1 files changed, 67 insertions, 0 deletions
diff --git a/openstackclient/common/progressbar.py b/openstackclient/common/progressbar.py
new file mode 100644
index 00000000..ef767a9c
--- /dev/null
+++ b/openstackclient/common/progressbar.py
@@ -0,0 +1,67 @@
+# Copyright 2013 OpenStack Foundation
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import sys
+
+
+class _ProgressBarBase(object):
+    """A progress bar provider for a wrapped obect.
+
+    Base abstract class used by specific class wrapper to show
+    a progress bar when the wrapped object are consumed.
+
+    :param wrapped: Object to wrap that hold data to be consumed.
+    :param totalsize: The total size of the data in the wrapped object.
+
+    :note: The progress will be displayed only if sys.stdout is a tty.
+    """
+
+    def __init__(self, wrapped, totalsize):
+        self._wrapped = wrapped
+        self._totalsize = float(totalsize)
+        self._show_progress = sys.stdout.isatty() and self._totalsize != 0
+        self._percent = 0
+
+    def _display_progress_bar(self, size_read):
+        if self._show_progress:
+            self._percent += size_read / self._totalsize
+            # Output something like this: [==========>             ] 49%
+            sys.stdout.write('\r[{0:<30}] {1:.0%}'.format(
+                '=' * int(round(self._percent * 29)) + '>', self._percent
+            ))
+            sys.stdout.flush()
+
+    def __getattr__(self, attr):
+        # Forward other attribute access to the wrapped object.
+        return getattr(self._wrapped, attr)
+
+
+class VerboseFileWrapper(_ProgressBarBase):
+    """A file wrapper with a progress bar.
+
+    The file wrapper shows and advances a progress bar whenever the
+    wrapped file's read method is called.
+    """
+
+    def read(self, *args, **kwargs):
+        data = self._wrapped.read(*args, **kwargs)
+        if data:
+            self._display_progress_bar(len(data))
+        else:
+            if self._show_progress:
+                # Break to a new line from the progress bar for incoming
+                # output.
+                sys.stdout.write('\n')
+        return data