gotosocial/vendor/github.com/jackc/pgx/v5/internal/nbconn/bufferqueue.go
tobi ec325fee14
[chore] Update a bunch of database dependencies (#1772)
* [chore] Update a bunch of database dependencies

* fix lil thing
2023-05-12 14:33:40 +02:00

71 lines
1.1 KiB
Go

package nbconn
import (
"sync"
)
const minBufferQueueLen = 8
type bufferQueue struct {
lock sync.Mutex
queue []*[]byte
r, w int
}
func (bq *bufferQueue) pushBack(buf *[]byte) {
bq.lock.Lock()
defer bq.lock.Unlock()
if bq.w >= len(bq.queue) {
bq.growQueue()
}
bq.queue[bq.w] = buf
bq.w++
}
func (bq *bufferQueue) pushFront(buf *[]byte) {
bq.lock.Lock()
defer bq.lock.Unlock()
if bq.w >= len(bq.queue) {
bq.growQueue()
}
copy(bq.queue[bq.r+1:bq.w+1], bq.queue[bq.r:bq.w])
bq.queue[bq.r] = buf
bq.w++
}
func (bq *bufferQueue) popFront() *[]byte {
bq.lock.Lock()
defer bq.lock.Unlock()
if bq.r == bq.w {
return nil
}
buf := bq.queue[bq.r]
bq.queue[bq.r] = nil // Clear reference so it can be garbage collected.
bq.r++
if bq.r == bq.w {
bq.r = 0
bq.w = 0
if len(bq.queue) > minBufferQueueLen {
bq.queue = make([]*[]byte, minBufferQueueLen)
}
}
return buf
}
func (bq *bufferQueue) growQueue() {
desiredLen := (len(bq.queue) + 1) * 3 / 2
if desiredLen < minBufferQueueLen {
desiredLen = minBufferQueueLen
}
newQueue := make([]*[]byte, desiredLen)
copy(newQueue, bq.queue)
bq.queue = newQueue
}