gotosocial/vendor/codeberg.org/gruf/go-structr/util.go
kim 7ec1e1332e
[performance] overhaul struct (+ result) caching library for simplicity, performance and multiple-result lookups (#2535)
* rewrite cache library as codeberg.org/gruf/go-structr, implement in gotosocial

* use actual go-structr release version (not just commit hash)

* revert go toolchain changes (damn you go for auto changing this)

* fix go mod woes

* ensure %w is used in calls to errs.Appendf()

* fix error checking

* fix possible panic

* remove unnecessary start/stop functions, move to main Cache{} struct, add note regarding which caches require start/stop

* fix copy-paste artifact... 😇

* fix all comment copy-paste artifacts

* remove dropID() function, now we can just use slices.DeleteFunc()

* use util.Deduplicate() instead of collate(), move collate to util

* move orderByIDs() to util package and "generify"

* add a util.DeleteIf() function, use this to delete entries on failed population

* use slices.DeleteFunc() instead of util.DeleteIf() (i had the logic mixed up in my head somehow lol)

* add note about how collate differs from deduplicate
2024-01-19 12:57:29 +00:00

118 lines
2.5 KiB
Go

package structr
import (
"fmt"
"reflect"
"sync"
"unicode"
"unicode/utf8"
"codeberg.org/gruf/go-byteutil"
"codeberg.org/gruf/go-mangler"
)
// findField will search for a struct field with given set of names, where names is a len > 0 slice of names account for nesting.
func findField(t reflect.Type, names []string, allowZero bool) (sfield structfield, ok bool) {
var (
// isExported returns whether name is exported
// from a package; can be func or struct field.
isExported = func(name string) bool {
r, _ := utf8.DecodeRuneInString(name)
return unicode.IsUpper(r)
}
// popName pops the next name from
// the provided slice of field names.
popName = func() string {
// Pop next name.
name := names[0]
names = names[1:]
// Ensure valid name.
if !isExported(name) {
panicf("field is not exported: %s", name)
}
return name
}
// field is the iteratively searched-for
// struct field value in below loop.
field reflect.StructField
)
for len(names) > 0 {
// Pop next name.
name := popName()
// Follow any ptrs leading to field.
for t.Kind() == reflect.Pointer {
t = t.Elem()
}
if t.Kind() != reflect.Struct {
// The end type after following ptrs must be struct.
panicf("field %s is not struct (ptr): %s", t, name)
}
// Look for next field by name.
field, ok = t.FieldByName(name)
if !ok {
return
}
// Append next set of indices required to reach field.
sfield.index = append(sfield.index, field.Index...)
// Set the next type.
t = field.Type
}
// Get final type mangler func.
sfield.mangler = mangler.Get(t)
if allowZero {
var buf []byte
// Allocate field instance.
v := reflect.New(field.Type)
v = v.Elem()
// Serialize this zero value into buf.
buf = sfield.mangler(buf, v.Interface())
// Set zero value str.
sfield.zero = string(buf)
}
return
}
// panicf provides a panic with string formatting.
func panicf(format string, args ...any) {
panic(fmt.Sprintf(format, args...))
}
// bufpool provides a memory pool of byte
// buffers used when encoding key types.
var bufPool sync.Pool
// getBuf fetches buffer from memory pool.
func getBuf() *byteutil.Buffer {
v := bufPool.Get()
if v == nil {
buf := new(byteutil.Buffer)
buf.B = make([]byte, 0, 512)
v = buf
}
return v.(*byteutil.Buffer)
}
// putBuf replaces buffer in memory pool.
func putBuf(buf *byteutil.Buffer) {
if buf.Cap() > int(^uint16(0)) {
return // drop large bufs
}
buf.Reset()
bufPool.Put(buf)
}