use go module for dependencies (#594)

mediaapi/thumbnailer/thumbnailer_bimg.go

@@ -0,0 +1,248 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build bimg
+
+package thumbnailer
+
+import (
+	"context"
+	"os"
+	"time"
+
+	"github.com/matrix-org/dendrite/common/config"
+	"github.com/matrix-org/dendrite/mediaapi/storage"
+	"github.com/matrix-org/dendrite/mediaapi/types"
+	log "github.com/sirupsen/logrus"
+	"gopkg.in/h2non/bimg.v1"
+)
+
+// GenerateThumbnails generates the configured thumbnail sizes for the source file
+func GenerateThumbnails(
+	ctx context.Context,
+	src types.Path,
+	configs []config.ThumbnailSize,
+	mediaMetadata *types.MediaMetadata,
+	activeThumbnailGeneration *types.ActiveThumbnailGeneration,
+	maxThumbnailGenerators int,
+	db *storage.Database,
+	logger *log.Entry,
+) (busy bool, errorReturn error) {
+	buffer, err := bimg.Read(string(src))
+	if err != nil {
+		logger.WithError(err).WithField("src", src).Error("Failed to read src file")
+		return false, err
+	}
+	img := bimg.NewImage(buffer)
+	for _, config := range configs {
+		// Note: createThumbnail does locking based on activeThumbnailGeneration
+		busy, err = createThumbnail(
+			ctx, src, img, config, mediaMetadata, activeThumbnailGeneration,
+			maxThumbnailGenerators, db, logger,
+		)
+		if err != nil {
+			logger.WithError(err).WithField("src", src).Error("Failed to generate thumbnails")
+			return false, err
+		}
+		if busy {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+// GenerateThumbnail generates the configured thumbnail size for the source file
+func GenerateThumbnail(
+	ctx context.Context,
+	src types.Path,
+	config types.ThumbnailSize,
+	mediaMetadata *types.MediaMetadata,
+	activeThumbnailGeneration *types.ActiveThumbnailGeneration,
+	maxThumbnailGenerators int,
+	db *storage.Database,
+	logger *log.Entry,
+) (busy bool, errorReturn error) {
+	buffer, err := bimg.Read(string(src))
+	if err != nil {
+		logger.WithError(err).WithFields(log.Fields{
+			"src": src,
+		}).Error("Failed to read src file")
+		return false, err
+	}
+	img := bimg.NewImage(buffer)
+	// Note: createThumbnail does locking based on activeThumbnailGeneration
+	busy, err = createThumbnail(
+		ctx, src, img, config, mediaMetadata, activeThumbnailGeneration,
+		maxThumbnailGenerators, db, logger,
+	)
+	if err != nil {
+		logger.WithError(err).WithFields(log.Fields{
+			"src": src,
+		}).Error("Failed to generate thumbnails")
+		return false, err
+	}
+	if busy {
+		return true, nil
+	}
+	return false, nil
+}
+
+// createThumbnail checks if the thumbnail exists, and if not, generates it
+// Thumbnail generation is only done once for each non-existing thumbnail.
+func createThumbnail(
+	ctx context.Context,
+	src types.Path,
+	img *bimg.Image,
+	config types.ThumbnailSize,
+	mediaMetadata *types.MediaMetadata,
+	activeThumbnailGeneration *types.ActiveThumbnailGeneration,
+	maxThumbnailGenerators int,
+	db *storage.Database,
+	logger *log.Entry,
+) (busy bool, errorReturn error) {
+	logger = logger.WithFields(log.Fields{
+		"Width":        config.Width,
+		"Height":       config.Height,
+		"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
+	isActive, busy, err := getActiveThumbnailGeneration(dst, config, activeThumbnailGeneration, maxThumbnailGenerators, logger)
+	if err != nil {
+		return false, err
+	}
+	if busy {
+		return true, nil
+	}
+
+	if isActive {
+		// Note: This is an active request that MUST broadcastGeneration to wake up waiting goroutines!
+		// Note: broadcastGeneration uses mutexes and conditions from activeThumbnailGeneration
+		defer func() {
+			// Note: errorReturn is the named return variable so we wrap this in a closure to re-evaluate the arguments at defer-time
+			if err := recover(); err != nil {
+				broadcastGeneration(dst, activeThumbnailGeneration, config, err.(error), logger)
+				panic(err)
+			}
+			broadcastGeneration(dst, activeThumbnailGeneration, config, errorReturn, logger)
+		}()
+	}
+
+	exists, err := isThumbnailExists(ctx, dst, config, mediaMetadata, db, logger)
+	if err != nil || exists {
+		return false, err
+	}
+
+	start := time.Now()
+	width, height, err := resize(dst, img, config.Width, config.Height, config.ResizeMethod == "crop", logger)
+	if err != nil {
+		return false, err
+	}
+	logger.WithFields(log.Fields{
+		"ActualWidth":  width,
+		"ActualHeight": height,
+		"processTime":  time.Now().Sub(start),
+	}).Info("Generated thumbnail")
+
+	stat, err := os.Stat(string(dst))
+	if err != nil {
+		return false, err
+	}
+
+	thumbnailMetadata := &types.ThumbnailMetadata{
+		MediaMetadata: &types.MediaMetadata{
+			MediaID: mediaMetadata.MediaID,
+			Origin:  mediaMetadata.Origin,
+			// Note: the code currently always creates a JPEG thumbnail
+			ContentType:   types.ContentType("image/jpeg"),
+			FileSizeBytes: types.FileSizeBytes(stat.Size()),
+		},
+		ThumbnailSize: types.ThumbnailSize{
+			Width:        config.Width,
+			Height:       config.Height,
+			ResizeMethod: config.ResizeMethod,
+		},
+	}
+
+	err = db.StoreThumbnail(ctx, thumbnailMetadata)
+	if err != nil {
+		logger.WithError(err).WithFields(log.Fields{
+			"ActualWidth":  width,
+			"ActualHeight": height,
+		}).Error("Failed to store thumbnail metadata in database.")
+		return false, err
+	}
+
+	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
+func resize(dst types.Path, inImage *bimg.Image, w, h int, crop bool, logger *log.Entry) (int, int, error) {
+	inSize, err := inImage.Size()
+	if err != nil {
+		return -1, -1, err
+	}
+
+	options := bimg.Options{
+		Type:    bimg.JPEG,
+		Quality: 85,
+	}
+	if crop {
+		options.Width = w
+		options.Height = h
+		options.Crop = true
+	} else {
+		inAR := float64(inSize.Width) / float64(inSize.Height)
+		outAR := float64(w) / float64(h)
+
+		if inAR > outAR {
+			// input has wider AR than requested output so use requested width and calculate height to match input AR
+			options.Width = w
+			options.Height = int(float64(w) / inAR)
+		} else {
+			// input has narrower AR than requested output so use requested height and calculate width to match input AR
+			options.Width = int(float64(h) * inAR)
+			options.Height = h
+		}
+	}
+
+	newImage, err := inImage.Process(options)
+	if err != nil {
+		return -1, -1, err
+	}
+
+	if err = bimg.Write(string(dst), newImage); err != nil {
+		logger.WithError(err).Error("Failed to resize image")
+		return -1, -1, err
+	}
+
+	return options.Width, options.Height, nil
+}