Fix to #473, http://bugs.skysql.com/show_bug.cgi?id=473
Several memory issues. Read the code.
In general one-off hint is only added to gwbuf and freed in gwbuf_free. Stacked hint is copied to stack and to gwbuf. gwbuf is freed after routing but stacked hint is freed either in stop or when session is closed. All this applies to named hint as well except that in addition, it has one more copy in named hint struct which is emptied when session is closed.
hintparser.c:hint_parser:when string token is found, create a copy of the token value instead of copying the its address because token will be freed before the value is used.
hint_next_token:didn't recognize '=' as TOK_EQUAL, fixed that. Read the code.
hint.c:hint_create_parameter: copy the pointer to parameter name instead of creating copy of it - pname is already copied from token before the call
readwritesplit.c:routeQuery:Hint name was copied when hint value was supposed to be copied, thus resulting invalid value for hinted parameter. Also fixed server type in trace log command.
skygw_debug.h:Added string for Relay server to macro STRSRVSTATUS.
session.c:session_setup_filters : fixed memory leak
hintparser.c: added token_free for HINT_TOKENs and fixed a few memory leaks.
mysql_client_server_protocol.h: added mysql_protocol_done which frees memory blocks pointed to by protocol members. Those can't be freed in dcb.c because dcb.c doesn't know about protocol's members.
mysql_backend.c:gw_backend_close: fixed memory leak
mysql_client.c: gw_client_close: fixed memory leak
mysql_common.c: added implementation of mysql_protocol_done
:protocol_archive_srv_command: tried to fix memory leak. Some memory is still leaking according to valgrind. Removed use of uninitialized local variable len.
readwritesplit.c: Fix to bug #469, http://bugs.skysql.com/show_bug.cgi?id=469, rwsplit counts every connection twice in master - counnection counts leak
execute_sescmd_in_backend: fixed a memory leak - visible only in DEBUG=Y build.
readwritesplit/test/makefile: added target for hints tests
buffer.c: added memory release for hint of a GWBUF
hint.c: added bool hint_exists()
hint.h: added placeholder for hint type HINT_ROUTE_TO_ALL which doesn't have implementation yet.
filter/Makefile: fixed dependency issue
hintparser.c: added const char* token_get_keyword(), hint_parser:added NULL check, hint_next_token: fixed off-by-one bug
readwritesplit.h: added bitfield for hints' use, which includes route targets and flag for case where user hinted to route to named backend server.
readwritesplit.c: added function route_target_t get_route_target() for resolving route target based on 1) query type (from query_classifier) 2) transaction state (active/not) and 3) hints. Modified get_dcb, which is called in routeQuery to provide pointer to correct backend DCB. Now get_dcb also takes server unique name as a parameter if such a hint was found. for hints' use, which includes enter the commit message for your changes.
Added counter clean-up code to readwritesplit closeSession. If operation counters have leaked, that is, due to some error in query routing some counter have been left positive, it is zeroed at session ending. This ensures that there is no garbage in global counter even if individual session wouldn't clean up its counters.
Fixed bug in session command resul handling. In case where backend sent error message the session command cursor wasn't updated properly.
Added check to bref_clear_state, if bref's waiter counter would go negative, decrement to global operation counter is skipped.
