fix type of event code

fixes #520

Author: mattn

Diff for: _example/trace/main.go

@@ -95,7 +95,7 @@ func main() {
 			ConnectHook: func(conn *sqlite3.SQLiteConn) error {
 				err := conn.SetTrace(&sqlite3.TraceConfig{
 					Callback:        traceCallback,
-					EventMask:       uint(eventMask),
+					EventMask:       eventMask,
 					WantExpandedSQL: true,
 				})
 				return err

Diff for: sqlite3_trace.go

@@ -28,10 +28,10 @@ import (
 // Trace... constants identify the possible events causing callback invocation.
 // Values are same as the corresponding SQLite Trace Event Codes.
 const (
-	TraceStmt    = C.SQLITE_TRACE_STMT
-	TraceProfile = C.SQLITE_TRACE_PROFILE
-	TraceRow     = C.SQLITE_TRACE_ROW
-	TraceClose   = C.SQLITE_TRACE_CLOSE
+	TraceStmt    = uint32(C.SQLITE_TRACE_STMT)
+	TraceProfile = uint32(C.SQLITE_TRACE_PROFILE)
+	TraceRow     = uint32(C.SQLITE_TRACE_ROW)
+	TraceClose   = uint32(C.SQLITE_TRACE_CLOSE)
 )
 
 type TraceInfo struct {
@@ -71,7 +71,7 @@ type TraceUserCallback func(TraceInfo) int
 
 type TraceConfig struct {
 	Callback        TraceUserCallback
-	EventMask       C.uint
+	EventMask       uint32
 	WantExpandedSQL bool
 }
 
@@ -105,6 +105,8 @@ func traceCallbackTrampoline(
 	// Parameter named 'X' in SQLite docs (eXtra event data?):
 	xValue unsafe.Pointer) C.int {
 
+	eventCode := uint32(traceEventCode)
+
 	if ctx == nil {
 		panic(fmt.Sprintf("No context (ev 0x%x)", traceEventCode))
 	}
@@ -114,7 +116,7 @@ func traceCallbackTrampoline(
 
 	var traceConf TraceConfig
 	var found bool
-	if traceEventCode == TraceClose {
+	if eventCode == TraceClose {
 		// clean up traceMap: 'pop' means get and delete
 		traceConf, found = popTraceMapping(connHandle)
 	} else {
@@ -123,16 +125,16 @@ func traceCallbackTrampoline(
 
 	if !found {
 		panic(fmt.Sprintf("Mapping not found for handle 0x%x (ev 0x%x)",
-			connHandle, traceEventCode))
+			connHandle, eventCode))
 	}
 
 	var info TraceInfo
 
-	info.EventCode = uint32(traceEventCode)
+	info.EventCode = eventCode
 	info.AutoCommit = (int(C.sqlite3_get_autocommit(contextDB)) != 0)
 	info.ConnHandle = connHandle
 
-	switch traceEventCode {
+	switch eventCode {
 	case TraceStmt:
 		info.StmtHandle = uintptr(p)
 
@@ -183,7 +185,7 @@ func traceCallbackTrampoline(
 	// registering this callback trampoline with SQLite --- for cleanup.
 	// In the future there may be more events forced to "selected" in SQLite
 	// for the driver's needs.
-	if traceConf.EventMask&traceEventCode == 0 {
+	if traceConf.EventMask&eventCode == 0 {
 		return 0
 	}