Removed the "all files are refs" error message and made the "no files, can't scan" message quicker. That's because when scanning iPhoto libraries with big libraries, the GUI would hang because these checks would involve loading the whole library.

cocoa/me/ResultWindow.m

@@ -69,8 +69,6 @@ http://www.hardcoded.net/licenses/hs_license
     [_py setMixFileKind:[ud objectForKey:@"mixFileKind"]];
     [_py setMatchSimilarWords:[ud objectForKey:@"matchSimilarWords"]];
     NSInteger r = n2i([py doScan]);
-    if (r == 1)
-        [Dialogs showMessage:@"You cannot make a duplicate scan with only reference directories."];
     if (r == 3)
     {
         [Dialogs showMessage:@"The selected directories contain no scannable file."];

cocoa/pe/ResultWindow.m

@@ -65,8 +65,6 @@ http://www.hardcoded.net/licenses/hs_license
     int r = n2i([py doScan]);
     if (r != 0)
         [[ProgressController mainProgressController] hide];
-    if (r == 1)
-        [Dialogs showMessage:@"You cannot make a duplicate scan with only reference directories."];
     if (r == 3)
     {
         [Dialogs showMessage:@"The selected directories contain no scannable file."];

cocoa/se/ResultWindow.m

@@ -59,8 +59,6 @@ http://www.hardcoded.net/licenses/hs_license
     int r = n2i([py doScan]);
     if (r != 0)
         [[ProgressController mainProgressController] hide];
-    if (r == 1)
-        [Dialogs showMessage:@"You cannot make a duplicate scan with only reference directories."];
     if (r == 3)
     {
         [Dialogs showMessage:@"The selected directories contain no scannable file."];

core/app.py

@@ -33,9 +33,6 @@ JOB_DELETE = 'job_delete'
 class NoScannableFileError(Exception):
     pass
 
-class AllFilesAreRefError(Exception):
-    pass
-
 class DupeGuru(RegistrableApplication, Broadcaster):
     DEMO_LIMIT_DESC = "In the demo version, only 10 duplicates per session can be sent to the recycle bin, moved or copied."
     
@@ -347,12 +344,8 @@ class DupeGuru(RegistrableApplication, Broadcaster):
             logging.info('Scanning %d files' % len(files))
             self.results.groups = self.scanner.GetDupeGroups(files, j)
         
-        files = self.directories.get_files()
+        if not self.directories.has_any_file():
-        first_file = first(files)
-        if first_file is None:
             raise NoScannableFileError()
-        if first_file.is_ref and all(f.is_ref for f in files):
-            raise AllFilesAreRefError()
         self.results.groups = []
         self._start_job(JOB_SCAN, do)
     

core/app_cocoa.py

@@ -76,6 +76,4 @@ class DupeGuru(app.DupeGuru):
             return 0
         except app.NoScannableFileError:
             return 3
-        except app.AllFilesAreRefError:
-            return 1
     

core/directories.py

@@ -124,6 +124,13 @@ class Directories(object):
         else:
             return STATE_NORMAL
     
+    def has_any_file(self):
+        try:
+            next(self.get_files())
+            return True
+        except StopIteration:
+            return False
+    
     def load_from_file(self, infile):
         try:
             root = ET.parse(infile).getroot()

core_pe/app_cocoa.py

@@ -122,6 +122,15 @@ class Directories(directories.Directories):
         else:
             directories.Directories.add_path(self, path)
     
+    def has_any_file(self):
+        # If we don't do that, it causes a hangup in the GUI when we click Start Scanning because
+        # checking if there's any file to scan involves reading the whole library. If we have the
+        # iPhoto library, we assume we have at least one file.
+        if any(path == Path('iPhoto Library') for path in self._dirs):
+            return True
+        else:
+            return directories.Directories.has_any_file(self)
+    
 
 class DupeGuruPE(app_cocoa.DupeGuru):
     def __init__(self):

qt/base/main_window.py

@@ -14,7 +14,7 @@ from PyQt4.QtGui import (QMainWindow, QMenu, QPixmap, QIcon, QToolButton, QLabel
 
 from hsutil.misc import nonone
 
-from core.app import NoScannableFileError, AllFilesAreRefError
+from core.app import NoScannableFileError
 
 from . import dg_rc
 from .main_window_ui import Ui_MainWindow
@@ -271,9 +271,6 @@ class MainWindow(QMainWindow, Ui_MainWindow):
             msg = "The selected directories contain no scannable file."
             QMessageBox.warning(self, title, msg)
             self.app.show_directories()
-        except AllFilesAreRefError:
-            msg = "You cannot make a duplicate scan with only reference directories."
-            QMessageBox.warning(self, title, msg)
     
     def showHelpTriggered(self):
         self.app.show_help()