97 lines
2.6 KiB
Go
97 lines
2.6 KiB
Go
// GoToSocial
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// Copyright (C) GoToSocial Authors admin@gotosocial.org
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// SPDX-License-Identifier: AGPL-3.0-or-later
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package queue
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import (
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"sync/atomic"
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"codeberg.org/gruf/go-structr"
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)
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// StructQueue wraps a structr.Queue{} to
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// provide simple index caching by name.
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type StructQueue[StructType any] struct {
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queue structr.Queue[StructType]
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index map[string]*structr.Index
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wait atomic.Pointer[chan struct{}]
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}
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// Init initializes queue with structr.QueueConfig{}.
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func (q *StructQueue[T]) Init(config structr.QueueConfig[T]) {
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q.index = make(map[string]*structr.Index, len(config.Indices))
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q.queue = structr.Queue[T]{}
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q.queue.Init(config)
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for _, cfg := range config.Indices {
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q.index[cfg.Fields] = q.queue.Index(cfg.Fields)
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}
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}
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// Pop: see structr.Queue{}.PopFront().
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func (q *StructQueue[T]) Pop() (value T, ok bool) {
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return q.queue.PopFront()
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}
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// Push wraps structr.Queue{}.PushBack() to awaken those blocking on <-.Wait().
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func (q *StructQueue[T]) Push(values ...T) {
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q.queue.PushBack(values...)
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q.broadcast()
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}
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// Delete pops (and drops!) all queued entries under index with key.
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func (q *StructQueue[T]) Delete(index string, key ...any) {
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i := q.index[index]
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_ = q.queue.Pop(i, i.Key(key...))
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}
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// Len: see structr.Queue{}.Len().
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func (q *StructQueue[T]) Len() int {
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return q.queue.Len()
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}
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// Wait returns current wait channel, which may be
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// blocked on to awaken when new value pushed to queue.
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func (q *StructQueue[T]) Wait() <-chan struct{} {
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var ch chan struct{}
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for {
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// Get channel ptr.
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ptr := q.wait.Load()
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if ptr != nil {
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return *ptr
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}
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if ch == nil {
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// Allocate new channel.
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ch = make(chan struct{})
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}
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// Try set the new wait channel ptr.
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if q.wait.CompareAndSwap(ptr, &ch) {
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return ch
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}
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}
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}
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// broadcast safely closes wait channel if
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// currently set, releasing waiting goroutines.
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func (q *StructQueue[T]) broadcast() {
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if ptr := q.wait.Swap(nil); ptr != nil {
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close(*ptr)
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}
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}
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