Update to latest mssqldriver (#7613)

* New driver does not tolerate USE - handle this by closing db and reopening db in the new dbname

vendor/github.com/denisenkom/go-mssqldb/internal/querytext/parser.go

@@ -0,0 +1,265 @@
+// Package querytext is the old query parser and parameter substitute process.
+// Do not use on new code.
+//
+// This package is not subject to any API compatibility guarantee.
+package querytext
+
+import (
+	"bytes"
+	"io"
+	"strconv"
+)
+
+type parser struct {
+	r          *bytes.Reader
+	w          bytes.Buffer
+	paramCount int
+	paramMax   int
+
+	// using map as a set
+	namedParams map[string]bool
+}
+
+func (p *parser) next() (rune, bool) {
+	ch, _, err := p.r.ReadRune()
+	if err != nil {
+		if err != io.EOF {
+			panic(err)
+		}
+		return 0, false
+	}
+	return ch, true
+}
+
+func (p *parser) unread() {
+	err := p.r.UnreadRune()
+	if err != nil {
+		panic(err)
+	}
+}
+
+func (p *parser) write(ch rune) {
+	p.w.WriteRune(ch)
+}
+
+type stateFunc func(*parser) stateFunc
+
+// ParseParams rewrites the query from using "?" placeholders
+// to using "@pN" parameter names that SQL Server will accept.
+//
+// This function and package is not subject to any API compatibility guarantee.
+func ParseParams(query string) (string, int) {
+	p := &parser{
+		r:           bytes.NewReader([]byte(query)),
+		namedParams: map[string]bool{},
+	}
+	state := parseNormal
+	for state != nil {
+		state = state(p)
+	}
+	return p.w.String(), p.paramMax + len(p.namedParams)
+}
+
+func parseNormal(p *parser) stateFunc {
+	for {
+		ch, ok := p.next()
+		if !ok {
+			return nil
+		}
+		if ch == '?' {
+			return parseOrdinalParameter
+		} else if ch == '$' || ch == ':' {
+			ch2, ok := p.next()
+			if !ok {
+				p.write(ch)
+				return nil
+			}
+			p.unread()
+			if ch2 >= '0' && ch2 <= '9' {
+				return parseOrdinalParameter
+			} else if 'a' <= ch2 && ch2 <= 'z' || 'A' <= ch2 && ch2 <= 'Z' {
+				return parseNamedParameter
+			}
+		}
+		p.write(ch)
+		switch ch {
+		case '\'':
+			return parseQuote
+		case '"':
+			return parseDoubleQuote
+		case '[':
+			return parseBracket
+		case '-':
+			return parseLineComment
+		case '/':
+			return parseComment
+		}
+	}
+}
+
+func parseOrdinalParameter(p *parser) stateFunc {
+	var paramN int
+	var ok bool
+	for {
+		var ch rune
+		ch, ok = p.next()
+		if ok && ch >= '0' && ch <= '9' {
+			paramN = paramN*10 + int(ch-'0')
+		} else {
+			break
+		}
+	}
+	if ok {
+		p.unread()
+	}
+	if paramN == 0 {
+		p.paramCount++
+		paramN = p.paramCount
+	}
+	if paramN > p.paramMax {
+		p.paramMax = paramN
+	}
+	p.w.WriteString("@p")
+	p.w.WriteString(strconv.Itoa(paramN))
+	if !ok {
+		return nil
+	}
+	return parseNormal
+}
+
+func parseNamedParameter(p *parser) stateFunc {
+	var paramName string
+	var ok bool
+	for {
+		var ch rune
+		ch, ok = p.next()
+		if ok && (ch >= '0' && ch <= '9' || 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z') {
+			paramName = paramName + string(ch)
+		} else {
+			break
+		}
+	}
+	if ok {
+		p.unread()
+	}
+	p.namedParams[paramName] = true
+	p.w.WriteString("@")
+	p.w.WriteString(paramName)
+	if !ok {
+		return nil
+	}
+	return parseNormal
+}
+
+func parseQuote(p *parser) stateFunc {
+	for {
+		ch, ok := p.next()
+		if !ok {
+			return nil
+		}
+		p.write(ch)
+		if ch == '\'' {
+			return parseNormal
+		}
+	}
+}
+
+func parseDoubleQuote(p *parser) stateFunc {
+	for {
+		ch, ok := p.next()
+		if !ok {
+			return nil
+		}
+		p.write(ch)
+		if ch == '"' {
+			return parseNormal
+		}
+	}
+}
+
+func parseBracket(p *parser) stateFunc {
+	for {
+		ch, ok := p.next()
+		if !ok {
+			return nil
+		}
+		p.write(ch)
+		if ch == ']' {
+			ch, ok = p.next()
+			if !ok {
+				return nil
+			}
+			if ch != ']' {
+				p.unread()
+				return parseNormal
+			}
+			p.write(ch)
+		}
+	}
+}
+
+func parseLineComment(p *parser) stateFunc {
+	ch, ok := p.next()
+	if !ok {
+		return nil
+	}
+	if ch != '-' {
+		p.unread()
+		return parseNormal
+	}
+	p.write(ch)
+	for {
+		ch, ok = p.next()
+		if !ok {
+			return nil
+		}
+		p.write(ch)
+		if ch == '\n' {
+			return parseNormal
+		}
+	}
+}
+
+func parseComment(p *parser) stateFunc {
+	var nested int
+	ch, ok := p.next()
+	if !ok {
+		return nil
+	}
+	if ch != '*' {
+		p.unread()
+		return parseNormal
+	}
+	p.write(ch)
+	for {
+		ch, ok = p.next()
+		if !ok {
+			return nil
+		}
+		p.write(ch)
+		for ch == '*' {
+			ch, ok = p.next()
+			if !ok {
+				return nil
+			}
+			p.write(ch)
+			if ch == '/' {
+				if nested == 0 {
+					return parseNormal
+				} else {
+					nested--
+				}
+			}
+		}
+		for ch == '/' {
+			ch, ok = p.next()
+			if !ok {
+				return nil
+			}
+			p.write(ch)
+			if ch == '*' {
+				nested++
+			}
+		}
+	}
+}