Changes in src/sas/sascalc/dataloader/loader.py [463e7ffc:dcb91cf] in sasview

File:

• src/sas/sascalc/dataloader/loader.py (modified) (5 diffs)

src/sas/sascalc/dataloader/loader.py

@@ -1 +1 @@
 """
     File handler to support different file extensions.
-    Uses reflectometry's registry utility.
+    Uses reflectometer registry utility.
 
     The default readers are found in the 'readers' sub-module
@@ -14 +14 @@
 """
 #####################################################################
-#This software was developed by the University of Tennessee as part of the
-#Distributed Data Analysis of Neutron Scattering Experiments (DANSE)
-#project funded by the US National Science Foundation.
-#See the license text in license.txt
-#copyright 2008, University of Tennessee
+# This software was developed by the University of Tennessee as part of the
+# Distributed Data Analysis of Neutron Scattering Experiments (DANSE)
+# project funded by the US National Science Foundation.
+# See the license text in license.txt
+# copyright 2008, University of Tennessee
 ######################################################################
 
@@ -29 +29 @@
 # Default readers are defined in the readers sub-module
 import readers
+from loader_exceptions import NoKnownLoaderException, FileContentsException,\
+    DefaultReaderException
 from readers import ascii_reader
 from readers import cansas_reader
+from readers import cansas_reader_HDF5
 
 logger = logging.getLogger(__name__)
+
 
 class Registry(ExtensionRegistry):
@@ -39 +43 @@
     Readers and writers are supported.
     """
-
     def __init__(self):
         super(Registry, self).__init__()
 
-        ## Writers
+        # Writers
         self.writers = {}
 
-        ## List of wildcards
+        # List of wildcards
         self.wildcards = ['All (*.*)|*.*']
 
-        ## Creation time, for testing
+        # Creation time, for testing
         self._created = time.time()
 
@@ -63 +66 @@
             of a particular reader
 
-        Defaults to the ascii (multi-column) reader
-        if no reader was registered for the file's
-        extension.
-        """
+        Defaults to the ascii (multi-column), cansas XML, and cansas NeXuS
+        readers if no reader was registered for the file's extension.
+        """
+        # Gets set to a string if the file has an associated reader that fails
+        msg_from_reader = None
         try:
             return super(Registry, self).load(path, format=format)
-        except:
-            try:
-                # No reader was found. Default to the ascii reader.
-                ascii_loader = ascii_reader.Reader()
-                return ascii_loader.read(path)
-            except:
-                cansas_loader = cansas_reader.Reader()
-                return cansas_loader.read(path)
+        except NoKnownLoaderException as nkl_e:
+            pass  # Try the ASCII reader
+        except FileContentsException as fc_exc:
+            # File has an associated reader but it failed.
+            # Save the error message to display later, but try the 3 default loaders
+            msg_from_reader = fc_exc.message
+        except Exception:
+            pass
+
+        # File has no associated reader, or the associated reader failed.
+        # Try the ASCII reader
+        try:
+            ascii_loader = ascii_reader.Reader()
+            return ascii_loader.read(path)
+        except DefaultReaderException:
+            pass  # Loader specific error to try the cansas XML reader
+        except FileContentsException as e:
+            if msg_from_reader is None:
+                raise RuntimeError(e.message)
+
+        # ASCII reader failed - try CanSAS xML reader
+        try:
+            cansas_loader = cansas_reader.Reader()
+            return cansas_loader.read(path)
+        except DefaultReaderException:
+            pass  # Loader specific error to try the NXcanSAS reader
+        except FileContentsException as e:
+            if msg_from_reader is None:
+                raise RuntimeError(e.message)
+        except Exception:
+            pass
+
+        # CanSAS XML reader failed - try NXcanSAS reader
+        try:
+            cansas_nexus_loader = cansas_reader_HDF5.Reader()
+            return cansas_nexus_loader.read(path)
+        except DefaultReaderException as e:
+            logging.error("No default loader can load the data")
+            # No known reader available. Give up and throw an error
+            if msg_from_reader is None:
+                msg = "\nUnknown data format: {}.\nThe file is not a ".format(path)
+                msg += "known format that can be loaded by SasView.\n"
+                raise NoKnownLoaderException(msg)
+            else:
+                # Associated reader and default readers all failed.
+                # Show error message from associated reader
+                raise RuntimeError(msg_from_reader)
+        except FileContentsException as e:
+            err_msg = msg_from_reader if msg_from_reader is not None else e.message
+            raise RuntimeError(err_msg)
 
     def find_plugins(self, dir):