template增加arg自定义函数

Author: xfali

README.md

@@ -284,7 +284,17 @@ DELETE FROM test_table
 {{where (ne .Id 0) "AND" "id" .Id "" | where (ne .Username "") "AND" "username" .Username | where (ne .Password "") "AND" "password" .Password}}
 {{end}}
 ```
-其中where和set是gobatis的自定义函数，用于智能的生成动态sql
+其中where、set、arg是gobatis的自定义函数，用于智能生成动态sql
+
+arg用于将对象动态转换为占位符，并保存为SQL参数，如:
+```cassandraql
+SELECT * FROM TABLENAME WHERE name = {{arg .Name}}
+```
+以mysql为例，将解析为：
+```cassandraql
+SELECT * FROM TABLENAME WHERE name = ? 
+```
+同时Name的值将自动保存为SQL参数，自动传入，起到类似xml中#{MODEL.Name}的效果。
 
 ### 9、gobatis-cmd生成文件使用示例
 

parsing/template/dynamic.go

@@ -7,10 +7,22 @@ package template
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 	"text/template"
 )
 
+const (
+	argPlaceHolder    = "_xfali_Arg_Holder"
+	argPlaceHolderLen = 17
+)
+
+type Dynamic interface {
+	getFuncMap() template.FuncMap
+	getParam() []interface{}
+	format(string) (string, []interface{})
+}
+
 func dummyUpdateSet(b bool, column string, value interface{}, origin string) string {
 	return origin
 }
@@ -19,11 +31,57 @@ func dummyWhere(b bool, cond, column string, value interface{}, origin string) s
 	return origin
 }
 
+func dummyParam(p interface{}) string {
+	return fmt.Sprint(p)
+}
+
 func commonAdd(a, b int) int {
 	return a + b
 }
 
-func mysqlUpdateSet(b bool, column string, value interface{}, origin string) string {
+type DummyDynamic struct{}
+
+var dummyFuncMap = template.FuncMap{
+	"set":   dummyUpdateSet,
+	"where": dummyWhere,
+	"add":   commonAdd,
+	"arg":   dummyParam,
+}
+
+var gDummyDynamic = &DummyDynamic{}
+
+func (d *DummyDynamic) getFuncMap() template.FuncMap {
+	return dummyFuncMap
+}
+
+func (d *DummyDynamic) getParam() []interface{} {
+	return nil
+}
+
+func (d *DummyDynamic) format(s string) (string, []interface{}) {
+	return s, nil
+}
+
+type MysqlDynamic struct {
+	index    int
+	keys     []string
+	paramMap map[string]interface{}
+}
+
+func (d *MysqlDynamic) getFuncMap() template.FuncMap {
+	return template.FuncMap{
+		"set":   d.mysqlUpdateSet,
+		"where": d.mysqlWhere,
+		"add":   commonAdd,
+		"arg":   d.Param,
+	}
+}
+
+func (d *MysqlDynamic) getParam() []interface{} {
+	return nil
+}
+
+func (d *MysqlDynamic) mysqlUpdateSet(b bool, column string, value interface{}, origin string) string {
 	if !b {
 		return origin
 	}
@@ -42,74 +100,121 @@ func mysqlUpdateSet(b bool, column string, value interface{}, origin string) str
 	buf.WriteString(column)
 	buf.WriteString("` = ")
 	if s, ok := value.(string); ok {
-		buf.WriteString(`'`)
-		buf.WriteString(s)
-		buf.WriteString(`'`)
+		if _, ok := d.paramMap[s]; ok {
+			buf.WriteString(s)
+		} else {
+			buf.WriteString(`'`)
+			buf.WriteString(s)
+			buf.WriteString(`'`)
+		}
 	} else {
 		buf.WriteString(fmt.Sprint(value))
 	}
 	return buf.String()
 }
 
-func postgresUpdateSet(b bool, column string, value interface{}, origin string) string {
+func (d *MysqlDynamic) mysqlWhere(b bool, cond, column string, value interface{}, origin string) string {
 	if !b {
 		return origin
 	}
 
 	buf := strings.Builder{}
 	if origin == "" {
-		buf.WriteString(" SET ")
