mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-15 03:36:37 +00:00
b93087ceb4
* updates go-structr and go-mangler to no longer rely on modern-go/reflect2 (*phew* now we're go1.23 safe) * update go-structr version * bump go-structr to improve memory usage (v. slightly) in certain conditions
130 lines
3.8 KiB
Go
130 lines
3.8 KiB
Go
package mangler
|
|
|
|
import (
|
|
"reflect"
|
|
"sync"
|
|
"unsafe"
|
|
)
|
|
|
|
// manglers is a map of runtime
|
|
// type ptrs => Mangler functions.
|
|
var manglers sync.Map
|
|
|
|
// Mangler is a function that will take an input interface value of known
|
|
// type, and append it in mangled serialized form to the given byte buffer.
|
|
// While the value type is an interface, the Mangler functions are accessed
|
|
// by the value's runtime type pointer, allowing the input value type to be known.
|
|
type Mangler func(buf []byte, ptr unsafe.Pointer) []byte
|
|
|
|
// Get will fetch the Mangler function for given runtime type.
|
|
// Note that the returned mangler will be a no-op in the case
|
|
// that an incorrect type is passed as the value argument.
|
|
func Get(t reflect.Type) Mangler {
|
|
var mng Mangler
|
|
|
|
// Get raw runtime type ptr
|
|
uptr := uintptr(eface_data(t))
|
|
|
|
// Look for a cached mangler
|
|
v, ok := manglers.Load(uptr)
|
|
|
|
if !ok {
|
|
// Load mangler function
|
|
mng = loadMangler(t)
|
|
} else {
|
|
// cast cached value
|
|
mng = v.(Mangler)
|
|
}
|
|
|
|
return func(buf []byte, ptr unsafe.Pointer) []byte {
|
|
// First write the type ptr (this adds
|
|
// a unique prefix for each runtime type).
|
|
buf = append_uint64(buf, uint64(uptr))
|
|
|
|
// Finally, mangle value
|
|
return mng(buf, ptr)
|
|
}
|
|
}
|
|
|
|
// Register will register the given Mangler function for use with vars of given runtime type. This allows
|
|
// registering performant manglers for existing types not implementing Mangled (e.g. std library types).
|
|
// NOTE: panics if there already exists a Mangler function for given type. Register on init().
|
|
func Register(t reflect.Type, m Mangler) {
|
|
if t == nil {
|
|
// Nil interface{} types cannot be searched by, do not accept
|
|
panic("cannot register mangler for nil interface{} type")
|
|
}
|
|
|
|
// Get raw runtime type ptr
|
|
uptr := uintptr(eface_data(t))
|
|
|
|
// Ensure this is a unique encoder
|
|
if _, ok := manglers.Load(uptr); ok {
|
|
panic("already registered mangler for type: " + t.String())
|
|
}
|
|
|
|
// Cache this encoder func
|
|
manglers.Store(uptr, m)
|
|
}
|
|
|
|
// Append will append the mangled form of input value 'a' to buffer 'b'.
|
|
// See mangler.String() for more information on mangled output.
|
|
func Append(b []byte, a any) []byte {
|
|
var mng Mangler
|
|
|
|
// Get reflect type of 'a'
|
|
t := reflect.TypeOf(a)
|
|
|
|
// Get raw runtime type ptr
|
|
uptr := uintptr(eface_data(t))
|
|
|
|
// Look for a cached mangler
|
|
v, ok := manglers.Load(uptr)
|
|
|
|
if !ok {
|
|
// Load into cache
|
|
mng = loadMangler(t)
|
|
manglers.Store(uptr, mng)
|
|
} else {
|
|
// cast cached value
|
|
mng = v.(Mangler)
|
|
}
|
|
|
|
// First write the type ptr (this adds
|
|
// a unique prefix for each runtime type).
|
|
b = append_uint64(b, uint64(uptr))
|
|
|
|
// Finally, mangle value
|
|
ptr := eface_data(a)
|
|
return mng(b, ptr)
|
|
}
|
|
|
|
// String will return the mangled format of input value 'a'. This
|
|
// mangled output will be unique for all default supported input types
|
|
// during a single runtime instance. Uniqueness cannot be guaranteed
|
|
// between separate runtime instances (whether running concurrently, or
|
|
// the same application running at different times).
|
|
//
|
|
// The exact formatting of the output data should not be relied upon,
|
|
// only that it is unique given the above constraints. Generally though,
|
|
// the mangled output is the binary formatted text of given input data.
|
|
//
|
|
// Uniqueness is guaranteed for similar input data of differing types
|
|
// (e.g. string("hello world") vs. []byte("hello world")) by prefixing
|
|
// mangled output with the input data's runtime type pointer.
|
|
//
|
|
// Default supported types include:
|
|
// - string
|
|
// - bool
|
|
// - int,int8,int16,int32,int64
|
|
// - uint,uint8,uint16,uint32,uint64,uintptr
|
|
// - float32,float64
|
|
// - complex64,complex128
|
|
// - arbitrary structs
|
|
// - all type aliases of above
|
|
// - all pointers to the above
|
|
// - all slices / arrays of the above
|
|
func String(a any) string {
|
|
b := Append(make([]byte, 0, 32), a)
|
|
return *(*string)(unsafe.Pointer(&b))
|
|
}
|