增加获得PageInfo方式

Author: xfali

README.md

@@ -6,9 +6,9 @@ pagehelper是与[gobatis](https://github.com/xfali/gobatis)配套的分页工具
 
 ## 待完成项
 
-select查询返回的result还未能携带page、pageSize、total信息，需要自己组装。
+v0.1.0已添加此特性 ：返回总记录数
 
-（此功能需gobatis支持，暂未实现）
+~~select查询返回的result还未能携带page、pageSize、total信息，需要自己组装。~~
 
 ## 使用
 
@@ -35,21 +35,49 @@ select查询返回的result还未能携带page、pageSize、total信息，需要
 ### 2、配置分页参数
 ```cassandraql
     session := sessMgr.NewSession()
-    ctx := pagehelper.StartPage(1, 10, context.Background())
+    ctx := pagehelper.StartPage(context.Background(), 1, 10)
 
     var ret []TestTable
     session.SetContext(ctx).Select("SELECT * FROM TBL_TEST").Param().Result(&ret)
 ```
 
-### 3、配置排序参数
+### 3、配置分页参数（带自动统计总记录数功能）
+```$xslt
+    session := sessMgr.NewSession()
+    ctx := pagehelper.StartPageWithCount(context.Background(), 1, 10, "")
+
+    var ret []TestTable
+    session.SetContext(ctx).Select("SELECT * FROM TBL_TEST").Param().Result(&ret)
+```
+获得分页信息（以1001条记录为例）
+```$xslt
+    pageInfo := pagehelper.GetPageInfo(ctx)
+    t.Log(
+        "pageNum: ", pageInfo.GetPageNum(),
+        "totalPage: ", pageInfo.GetTotalPage(),
+        "pageSize: ", pageInfo.GetPageSize(),
+        "total: ", pageInfo.GetTotal())
+```
+输出：
+```$xslt
+pageNum:        1 
+GetPages:       101 
+GetPageSize:    10 
+total:          1001
+```
+*注意：*
+
+会自动生成和执行带子查询的countSQL，请自行评估是否使用此功能，转而使用自定义SQL获取总记录数。
+
+### 4、配置排序参数
 ```cassandraql
     session := sessMgr.NewSession()
-    ctx := pagehelper.OrderBy("myfield", pagehelper.DESC, context.Background())
+    ctx := pagehelper.OrderBy(context.Background(), "myfield", pagehelper.DESC)
 
     var ret []TestTable
     session.SetContext(ctx).Select("SELECT * FROM TBL_TEST").Param().Result(&ret)
 ```
-*注意:*
+*注意：*
 
