forked from gitea/gitea
71 lines
2.5 KiB
Markdown
71 lines
2.5 KiB
Markdown
# reflect2
|
|
|
|
[](https://sourcegraph.com/github.com/modern-go/reflect2?badge)
|
|
[](http://godoc.org/github.com/modern-go/reflect2)
|
|
[](https://travis-ci.org/modern-go/reflect2)
|
|
[](https://codecov.io/gh/modern-go/reflect2)
|
|
[](https://goreportcard.com/report/github.com/modern-go/reflect2)
|
|
[](https://raw.githubusercontent.com/modern-go/reflect2/master/LICENSE)
|
|
|
|
reflect api that avoids runtime reflect.Value cost
|
|
|
|
* reflect get/set interface{}, with type checking
|
|
* reflect get/set unsafe.Pointer, without type checking
|
|
* `reflect2.TypeByName` works like `Class.forName` found in java
|
|
|
|
[json-iterator](https://github.com/json-iterator/go) use this package to save runtime dispatching cost.
|
|
This package is designed for low level libraries to optimize reflection performance.
|
|
General application should still use reflect standard library.
|
|
|
|
# reflect2.TypeByName
|
|
|
|
```go
|
|
// given package is github.com/your/awesome-package
|
|
type MyStruct struct {
|
|
// ...
|
|
}
|
|
|
|
// will return the type
|
|
reflect2.TypeByName("awesome-package.MyStruct")
|
|
// however, if the type has not been used
|
|
// it will be eliminated by compiler, so we can not get it in runtime
|
|
```
|
|
|
|
# reflect2 get/set interface{}
|
|
|
|
```go
|
|
valType := reflect2.TypeOf(1)
|
|
i := 1
|
|
j := 10
|
|
valType.Set(&i, &j)
|
|
// i will be 10
|
|
```
|
|
|
|
to get set `type`, always use its pointer `*type`
|
|
|
|
# reflect2 get/set unsafe.Pointer
|
|
|
|
```go
|
|
valType := reflect2.TypeOf(1)
|
|
i := 1
|
|
j := 10
|
|
valType.UnsafeSet(unsafe.Pointer(&i), unsafe.Pointer(&j))
|
|
// i will be 10
|
|
```
|
|
|
|
to get set `type`, always use its pointer `*type`
|
|
|
|
# benchmark
|
|
|
|
Benchmark is not necessary for this package. It does nothing actually.
|
|
As it is just a thin wrapper to make go runtime public.
|
|
Both `reflect2` and `reflect` call same function
|
|
provided by `runtime` package exposed by go language.
|
|
|
|
# unsafe safety
|
|
|
|
Instead of casting `[]byte` to `sliceHeader` in your application using unsafe.
|
|
We can use reflect2 instead. This way, if `sliceHeader` changes in the future,
|
|
only reflect2 need to be upgraded.
|
|
|
|
reflect2 tries its best to keep the implementation same as reflect (by testing). |