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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package ffmpeg
import (
"context"
"codeberg.org/gruf/go-ffmpreg/wasm"
)
// wasmInstancePool wraps a wasm.Instantiator{} and a
// channel of wasm.Instance{}s to provide a concurrency
// safe pool of WebAssembly module instances capable of
// compiling new instances on-the-fly, with a predetermined
// maximum number of concurrent instances at any one time.
type wasmInstancePool struct {
inst wasm.Instantiator
pool chan *wasm.Instance
}
func (p *wasmInstancePool) Init(ctx context.Context, sz int) error {
// Initialize for first time
// to preload module into the
// wazero compilation cache.
inst, err := p.inst.New(ctx)
if err != nil {
return err
}
// Clamp to 1.
if sz <= 0 {
sz = 1
}
// Allocate new pool instance channel.
p.pool = make(chan *wasm.Instance, sz)
// Store only one
// open instance
// at init time.
p.pool <- inst
// Fill reminaing with closed
// instances for later opening.
for i := 0; i < sz-1; i++ {
p.pool <- new(wasm.Instance)
}
return nil
}
func (p *wasmInstancePool) Run(ctx context.Context, args wasm.Args) (uint32, error) {
var inst *wasm.Instance
select {
// Context canceled.
case <-ctx.Done():
return 0, ctx.Err()
// Acquire instance.
case inst = <-p.pool:
// Ensure instance is
// ready for running.
if inst.IsClosed() {
var err error
inst, err = p.inst.New(ctx)
if err != nil {
return 0, err
}
}
}
// Release instance to pool on end.
defer func() { p.pool <- inst }()
// Pass args to instance.
return inst.Run(ctx, args)
}
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