+		buf.WriteString(" WHERE ")
+		cond = ""
 	} else {
-		origin = strings.TrimSpace(origin)
-		buf.WriteString(origin)
-		if origin[:len(origin)-1] != "," {
-			buf.WriteString(",")
-		}
+		buf.WriteString(strings.TrimSpace(origin))
+		buf.WriteString(" ")
+		buf.WriteString(cond)
+		buf.WriteString(" ")
 	}
-	buf.WriteString(`"`)
+
+	buf.WriteString("`")
 	buf.WriteString(column)
-	buf.WriteString(`"`)
-	buf.WriteString(" = ")
+	buf.WriteString("` = ")
 	if s, ok := value.(string); ok {
-		buf.WriteString(`'`)
-		buf.WriteString(s)
-		buf.WriteString(`'`)
+		if _, ok := d.paramMap[s]; ok {
+			buf.WriteString(s)
+		} else {
+			buf.WriteString(`'`)
+			buf.WriteString(s)
+			buf.WriteString(`'`)
+		}
 	} else {
 		buf.WriteString(fmt.Sprint(value))
 	}
 	return buf.String()
 }
 
-func mysqlWhere(b bool, cond, column string, value interface{}, origin string) string {
+func (d *MysqlDynamic) Param(p interface{}) string {
+	d.index++
+	key := argPlaceHolder + strconv.Itoa(d.index)
+	d.paramMap[key] = p
+	d.keys = append(d.keys, key)
+	return key
+}
+
+func (d *MysqlDynamic) format(s string) (string, []interface{}) {
+	i := 0
+	var params []interface{}
+	for _, k := range d.keys {
+		s, i = replace(s, k, "?", -1)
+		if i > 0 {
+			params = append(params, d.paramMap[k])
+		}
+	}
+	return s, params
+}
+
+type PostgresDynamic struct {
+	index    int
+	keys     [] string
+	paramMap map[string]interface{}
+}
+
+func (d *PostgresDynamic) getFuncMap() template.FuncMap {
+	return template.FuncMap{
+		"set":   d.postgresUpdateSet,
+		"where": d.postgresWhere,
+		"add":   commonAdd,
+		"arg":   d.Param,
+	}
+}
+
+func (d *PostgresDynamic) postgresUpdateSet(b bool, column string, value interface{}, origin string) string {
 	if !b {
 		return origin
 	}
 
 	buf := strings.Builder{}
 	if origin == "" {
-		buf.WriteString(" WHERE ")
-		cond = ""
+		buf.WriteString(" SET ")
 	} else {
-		buf.WriteString(strings.TrimSpace(origin))
-		buf.WriteString(" ")
-		buf.WriteString(cond)
-		buf.WriteString(" ")
+		origin = strings.TrimSpace(origin)
+		buf.WriteString(origin)
+		if origin[:len(origin)-1] != "," {
+			buf.WriteString(",")
+		}
 	}
-
-	buf.WriteString("`")
+	buf.WriteString(`"`)
 	buf.WriteString(column)
-	buf.WriteString("` = ")
+	buf.WriteString(`"`)
+	buf.WriteString(" = ")
 	if s, ok := value.(string); ok {
-		buf.WriteString(`'`)
-		buf.WriteString(s)
-		buf.WriteString(`'`)
+		if _, ok := d.paramMap[s]; ok {
+			buf.WriteString(s)
+		} else {
+			buf.WriteString(`'`)
+			buf.WriteString(s)
+			buf.WriteString(`'`)
+		}
 	} else {
 		buf.WriteString(fmt.Sprint(value))
 	}
 	return buf.String()
 }
 
-func postgresWhere(b bool, cond, column string, value interface{}, origin string) string {
+func (d *PostgresDynamic) postgresWhere(b bool, cond, column string, value interface{}, origin string) string {
 	if !b {
 		return origin
 	}
@@ -130,41 +235,94 @@ func postgresWhere(b bool, cond, column string, value interface{}, origin string
 	buf.WriteString(`"`)
 	buf.WriteString(" = ")
 	if s, ok := value.(string); ok {
-		buf.WriteString(`'`)
-		buf.WriteString(s)
-		buf.WriteString(`'`)
