pq -> v1.7.0 (#11905)

Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/github.com/lib/pq/notice.go

@@ -0,0 +1,71 @@
+// +build go1.10
+
+package pq
+
+import (
+	"context"
+	"database/sql/driver"
+)
+
+// NoticeHandler returns the notice handler on the given connection, if any. A
+// runtime panic occurs if c is not a pq connection. This is rarely used
+// directly, use ConnectorNoticeHandler and ConnectorWithNoticeHandler instead.
+func NoticeHandler(c driver.Conn) func(*Error) {
+	return c.(*conn).noticeHandler
+}
+
+// SetNoticeHandler sets the given notice handler on the given connection. A
+// runtime panic occurs if c is not a pq connection. A nil handler may be used
+// to unset it. This is rarely used directly, use ConnectorNoticeHandler and
+// ConnectorWithNoticeHandler instead.
+//
+// Note: Notice handlers are executed synchronously by pq meaning commands
+// won't continue to be processed until the handler returns.
+func SetNoticeHandler(c driver.Conn, handler func(*Error)) {
+	c.(*conn).noticeHandler = handler
+}
+
+// NoticeHandlerConnector wraps a regular connector and sets a notice handler
+// on it.
+type NoticeHandlerConnector struct {
+	driver.Connector
+	noticeHandler func(*Error)
+}
+
+// Connect calls the underlying connector's connect method and then sets the
+// notice handler.
+func (n *NoticeHandlerConnector) Connect(ctx context.Context) (driver.Conn, error) {
+	c, err := n.Connector.Connect(ctx)
+	if err == nil {
+		SetNoticeHandler(c, n.noticeHandler)
+	}
+	return c, err
+}
+
+// ConnectorNoticeHandler returns the currently set notice handler, if any. If
+// the given connector is not a result of ConnectorWithNoticeHandler, nil is
+// returned.
+func ConnectorNoticeHandler(c driver.Connector) func(*Error) {
+	if c, ok := c.(*NoticeHandlerConnector); ok {
+		return c.noticeHandler
+	}
+	return nil
+}
+
+// ConnectorWithNoticeHandler creates or sets the given handler for the given
+// connector. If the given connector is a result of calling this function
+// previously, it is simply set on the given connector and returned. Otherwise,
+// this returns a new connector wrapping the given one and setting the notice
+// handler. A nil notice handler may be used to unset it.
+//
+// The returned connector is intended to be used with database/sql.OpenDB.
+//
+// Note: Notice handlers are executed synchronously by pq meaning commands
+// won't continue to be processed until the handler returns.
+func ConnectorWithNoticeHandler(c driver.Connector, handler func(*Error)) *NoticeHandlerConnector {
+	if c, ok := c.(*NoticeHandlerConnector); ok {
+		c.noticeHandler = handler
+		return c
+	}
+	return &NoticeHandlerConnector{Connector: c, noticeHandler: handler}
+}