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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// 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 (
"cmp"
"errors"
"fmt"
"image"
"io"
"os"
"golang.org/x/image/webp"
"codeberg.org/gruf/go-bytesize"
"codeberg.org/gruf/go-iotools"
"codeberg.org/gruf/go-mimetypes"
"github.com/buckket/go-blurhash"
"github.com/disintegration/imaging"
)
// thumbSize returns the dimensions to use for an input
// image of given width / height, for its outgoing thumbnail.
// This attempts to maintains the original image aspect ratio.
func thumbSize(width, height int, aspect float32) (int, int) {
const (
maxThumbWidth = 512
maxThumbHeight = 512
)
switch {
// Simplest case, within bounds!
case width < maxThumbWidth &&
height < maxThumbHeight:
return width, height
// Width is larger side.
case width > height:
// i.e. height = newWidth * (height / width)
height = int(float32(maxThumbWidth) / aspect)
return maxThumbWidth, height
// Height is larger side.
case height > width:
// i.e. width = newHeight * (width / height)
width = int(float32(maxThumbHeight) * aspect)
return width, maxThumbHeight
// Square.
default:
return maxThumbWidth, maxThumbHeight
}
}
// webpDecode decodes the WebP at filepath into parsed image.Image.
func webpDecode(filepath string) (image.Image, error) {
// Open the file at given path.
file, err := os.Open(filepath)
if err != nil {
return nil, err
}
// Decode image from file.
img, err := webp.Decode(file)
// Done with file.
_ = file.Close()
return img, err
}
// generateBlurhash generates a blurhash for JPEG at filepath.
func generateBlurhash(filepath string) (string, error) {
// Decode JPEG file at given path.
img, err := webpDecode(filepath)
if err != nil {
return "", err
}
// for generating blurhashes, it's more cost effective to
// lose detail since it's blurry, so make a tiny version.
tiny := imaging.Resize(img, 64, 64, imaging.NearestNeighbor)
// Drop the larger image
// ref as soon as possible
// to allow GC to claim.
img = nil //nolint
// Generate blurhash for thumbnail.
return blurhash.Encode(4, 3, tiny)
}
// getMimeType returns a suitable mimetype for file extension.
func getMimeType(ext string) string {
const defaultType = "application/octet-stream"
return cmp.Or(mimetypes.MimeTypes[ext], defaultType)
}
// drainToTmp drains data from given reader into a new temp file
// and closes it, returning the path of the resulting temp file.
//
// Note that this function specifically makes attempts to unwrap the
// io.ReadCloser as much as it can to underlying type, to maximise
// chance that Linux's sendfile syscall can be utilised for optimal
// draining of data source to temporary file storage.
func drainToTmp(rc io.ReadCloser) (string, error) {
defer rc.Close()
// Open new temporary file.
tmp, err := os.CreateTemp(
os.TempDir(),
"gotosocial-*",
)
if err != nil {
return "", err
}
defer tmp.Close()
// Extract file path.
path := tmp.Name()
// Limited reader (if any).
var lr *io.LimitedReader
var limit int64
// Reader type to use
// for draining to tmp.
rd := (io.Reader)(rc)
// Check if reader is actually wrapped,
// (as our http client wraps close func).
rct, ok := rc.(*iotools.ReadCloserType)
if ok {
// Get unwrapped.
rd = rct.Reader
// Extract limited reader if wrapped.
lr, limit = iotools.GetReaderLimit(rd)
}
// Drain reader into tmp.
_, err = tmp.ReadFrom(rd)
if err != nil {
return path, err
}
// Check to see if limit was reached,
// (produces more useful error messages).
if lr != nil && !iotools.AtEOF(lr.R) {
return path, fmt.Errorf("reached read limit %s", bytesize.Size(limit))
}
return path, nil
}
// remove only removes paths if not-empty.
func remove(paths ...string) error {
var errs []error
for _, path := range paths {
if path != "" {
if err := os.Remove(path); err != nil {
errs = append(errs, fmt.Errorf("error removing %s: %w", path, err))
}
}
}
return errors.Join(errs...)
}
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