91 lines
2.6 KiB
Go
91 lines
2.6 KiB
Go
//go:build !cgolottie
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package helper
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import (
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"io/ioutil"
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"os"
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"os/exec"
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"github.com/sirupsen/logrus"
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)
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// CanConvertTgsToX Checks whether the external command necessary for ConvertTgsToX works.
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func CanConvertTgsToX() error {
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// We depend on the fact that `lottie_convert.py --help` has exit status 0.
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// Hyrum's Law predicted this, and Murphy's Law predicts that this will break eventually.
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// However, there is no alternative like `lottie_convert.py --is-properly-installed`
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cmd := exec.Command("lottie_convert.py", "--help")
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return cmd.Run()
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}
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// ConvertTgsToWebP convert input data (which should be tgs format) to WebP format
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// This relies on an external command, which is ugly, but works.
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func ConvertTgsToX(data *[]byte, outputFormat string, logger *logrus.Entry) error {
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// lottie can't handle input from a pipe, so write to a temporary file:
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tmpInFile, err := ioutil.TempFile(os.TempDir(), "matterbridge-lottie-input-*.tgs")
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if err != nil {
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return err
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}
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tmpInFileName := tmpInFile.Name()
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defer func() {
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if removeErr := os.Remove(tmpInFileName); removeErr != nil {
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logger.Errorf("Could not delete temporary (input) file %s: %v", tmpInFileName, removeErr)
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}
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}()
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// lottie can handle writing to a pipe, but there is no way to do that platform-independently.
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// "/dev/stdout" won't work on Windows, and "-" upsets Cairo for some reason. So we need another file:
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tmpOutFile, err := ioutil.TempFile(os.TempDir(), "matterbridge-lottie-output-*.data")
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if err != nil {
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return err
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}
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tmpOutFileName := tmpOutFile.Name()
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defer func() {
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if removeErr := os.Remove(tmpOutFileName); removeErr != nil {
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logger.Errorf("Could not delete temporary (output) file %s: %v", tmpOutFileName, removeErr)
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}
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}()
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if _, writeErr := tmpInFile.Write(*data); writeErr != nil {
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return writeErr
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}
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// Must close before calling lottie to avoid data races:
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if closeErr := tmpInFile.Close(); closeErr != nil {
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return closeErr
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}
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// Call lottie to transform:
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cmd := exec.Command("lottie_convert.py", "--input-format", "lottie", "--output-format", outputFormat, tmpInFileName, tmpOutFileName)
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cmd.Stdout = nil
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cmd.Stderr = nil
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// NB: lottie writes progress into to stderr in all cases.
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_, stderr := cmd.Output()
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if stderr != nil {
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// 'stderr' already contains some parts of Stderr, because it was set to 'nil'.
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return stderr
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}
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dataContents, err := ioutil.ReadFile(tmpOutFileName)
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if err != nil {
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return err
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}
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*data = dataContents
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return nil
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}
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func SupportsFormat(format string) bool {
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switch format {
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case "png":
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fallthrough
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case "webp":
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return true
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default:
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return false
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}
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return false
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}
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func LottieBackend() string {
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return "lottie_convert.py"
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}
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