1 files changed, 59 insertions, 4 deletions
diff --git a/fastimport/errors.py b/fastimport/errors.py
index 9a71d77..f2d5d88 100644
--- a/fastimport/errors.py
+++ b/fastimport/errors.py
@@ -16,18 +16,73 @@
 
 """Exception classes for fastimport"""
 
-from bzrlib import errors as bzr_errors
-
-
 # Prefix to messages to show location information
 _LOCATION_FMT = "line %(lineno)d: "
 
+# ImportError is heavily based on BzrError
 
-class ImportError(bzr_errors.BzrError):
+class ImportError(StandardError):
     """The base exception class for all import processing exceptions."""
 
     _fmt = "Unknown Import Error"
 
+    def __init__(self, msg=None, **kwds):
+        StandardError.__init__(self)
+        if msg is not None:
+            self._preformatted_string = msg
+        else:
+            self._preformatted_string = None
+            for key, value in kwds.items():
+                setattr(self, key, value)
+
+    def _format(self):
+        s = getattr(self, '_preformatted_string', None)
+        if s is not None:
+            # contains a preformatted message
+            return s
+        try:
+            fmt = self._fmt
+            if fmt:
+                d = dict(self.__dict__)
+                s = fmt % d
+                # __str__() should always return a 'str' object
+                # never a 'unicode' object.
+                return s
+        except (AttributeError, TypeError, NameError, ValueError, KeyError), e:
+            return 'Unprintable exception %s: dict=%r, fmt=%r, error=%r' \
+                % (self.__class__.__name__,
+                   self.__dict__,
+                   getattr(self, '_fmt', None),
+                   e)
+
+    def __unicode__(self):
+        u = self._format()
+        if isinstance(u, str):
+            # Try decoding the str using the default encoding.
+            u = unicode(u)
+        elif not isinstance(u, unicode):
+            # Try to make a unicode object from it, because __unicode__ must
+            # return a unicode object.
+            u = unicode(u)
+        return u
+
+    def __str__(self):
+        s = self._format()
+        if isinstance(s, unicode):
+            s = s.encode('utf8')
+        else:
+            # __str__ must return a str.
+            s = str(s)
+        return s
+
+    def __repr__(self):
+        return '%s(%s)' % (self.__class__.__name__, str(self))
+
+    def __eq__(self, other):
+        if self.__class__ is not other.__class__:
+            return NotImplemented
+        return self.__dict__ == other.__dict__
+
 
 class ParsingError(ImportError):
     """The base exception class for all import processing exceptions."""