Switch to strings.Builder and expose SQL Builder (#13)

builder.go

@@ -0,0 +1,39 @@
+package sq
+
+import "strings"
+
+// Builder is a helper that allows to write many Sqlizers one by one
+// without constant checks for errors that may come from Sqlizer
+type Builder struct {
+	strings.Builder
+	args []any
+	err  error
+}
+
+// WriteSql converts Sqlizer to SQL strings and writes it to strings.Builder
+func (b *Builder) WriteSql(item Sqlizer) {
+	if b.err != nil {
+		return
+	}
+
+	var str string
+	var args []any
+	str, args, b.err = nestedToSql(item)
+
+	if b.err != nil {
+		return
+	}
+
+	if b.Len() > 0 {
+		b.WriteByte(' ')
+	}
+	b.WriteString(str)
+	b.args = append(b.args, args...)
+}
+
+func (b *Builder) ToSql() (string, []any, error) {
+	if b.err != nil {
+		return "", nil, b.err
+	}
+	return b.String(), b.args, nil
+}

builder_test.go

@@ -0,0 +1,66 @@
+package sq
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestBuilder(t *testing.T) {
+	b := Builder{}
+	b.WriteSql(Raw("test"))
+	sql, args, err := b.ToSql()
+	require.Equal(t, "test", sql)
+	require.Empty(t, args)
+	require.NoError(t, err)
+
+	b = Builder{}
+	b.WriteSql(Raw("one"))
+	b.WriteSql(Raw("two"))
+	sql, args, err = b.ToSql()
+	require.Equal(t, "one two", sql)
+	require.Empty(t, args)
+	require.NoError(t, err)
+
+	b = Builder{}
+	b.WriteString("one")
+	b.WriteSql(Raw("two"))
+	sql, args, err = b.ToSql()
+	require.Equal(t, "one two", sql)
+	require.Empty(t, args)
+	require.NoError(t, err)
+
+	b = Builder{}
+	b.WriteSql(Expr("one = ?", 1))
+	sql, args, err = b.ToSql()
+	require.Equal(t, "one = ?", sql)
+	require.Len(t, args, 1)
+	require.Equal(t, 1, args[0])
+	require.NoError(t, err)
+
+	b = Builder{}
+	b.WriteSql(Expr("one = ?", 1))
+	b.WriteSql(Expr("AND two = ?", 2))
+	sql, args, err = b.ToSql()
+	require.Equal(t, "one = ? AND two = ?", sql)
+	require.Len(t, args, 2)
+	require.Equal(t, 1, args[0])
+	require.Equal(t, 2, args[1])
+	require.NoError(t, err)
+
+	b = Builder{}
+	b.WriteSql(Expr("one = ?", 1))
+	b.WriteSql(sqlizeError{err: errors.New("fail")})
+	b.WriteSql(Expr("two = ?", 2))
+	sql, args, err = b.ToSql()
+	require.Empty(t, sql)
+	require.Empty(t, args)
+	require.EqualError(t, err, "fail")
+}
+
+type sqlizeError struct {
+	err error
+}
+
+func (se sqlizeError) ToSql() (string, []any, error) { return "", nil, se.err }

case.go

@@ -1,7 +1,6 @@
 package sq
 
 import (
-	"bytes"
 	"errors"
 
 	"github.com/userhubdev/sq/internal/builder"
@@ -11,37 +10,6 @@ func init() {
 	builder.Register(CaseBuilder{}, caseData{})
 }
 
-// sqlizerBuffer is a helper that allows to write many Sqlizers one by one
-// without constant checks for errors that may come from Sqlizer
-type sqlizerBuffer struct {
-	bytes.Buffer
-	args []any
-	err  error
-}
-
-// WriteSql converts Sqlizer to SQL strings and writes it to buffer
-func (b *sqlizerBuffer) WriteSql(item Sqlizer) {
-	if b.err != nil {
-		return
-	}
-
-	var str string
-	var args []any
-	str, args, b.err = nestedToSql(item)
-
-	if b.err != nil {
-		return
-	}
-
-	b.WriteString(str)
-	b.WriteByte(' ')
-	b.args = append(b.args, args...)
-}
-
-func (b *sqlizerBuffer) ToSql() (string, []any, error) {
-	return b.String(), b.args, b.err
-}
-
 // whenPart is a helper structure to describe SQLs "WHEN ... THEN ..." expression
 type whenPart struct {
 	when Sqlizer
@@ -67,26 +35,26 @@ func (d *caseData) ToSql() (sqlStr string, args []any, err error) {
 		return
 	}
 
-	sql := sqlizerBuffer{}
+	sql := Builder{}
 
-	sql.WriteString("CASE ")
+	sql.WriteString("CASE")
 	if d.What != nil {
 		sql.WriteSql(d.What)
 	}
 
 	for _, p := range d.WhenParts {
-		sql.WriteString("WHEN ")
+		sql.WriteString(" WHEN")
 		sql.WriteSql(p.when)
-		sql.WriteString("THEN ")
+		sql.WriteString(" THEN")
 		sql.WriteSql(p.then)
 	}
 
 	if d.Else != nil {
-		sql.WriteString("ELSE ")
+		sql.WriteString(" ELSE")
 		sql.WriteSql(d.Else)
 	}
 
