github.com/matrixorigin/matrixone@v0.7.0/pkg/txn/storage/tae/read.go (about)

     1  // Copyright 2021 - 2022 Matrix Origin
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package taestorage
    16  
    17  import (
    18  	"bytes"
    19  	"context"
    20  	"encoding/gob"
    21  	"github.com/matrixorigin/matrixone/pkg/common/moerr"
    22  	apipb "github.com/matrixorigin/matrixone/pkg/pb/api"
    23  	"github.com/matrixorigin/matrixone/pkg/pb/txn"
    24  	"github.com/matrixorigin/matrixone/pkg/txn/storage"
    25  	"io"
    26  )
    27  
    28  // Read implements storage.TxnTAEStorage
    29  
    30  func (s *taeStorage) Read(
    31  	ctx context.Context,
    32  	txnMeta txn.TxnMeta,
    33  	op uint32,
    34  	payload []byte) (res storage.ReadResult, err error) {
    35  
    36  	switch op {
    37  
    38  	case uint32(apipb.OpCode_OpGetLogTail):
    39  		return handleRead(
    40  			ctx, s,
    41  			txnMeta, payload,
    42  			s.taeHandler.HandleGetLogTail,
    43  		)
    44  	default:
    45  		panic(moerr.NewInfoNoCtx("op is not supported"))
    46  	}
    47  
    48  }
    49  
    50  func handleRead[Req any, Resp any](
    51  	ctx context.Context,
    52  	s *taeStorage,
    53  	txnMeta txn.TxnMeta,
    54  	payload []byte,
    55  	fn func(
    56  		ctx context.Context,
    57  		meta txn.TxnMeta,
    58  		req Req,
    59  		resp *Resp,
    60  	) (
    61  		err error,
    62  	),
    63  ) (
    64  	res storage.ReadResult,
    65  	err error,
    66  ) {
    67  
    68  	var req Req
    69  	if len(payload) != 0 {
    70  		if err := gob.NewDecoder(bytes.NewReader(payload)).Decode(&req); err != nil {
    71  			return nil, err
    72  		}
    73  	}
    74  
    75  	var resp Resp
    76  	defer logReq("read", req, txnMeta, &resp, &err)()
    77  	defer func() {
    78  		if closer, ok := (any)(resp).(io.Closer); ok {
    79  			_ = closer.Close()
    80  		}
    81  	}()
    82  
    83  	err = fn(ctx, txnMeta, req, &resp)
    84  	if err != nil {
    85  		return nil, err
    86  	}
    87  
    88  	buf := new(bytes.Buffer)
    89  	if err := gob.NewEncoder(buf).Encode(resp); err != nil {
    90  		return nil, err
    91  	}
    92  	res = &readResult{
    93  		payload: buf.Bytes(),
    94  	}
    95  
    96  	return res, nil
    97  }