New Prepare useage (#2061)

Fix #2060, Three ways to use the `Prepare`.

The first

```go
engine.Prepare().Where().Get()
```

The second

```go
sess := engine.NewSession()
defer sess.Close()

sess.Prepare().Where().Get()

sess.Prepare().Where().Get()
```

The third
```go
sess := engine.NewSession()
defer sess.Close()

sess.Begin()

sess.Prepare().Where().Get()

sess.Prepare().Where().Get()

sess.Commit()
```

Or

```go
sess := engine.NewSession()
defer sess.Close()

sess.Begin()

sess.Prepare().Insert()

sess.Prepare().Insert()

sess.Commit()
```

Reviewed-on: https://gitea.com/xorm/xorm/pulls/2061
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-committed-by: Lunny Xiao <xiaolunwen@gmail.com>

core/stmt.go

@@ -93,7 +93,7 @@ func (s *Stmt) ExecContext(ctx context.Context, args ...interface{}) (sql.Result
 	if err != nil {
 		return nil, err
 	}
-	res, err := s.Stmt.ExecContext(ctx, args)
+	res, err := s.Stmt.ExecContext(ctx, args...)
 	hookCtx.End(ctx, res, err)
 	if err := s.db.afterProcess(hookCtx); err != nil {
 		return nil, err

integrations/session_get_test.go

@@ -915,3 +915,64 @@ func TestGetVars(t *testing.T) {
 	assert.EqualValues(t, "xlw", name)
 	assert.EqualValues(t, 42, age)
 }
+
+func TestGetWithPrepare(t *testing.T) {
+	type GetVarsWithPrepare struct {
+		Id   int64
+		Name string
+		Age  int
+	}
+
+	assert.NoError(t, PrepareEngine())
+	assertSync(t, new(GetVarsWithPrepare))
+
+	_, err := testEngine.Insert(&GetVarsWithPrepare{
+		Name: "xlw",
+		Age:  42,
+	})
+	assert.NoError(t, err)
+
+	var v1 GetVarsWithPrepare
+	has, err := testEngine.Prepare().ID(1).Get(&v1)
+	assert.NoError(t, err)
+	assert.True(t, has)
+	assert.EqualValues(t, "xlw", v1.Name)
+	assert.EqualValues(t, 42, v1.Age)
+
+	sess := testEngine.NewSession()
+	defer sess.Close()
+
+	var v2 GetVarsWithPrepare
+	has, err = sess.Prepare().ID(1).Get(&v2)
+	assert.NoError(t, err)
+	assert.True(t, has)
+	assert.EqualValues(t, "xlw", v2.Name)
+	assert.EqualValues(t, 42, v2.Age)
+
+	var v3 GetVarsWithPrepare
+	has, err = sess.Prepare().ID(1).Get(&v3)
+	assert.NoError(t, err)
+	assert.True(t, has)
+	assert.EqualValues(t, "xlw", v3.Name)
+	assert.EqualValues(t, 42, v3.Age)
+
+	err = sess.Begin()
+	assert.NoError(t, err)
+
+	cnt, err := sess.Prepare().Insert(&GetVarsWithPrepare{
+		Name: "xlw2",
+		Age:  12,
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+
+	cnt, err = sess.Prepare().Insert(&GetVarsWithPrepare{
+		Name: "xlw3",
+		Age:  13,
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+
+	err = sess.Commit()
+	assert.NoError(t, err)
+}

interface.go

@@ -99,6 +99,7 @@ type EngineInterface interface {
 	MapCacher(interface{}, caches.Cacher) error
 	NewSession() *Session
 	NoAutoTime() *Session
+	Prepare() *Session
 	Quote(string) string
 	SetCacher(string, caches.Cacher)
 	SetConnMaxLifetime(time.Duration)

session.go

@@ -79,7 +79,8 @@ type Session struct {
 	afterClosures   []func(interface{})
 	afterProcessors []executedProcessor
 
