fork github.com/doug-martin

internal/sb/sql_builder.go

@@ -0,0 +1,101 @@
+package sb
+
+import (
+	"bytes"
+)
+
+// Builder that is composed of a bytes.Buffer. It is used internally and by adapters to build SQL statements
+type (
+	SQLBuilder interface {
+		Error() error
+		SetError(err error) SQLBuilder
+		WriteArg(i ...interface{}) SQLBuilder
+		Write(p []byte) SQLBuilder
+		WriteStrings(ss ...string) SQLBuilder
+		WriteRunes(r ...rune) SQLBuilder
+		IsPrepared() bool
+		CurrentArgPosition() int
+		ToSQL() (sql string, args []interface{}, err error)
+	}
+	sqlBuilder struct {
+		buf *bytes.Buffer
+		// True if the sql should not be interpolated
+		isPrepared bool
+		// Current Number of arguments, used by adapters that need positional placeholders
+		currentArgPosition int
+		args               []interface{}
+		err                error
+	}
+)
+
+func NewSQLBuilder(isPrepared bool) SQLBuilder {
+	return &sqlBuilder{
+		buf:                &bytes.Buffer{},
+		isPrepared:         isPrepared,
+		args:               make([]interface{}, 0),
+		currentArgPosition: 1,
+	}
+}
+
+func (b *sqlBuilder) Error() error {
+	return b.err
+}
+
+func (b *sqlBuilder) SetError(err error) SQLBuilder {
+	if b.err == nil {
+		b.err = err
+	}
+	return b
+}
+
+func (b *sqlBuilder) Write(bs []byte) SQLBuilder {
+	if b.err == nil {
+		b.buf.Write(bs)
+	}
+	return b
+}
+
+func (b *sqlBuilder) WriteStrings(ss ...string) SQLBuilder {
+	if b.err == nil {
+		for _, s := range ss {
+			b.buf.WriteString(s)
+		}
+	}
+	return b
+}
+
+func (b *sqlBuilder) WriteRunes(rs ...rune) SQLBuilder {
+	if b.err == nil {
+		for _, r := range rs {
+			b.buf.WriteRune(r)
+		}
+	}
+	return b
+}
+
+// Returns true if the sql is a prepared statement
+func (b *sqlBuilder) IsPrepared() bool {
+	return b.isPrepared
+}
+
+// Returns true if the sql is a prepared statement
+func (b *sqlBuilder) CurrentArgPosition() int {
+	return b.currentArgPosition
+}
+
+// Adds an argument to the builder, used when IsPrepared is false
+func (b *sqlBuilder) WriteArg(i ...interface{}) SQLBuilder {
+	if b.err == nil {
+		b.currentArgPosition += len(i)
+		b.args = append(b.args, i...)
+	}
+	return b
+}
+
+// Returns the sql string, and arguments.
+func (b *sqlBuilder) ToSQL() (sql string, args []interface{}, err error) {
+	if b.err != nil {
+		return sql, args, b.err
+	}
+	return b.buf.String(), b.args, nil
+}