mirror of
https://github.com/superseriousbusiness/gotosocial
synced 2024-12-12 08:36:31 +01:00
adf345f1ec
* update go-structr library -> v0.6.0, add necessary wrapping types + code changes to support these changes
* update readme with go-structr package changes
* improved wrapping of the SliceCache type
* add code comments for the cache wrapper types
* remove test.out 😇
---------
Co-authored-by: tobi <31960611+tsmethurst@users.noreply.github.com>
126 lines
2.9 KiB
Go
126 lines
2.9 KiB
Go
package structr
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
"unicode"
|
|
"unicode/utf8"
|
|
"unsafe"
|
|
|
|
"codeberg.org/gruf/go-mangler"
|
|
"github.com/modern-go/reflect2"
|
|
)
|
|
|
|
// struct_field contains pre-prepared type
|
|
// information about a struct's field member,
|
|
// including memory offset and hash function.
|
|
type struct_field struct {
|
|
|
|
// type2 is the runtime type pointer
|
|
// underlying the struct field type.
|
|
// used for repacking our own erfaces.
|
|
type2 reflect2.Type
|
|
|
|
// offset is the offset in memory
|
|
// of this struct field from the
|
|
// outer-most value ptr location.
|
|
offset uintptr
|
|
|
|
// struct field type mangling
|
|
// (i.e. fast serializing) fn.
|
|
mangle mangler.Mangler
|
|
|
|
// mangled zero value string,
|
|
// if set this indicates zero
|
|
// values of field not allowed
|
|
zero string
|
|
}
|
|
|
|
// find_field will search for a struct field with given set of names,
|
|
// where names is a len > 0 slice of names account for struct nesting.
|
|
func find_field(t reflect.Type, names []string) (sfield struct_field) {
|
|
var (
|
|
// is_exported returns whether name is exported
|
|
// from a package; can be func or struct field.
|
|
is_exported = func(name string) bool {
|
|
r, _ := utf8.DecodeRuneInString(name)
|
|
return unicode.IsUpper(r)
|
|
}
|
|
|
|
// pop_name pops the next name from
|
|
// the provided slice of field names.
|
|
pop_name = func() string {
|
|
name := names[0]
|
|
names = names[1:]
|
|
if !is_exported(name) {
|
|
panicf("field is not exported: %s", name)
|
|
}
|
|
return name
|
|
}
|
|
|
|
// field is the iteratively searched
|
|
// struct field value in below loop.
|
|
field reflect.StructField
|
|
)
|
|
|
|
for len(names) > 0 {
|
|
var ok bool
|
|
|
|
// Pop next name.
|
|
name := pop_name()
|
|
|
|
// Check for valid struct type.
|
|
if t.Kind() != reflect.Struct {
|
|
panicf("field %s is not struct: %s", t, name)
|
|
}
|
|
|
|
// Look for next field by name.
|
|
field, ok = t.FieldByName(name)
|
|
if !ok {
|
|
panicf("unknown field: %s", name)
|
|
}
|
|
|
|
// Increment total field offset.
|
|
sfield.offset += field.Offset
|
|
|
|
// Set the next type.
|
|
t = field.Type
|
|
}
|
|
|
|
// Get field type as reflect2.
|
|
sfield.type2 = reflect2.Type2(t)
|
|
|
|
// Find mangler for field type.
|
|
sfield.mangle = mangler.Get(t)
|
|
|
|
return
|
|
}
|
|
|
|
// extract_fields extracts given structfields from the provided value type,
|
|
// this is done using predetermined struct field memory offset locations.
|
|
func extract_fields[T any](value T, fields []struct_field) []any {
|
|
// Get ptr to raw value data.
|
|
ptr := unsafe.Pointer(&value)
|
|
|
|
// If this is a pointer type deref the value ptr.
|
|
if reflect.TypeOf(value).Kind() == reflect.Pointer {
|
|
ptr = *(*unsafe.Pointer)(ptr)
|
|
}
|
|
|
|
// Prepare slice of field ifaces.
|
|
ifaces := make([]any, len(fields))
|
|
|
|
for i := 0; i < len(fields); i++ {
|
|
// Manually access field at memory offset and pack eface.
|
|
ptr := unsafe.Pointer(uintptr(ptr) + fields[i].offset)
|
|
ifaces[i] = fields[i].type2.UnsafeIndirect(ptr)
|
|
}
|
|
|
|
return ifaces
|
|
}
|
|
|
|
// panicf provides a panic with string formatting.
|
|
func panicf(format string, args ...any) {
|
|
panic(fmt.Sprintf(format, args...))
|
|
}
|