 由于golang对order by不能使用placeholder的方式，所以存在注入风险，请谨慎使用排序功能，如果使用，则需要自己做防注入的工作。
 
@@ -63,10 +91,10 @@ if !valid.MatchString(ordCol) {
 }
 ```
 
-### 4、使用builder
+### 5、使用builder
 ```$xslt
 session := sessMgr.NewSession()
-ctx := pagehelper.C(context.Background()).Page(1, 3).Order("test", pagehelper.ASC).Build()
+ctx := pagehelper.C(context.Background()).Page(1, 3).OrderBy("test", pagehelper.ASC).Build()
 var ret []TestTable
 session.SetContext(ctx).Select("SELECT * FROM TBL_TEST").Param().Result(&ret)
 ```

builder.go

@@ -9,6 +9,9 @@ package pagehelper
 import "context"
 
 type builder struct {
+    page  PageInfo
+    order OrderByInfo
+
     ctx context.Context
 }
 
@@ -22,41 +25,67 @@ func C(ctx context.Context) *builder {
 //page 页码
 //pageSize 分页大小
 func (b *builder) Page(page, pageSize int) *builder {
-    b.ctx = StartPage(page, pageSize, b.ctx)
+    b.page.Page = page
+    b.page.PageSize = pageSize
+    b.page.total = 0
     return b
 }
 
 //分页
 //page 页码
 //pageSize 分页大小
-func (b *builder) PageWithTotal(page, pageSize int, countColumn string) *builder {
-    b.ctx = StartPageWithTotal(page, pageSize, countColumn, b.ctx)
+func (b *builder) PageWithCount(page, pageSize int, countColumn string) *builder {
+    b.page.Page = page
+    b.page.PageSize = pageSize
+    b.page.countColumn = countColumn
+    b.page.total = -1
+    return b
+}
+
+func (b *builder) Total(countColumn string) *builder {
+    b.page.countColumn = countColumn
+    b.page.total = -1
     return b
 }
 
 //手动指定字段和排序
 //field 字段
 //order 排序 [ASC | DESC]
 func (b *builder) Order(field, order string) *builder {
-    b.ctx = OrderBy(field, order, b.ctx)
+    b.order.Field = field
+    b.order.Order = order
     return b
 }
 
 //升序（默认）
 //field 字段
 func (b *builder) ASC(field string) *builder {
-    b.ctx = OrderBy(field, ASC, b.ctx)
-    return b
+    return b.Order(field, ASC)
 }
 
 //降序
 //field 字段
 func (b *builder) DESC(field string) *builder {
-    b.ctx = OrderBy(field, DESC, b.ctx)
-    return b
+    return b.Order(field, DESC)
 }
 
 //获得含分页/排序信息的context
 func (b *builder) Build() context.Context {
+    if b.page.PageSize > 0 {
+        if b.page.total != -1 {
+            b.ctx = StartPage(b.ctx, b.page.Page, b.page.PageSize)
+        } else {
+            b.ctx = StartPageWithCount(b.ctx, b.page.Page, b.page.PageSize, b.page.countColumn)
+        }
+    }
+
+    if b.order.Field != "" {
+        if b.order.Order == "" {
+            b.order.Order = ASC
+        }
+
+        b.ctx = OrderBy(b.ctx, b.order.Field, b.order.Order)
+    }
+
     return b.ctx
 }

orm.go

@@ -0,0 +1,157 @@
+// Copyright (C) 2019, Xiongfa Li.
+// All right reserved.
+// @author xiongfa.li
+// @version V1.0
+// Description: 
+
+package pagehelper
+
+import (
+    "context"
+    "fmt"
+    "github.com/xfali/gobatis"
+    "github.com/xfali/gobatis/common"
+    "github.com/xfali/gobatis/executor"
+    "github.com/xfali/gobatis/factory"
+    "github.com/xfali/gobatis/logging"
+    "github.com/xfali/gobatis/reflection"
+    "github.com/xfali/gobatis/session"
+    "github.com/xfali/gobatis/transaction"
+    "strings"
+)
+
+const (
+    pageHelperValue  = "_page_helper_value"
+    orderHelperValue = "_order_helper_value"
+
+    ASC  = "ASC"
+    DESC = "DESC"
+)
+
+var (
+    OrderByModifier = modifyOrderSql
+    PageModifier    = modifyPageSql
+    CountModifier   = modifyCountSql
+)
+
+type Factory struct {
+    fac factory.Factory
+}
+
+type Executor struct {
+    exec executor.Executor
+    log  logging.LogFunc
+}
+
+func New(f factory.Factory) *Factory {
+    return &Factory{f}
+}
+
+func (exec *Executor) Close(rollback bool) {
+    exec.exec.Close(rollback)
+}
+
+func (exec *Executor) Exec(ctx context.Context, sql string, params ...interface{}) (common.Result, error) {
+    return exec.exec.Exec(ctx, sql, params...)
+}
+
+func (exec *Executor) Begin() error {
+    return exec.exec.Begin()
+}
+
+func (exec *Executor) Commit(require bool) error {
+    return exec.exec.Commit(require)
+}
+
+func (exec *Executor) Rollback(require bool) error {
+    return exec.exec.Rollback(require)
+}
+
+func (exec *Executor) Query(ctx context.Context, result reflection.Object, sql string, params ...interface{}) error {
+    originSql := sql
+    o := ctx.Value(orderHelperValue)
+    if o != nil {
+        if param, ok := o.(*OrderByInfo); ok {
+            sql = OrderByModifier(sql, param)
+        }
+    }
+
+    p := ctx.Value(pageHelperValue)
+    if p != nil {
+        if param, ok := p.(*PageInfo); ok {
+            sql = PageModifier(sql, param)
+            if param.total == -1 {
+                param.total = exec.getTotal(ctx, originSql, param.countColumn, params...)
+            }
+        }
+    }
+    exec.log(logging.DEBUG, "PageHelper Query: [%s], params: %s\n", sql, fmt.Sprint(params))
+    return exec.exec.Query(ctx, result, sql, params...)
+}
+
+func (f *Factory) InitDB() error {
+    return f.fac.InitDB()
+}
+
+func (f *Factory) CreateTransaction() transaction.Transaction {
+    return f.fac.CreateTransaction()
+}
+
+func (f *Factory) CreateSession() session.SqlSession {
+    tx := f.CreateTransaction()
+    return session.NewDefaultSqlSession(f.LogFunc(), tx, f.CreateExecutor(tx), false)
+}
+
+func (f *Factory) LogFunc() logging.LogFunc {
+    return f.fac.LogFunc()
+}
+
+func (f *Factory) CreateExecutor(transaction transaction.Transaction) executor.Executor {
+    return &Executor{
+        exec: executor.NewSimpleExecutor(transaction),
+        log:  f.LogFunc(),
+    }
+}
+
+func modifyOrderSql(sql string, p *OrderByInfo) string {
+    if p.Field == "" {
+        return sql
+    }
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" ORDER BY `%s` %s ", p.Field, p.Order))
+    return b.String()
+}
+
+func modifyPageSql(sql string, p *PageInfo) string {
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" LIMIT %d, %d ", p.Page*p.PageSize, p.PageSize))
+    return b.String()
+}
+
+func (exec *Executor) getTotal(ctx context.Context, sql, countColumn string, params ...interface{}) int64 {
+    totalSql := CountModifier(sql, countColumn)
+    var total int64
+    obj, err := gobatis.ParseObject(&total)
+    if err == nil {
+        exec.exec.Query(ctx, obj, totalSql, params...)
+        return total
+    }
+    return 0
+}
+
+func modifyCountSql(sql, countColumn string) string {
+    if countColumn == "" {
+        countColumn = "0"
+    } else {
+        countColumn = "`" + countColumn + "`"
+    }
+    b := strings.Builder{}
+    b.WriteString("SELECT COUNT(")
+    b.WriteString(countColumn)
+    b.WriteString(") FROM (")
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(") AS __hp_tempCountTl")
+    return b.String()
+}