Index: subversion/libsvn_delta/svndiff.c
===================================================================
--- subversion/libsvn_delta/svndiff.c	(revision 1416173)
+++ subversion/libsvn_delta/svndiff.c	(working copy)
@@ -34,6 +34,8 @@
 #include "private/svn_error_private.h"
 #include "private/svn_delta_private.h"
 
+static void log_window(svn_txdelta_window_t *window);
+
 /* The zlib compressBound function was not exported until 1.2.0. */
 #if ZLIB_VERNUM >= 0x1200
 #define svnCompressBound(LEN) compressBound(LEN)
@@ -230,9 +232,9 @@
     }
 
   /* encode the window header.  */
-  header_current[0] = 0;  /* source offset == 0 */
-  header_current[1] = 0;  /* source length == 0 */
-  header_current = encode_int(header_current + 2, window->tview_len);
+  header_current = encode_int(header_current, window->sview_offset);
+  header_current = encode_int(header_current, window->sview_len);
+  header_current = encode_int(header_current, window->tview_len);
   header_current[0] = (unsigned char)ip_len;  /* 1 instruction */
   header_current = encode_int(&header_current[1], len);
 
@@ -263,6 +265,8 @@
   const svn_txdelta_op_t *op;
   apr_size_t len;
 
+  log_window(window);
+
   /* use specialized code if there is no source */
   if (window && !window->src_ops && window->num_ops == 1 && !eb->version)
     return svn_error_trace(send_simple_insertion_window(window, eb));
@@ -770,6 +774,21 @@
   return SVN_NO_ERROR;
 }
 
+static void
+log_window(svn_txdelta_window_t *window)
+{
+  if (window)
+    fprintf(stderr, "handler window: "
+            "{sview_offset = %ld, sview_len = %ld, tview_len = %ld, num_ops = %d, "
+            "src_ops = %d, ops->action = %s, new_data = 0x%x}\n",
+            window->sview_offset, window->sview_len, window->tview_len,
+            window->num_ops, window->src_ops,
+            window->ops->action_code == svn_txdelta_new ? "svn_txdelta_new" : "?",
+            window->new_data);
+  else
+    fprintf(stderr, "handler window: null\n");
+}
+
 static svn_error_t *
 write_handler(void *baton,
               const char *buffer,
@@ -877,6 +896,7 @@
                             inslen, newlen, p, db->subpool,
                             db->version));
       SVN_ERR(db->consumer_func(&window, db->consumer_baton));
+      log_window(&window);
 
       /* Make a new subpool and buffer, saving aside the remaining
          data in the old buffer.  */