mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-05 06:30:41 +01:00
51c156cca1
Signed-off-by: kim <grufwub@gmail.com>
155 lines
4.6 KiB
Go
155 lines
4.6 KiB
Go
package mangler
|
|
|
|
import (
|
|
"reflect"
|
|
"sync"
|
|
"unsafe"
|
|
)
|
|
|
|
// manglers is a map of runtime type ptrs => Mangler functions.
|
|
var manglers sync.Map
|
|
|
|
// Mangled is an interface that allows any type to implement a custom
|
|
// Mangler function to improve performance when mangling this type.
|
|
type Mangled interface {
|
|
Mangle(buf []byte) []byte
|
|
}
|
|
|
|
// 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, value any) []byte
|
|
|
|
// rMangler is functionally the same as a Mangler function, but it
|
|
// takes the value input in reflected form. By specifying these differences
|
|
// in mangler function types, it allows us to cut back on new calls to
|
|
// `reflect.ValueOf()` and instead pass by existing reflected values.
|
|
type rMangler func(buf []byte, value reflect.Value) []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(iface_value(t))
|
|
|
|
// Look for a cached mangler
|
|
v, ok := manglers.Load(uptr)
|
|
|
|
if !ok {
|
|
// Load mangler function
|
|
mng = loadMangler(nil, t)
|
|
} else {
|
|
// cast cached value
|
|
mng = v.(Mangler)
|
|
}
|
|
|
|
return func(buf []byte, value any) []byte {
|
|
// Type check passed value against original arg type.
|
|
if vt := reflect.TypeOf(value); vt != t {
|
|
return buf
|
|
}
|
|
|
|
// First write the type ptr (this adds
|
|
// a unique prefix for each runtime type).
|
|
buf = mangle_platform_int(buf, uptr)
|
|
|
|
// Finally, mangle value
|
|
return mng(buf, value)
|
|
}
|
|
}
|
|
|
|
// 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(iface_value(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(iface_value(t))
|
|
|
|
// Look for a cached mangler
|
|
v, ok := manglers.Load(uptr)
|
|
|
|
if !ok {
|
|
// Load mangler into cache
|
|
mng = loadMangler(nil, 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 = mangle_platform_int(b, uptr)
|
|
|
|
// Finally, mangle value
|
|
return mng(b, a)
|
|
}
|
|
|
|
// 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
|
|
// - all type aliases of above
|
|
// - time.Time{}
|
|
// - url.URL{}
|
|
// - net.IPAddr{}
|
|
// - netip.Addr{}, netip.AddrPort{}
|
|
// - mangler.Mangled{}
|
|
// - fmt.Stringer{}
|
|
// - json.Marshaler{}
|
|
// - encoding.BinaryMarshaler{}
|
|
// - encoding.TextMarshaler{}
|
|
// - all pointers to the above
|
|
// - all slices / arrays of the above
|
|
// - all map keys / values of the above
|
|
func String(a any) string {
|
|
b := Append(make([]byte, 0, 32), a)
|
|
return *(*string)(unsafe.Pointer(&b))
|
|
}
|