blob: c0d1889cb4b75c7e69fe3298004ba8dbc3d60469 [file] [log] [blame]
package git
import (
type HandleList struct {
// stores the Go pointers
handles []interface{}
// indicates which indices are in use
set map[uintptr]bool
func NewHandleList() *HandleList {
return &HandleList{
handles: make([]interface{}, 5),
// findUnusedSlot finds the smallest-index empty space in our
// list. You must only run this function while holding a write lock.
func (v *HandleList) findUnusedSlot() uintptr {
for i := 0; i < len(v.handles); i++ {
isUsed := v.set[uintptr(i)]
if !isUsed {
return uintptr(i)
// reaching here means we've run out of entries so append and
// return the new index, which is equal to the old length.
slot := len(v.handles)
v.handles = append(v.handles, nil)
return uintptr(slot)
// Track adds the given pointer to the list of pointers to track and
// returns a pointer value which can be passed to C as an opaque
// pointer.
func (v *HandleList) Track(pointer interface{}) unsafe.Pointer {
slot := v.findUnusedSlot()
v.handles[slot] = pointer
v.set[slot] = true
return unsafe.Pointer(slot)
// Untrack stops tracking the pointer given by the handle
func (v *HandleList) Untrack(handle unsafe.Pointer) {
slot := uintptr(handle)
v.handles[slot] = nil
delete(v.set, slot)
// Get retrieves the pointer from the given handle
func (v *HandleList) Get(handle unsafe.Pointer) interface{} {
slot := uintptr(handle)
if _, ok := v.set[slot]; !ok {
panic("invalid pointer handle")
ptr := v.handles[slot]
return ptr