forgejo/vendor/github.com/go-xorm/builder/cond.go

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// Copyright 2016 The Xorm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
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package builder
import (
"io"
)
// Writer defines the interface
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type Writer interface {
io.Writer
Append(...interface{})
}
var _ Writer = NewWriter()
// BytesWriter implments Writer and save SQL in bytes.Buffer
type BytesWriter struct {
writer *StringBuilder
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args []interface{}
}
// NewWriter creates a new string writer
func NewWriter() *BytesWriter {
w := &BytesWriter{
writer: &StringBuilder{},
}
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return w
}
// Write writes data to Writer
func (s *BytesWriter) Write(buf []byte) (int, error) {
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return s.writer.Write(buf)
}
// Append appends args to Writer
func (s *BytesWriter) Append(args ...interface{}) {
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s.args = append(s.args, args...)
}
// Cond defines an interface
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type Cond interface {
WriteTo(Writer) error
And(...Cond) Cond
Or(...Cond) Cond
IsValid() bool
}
type condEmpty struct{}
var _ Cond = condEmpty{}
// NewCond creates an empty condition
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func NewCond() Cond {
return condEmpty{}
}
func (condEmpty) WriteTo(w Writer) error {
return nil
}
func (condEmpty) And(conds ...Cond) Cond {
return And(conds...)
}
func (condEmpty) Or(conds ...Cond) Cond {
return Or(conds...)
}
func (condEmpty) IsValid() bool {
return false
}
func condToSQL(cond Cond) (string, []interface{}, error) {
if cond == nil || !cond.IsValid() {
return "", nil, nil
}
w := NewWriter()
if err := cond.WriteTo(w); err != nil {
return "", nil, err
}
return w.writer.String(), w.args, nil
}