-	sql.WriteString("END")
+	sql.WriteString(" END")
 
 	return sql.ToSql()
 }

delete.go

@@ -1,7 +1,6 @@
 package sq
 
 import (
-	"bytes"
 	"fmt"
 	"strings"
 
@@ -25,7 +24,7 @@ func (d *deleteData) ToSql() (sqlStr string, args []any, err error) {
 		return
 	}
 
-	sql := &bytes.Buffer{}
+	sql := &strings.Builder{}
 
 	if len(d.Prefixes) > 0 {
 		args, err = appendToSql(d.Prefixes, sql, " ", args)

expr.go

@@ -1,7 +1,6 @@
 package sq
 
 import (
-	"bytes"
 	"database/sql/driver"
 	"fmt"
 	"reflect"
@@ -40,7 +39,7 @@ func (e expr) ToSql() (sql string, args []any, err error) {
 		return e.sql, e.args, nil
 	}
 
-	buf := &bytes.Buffer{}
+	b := &strings.Builder{}
 	ap := e.args
 	sp := e.sql
 
@@ -55,20 +54,20 @@ func (e expr) ToSql() (sql string, args []any, err error) {
 		}
 		if len(sp) > i+1 && sp[i+1:i+2] == "?" {
 			// escaped "??"; append it and step past
-			buf.WriteString(sp[:i+2])
+			b.WriteString(sp[:i+2])
 			sp = sp[i+2:]
 			continue
 		}
 
 		if as, ok := ap[0].(Sqlizer); ok {
 			// sqlizer argument; expand it and append the result
 			isql, iargs, err = nestedToSql(as)
-			buf.WriteString(sp[:i])
-			buf.WriteString(isql)
+			b.WriteString(sp[:i])
+			b.WriteString(isql)
 			args = append(args, iargs...)
 		} else {
 			// normal argument; append it and the placeholder
-			buf.WriteString(sp[:i+1])
+			b.WriteString(sp[:i+1])
 			args = append(args, ap[0])
 		}
 
@@ -78,8 +77,8 @@ func (e expr) ToSql() (sql string, args []any, err error) {
 	}
 
 	// append the remaining sql and arguments
-	buf.WriteString(sp)
-	return buf.String(), append(args, ap...), err
+	b.WriteString(sp)
+	return b.String(), append(args, ap...), err
 }
 
 type concatExpr []any

insert.go

@@ -1,7 +1,6 @@
 package sq
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -33,7 +32,7 @@ func (d *insertData) ToSql() (sqlStr string, args []any, err error) {
 		return
 	}
 
-	sql := &bytes.Buffer{}
+	sql := &strings.Builder{}
 
 	if len(d.Prefixes) > 0 {
 		args, err = appendToSql(d.Prefixes, sql, " ", args)

internal/ps/map.go

@@ -10,8 +10,8 @@
 package ps
 
 import (
-	"bytes"
 	"fmt"
+	"strings"
 )
 
 // Any is a shorthand for Go's verbose interface{} type.
@@ -279,11 +279,12 @@ func (m *tree) Keys() []string {
 // make it easier to display maps for debugging
 func (m *tree) String() string {
 	keys := m.Keys()
-	buf := bytes.NewBufferString("{")
+	var b strings.Builder
+	b.WriteString("{")
 	for _, key := range keys {
 		val, _ := m.Lookup(key)
-		fmt.Fprintf(buf, "%s: %s, ", key, val)
+		fmt.Fprintf(&b, "%s: %s, ", key, val)
 	}
-	fmt.Fprintf(buf, "}\n")
-	return buf.String()
+	fmt.Fprintf(&b, "}\n")
+	return b.String()
 }

placeholder.go

@@ -1,7 +1,6 @@
 package sq
 
 import (
-	"bytes"
 	"fmt"
 	"strings"
 )
@@ -86,7 +85,7 @@ func Placeholders(count int) string {
 }
 
 func replacePositionalPlaceholders(sql, prefix string) (string, error) {
-	buf := &bytes.Buffer{}
+	b := &strings.Builder{}
 	i := 0
 	for {
 		p := strings.Index(sql, "?")
@@ -95,20 +94,20 @@ func replacePositionalPlaceholders(sql, prefix string) (string, error) {
 		}
 
 		if len(sql[p:]) > 1 && sql[p:p+2] == "??" { // escape ?? => ?
-			buf.WriteString(sql[:p])
-			buf.WriteString("?")
+			b.WriteString(sql[:p])
+			b.WriteString("?")
 			if len(sql[p:]) == 1 {
 				break
 			}
 			sql = sql[p+2:]
 		} else {
 			i++
-			buf.WriteString(sql[:p])
-			fmt.Fprintf(buf, "%s%d", prefix, i)
+			b.WriteString(sql[:p])
+			fmt.Fprintf(b, "%s%d", prefix, i)
 			sql = sql[p+1:]
 		}
 	}
 
-	buf.WriteString(sql)
-	return buf.String(), nil
+	b.WriteString(sql)
+	return b.String(), nil
 }

select.go

@@ -1,7 +1,6 @@
 package sq
 
 import (
-	"bytes"
 	"fmt"
 	"strings"
 
@@ -40,7 +39,7 @@ func (d *selectData) ToSqlRaw() (sqlStr string, args []any, err error) {
 		return
 	}
 
-	sql := &bytes.Buffer{}
+	sql := &strings.Builder{}
 
 	if len(d.Prefixes) > 0 {
 		args, err = appendToSql(d.Prefixes, sql, " ", args)