Restructure go project (#2356)

* Move main to cmd
* Move api to internal
* Move logger and manager to internal
* Move shell hiding code to separate package
* Decouple job from desktop and utils
* Decouple session from config
* Move static into internal
* Decouple config from dlna
* Move desktop to internal
* Move dlna to internal
* Decouple remaining packages from config
* Move config into internal
* Move jsonschema and paths to models
* Make ffmpeg functions private
* Move file utility methods into fsutil package
* Move symwalk into fsutil
* Move single-use util functions into client package
* Move slice functions to separate packages
* Add env var to suppress windowsgui arg
* Move hash functions into separate package
* Move identify to internal
* Move autotag to internal
* Touch UI when generating backend

internal/api/byterange.go

@@ -0,0 +1,51 @@
+package api
+
+import (
+	"strconv"
+	"strings"
+)
+
+type byteRange struct {
+	Start     int64
+	End       *int64
+	RawString string
+}
+
+func createByteRange(s string) byteRange {
+	// strip bytes=
+	r := strings.TrimPrefix(s, "bytes=")
+	e := strings.Split(r, "-")
+
+	ret := byteRange{
+		RawString: s,
+	}
+	if len(e) > 0 {
+		ret.Start, _ = strconv.ParseInt(e[0], 10, 64)
+	}
+	if len(e) > 1 && e[1] != "" {
+		end, _ := strconv.ParseInt(e[1], 10, 64)
+		ret.End = &end
+	}
+
+	return ret
+}
+
+func (r byteRange) toHeaderValue(fileLength int64) string {
+	if r.End == nil {
+		return ""
+	}
+	end := *r.End
+	return "bytes " + strconv.FormatInt(r.Start, 10) + "-" + strconv.FormatInt(end, 10) + "/" + strconv.FormatInt(fileLength, 10)
+}
+
+func (r byteRange) apply(bytes []byte) []byte {
+	if r.End == nil {
+		return bytes[r.Start:]
+	}
+
+	end := *r.End + 1
+	if int(end) > len(bytes) {
+		end = int64(len(bytes))
+	}
+	return bytes[r.Start:end]
+}