gotosocial/vendor/github.com/DmitriyVTitov/size/size.go

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[feature] simpler cache size configuration (#2051) * add automatic cache max size generation based on ratios of a singular fixed memory target Signed-off-by: kim <grufwub@gmail.com> * remove now-unused cache max-size config variables Signed-off-by: kim <grufwub@gmail.com> * slight ratio tweak Signed-off-by: kim <grufwub@gmail.com> * remove unused visibility config var Signed-off-by: kim <grufwub@gmail.com> * add secret little ratio config trick Signed-off-by: kim <grufwub@gmail.com> * fixed a word Signed-off-by: kim <grufwub@gmail.com> * update cache library to remove use of TTL in result caches + slice cache Signed-off-by: kim <grufwub@gmail.com> * update other cache usages to use correct interface Signed-off-by: kim <grufwub@gmail.com> * update example config to explain the cache memory target Signed-off-by: kim <grufwub@gmail.com> * update env parsing test with new config values Signed-off-by: kim <grufwub@gmail.com> * do some ratio twiddling Signed-off-by: kim <grufwub@gmail.com> * add missing header * update envparsing with latest defaults Signed-off-by: kim <grufwub@gmail.com> * update size calculations to take into account result cache, simple cache and extra map overheads Signed-off-by: kim <grufwub@gmail.com> * tweak the ratios some more Signed-off-by: kim <grufwub@gmail.com> * more nan rampaging Signed-off-by: kim <grufwub@gmail.com> * fix envparsing script Signed-off-by: kim <grufwub@gmail.com> * update cache library, add sweep function to keep caches trim Signed-off-by: kim <grufwub@gmail.com> * sweep caches once a minute Signed-off-by: kim <grufwub@gmail.com> * add a regular job to sweep caches and keep under 80% utilisation Signed-off-by: kim <grufwub@gmail.com> * remove dead code Signed-off-by: kim <grufwub@gmail.com> * add new size library used to libraries section of readme Signed-off-by: kim <grufwub@gmail.com> * add better explanations for the mem-ratio numbers Signed-off-by: kim <grufwub@gmail.com> * update go-cache Signed-off-by: kim <grufwub@gmail.com> * library version bump Signed-off-by: kim <grufwub@gmail.com> * update cache.result{} size model estimation Signed-off-by: kim <grufwub@gmail.com> --------- Signed-off-by: kim <grufwub@gmail.com>
2023-08-03 09:34:35 +00:00
// Package size implements run-time calculation of size of the variable.
// Source code is based on "binary.Size()" function from Go standard library.
// size.Of() omits size of slices, arrays and maps containers itself (24, 24 and 8 bytes).
// When counting maps separate calculations are done for keys and values.
package size
import (
"reflect"
"unsafe"
)
// Of returns the size of 'v' in bytes.
// If there is an error during calculation, Of returns -1.
func Of(v interface{}) int {
// Cache with every visited pointer so we don't count two pointers
// to the same memory twice.
cache := make(map[uintptr]bool)
return sizeOf(reflect.Indirect(reflect.ValueOf(v)), cache)
}
// sizeOf returns the number of bytes the actual data represented by v occupies in memory.
// If there is an error, sizeOf returns -1.
func sizeOf(v reflect.Value, cache map[uintptr]bool) int {
switch v.Kind() {
case reflect.Array:
sum := 0
for i := 0; i < v.Len(); i++ {
s := sizeOf(v.Index(i), cache)
if s < 0 {
return -1
}
sum += s
}
return sum + (v.Cap()-v.Len())*int(v.Type().Elem().Size())
case reflect.Slice:
// return 0 if this node has been visited already
if cache[v.Pointer()] {
return 0
}
cache[v.Pointer()] = true
sum := 0
for i := 0; i < v.Len(); i++ {
s := sizeOf(v.Index(i), cache)
if s < 0 {
return -1
}
sum += s
}
sum += (v.Cap() - v.Len()) * int(v.Type().Elem().Size())
return sum + int(v.Type().Size())
case reflect.Struct:
sum := 0
for i, n := 0, v.NumField(); i < n; i++ {
s := sizeOf(v.Field(i), cache)
if s < 0 {
return -1
}
sum += s
}
// Look for struct padding.
padding := int(v.Type().Size())
for i, n := 0, v.NumField(); i < n; i++ {
padding -= int(v.Field(i).Type().Size())
}
return sum + padding
case reflect.String:
s := v.String()
hdr := (*reflect.StringHeader)(unsafe.Pointer(&s))
if cache[hdr.Data] {
return int(v.Type().Size())
}
cache[hdr.Data] = true
return len(s) + int(v.Type().Size())
case reflect.Ptr:
// return Ptr size if this node has been visited already (infinite recursion)
if cache[v.Pointer()] {
return int(v.Type().Size())
}
cache[v.Pointer()] = true
if v.IsNil() {
return int(reflect.New(v.Type()).Type().Size())
}
s := sizeOf(reflect.Indirect(v), cache)
if s < 0 {
return -1
}
return s + int(v.Type().Size())
case reflect.Bool,
reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Int, reflect.Uint,
reflect.Chan,
reflect.Uintptr,
reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128,
reflect.Func:
return int(v.Type().Size())
case reflect.Map:
// return 0 if this node has been visited already (infinite recursion)
if cache[v.Pointer()] {
return 0
}
cache[v.Pointer()] = true
sum := 0
keys := v.MapKeys()
for i := range keys {
val := v.MapIndex(keys[i])
// calculate size of key and value separately
sv := sizeOf(val, cache)
if sv < 0 {
return -1
}
sum += sv
sk := sizeOf(keys[i], cache)
if sk < 0 {
return -1
}
sum += sk
}
// Include overhead due to unused map buckets. 10.79 comes
// from https://golang.org/src/runtime/map.go.
return sum + int(v.Type().Size()) + int(float64(len(keys))*10.79)
case reflect.Interface:
return sizeOf(v.Elem(), cache) + int(v.Type().Size())
}
return -1
}