Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/app/imaging/orientation.go

@@ -0,0 +1,77 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package imaging
+
+import (
+	"fmt"
+	"image"
+	"io"
+
+	"github.com/disintegration/imaging"
+	"github.com/rwcarlsen/goexif/exif"
+)
+
+const (
+	/*
+	  EXIF Image Orientations
+	  1        2       3      4         5            6           7          8
+
+	  888888  888888      88  88      8888888888  88                  88  8888888888
+	  88          88      88  88      88  88      88  88          88  88      88  88
+	  8888      8888    8888  8888    88          8888888888  8888888888          88
+	  88          88      88  88
+	  88          88  888888  888888
+	*/
+	Upright = iota + 1
+	UprightMirrored
+	UpsideDown
+	UpsideDownMirrored
+	RotatedCWMirrored
+	RotatedCCW
+	RotatedCCWMirrored
+	RotatedCW
+)
+
+// MakeImageUpright changes the orientation of the given image.
+func MakeImageUpright(img image.Image, orientation int) image.Image {
+	switch orientation {
+	case UprightMirrored:
+		return imaging.FlipH(img)
+	case UpsideDown:
+		return imaging.Rotate180(img)
+	case UpsideDownMirrored:
+		return imaging.FlipV(img)
+	case RotatedCWMirrored:
+		return imaging.Transpose(img)
+	case RotatedCCW:
+		return imaging.Rotate270(img)
+	case RotatedCCWMirrored:
+		return imaging.Transverse(img)
+	case RotatedCW:
+		return imaging.Rotate90(img)
+	default:
+		return img
+	}
+}
+
+// GetImageOrientation reads the input data and returns the EXIF encoded
+// image orientation.
+func GetImageOrientation(input io.Reader) (int, error) {
+	exifData, err := exif.Decode(input)
+	if err != nil {
+		return Upright, fmt.Errorf("failed to decode exif data: %w", err)
+	}
+
+	tag, err := exifData.Get("Orientation")
+	if err != nil {
+		return Upright, fmt.Errorf("failed to get orientation field from exif data: %w", err)
+	}
+
+	orientation, err := tag.Int(0)
+	if err != nil {
+		return Upright, fmt.Errorf("failed to get value from exif tag: %w", err)
+	}
+
+	return orientation, nil
+}