uriloader/exthandler/nsIHandlerService.idl

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  20  * Contributor(s):
  21  *   Myk Melez <myk@mozilla.org>
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  36
  37 #include "nsISupports.idl"
  38
  39 interface nsIHandlerInfo;
  40 interface nsISimpleEnumerator;
  41
  42 [scriptable, uuid(53f0ad17-ec62-46a1-adbc-efccc06babcd)]
  43 interface nsIHandlerService : nsISupports
  44 {
  45   /**
  46    * Retrieve a list of all handlers in the datastore.  This list is not
  47    * guaranteed to be in any particular order, and callers should not assume
  48    * it will remain in the same order in the future.
  49    *
  50    * @returns a list of all handlers in the datastore
  51    */
  52   nsISimpleEnumerator enumerate();
  53
  54   /**
  55    * Fill a handler info object with information from the datastore.
  56    *
  57    * Note: because of the way the external helper app service currently mixes
  58    * OS and user handler info in the same handler info object, this method
  59    * takes an existing handler info object (probably retrieved from the OS)
  60    * and "fills it in" with information from the datastore, overriding any
  61    * existing properties on the object with properties from the datastore.
  62    *
  63    * Ultimately, however, we're going to separate OS and user handler info
  64    * into separate objects, at which point this method should be renamed to
  65    * something like "get" or "retrieve", take a class and type (or perhaps
  66    * a type whose class can be determined by querying the type, for example
  67    * an nsIContentType which is also an nsIMIMEType or an nsIProtocolScheme),
  68    * and return a handler info object representing only the user info.
  69    *
  70    * Note: if you specify an override type, then the service will fill in
  71    * the handler info object with information about that type instead of
  72    * the type specified by the object's nsIHandlerInfo::type attribute.
  73    *
  74    * This is useful when you are trying to retrieve information about a MIME
  75    * type that doesn't exist in the datastore, but you have a file extension
  76    * for that type, and nsIHandlerService::getTypeFromExtension returns another
  77    * MIME type that does exist in the datastore and can handle that extension.
  78    *
  79    * For example, the user clicks on a link, and the content has a MIME type
  80    * that isn't in the datastore, but the link has a file extension, and that
  81    * extension is associated with another MIME type in the datastore (perhaps
  82    * an unofficial MIME type preceded an official one, like with image/x-png
  83    * and image/png).
  84    *
  85    * In that situation, you can call this method to fill in the handler info
  86    * object with information about that other type by passing the other type
  87    * as the aOverrideType parameter.
  88    *
  89    * @param aHandlerInfo   the handler info object
  90    * @param aOverrideType  a type to use instead of aHandlerInfo::type
  91    *
  92    * Note: if there is no information in the datastore about this type,
  93    * this method throws NS_ERROR_NOT_AVAILABLE. Callers are encouraged to
  94    * check exists() before calling fillHandlerInfo(), to prevent spamming the
  95    * console with XPCOM exception errors.
  96    */
  97   void fillHandlerInfo(in nsIHandlerInfo aHandlerInfo,
  98                        in ACString aOverrideType);
  99
 100   /**
 101    * Save the preferred action, preferred handler, possible handlers, and
 102    * always ask properties of the given handler info object to the datastore.
 103    * Updates an existing record or creates a new one if necessary.
 104    *
 105    * Note: if preferred action is undefined or invalid, then we assume
 106    * the default value nsIHandlerInfo::useHelperApp.
 107    *
 108    * @param aHandlerInfo  the handler info object
 109    */
 110   void store(in nsIHandlerInfo aHandlerInfo);
 111
 112   /**
 113    * Whether or not a record for the given handler info object exists
 114    * in the datastore. If the datastore is corrupt (or some other error
 115    * is caught in the implementation), false will be returned.
 116    *
 117    * @param aHandlerInfo  a handler info object
 118    *
 119    * @returns whether or not a record exists
 120    */
 121   boolean exists(in nsIHandlerInfo aHandlerInfo);
 122
 123   /**
 124    * Remove the given handler info object from the datastore.  Deletes all
 125    * records associated with the object, including the preferred handler, info,
 126    * and type records plus the entry in the list of types, if they exist.
 127    * Otherwise, it does nothing and does not return an error.
 128    *
 129    * @param aHandlerInfo  the handler info object
 130    */
 131   void remove(in nsIHandlerInfo aHandlerInfo);
 132
 133   /**
 134    * Get the MIME type mapped to the given file extension in the datastore.
 135    *
 136    * XXX If we ever support extension -> protocol scheme mappings, then this
 137    * method should work for those as well.
 138    *
 139    * Note: in general, you should use nsIMIMEService::getTypeFromExtension
 140    * to get a MIME type from a file extension, as that method checks a variety
 141    * of other sources besides just the datastore.  Use this only when you want
 142    * to specifically get only the mapping available in the datastore.
 143    *
 144    * @param aFileExtension  the file extension
 145    *
 146    * @returns the MIME type, if any; otherwise returns an empty string ("").
 147    */
 148   ACString getTypeFromExtension(in ACString aFileExtension);
 149 };