Scan refactor (#1816)

* Add file scanner
* Scan scene changes
* Split scan files
* Generalise scan
* Refactor ffprobe
* Refactor ffmpeg encoder
* Move scene scan code to scene package
* Move matchExtension to utils
* Refactor gallery scanning
* Refactor image scanning
* Prevent race conditions on identical hashes
* Refactor image thumbnail generation
* Perform count concurrently
* Allow progress increment before total set
* Make progress updates more frequent

pkg/image/vips.go

@@ -0,0 +1,48 @@
+package image
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+	"strings"
+
+	"github.com/stashapp/stash/pkg/logger"
+)
+
+type vipsEncoder string
+
+func (e *vipsEncoder) ImageThumbnail(image *bytes.Buffer, maxSize int) ([]byte, error) {
+	args := []string{
+		"thumbnail_source",
+		"[descriptor=0]",
+		".jpg[Q=70,strip]",
+		fmt.Sprint(maxSize),
+		"--size", "down",
+	}
+	data, err := e.run(args, image)
+
+	return []byte(data), err
+}
+
+func (e *vipsEncoder) run(args []string, stdin *bytes.Buffer) (string, error) {
+	cmd := exec.Command(string(*e), args...)
+
+	var stdout, stderr bytes.Buffer
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	cmd.Stdin = stdin
+
+	if err := cmd.Start(); err != nil {
+		return "", err
+	}
+
+	err := cmd.Wait()
+
+	if err != nil {
+		// error message should be in the stderr stream
+		logger.Errorf("image encoder error when running command <%s>: %s", strings.Join(cmd.Args, " "), stderr.String())
+		return stdout.String(), err
+	}
+
+	return stdout.String(), nil
+}