+		if _, ok := d.paramMap[s]; ok {
+			buf.WriteString(s)
+		} else {
+			buf.WriteString(`'`)
+			buf.WriteString(s)
+			buf.WriteString(`'`)
+		}
 	} else {
 		buf.WriteString(fmt.Sprint(value))
 	}
 	return buf.String()
 }
 
-var mysqlFuncMap = template.FuncMap{
-	"set":   mysqlUpdateSet,
-	"where": mysqlWhere,
-	"add":   commonAdd,
+func (d *PostgresDynamic) getParam() []interface{} {
+	return nil
 }
 
-var postgresFuncMap = template.FuncMap{
-	"set":   postgresUpdateSet,
-	"where": postgresWhere,
-	"add":   commonAdd,
+func (d *PostgresDynamic) Param(p interface{}) string {
+	d.index++
+	key := argPlaceHolder + strconv.Itoa(d.index)
+	d.paramMap[key] = p
+	d.keys = append(d.keys, key)
+	return key
 }
 
-var dummyFuncMap = template.FuncMap{
-	"set":   dummyUpdateSet,
-	"where": dummyWhere,
-	"add":   commonAdd,
+func (d *PostgresDynamic) format(s string) (string, []interface{}) {
+	i, index := 0, 1
+	var params []interface{}
+	for _, k := range d.keys {
+		s, i = replace(s, k, "$"+strconv.Itoa(index), -1)
+		if i > 0 {
+			params = append(params, d.paramMap[k])
+			index++
+		}
+	}
+	return s, params
 }
 
-var funcMap = map[string]template.FuncMap{
-	"mysql":    mysqlFuncMap,
-	"postgres": postgresFuncMap,
+var dynamicMap = map[string]Dynamic{
+	"mysql":    &MysqlDynamic{paramMap: map[string]interface{}{}},
+	"postgres": &PostgresDynamic{paramMap: map[string]interface{}{}},
 }
 
-func selectFuncMap(driverName string) template.FuncMap {
-	if v, ok := funcMap[driverName]; ok {
+func selectDynamic(driverName string) Dynamic {
+	if v, ok := dynamicMap[driverName]; ok {
 		return v
 	}
-	return dummyFuncMap
+	return gDummyDynamic
+}
+
+func replace(s, old, new string, n int) (string, int) {
+	if old == new || n == 0 {
+		return s, 0 // avoid allocation
+	}
+
+	if old == "" {
+		return s, 0
+	}
+
+	if n < 0 {
+		if m := strings.Count(s, old); m == 0 {
+			return s, 0 // avoid allocation
+		} else if n < 0 || m < n {
+			n = m
+		}
+	}
+	makeSize := len(s) + n*(len(new)-len(old))
+	// Apply replacements to buffer.
+	t := make([]byte, makeSize)
+	w, count := 0, 0
+	start := 0
+	for {
+		if n == 0 {
+			break
+		}
+		j := start
+		index := strings.Index(s[start:], old)
+		if index == -1 {
+			return string(t[0:w]), count
+		} else {
+			j += index
+			count++
+		}
+		w += copy(t[w:], s[start:j])
+		w += copy(t[w:], new)
+		start = j + len(old)
+		n--
+	}
+	w += copy(t[w:], s[start:])
+	return string(t[0:w]), count
 }

parsing/template/parse.go

@@ -25,8 +25,8 @@ func (p *Parser) ParseMetadata(driverName string, params ...interface{}) (*sqlpa
 	if len(params) > 0 {
 		param = params[0]
 	}
-	fm := selectFuncMap(driverName)
-	tpl := p.tpl.Funcs(fm)
+	dynamic := selectDynamic(driverName)
+	tpl := p.tpl.Funcs(dynamic.getFuncMap())
 	err := tpl.Execute(&b, param)
 	if err != nil {
 		return nil, err
@@ -37,8 +37,7 @@ func (p *Parser) ParseMetadata(driverName string, params ...interface{}) (*sqlpa
 	action := sql[:6]
 	action = strings.ToLower(action)
 	ret.Action = action
-	ret.PrepareSql = sql
-	ret.Params = nil
+	ret.PrepareSql, ret.Params = dynamic.format(sql)
 
 	return ret, nil
 }