    * into separate objects, at which point this method should be renamed to
  33    * something like "get" or "retrieve", take a class and type (or perhaps
  34    * a type whose class can be determined by querying the type, for example
  35    * an nsIContentType which is also an nsIMIMEType or an nsIProtocolScheme),
  36    * and return a handler info object representing only the user info.
  37    *
  38    * Note: if you specify an override type, then the service will fill in
  39    * the handler info object with information about that type instead of
  40    * the type specified by the object's nsIHandlerInfo::type attribute.
  41    *
  42    * This is useful when you are trying to retrieve information about a MIME
  43    * type that doesn't exist in the datastore, but you have a file extension
  44    * for that type, and nsIHandlerService::getTypeFromExtension returns another
  45    * MIME type that does exist in the datastore and can handle that extension.
  46    *
  47    * For example, the user clicks on a link, and the content has a MIME type
  48    * that isn't in the datastore, but the link has a file extension, and that
  49    * extension is associated with another MIME type in the datastore (perhaps
  50    * an unofficial MIME type preceded an official one, like with image/x-png
  51    * and image/png).
  52    *
  53    * In that situation, you can call this method to fill in the handler info
  54    * object with information about that other type by passing the other type
  55    * as the aOverrideType parameter.
  56    *
  57    * @param aHandlerInfo   the handler info object
  58    * @param aOverrideType  a type to use instead of aHandlerInfo::type
  59    *
  60    * Note: if there is no information in the datastore about this type,
  61    * this method throws NS_ERROR_NOT_AVAILABLE. Callers are encouraged to
  62    * check exists() before calling fillHandlerInfo(), to prevent spamming the
  63    * console with XPCOM exception errors.
  64    */
  65   void fillHandlerInfo(in nsIHandlerInfo aHandlerInfo,
  66                        in ACString aOverrideType);
  67
  68   /**
  69    * Save the preferred action, preferred handler, possible handlers, and
  70    * always ask properties of the given handler info object to the datastore.
  71    * Updates an existing record or creates a new one if necessary.
  72    *
  73    * Note: if preferred action is undefined or invalid, then we assume
  74    * the default value nsIHandlerInfo::useHelperApp.
  75    *
  76    * @param aHandlerInfo  the handler info object
  77    */
  78   void store(in nsIHandlerInfo aHandlerInfo);
  79
  80   /**
  81    * Whether or not a record for the given handler info object exists
  82    * in the datastore. If the datastore is corrupt (or some other error
  83    * is caught in the implementation), false will be returned.
  84    *
  85    * @param aHandlerInfo  a handler info object
  86    *
  87    * @returns whether or not a record exists
  88    */
  89   boolean exists(in nsIHandlerInfo aHandlerInfo);
  90
  91   /**
  92    * Remove the given handler info object from the datastore.  Deletes all
  93    * records associated with the object, including the preferred handler, info,
  94    * and type records plus the entry in the list of types, if they exist.
  95    * Otherwise, it does nothing and does not return an error.
  96    *
  97    * @param aHandlerInfo  the handler info object
  98    */
  99   void remove(in nsIHandlerInfo aHandlerInfo);
 100
 101   /**
 102    * Get the MIME type mapped to the given file extension in the datastore.
 103    *
 104    * XXX If we ever support extension -> protocol scheme mappings, then this
 105    * method should work for those as well.
 106    *
 107    * Note: in general, you should use nsIMIMEService::getTypeFromExtension
 108    * to get a MIME type from a file extension, as that method checks a variety
 109    * of other sources besides just the datastore.  Use this only when you want
 110    * to specifically get only the mapping available in the datastore.
 111    *
 112    * @param aFileExtension  the file extension
 113    *
 114    * @returns the MIME type, if any; otherwise returns an empty string ("").
 115    */
 116   ACString getTypeFromExtension(in ACString aFileExtension);
 117 };