immutable: ValidatedExtendedURIProxy computes and stores the tail data size as a...

The "tail data size" is how many of the bytes of the tail segment are data (as opposed to padding).

diff --git a/src/allmydata/immutable/download.py b/src/allmydata/immutable/download.py
index 0f5a0f81f7292d3560f836039e018639e66382bf..25b3adb64f947fba67bf6790fc7f95cf6c8df388 100644 (file)
--- a/src/allmydata/immutable/download.py
+++ b/src/allmydata/immutable/download.py
@@ -204,6 +204,7 @@ class ValidatedExtendedURIProxy:
         self.block_size = None
         self.share_size = None
         self.num_segments = None
+        self.tail_data_size = None
         self.tail_segment_size = None
 
         # optional
@@ -246,11 +247,11 @@ class ValidatedExtendedURIProxy:
         self.block_size = mathutil.div_ceil(self.segment_size, self._verifycap.needed_shares)
         self.num_segments = mathutil.div_ceil(self._verifycap.size, self.segment_size)
 
-        tail_data_size = self._verifycap.size % self.segment_size
-        if not tail_data_size:
-            tail_data_size = self.segment_size
+        self.tail_data_size = self._verifycap.size % self.segment_size
+        if not self.tail_data_size:
+            self.tail_data_size = self.segment_size
         # padding for erasure code
-        self.tail_segment_size = mathutil.next_multiple(tail_data_size, self._verifycap.needed_shares)
+        self.tail_segment_size = mathutil.next_multiple(self.tail_data_size, self._verifycap.needed_shares)
 
         # Ciphertext hash tree root is mandatory, so that there is at most one ciphertext that
         # matches this read-cap or verify-cap.  The integrity check on the shares is not