Caption support (#2462)

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

vendor/github.com/asticode/go-astikit/ssh.go

@@ -0,0 +1,113 @@
+package astikit
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+// SSHSession represents an SSH Session
+type SSHSession interface {
+	Run(string) error
+	Start(string) error
+	StdinPipe() (io.WriteCloser, error)
+	Wait() error
+}
+
+// SSHSessionFunc represents a func that can return an SSHSession
+type SSHSessionFunc func() (s SSHSession, c *Closer, err error)
+
+// SSHCopyFileFunc is the SSH CopyFileFunc that allows doing SSH copies
+func SSHCopyFileFunc(fn SSHSessionFunc) CopyFileFunc {
+	return func(ctx context.Context, dst string, srcStat os.FileInfo, srcFile *os.File) (err error) {
+		// Check context
+		if err = ctx.Err(); err != nil {
+			return
+		}
+
+		// Using local closure allows better readibility for the defer c.Close() since it
+		// isolates the use of the ssh session
+		if err = func() (err error) {
+			// Create ssh session
+			var s SSHSession
+			var c *Closer
+			if s, c, err = fn(); err != nil {
+				err = fmt.Errorf("astikit: creating ssh session failed: %w", err)
+				return
+			}
+			defer c.Close()
+
+			// Create the destination folder
+			if err = s.Run("mkdir -p " + filepath.Dir(dst)); err != nil {
+				err = fmt.Errorf("astikit: creating %s failed: %w", filepath.Dir(dst), err)
+				return
+			}
+			return
+		}(); err != nil {
+			return
+		}
+
+		// Using local closure allows better readibility for the defer c.Close() since it
+		// isolates the use of the ssh session
+		if err = func() (err error) {
+			// Create ssh session
+			var s SSHSession
+			var c *Closer
+			if s, c, err = fn(); err != nil {
+				err = fmt.Errorf("astikit: creating ssh session failed: %w", err)
+				return
+			}
+			defer c.Close()
+
+			// Create stdin pipe
+			var stdin io.WriteCloser
+			if stdin, err = s.StdinPipe(); err != nil {
+				err = fmt.Errorf("astikit: creating stdin pipe failed: %w", err)
+				return
+			}
+			defer stdin.Close()
+
+			// Use "scp" command
+			if err = s.Start("scp -qt \"" + filepath.Dir(dst) + "\""); err != nil {
+				err = fmt.Errorf("astikit: scp to %s failed: %w", dst, err)
+				return
+			}
+
+			// Send metadata
+			if _, err = fmt.Fprintln(stdin, fmt.Sprintf("C%04o", srcStat.Mode().Perm()), srcStat.Size(), filepath.Base(dst)); err != nil {
+				err = fmt.Errorf("astikit: sending metadata failed: %w", err)
+				return
+			}
+
+			// Copy
+			if _, err = Copy(ctx, stdin, srcFile); err != nil {
+				err = fmt.Errorf("astikit: copying failed: %w", err)
+				return
+			}
+
+			// Send close
+			if _, err = fmt.Fprint(stdin, "\x00"); err != nil {
+				err = fmt.Errorf("astikit: sending close failed: %w", err)
+				return
+			}
+
+			// Close stdin
+			if err = stdin.Close(); err != nil {
+				err = fmt.Errorf("astikit: closing failed: %w", err)
+				return
+			}
+
+			// Wait
+			if err = s.Wait(); err != nil {
+				err = fmt.Errorf("astikit: waiting failed: %w", err)
+				return
+			}
+			return
+		}(); err != nil {
+			return
+		}
+		return
+	}
+}