67 lines
1.6 KiB
Go
67 lines
1.6 KiB
Go
package app
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import (
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"context"
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"fmt"
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"io"
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"os/exec"
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)
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type playbackProcess struct {
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command *exec.Cmd
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cancel context.CancelFunc
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stdout io.ReadCloser
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log *playbackLog
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waited bool
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release func()
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}
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func (app *UIApp) startBudgetedPlaybackProcess(ctx context.Context, ffmpeg string, args []string, kind string) (*playbackProcess, error) {
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optional, _ := ctx.Value(playbackPrefetchKey{}).(bool)
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release, err := app.mediaResources().acquire(ctx, kind, optional)
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if err != nil {
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return nil, err
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}
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process, err := startPlaybackProcess(ctx, ffmpeg, args)
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if err != nil {
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release()
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return nil, err
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}
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process.release = release
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return process, nil
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}
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func startPlaybackProcess(ctx context.Context, ffmpeg string, args []string) (*playbackProcess, error) {
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ctx, cancel := context.WithCancel(ctx)
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command := ffmpegMediaCommand(ctx, ffmpeg, args...)
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stdout, err := command.StdoutPipe()
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if err != nil {
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cancel()
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return nil, err
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}
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log := &playbackLog{text: cappedStringWriter{limit: 64 * 1024}, ready: make(chan struct{})}
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command.Stderr = log
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if err := command.Start(); err != nil {
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cancel()
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_ = stdout.Close()
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return nil, fmt.Errorf("无法启动在线播放处理：%w", err)
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}
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return &playbackProcess{command: command, cancel: cancel, stdout: stdout, log: log}, nil
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}
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func (process *playbackProcess) Wait() error {
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process.waited = true
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if process.release != nil {
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defer process.release()
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}
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return process.command.Wait()
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}
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func (process *playbackProcess) Close() {
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process.cancel()
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_ = process.stdout.Close()
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if !process.waited {
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_ = process.Wait()
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}
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}
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