Changes in src/sas/sascalc/data_util/registry.py [3ece5dd:a1b8fee] in sasview

File:

• src/sas/sascalc/data_util/registry.py (modified) (8 diffs)

src/sas/sascalc/data_util/registry.py

@@ +1 @@
+# This program is public domain
 """
 File extension registry.
@@ -5 +6 @@
 and registers the built-in file extensions.
 """
+from __future__ import print_function
 
-from sas.sascalc.dataloader.loader_exceptions import NoKnownLoaderException
-
+import os.path
 
 class ExtensionRegistry(object):
@@ -21 +22 @@
         # Add an association by setting an element
         registry['.zip'] = unzip
-
+        
         # Multiple extensions for one loader
         registry['.tgz'] = untar
         registry['.tar.gz'] = untar
 
-        # Generic extensions to use after trying more specific extensions;
+        # Generic extensions to use after trying more specific extensions; 
         # these will be checked after the more specific extensions fail.
         registry['.gz'] = gunzip
@@ -37 +38 @@
         # Show registered extensions
         print registry.extensions()
-
+        
         # Can also register a format name for explicit control from caller
         registry['cx3'] = cx3
@@ -61 +62 @@
     def __init__(self, **kw):
         self.loaders = {}
-
     def __setitem__(self, ext, loader):
         if ext not in self.loaders:
             self.loaders[ext] = []
         self.loaders[ext].insert(0,loader)
-
     def __getitem__(self, ext):
         return self.loaders[ext]
-
     def __contains__(self, ext):
         return ext in self.loaders
-
     def formats(self):
         """
@@ -80 +77 @@
         names.sort()
         return names
-
     def extensions(self):
         """
@@ -88 +84 @@
         exts.sort()
         return exts
-
     def lookup(self, path):
         """
         Return the loader associated with the file type of path.
-
-        :param path: Data file path
-        :raises ValueError: When no loaders are found for the file.
-        :return: List of available readers for the file extension
-        """
+        
+        Raises ValueError if file type is not known.
+        """        
         # Find matching extensions
         extlist = [ext for ext in self.extensions() if path.endswith(ext)]
@@ -113 +106 @@
         # Raise an error if there are no matching extensions
         if len(loaders) == 0:
-            raise ValueError("Unknown file type for "+path)
+            raise ValueError, "Unknown file type for "+path
+        # All done
         return loaders
-
     def load(self, path, format=None):
         """
         Call the loader for the file type of path.
 
-        :raise ValueError: if no loader is available.
-        :raise KeyError: if format is not available.
-        May raise a loader-defined exception if loader fails.
+        Raises ValueError if no loader is available.
+        Raises KeyError if format is not available.
+        May raise a loader-defined exception if loader fails.        
         """
-        loaders = []
         if format is None:
-            try:
-                loaders = self.lookup(path)
-            except ValueError as e:
-                pass
+            loaders = self.lookup(path)
         else:
-            try:
-                loaders = self.loaders[format]
-            except KeyError as e:
-                pass
-        last_exc = None
+            loaders = self.loaders[format]
         for fn in loaders:
             try:
                 return fn(path)
-            except Exception as e:
-                last_exc = e
-                pass  # give other loaders a chance to succeed
+            except:
+                pass # give other loaders a chance to succeed
         # If we get here it is because all loaders failed
-        if last_exc is not None and len(loaders) != 0:
-            # If file has associated loader(s) and they;ve failed
-            raise last_exc
-        raise NoKnownLoaderException(e.message)  # raise generic exception
+        raise # reraises last exception
+
+def test():
+    reg = ExtensionRegistry()
+    class CxError(Exception): pass
+    def cx(file): return 'cx'
+    def new_cx(file): return 'new_cx'
+    def fail_cx(file): raise CxError
+    def cat(file): return 'cat'
+    def gunzip(file): return 'gunzip'
+    reg['.cx'] = cx
+    reg['.cx1'] = cx
+    reg['.cx'] = new_cx
+    reg['.gz'] = gunzip
+    reg['.cx.gz'] = new_cx
+    reg['.cx1.gz'] = fail_cx
+    reg['.cx1'] = fail_cx
+    reg['.cx2'] = fail_cx
+    reg['new_cx'] = new_cx
+
+    # Two loaders associated with .cx
+    assert reg.lookup('hello.cx') == [new_cx,cx]
+    # Make sure the last loader applies first
+    assert reg.load('hello.cx') == 'new_cx'
+    # Make sure the next loader applies if the first fails
+    assert reg.load('hello.cx1') == 'cx'
+    # Make sure the format override works
+    assert reg.load('hello.cx1',format='.cx.gz') == 'new_cx'
+    # Make sure the format override works
+    assert reg.load('hello.cx1',format='new_cx') == 'new_cx'
+    # Make sure the case of all loaders failing is correct
+    try:  reg.load('hello.cx2')
+    except CxError: pass # correct failure
+    else: raise AssertError,"Incorrect error on load failure"
+    # Make sure the case of no loaders fails correctly
+    try: reg.load('hello.missing')
+    except ValueError,msg:
+        assert str(msg)=="Unknown file type for hello.missing",'Message: <%s>'%(msg)
+    else: raise AssertError,"No error raised for missing extension"
+    assert reg.formats() == ['new_cx']
+    assert reg.extensions() == ['.cx','.cx.gz','.cx1','.cx1.gz','.cx2','.gz']
+    # make sure that it supports multiple '.' in filename
+    assert reg.load('hello.extra.cx1') == 'cx'
+    assert reg.load('hello.gz') == 'gunzip'
+    assert reg.load('hello.cx1.gz') == 'gunzip' # Since .cx1.gz fails
+
+if __name__ == "__main__": test()