Add support for new query cancel functions of PostgreSQL-17

This adds the new class `PG::CancelConnection` which provides the ability to cancel a query per blocking or per non-blocking functions.
If the new functions are available they are used and the older no longer compiled in.

This way we can get rid of reading out the internal `PGcancel` struct by `Connection#backend_key` .

Author: larskanis

ext/gvl_wrappers.c

@@ -12,6 +12,9 @@ PGresult *PQclosePortal(PGconn *conn, const char *portalName){return NULL;}
 int PQsendClosePrepared(PGconn *conn, const char *stmtName){return 0;}
 int PQsendClosePortal(PGconn *conn, const char *portalName){return 0;}
 int PQsendPipelineSync(PGconn *conn){return 0;}
+int PQcancelBlocking(PGcancelConn *cancelConn){return 0;}
+int PQcancelStart(PGcancelConn *cancelConn){return 0;}
+PostgresPollingStatusType PQcancelPoll(PGcancelConn *cancelConn){return PGRES_POLLING_FAILED;}
 #endif
 #ifndef HAVE_PQENTERPIPELINEMODE
 int PQpipelineSync(PGconn *conn){return 0;}

ext/gvl_wrappers.h

@@ -21,6 +21,10 @@
 #	include RUBY_EXTCONF_H
 #endif
 
+#ifndef HAVE_PQSETCHUNKEDROWSMODE
+typedef struct pg_cancel_conn PGcancelConn;
+#endif
+
 #define DEFINE_PARAM_LIST1(type, name) \
 	name,
 
@@ -217,6 +221,10 @@
 
 #define FOR_EACH_PARAM_OF_PQisBusy(param)
 
+#define FOR_EACH_PARAM_OF_PQcancelBlocking(param)
+#define FOR_EACH_PARAM_OF_PQcancelStart(param)
+#define FOR_EACH_PARAM_OF_PQcancelPoll(param)
+
 #define FOR_EACH_PARAM_OF_PQencryptPasswordConn(param) \
 	param(PGconn *, conn) \
 	param(const char *, passwd) \
@@ -260,6 +268,9 @@
 	function(PQsendPipelineSync, GVL_TYPE_NONVOID, int, PGconn *, conn) \
 	function(PQsetClientEncoding, GVL_TYPE_NONVOID, int, const char *, encoding) \
 	function(PQisBusy, GVL_TYPE_NONVOID, int, PGconn *, conn) \
+	function(PQcancelBlocking, GVL_TYPE_NONVOID, int, PGcancelConn *, conn) \
+	function(PQcancelStart, GVL_TYPE_NONVOID, int, PGcancelConn *, conn) \
+	function(PQcancelPoll, GVL_TYPE_NONVOID, PostgresPollingStatusType, PGcancelConn *, conn) \
 	function(PQencryptPasswordConn, GVL_TYPE_NONVOID, char *, const char *, algorithm) \
 	function(PQcancel, GVL_TYPE_NONVOID, int, int, errbufsize);
 

ext/pg.c

@@ -404,6 +404,10 @@ Init_pg_ext(void)
 	/* Checking if server is in standby mode. Available since PostgreSQL-14. */
 	rb_define_const(rb_mPGconstants, "CONNECTION_CHECK_STANDBY", INT2FIX(CONNECTION_CHECK_STANDBY));
 #endif
+#if PG_MAJORVERSION_NUM >= 17
+	/* Waiting for connection attempt to be started. Available since PostgreSQL-17. */
+	rb_define_const(rb_mPGconstants, "CONNECTION_ALLOCATED", INT2FIX(CONNECTION_ALLOCATED));
+#endif
 
 	/******     PG::Connection CLASS CONSTANTS: Nonblocking connection polling status     ******/
 
@@ -689,4 +693,5 @@ Init_pg_ext(void)
 	init_pg_copycoder();
 	init_pg_recordcoder();
 	init_pg_tuple();
+	init_pg_cancon();
 }

ext/pg.h

@@ -305,6 +305,7 @@ void init_pg_text_decoder                              _(( void ));
 void init_pg_binary_encoder                            _(( void ));
 void init_pg_binary_decoder                            _(( void ));
 void init_pg_tuple                                     _(( void ));
+void init_pg_cancon                                    _(( void ));
 VALUE lookup_error_class                               _(( const char * ));
 VALUE pg_bin_dec_bytea                                 _(( t_pg_coder*, const char *, int, int, int, int ));
 VALUE pg_text_dec_string                               _(( t_pg_coder*, const char *, int, int, int, int ));
@@ -344,6 +345,10 @@ void pg_typemap_compact                                _(( void * ));
 PGconn *pg_get_pgconn                                  _(( VALUE ));
 t_pg_connection *pg_get_connection                     _(( VALUE ));
 VALUE pgconn_block                                     _(( int, VALUE *, VALUE ));
+#ifdef __GNUC__
+__attribute__((format(printf, 3, 4)))
+#endif
+NORETURN(void pg_raise_conn_error                      _(( VALUE klass, VALUE self, const char *format, ...)));
 
 VALUE pg_new_result                                    _(( PGresult *, VALUE ));
 VALUE pg_new_result_autoclear                          _(( PGresult *, VALUE ));