From f7e16450a214aa3f5db5b864899b67b39fb84a87 Mon Sep 17 00:00:00 2001
From: Robert Swain <rob@matrix.org>
Date: Thu, 8 Jun 2017 13:07:41 +0200
Subject: [PATCH] mediaapi/thumbnailer: Check if request is larger than
 original

---
 .../mediaapi/thumbnailer/thumbnailer_bimg.go        | 13 +++++++++++++
 .../mediaapi/thumbnailer/thumbnailer_nfnt.go        |  5 +++++
 2 files changed, 18 insertions(+)

diff --git a/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_bimg.go b/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_bimg.go
index d8400a641..41edce7cb 100644
--- a/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_bimg.go
+++ b/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_bimg.go
@@ -81,6 +81,11 @@ func createThumbnail(src types.Path, img *bimg.Image, config types.ThumbnailSize
 		"ResizeMethod": config.ResizeMethod,
 	})
 
+	// Check if request is larger than original
+	if isLargerThanOriginal(config, img) {
+		return false, nil
+	}
+
 	dst := GetThumbnailPath(src, config)
 
 	// Note: getActiveThumbnailGeneration uses mutexes and conditions from activeThumbnailGeneration
@@ -153,6 +158,14 @@ func createThumbnail(src types.Path, img *bimg.Image, config types.ThumbnailSize
 	return false, nil
 }
 
+func isLargerThanOriginal(config types.ThumbnailSize, img *bimg.Image) bool {
+	imgSize, err := img.Size()
+	if err == nil && config.Width >= imgSize.Width && config.Height >= imgSize.Height {
+		return true
+	}
+	return false
+}
+
 // resize scales an image to fit within the provided width and height
 // If the source aspect ratio is different to the target dimensions, one edge will be smaller than requested
 // If crop is set to true, the image will be scaled to fill the width and height with any excess being cropped off
diff --git a/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_nfnt.go b/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_nfnt.go
index 476e1cb35..0b75ea52a 100644
--- a/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_nfnt.go
+++ b/src/github.com/matrix-org/dendrite/mediaapi/thumbnailer/thumbnailer_nfnt.go
@@ -113,6 +113,11 @@ func createThumbnail(src types.Path, img image.Image, config types.ThumbnailSize
 		"ResizeMethod": config.ResizeMethod,
 	})
 
+	// Check if request is larger than original
+	if config.Width >= img.Bounds().Dx() && config.Height >= img.Bounds().Dy() {
+		return false, nil
+	}
+
 	dst := GetThumbnailPath(src, config)
 
 	// Note: getActiveThumbnailGeneration uses mutexes and conditions from activeThumbnailGeneration