Fix for BUG#26194 "mysqlbinlog --base64-output produces invalid SQL";

when it was printing a Query event, it produced invalid SQL (missing
the BINLOG keyword, so the SQL started with the base64 string, which
is incorrect).
Note: no testcase; I have a .test which shows that the bugfix works,
but it triggers BUG#26361 and so gives Valgrind warnings. I'm sending
this test to the fixer of BUG#26361 for her/him to push when she/he
fixes BUG#26361.


client/mysqlbinlog.cc:
  writing the header (a line started with "#", i.e. a comment) and the
  body (the real operation) of an event to the same IO_CACHE
  (result_cache) confused the logic of Log_event::print_base64()
  (which is that if the cache is not empty then the BINLOG keyword
  should not be printed); it caused the BINLOG keyword to miss hence
  a syntactically wrong output of "mysqlbinlog --base64-output"
  for Query events.
  So we just use the two IO_CACHE already available in "print_event_info".
sql/log_event.cc:
  using the new small inline function.
  Note that the replication code should one day be fixed to trap all
  errors (like disk write errors).
sql/log_event.h:
  small inline function to group two operations: copying an IO_CACHE
  to a FILE, and reinitializing this IO_CACHE for being filled again.
sql/records.cc:
  fix after merge

1 files changed, 3 insertions, 6 deletions

diff --git a/sql/log_event.cc b/sql/log_event.cc
index f8d3c43bfba..dc411c14f93 100644
--- a/sql/log_event.cc
+++ b/sql/log_event.cc
@@ -75,8 +75,7 @@ public:
 
   ~Write_on_release_cache()
   {
-    if (!my_b_copy_to_file(m_cache, m_file))
-      reinit_io_cache(m_cache, WRITE_CACHE, 0L, FALSE, TRUE);
+    copy_event_cache_to_file_and_reinit(m_cache, m_file);
     if (m_flags | FLUSH_F)
       fflush(m_file);
   }
@@ -6160,10 +6159,8 @@ void Rows_log_event::print_helper(FILE *file,
 
   if (get_flags(STMT_END_F))
   {
-    my_b_copy_to_file(head, file);
-    my_b_copy_to_file(body, file);
-    reinit_io_cache(head, WRITE_CACHE, 0, FALSE, TRUE);
-    reinit_io_cache(body, WRITE_CACHE, 0, FALSE, TRUE);
+    copy_event_cache_to_file_and_reinit(head, file);
+    copy_event_cache_to_file_and_reinit(body, file);
   }
 }
 #endif