Change loaders registration to associate priority with MIME type

This changes the loader registration to associate a loader priority
with the MIME type.  This is more flexible than just associating a
priority with a loader itself.

Despite the difference, the API for ginga.util.loader has not changed.

ginga/rv/Control.py

@@ -834,7 +834,7 @@ def _check_open(errmsg):
                               "\nPlease choose an opener or cancel, for file:\n"
                               "{1:}".format(mimetype, filepath))
                     self.gui_do(self.gui_choose_file_opener, errmsg, openers,
-                                _open_file, '*', filepath)
+                                _open_file, mimetype, filepath)
 
         future = Future.Future()
         future.freeze(_check_open, warnmsg)
@@ -2505,17 +2505,13 @@ def choose_opener_cb(self, w, rsp, wgts, openers, open_cb, mimetype):
         bnch = bnchs[0]
         self.ds.remove_dialog(w)
 
-        if wgts.choice is not None and wgts.choice.get_state():
+        if (wgts.choice is not None and wgts.choice.get_state() and
+            mimetype is not None):
             # user wants us to remember their choice
-            if mimetype != '*':
-                # loader is not registered for this mimetype, so go ahead
-                # and do it
-                loader.add_opener(bnch.opener, [mimetype],
-                                  priority=bnch.priority, note=bnch.note)
-            else:
-                # multiple loaders for the same mimetype--
-                # remember setting by prioritizing choice
-                bnch.priority = -1
+            # loader is not registered for this mimetype, so go ahead
+            # and do it
+            loader.add_opener(bnch.opener, [mimetype],
+                              priority=-99, note=bnch.note)
 
         self.nongui_do(open_cb, bnch.opener)
         self.__next_dialog()

ginga/rv/main.py

@@ -448,13 +448,8 @@ def main(self, options, args):
 
         try:
             from ginga.util.io import io_fits
-            from ginga.util import loader
             if fitspkg != 'choose':
                 assert io_fits.use(fitspkg) is True
-                # opener name is not necessarily the same
-                opener = loader.get_opener(io_fits.fitsLoaderClass.name)
-                # set this opener as the priority one
-                opener.priority = -99
 
         except Exception as e:
             logger.warning(

ginga/util/io/io_fits.py

@@ -24,7 +24,7 @@
 from ginga.table.AstroTable import AstroTable
 
 from ginga.misc import Bunch
-from ginga.util import iohelper
+from ginga.util import iohelper, loader
 from ginga.util.io import io_base
 
 fits_configured = False
@@ -55,6 +55,9 @@ def use(fitspkg, raise_err=True):
         if have_astropy:
             fitsLoaderClass = AstropyFitsFileHandler
             fits_configured = True
+            # set this opener as the priority one
+            loader.add_opener(fitsLoaderClass, fitsLoaderClass.mimetypes,
+                              priority=-99, note=fitsLoaderClass.__doc__)
             return True
 
         elif raise_err:
@@ -67,6 +70,9 @@ def use(fitspkg, raise_err=True):
         if have_fitsio:
             fitsLoaderClass = FitsioFileHandler
             fits_configured = True
+            # set this opener as the priority one
+            loader.add_opener(fitsLoaderClass, fitsLoaderClass.mimetypes,
+                              priority=-99, note=fitsLoaderClass.__doc__)
             return True
 
         elif raise_err:

ginga/util/loader.py

@@ -103,17 +103,16 @@ def add_opener(opener, mimetypes, priority=0, note=''):
     global loader_by_mimetype, loader_registry
     if opener.name in loader_registry:
         loader_rec = loader_registry[opener.name]
+        loader_rec.mimetypes.update(set(mimetypes))
     else:
         loader_rec = Bunch.Bunch(name=opener.name, opener=opener,
-                                 mimetypes=mimetypes, priority=priority,
-                                 note=note)
+                                 mimetypes=set(mimetypes), note=note)
         loader_registry[opener.name] = loader_rec
 
+    mimetype_rec = Bunch.Bunch(opener=loader_rec, priority=priority)
     for mimetype in mimetypes:
-        bnchs = loader_by_mimetype.setdefault(mimetype, [])
-        if loader_rec not in bnchs:
-            bnchs.append(loader_rec)
-            bnchs.sort(key=lambda bnch: bnch.priority)
+        bnchs = loader_by_mimetype.setdefault(mimetype, {})
+        bnchs[opener.name] = mimetype_rec
 
 
 def get_opener(name):
@@ -128,14 +127,15 @@ def get_openers(mimetype):
     files, with all but the best (matching) priority removed.
     """
     global loader_by_mimetype
-    bnchs = loader_by_mimetype.setdefault(mimetype, [])
-    if len(bnchs) <= 1:
-        return bnchs
+    bnchs = loader_by_mimetype.setdefault(mimetype, {})
+    if len(bnchs) == 0:
+        return []
 
     # if there is more than one possible opener, return the list of
     # those that have the best (i.e. lowest) equal priority
-    priority = min([bnch.priority for bnch in bnchs])
-    return [bnch for bnch in bnchs if bnch.priority <= priority]
+    priority = min([bnch.priority for bnch in bnchs.values()])
+    return [loader_registry[name] for name, bnch in bnchs.items()
+            if bnch.priority <= priority]
 
 
 def get_all_openers():