test the media manager a bit, add shutdown logic

internal/media/processing.go

@@ -0,0 +1,256 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package media
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"codeberg.org/gruf/go-store/kv"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+type processState int
+
+const (
+	received processState = iota // processing order has been received but not done yet
+	complete                     // processing order has been completed successfully
+	errored                      // processing order has been completed with an error
+)
+
+// Processing represents a piece of media that is currently being processed. It exposes
+// various functions for retrieving data from the process.
+type Processing struct {
+	mu sync.Mutex
+
+	/*
+		below fields should be set on newly created media;
+		attachment will be updated incrementally as media goes through processing
+	*/
+
+	attachment *gtsmodel.MediaAttachment // will only be set if the media is an attachment
+	emoji      *gtsmodel.Emoji           // will only be set if the media is an emoji
+
+	rawData []byte
+
+	/*
+		below fields represent the processing state of the media thumbnail
+	*/
+
+	thumbstate processState
+	thumb      *ImageMeta
+
+	/*
+		below fields represent the processing state of the full-sized media
+	*/
+
+	fullSizeState processState
+	fullSize      *ImageMeta
+
+	/*
+		below pointers to database and storage are maintained so that
+		the media can store and update itself during processing steps
+	*/
+
+	database db.DB
+	storage  *kv.KVStore
+
+	err error // error created during processing, if any
+}
+
+func (p *Processing) Thumb(ctx context.Context) (*ImageMeta, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	switch p.thumbstate {
+	case received:
+		// we haven't processed a thumbnail for this media yet so do it now
+
+		// check if we need to create a blurhash or if there's already one set
+		var createBlurhash bool
+		if p.attachment.Blurhash == "" {
+			// no blurhash created yet
+			createBlurhash = true
+		}
+
+		thumb, err := deriveThumbnail(p.rawData, p.attachment.File.ContentType, createBlurhash)
+		if err != nil {
+			p.err = fmt.Errorf("error deriving thumbnail: %s", err)
+			p.thumbstate = errored
+			return nil, p.err
+		}
+
+		// put the thumbnail in storage
+		if err := p.storage.Put(p.attachment.Thumbnail.Path, thumb.image); err != nil {
+			p.err = fmt.Errorf("error storing thumbnail: %s", err)
+			p.thumbstate = errored
+			return nil, p.err
+		}
+
+		// set appropriate fields on the attachment based on the thumbnail we derived
+		if createBlurhash {
+			p.attachment.Blurhash = thumb.blurhash
+		}
+
+		p.attachment.FileMeta.Small = gtsmodel.Small{
+			Width:  thumb.width,
+			Height: thumb.height,
+			Size:   thumb.size,
+			Aspect: thumb.aspect,
+		}
+		p.attachment.Thumbnail.FileSize = thumb.size
+
+		if err := putOrUpdateAttachment(ctx, p.database, p.attachment); err != nil {
+			p.err = err
+			p.thumbstate = errored
+			return nil, err
+		}
+
+		// set the thumbnail of this media
+		p.thumb = thumb
+
+		// we're done processing the thumbnail!
+		p.thumbstate = complete
+		fallthrough
+	case complete:
+		return p.thumb, nil
+	case errored:
+		return nil, p.err
+	}
+
+	return nil, fmt.Errorf("thumbnail processing status %d unknown", p.thumbstate)
+}
+
+func (p *Processing) FullSize(ctx context.Context) (*ImageMeta, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	switch p.fullSizeState {
+	case received:
+		var clean []byte
+		var err error
+		var decoded *ImageMeta
+
+		ct := p.attachment.File.ContentType
+		switch ct {
+		case mimeImageJpeg, mimeImagePng:
+			// first 'clean' image by purging exif data from it
+			var exifErr error
+			if clean, exifErr = purgeExif(p.rawData); exifErr != nil {
+				err = exifErr
+				break
+			}
+			decoded, err = decodeImage(clean, ct)
+		case mimeImageGif:
+			// gifs are already clean - no exif data to remove
+			clean = p.rawData
+			decoded, err = decodeGif(clean)
+		default:
+			err = fmt.Errorf("content type %s not a processible image type", ct)
+		}
+
+		if err != nil {
+			p.err = err
+			p.fullSizeState = errored
+			return nil, err
+		}
+
+		// put the full size in storage
+		if err := p.storage.Put(p.attachment.File.Path, decoded.image); err != nil {
+			p.err = fmt.Errorf("error storing full size image: %s", err)
+			p.fullSizeState = errored
+			return nil, p.err
+		}
+
+		// set appropriate fields on the attachment based on the image we derived
+		p.attachment.FileMeta.Original = gtsmodel.Original{
+			Width:  decoded.width,
+			Height: decoded.height,
+			Size:   decoded.size,
+			Aspect: decoded.aspect,
+		}
+		p.attachment.File.FileSize = decoded.size
+		p.attachment.File.UpdatedAt = time.Now()
+		p.attachment.Processing = gtsmodel.ProcessingStatusProcessed
+
+		if err := putOrUpdateAttachment(ctx, p.database, p.attachment); err != nil {
+			p.err = err
+			p.fullSizeState = errored
+			return nil, err
+		}
+
+		// set the fullsize of this media
+		p.fullSize = decoded
+
+		// we're done processing the full-size image
+		p.fullSizeState = complete
+		fallthrough
+	case complete:
+		return p.fullSize, nil
+	case errored:
+		return nil, p.err
+	}
+
+	return nil, fmt.Errorf("full size processing status %d unknown", p.fullSizeState)
+}
+
+// AttachmentID returns the ID of the underlying media attachment without blocking processing.
+func (p *Processing) AttachmentID() string {
+	return p.attachment.ID
+}
+
+// Load blocks until the thumbnail and fullsize content has been processed, and then
+// returns the completed attachment.
+func (p *Processing) Load(ctx context.Context) (*gtsmodel.MediaAttachment, error) {
+	if _, err := p.Thumb(ctx); err != nil {
+		return nil, err
+	}
+
+	if _, err := p.FullSize(ctx); err != nil {
+		return nil, err
+	}
+
+	return p.attachment, nil
+}
+
+func (p *Processing) LoadEmoji(ctx context.Context) (*gtsmodel.Emoji, error) {
+	return nil, nil
+}
+
+func (p *Processing) Finished() bool {
+	return p.thumbstate == complete && p.fullSizeState == complete
+}
+
+// putOrUpdateAttachment is just a convenience function for first trying to PUT the attachment in the database,
+// and then if that doesn't work because the attachment already exists, updating it instead.
+func putOrUpdateAttachment(ctx context.Context, database db.DB, attachment *gtsmodel.MediaAttachment) error {
+	if err := database.Put(ctx, attachment); err != nil {
+		if err != db.ErrAlreadyExists {
+			return fmt.Errorf("putOrUpdateAttachment: proper error while putting attachment: %s", err)
+		}
+		if err := database.UpdateByPrimaryKey(ctx, attachment); err != nil {
+			return fmt.Errorf("putOrUpdateAttachment: error while updating attachment: %s", err)
+		}
+	}
+
+	return nil
+}