README
¶
deepcopy
import "github.com/fufuok/utils/generic/deepcopy"
Package deepcopy implements the proposal https://go.dev/issue/51520.
Example
package main
import (
"fmt"
"github.com/fufuok/utils/generic/deepcopy"
"github.com/fufuok/utils/generic/maps"
"github.com/fufuok/utils/generic/slices"
"reflect"
)
func main() {
type tFN struct {
fn func() int
}
type tMap map[bool][]tFN
m1 := tMap{true: []tFN{{func() int { return 1 }}}}
// 深拷贝
m2 := deepcopy.Value(m1)
// equal: false 1
fmt.Printf("equal: %v %+v\n", reflect.DeepEqual(m1, m2), m2[true][0].fn())
// 浅拷贝
m3 := maps.Clone[tMap](m1)
// equal: true 1
fmt.Printf("equal: %v %+v\n", reflect.DeepEqual(m1, m3), m3[true][0].fn())
// 改变 m1 后
m1[true][0] = tFN{func() int { return 0 }}
// m1: 0, m2: 1, m3: 0
fmt.Printf("m1: %d, m2: %d, m3: %d\n", m1[true][0].fn(), m2[true][0].fn(), m3[true][0].fn())
s1 := []tMap{m1}
s2 := deepcopy.Value(s1)
s3 := slices.Clone(s1)
m1[true][0] = tFN{func() int { return 2 }}
// s1: 2, s2: 0, s3: 2
fmt.Printf("s1: %d, s2: %d, s3: %d\n", s1[0][true][0].fn(), s2[0][true][0].fn(), s3[0][true][0].fn())
}
Output
equal: false 1
equal: true 1
m1: 0, m2: 1, m3: 0
s1: 2, s2: 0, s3: 2
Index
func Value
func Value[T any](src T) (dst T)
Value copies src to dst recursively.
Two values of identical type are deeply copied if one of the following cases apply.
Numbers, bools, strings are deeply copied and have different underlying memory address.
Slice and Array values are deeply copied, including its elements.
Map values are deeply copied for all of its key and corresponding values.
Pointer values are deeply copied for their pointed value, and the pointer points to the deeply copied value.
Struct values are deeply copied for all fields, including exported and unexported.
Interface values are deeply copied if the underlying type can be deeply copied.
There are a few exceptions that may result in a deeply copied value not deeply equal (asserted by DeepEqual(dst, src)) to the source value:
1) Func values are still refer to the same function 2) Chan values are replaced by newly created channels 3) One-way Chan values (receive or read-only) values are still refer to the same channel
Note that while correct uses of Value do exist, they are not rare. The use of Value often indicates the copying object does not contain a singleton or is never meant to be copied, such as sync.Mutex, os.File, net.Conn, js.Value, etc. In these cases, the copied value retains the memory representations of the source value but may result in unexpected consequences in follow-up usage, the caller should clear these values depending on their usage context.
Example
package main
import (
"fmt"
"github.com/fufuok/utils/generic/deepcopy"
)
func main() {
tests := []any{
`"Now cut that out!"`,
39,
true,
false,
2.14,
[]string{
"Phil Harris",
"Rochester van Jones",
"Mary Livingstone",
"Dennis Day",
},
[2]string{
"Jell-O",
"Grape-Nuts",
},
}
for _, expected := range tests {
actual := deepcopy.Value(expected)
fmt.Println(actual)
}
}
Output
"Now cut that out!"
39
true
false
2.14
[Phil Harris Rochester van Jones Mary Livingstone Dennis Day]
[Jell-O Grape-Nuts]
Generated by gomarkdoc
Documentation
¶
Overview ¶
Package deepcopy implements the proposal https://go.dev/issue/51520.
Example ¶
package main
import (
"fmt"
"reflect"
"github.com/fufuok/utils/generic/deepcopy"
"github.com/fufuok/utils/generic/maps"
"github.com/fufuok/utils/generic/slices"
)
func main() {
type tFN struct {
fn func() int
}
type tMap map[bool][]tFN
m1 := tMap{true: []tFN{{func() int { return 1 }}}}
// 深拷贝
m2 := deepcopy.Value(m1)
// equal: false 1
fmt.Printf("equal: %v %+v\n", reflect.DeepEqual(m1, m2), m2[true][0].fn())
// 浅拷贝
m3 := maps.Clone[tMap](m1)
// equal: true 1
fmt.Printf("equal: %v %+v\n", reflect.DeepEqual(m1, m3), m3[true][0].fn())
// 改变 m1 后
m1[true][0] = tFN{func() int { return 0 }}
// m1: 0, m2: 1, m3: 0
fmt.Printf("m1: %d, m2: %d, m3: %d\n", m1[true][0].fn(), m2[true][0].fn(), m3[true][0].fn())
s1 := []tMap{m1}
s2 := deepcopy.Value(s1)
s3 := slices.Clone(s1)
m1[true][0] = tFN{func() int { return 2 }}
// s1: 2, s2: 0, s3: 2
fmt.Printf("s1: %d, s2: %d, s3: %d\n", s1[0][true][0].fn(), s2[0][true][0].fn(), s3[0][true][0].fn())
}
Output: equal: false 1 equal: true 1 m1: 0, m2: 1, m3: 0 s1: 2, s2: 0, s3: 2
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Value ¶
func Value[T any](src T) (dst T)
Value copies src to dst recursively.
Two values of identical type are deeply copied if one of the following cases apply.
Numbers, bools, strings are deeply copied and have different underlying memory address.
Slice and Array values are deeply copied, including its elements.
Map values are deeply copied for all of its key and corresponding values.
Pointer values are deeply copied for their pointed value, and the pointer points to the deeply copied value.
Struct values are deeply copied for all fields, including exported and unexported.
Interface values are deeply copied if the underlying type can be deeply copied.
There are a few exceptions that may result in a deeply copied value not deeply equal (asserted by DeepEqual(dst, src)) to the source value:
- Func values are still refer to the same function
- Chan values are replaced by newly created channels
- One-way Chan values (receive or read-only) values are still refer to the same channel
Note that while correct uses of Value do exist, they are not rare. The use of Value often indicates the copying object does not contain a singleton or is never meant to be copied, such as sync.Mutex, os.File, net.Conn, js.Value, etc. In these cases, the copied value retains the memory representations of the source value but may result in unexpected consequences in follow-up usage, the caller should clear these values depending on their usage context.
Example ¶
package main
import (
"fmt"
"github.com/fufuok/utils/generic/deepcopy"
)
func main() {
tests := []any{
`"Now cut that out!"`,
39,
true,
false,
2.14,
[]string{
"Phil Harris",
"Rochester van Jones",
"Mary Livingstone",
"Dennis Day",
},
[2]string{
"Jell-O",
"Grape-Nuts",
},
}
for _, expected := range tests {
actual := deepcopy.Value(expected)
fmt.Println(actual)
}
}
Output: "Now cut that out!" 39 true false 2.14 [Phil Harris Rochester van Jones Mary Livingstone Dennis Day] [Jell-O Grape-Nuts]
Types ¶
This section is empty.
Source Files