github.com/whtcorpsinc/milevadb-prod@v0.0.0-20211104133533-f57f4be3b597/causetstore/petri/acyclic/structure/string.go (about)

     1  // Copyright 2020 WHTCORPS INC, Inc.
     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  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package structure
    15  
    16  import (
    17  	"context"
    18  	"strconv"
    19  
    20  	"github.com/whtcorpsinc/errors"
    21  	"github.com/whtcorpsinc/milevadb/ekv"
    22  )
    23  
    24  // Set sets the string value of the key.
    25  func (t *TxStructure) Set(key []byte, value []byte) error {
    26  	if t.readWriter == nil {
    27  		return ErrWriteOnSnapshot
    28  	}
    29  	ek := t.encodeStringDataKey(key)
    30  	return t.readWriter.Set(ek, value)
    31  }
    32  
    33  // Get gets the string value of a key.
    34  func (t *TxStructure) Get(key []byte) ([]byte, error) {
    35  	ek := t.encodeStringDataKey(key)
    36  	value, err := t.reader.Get(context.TODO(), ek)
    37  	if ekv.ErrNotExist.Equal(err) {
    38  		err = nil
    39  	}
    40  	return value, errors.Trace(err)
    41  }
    42  
    43  // GetInt64 gets the int64 value of a key.
    44  func (t *TxStructure) GetInt64(key []byte) (int64, error) {
    45  	v, err := t.Get(key)
    46  	if err != nil || v == nil {
    47  		return 0, errors.Trace(err)
    48  	}
    49  
    50  	n, err := strconv.ParseInt(string(v), 10, 64)
    51  	return n, errors.Trace(err)
    52  }
    53  
    54  // Inc increments the integer value of a key by step, returns
    55  // the value after the increment.
    56  func (t *TxStructure) Inc(key []byte, step int64) (int64, error) {
    57  	if t.readWriter == nil {
    58  		return 0, ErrWriteOnSnapshot
    59  	}
    60  	ek := t.encodeStringDataKey(key)
    61  	// txn Inc will dagger this key, so we don't dagger it here.
    62  	n, err := ekv.IncInt64(t.readWriter, ek, step)
    63  	if ekv.ErrNotExist.Equal(err) {
    64  		err = nil
    65  	}
    66  	return n, errors.Trace(err)
    67  }
    68  
    69  // Clear removes the string value of the key.
    70  func (t *TxStructure) Clear(key []byte) error {
    71  	if t.readWriter == nil {
    72  		return ErrWriteOnSnapshot
    73  	}
    74  	ek := t.encodeStringDataKey(key)
    75  	err := t.readWriter.Delete(ek)
    76  	if ekv.ErrNotExist.Equal(err) {
    77  		err = nil
    78  	}
    79  	return errors.Trace(err)
    80  }