From db5efc27c51ee2422bdb2ee794897531bdef3ac5 Mon Sep 17 00:00:00 2001
From: Brandon Salmon <brandonsalmon@google.com>
Date: Wed, 24 Jun 2015 12:06:59 -0700
Subject: [PATCH] Fixed off by one error in GetRange.

---
 apitools/base/py/transfer.py      | 20 ++++++++++++++------
 apitools/base/py/transfer_test.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/apitools/base/py/transfer.py b/apitools/base/py/transfer.py
index 35a4774a..f1802f04 100644
--- a/apitools/base/py/transfer.py
+++ b/apitools/base/py/transfer.py
@@ -366,10 +366,18 @@ def __ComputeEndByte(self, start, end=None, use_chunks=True):
         end_byte = end
         if use_chunks:
             alternate = start + self.chunksize - 1
-            end_byte = min(end_byte, alternate) if end_byte else alternate
+            if end_byte is not None:
+                end_byte = min(end_byte, alternate)
+            else:
+                end_byte = alternate
+
         if self.total_size:
             alternate = self.total_size - 1
-            end_byte = min(end_byte, alternate) if end_byte else alternate
+            if end_byte is not None:
+                end_byte = min(end_byte, alternate)
+            else:
+                end_byte = alternate
+
         return end_byte
 
     def __GetChunk(self, start, end, additional_headers=None):
@@ -434,18 +442,18 @@ def GetRange(self, start, end=None, additional_headers=None,
         self.EnsureInitialized()
         progress_end_normalized = False
         if self.total_size is not None:
-            progress, end = self.__NormalizeStartEnd(start, end)
+            progress, end_byte = self.__NormalizeStartEnd(start, end)
             progress_end_normalized = True
         else:
             progress = start
-        while not progress_end_normalized or progress < end:
-            end_byte = self.__ComputeEndByte(progress, end=end,
+        while not progress_end_normalized or progress <= end_byte:
+            end_byte = self.__ComputeEndByte(progress, end=end_byte,
                                              use_chunks=use_chunks)
             response = self.__GetChunk(progress, end_byte,
                                        additional_headers=additional_headers)
             if not progress_end_normalized:
                 self.__SetTotal(response.info)
-                progress, end = self.__NormalizeStartEnd(start, end)
+                progress, end_byte = self.__NormalizeStartEnd(start, end)
                 progress_end_normalized = True
             response = self.__ProcessResponse(response)
             progress += response.length
diff --git a/apitools/base/py/transfer_test.py b/apitools/base/py/transfer_test.py
index 9d58b1ea..8e29f128 100644
--- a/apitools/base/py/transfer_test.py
+++ b/apitools/base/py/transfer_test.py
@@ -76,6 +76,36 @@ def testComputeEndByteSmallTotal(self):
                              download._Download__ComputeEndByte(start),
                              msg='Failed on start={0}'.format(start))
 
+    def testGetRange(self):
+        for (start_byte, end_byte) in [(0, 25), (5, 15), (0, 0), (25, 25)]:
+            bytes_http = object()
+            http = object()
+            download_stream = six.StringIO()
+            download = transfer.Download.FromStream(download_stream,
+                                                    total_size=26,
+                                                    auto_transfer=False)
+            download.bytes_http = bytes_http
+            base_url = 'https://part.one/'
+            with mock.patch.object(http_wrapper, 'MakeRequest',
+                                   autospec=True) as make_request:
+                make_request.return_value = http_wrapper.Response(
+                    info={
+                        'content-range': 'bytes %d-%d/26' %
+                                         (start_byte, end_byte),
+                        'status': http_client.OK,
+                    },
+                    content=string.ascii_lowercase[start_byte:end_byte+1],
+                    request_url=base_url,
+                )
+                request = http_wrapper.Request(url='https://part.one/')
+                download.InitializeDownload(request, http=http)
+                download.GetRange(start_byte, end_byte)
+                self.assertEqual(1, make_request.call_count)
+                received_request = make_request.call_args[0][1]
+                self.assertEqual(base_url, received_request.url)
+                self.assertRangeAndContentRangeCompatible(
+                    received_request, make_request.return_value)
+
     def testNonChunkedDownload(self):
         bytes_http = object()
         http = object()