89 lines
2.7 KiB
Go
89 lines
2.7 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 cache
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import (
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"context"
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"errors"
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"fmt"
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"time"
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"codeberg.org/gruf/go-cache/v3/result"
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errorsv2 "codeberg.org/gruf/go-errors/v2"
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"github.com/superseriousbusiness/gotosocial/internal/log"
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)
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// SentinelError is returned to indicate a non-permanent error return,
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// i.e. a situation in which we do not want a cache a negative result.
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var SentinelError = errors.New("BUG: error should not be returned") //nolint:revive
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// ignoreErrors is an error ignoring function capable of being passed to
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// caches, which specifically catches and ignores our sentinel error type.
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func ignoreErrors(err error) bool {
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return errorsv2.Comparable(
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err,
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SentinelError,
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context.DeadlineExceeded,
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context.Canceled,
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)
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}
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// nocopy when embedded will signal linter to
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// error on pass-by-value of parent struct.
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type nocopy struct{}
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func (*nocopy) Lock() {}
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func (*nocopy) Unlock() {}
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// tryStart will attempt to start the given cache only if sweep duration > 0 (sweeping is enabled).
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func tryStart[ValueType any](cache *result.Cache[ValueType], sweep time.Duration) {
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if sweep > 0 {
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var z ValueType
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msg := fmt.Sprintf("starting %T cache", z)
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tryUntil(msg, 5, func() bool {
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return cache.Start(sweep)
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})
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}
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}
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// tryStop will attempt to stop the given cache only if sweep duration > 0 (sweeping is enabled).
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func tryStop[ValueType any](cache *result.Cache[ValueType], sweep time.Duration) {
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if sweep > 0 {
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var z ValueType
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msg := fmt.Sprintf("stopping %T cache", z)
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tryUntil(msg, 5, cache.Stop)
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}
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}
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// tryUntil will attempt to call 'do' for 'count' attempts, before panicking with 'msg'.
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func tryUntil(msg string, count int, do func() bool) {
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for i := 0; i < count; i++ {
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if do() {
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// success.
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return
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}
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// Sleep for a little before retry (a bcakoff).
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time.Sleep(time.Millisecond * 1 << (i + 1))
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}
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// panic on total failure as this shouldn't happen.
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log.Panicf(nil, "failed %s after %d tries", msg, count)
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}
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