github.com/ecodeclub/eorm@v0.0.2-0.20231001112437-dae71da914d0/internal/valuer/unsafe.go (about)

     1  // Copyright 2021 ecodeclub
     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 valuer
    16  
    17  import (
    18  	"reflect"
    19  	"unsafe"
    20  
    21  	"github.com/ecodeclub/eorm/internal/rows"
    22  
    23  	"github.com/ecodeclub/eorm/internal/errs"
    24  	"github.com/ecodeclub/eorm/internal/model"
    25  )
    26  
    27  var _ Creator = NewUnsafeValue
    28  
    29  type unsafeValue struct {
    30  	val  reflect.Value
    31  	addr unsafe.Pointer
    32  	meta *model.TableMeta
    33  }
    34  
    35  func NewUnsafeValue(val interface{}, meta *model.TableMeta) Value {
    36  	refVal := reflect.ValueOf(val)
    37  	return unsafeValue{
    38  		meta: meta,
    39  		val:  refVal.Elem(),
    40  		addr: unsafe.Pointer(refVal.Pointer()),
    41  	}
    42  }
    43  
    44  func (u unsafeValue) Field(name string) (reflect.Value, error) {
    45  	fd, ok := u.meta.FieldMap[name]
    46  	if !ok {
    47  		return reflect.Value{}, errs.NewInvalidFieldError(name)
    48  	}
    49  	ptr := unsafe.Pointer(uintptr(u.addr) + fd.Offset)
    50  	val := reflect.NewAt(fd.Typ, ptr).Elem()
    51  	return val, nil
    52  }
    53  
    54  func (u unsafeValue) SetColumns(rows rows.Rows) error {
    55  
    56  	cs, err := rows.Columns()
    57  	if err != nil {
    58  		return err
    59  	}
    60  	if len(cs) > len(u.meta.Columns) {
    61  		return errs.ErrTooManyColumns
    62  	}
    63  
    64  	// TODO 性能优化
    65  	colValues := make([]interface{}, len(cs))
    66  	for i, c := range cs {
    67  		cm, ok := u.meta.ColumnMap[c]
    68  		if !ok {
    69  			return errs.NewInvalidColumnError(c)
    70  		}
    71  		ptr := unsafe.Pointer(uintptr(u.addr) + cm.Offset)
    72  		val := reflect.NewAt(cm.Typ, ptr)
    73  		colValues[i] = val.Interface()
    74  	}
    75  	return rows.Scan(colValues...)
    76  }