-	stmtCache map[uint32]*core.Stmt //key: hash.Hash32 of (queryStr, len(queryStr))
+	stmtCache   map[uint32]*core.Stmt //key: hash.Hash32 of (queryStr, len(queryStr))
+	txStmtCache map[uint32]*core.Stmt // for tx statement
 
 	lastSQL     string
 	lastSQLArgs []interface{}
@@ -130,6 +131,7 @@ func newSession(engine *Engine) *Session {
 		afterClosures:    make([]func(interface{}), 0),
 		afterProcessors:  make([]executedProcessor, 0),
 		stmtCache:        make(map[uint32]*core.Stmt),
+		txStmtCache:      make(map[uint32]*core.Stmt),
 
 		lastSQL:     "",
 		lastSQLArgs: make([]interface{}, 0),
@@ -150,6 +152,12 @@ func (session *Session) Close() error {
 		}
 	}
 
+	for _, v := range session.txStmtCache {
+		if err := v.Close(); err != nil {
+			return err
+		}
+	}
+
 	if !session.isClosed {
 		// When Close be called, if session is a transaction and do not call
 		// Commit or Rollback, then call Rollback.
@@ -160,6 +168,7 @@ func (session *Session) Close() error {
 		}
 		session.tx = nil
 		session.stmtCache = nil
+		session.txStmtCache = nil
 		session.isClosed = true
 	}
 	return nil
@@ -200,6 +209,7 @@ func (session *Session) IsClosed() bool {
 func (session *Session) resetStatement() {
 	if session.autoResetStatement {
 		session.statement.Reset()
+		session.prepareStmt = false
 	}
 }
 
@@ -370,6 +380,21 @@ func (session *Session) doPrepare(db *core.DB, sqlStr string) (stmt *core.Stmt,
 	return
 }
 
+func (session *Session) doPrepareTx(sqlStr string) (stmt *core.Stmt, err error) {
+	crc := crc32.ChecksumIEEE([]byte(sqlStr))
+	// TODO try hash(sqlStr+len(sqlStr))
+	var has bool
+	stmt, has = session.txStmtCache[crc]
+	if !has {
+		stmt, err = session.tx.PrepareContext(session.ctx, sqlStr)
+		if err != nil {
+			return nil, err
+		}
+		session.txStmtCache[crc] = stmt
+	}
+	return
+}
+
 func getField(dataStruct *reflect.Value, table *schemas.Table, colName string, idx int) (*schemas.Column, *reflect.Value, error) {
 	var col = table.GetColumnIdx(colName, idx)
 	if col == nil {

session_raw.go

@@ -46,25 +46,22 @@ func (session *Session) queryRows(sqlStr string, args ...interface{}) (*core.Row
 				return nil, err
 			}
 
-			rows, err := stmt.QueryContext(session.ctx, args...)
+			return stmt.QueryContext(session.ctx, args...)
-			if err != nil {
-				return nil, err
-			}
-			return rows, nil
 		}
 
-		rows, err := db.QueryContext(session.ctx, sqlStr, args...)
+		return db.QueryContext(session.ctx, sqlStr, args...)
+	}
+
+	if session.prepareStmt {
+		stmt, err := session.doPrepareTx(sqlStr)
 		if err != nil {
 			return nil, err
 		}
-		return rows, nil
+
+		return stmt.QueryContext(session.ctx, args...)
 	}
 
-	rows, err := session.tx.QueryContext(session.ctx, sqlStr, args...)
+	return session.tx.QueryContext(session.ctx, sqlStr, args...)
-	if err != nil {
-		return nil, err
-	}
-	return rows, nil
 }
 
 func (session *Session) queryRow(sqlStr string, args ...interface{}) *core.Row {
@@ -160,6 +157,13 @@ func (session *Session) exec(sqlStr string, args ...interface{}) (sql.Result, er
 	session.lastSQLArgs = args
 
 	if !session.isAutoCommit {
+		if session.prepareStmt {
+			stmt, err := session.doPrepareTx(sqlStr)
+			if err != nil {
+				return nil, err
+			}
+			return stmt.ExecContext(session.ctx, args...)
+		}
 		return session.tx.ExecContext(session.ctx, sqlStr, args...)
 	}
 
@@ -168,12 +172,7 @@ func (session *Session) exec(sqlStr string, args ...interface{}) (sql.Result, er
 		if err != nil {
 			return nil, err
 		}
-
+		return stmt.ExecContext(session.ctx, args...)
-		res, err := stmt.ExecContext(session.ctx, args...)
-		if err != nil {
-			return nil, err
-		}
-		return res, nil
 	}
 
 	return session.DB().ExecContext(session.ctx, sqlStr, args...)