diff options
Diffstat (limited to 'vendor/codeberg.org/superseriousbusiness/exif-terminator/terminator.go')
-rw-r--r-- | vendor/codeberg.org/superseriousbusiness/exif-terminator/terminator.go | 158 |
1 files changed, 0 insertions, 158 deletions
diff --git a/vendor/codeberg.org/superseriousbusiness/exif-terminator/terminator.go b/vendor/codeberg.org/superseriousbusiness/exif-terminator/terminator.go deleted file mode 100644 index 7dd3d9ad7..000000000 --- a/vendor/codeberg.org/superseriousbusiness/exif-terminator/terminator.go +++ /dev/null @@ -1,158 +0,0 @@ -/* - exif-terminator - Copyright (C) 2022 SuperSeriousBusiness 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 terminator - -import ( - "bufio" - "bytes" - "errors" - "fmt" - "io" - - jpegstructure "github.com/superseriousbusiness/go-jpeg-image-structure/v2" - pngstructure "github.com/superseriousbusiness/go-png-image-structure/v2" -) - -func Terminate(in io.Reader, fileSize int, mediaType string) (io.Reader, error) { - // To avoid keeping too much stuff - // in memory we want to pipe data - // directly to the reader. - pipeReader, pipeWriter := io.Pipe() - - // We don't know ahead of time how long - // segments might be: they could be as - // large as the file itself, so we need - // a buffer with generous overhead. - scanner := bufio.NewScanner(in) - scanner.Buffer([]byte{}, fileSize) - - var err error - switch mediaType { - case "image/jpeg", "jpeg", "jpg": - err = terminateJpeg(scanner, pipeWriter, fileSize) - - case "image/webp", "webp": - err = terminateWebp(scanner, pipeWriter) - - case "image/png", "png": - // For pngs we need to skip the header bytes, so read - // them in and check we're really dealing with a png. - header := make([]byte, len(pngstructure.PngSignature)) - if _, headerError := in.Read(header); headerError != nil { - err = headerError - break - } - - if !bytes.Equal(header, pngstructure.PngSignature[:]) { - err = errors.New("could not decode png: invalid header") - break - } - - err = terminatePng(scanner, pipeWriter) - default: - err = fmt.Errorf("mediaType %s cannot be processed", mediaType) - } - - return pipeReader, err -} - -func terminateJpeg(scanner *bufio.Scanner, writer *io.PipeWriter, expectedFileSize int) error { - v := &jpegVisitor{ - writer: writer, - expectedFileSize: expectedFileSize, - } - - // Provide the visitor to the splitter so - // that it triggers on every section scan. - js := jpegstructure.NewJpegSplitter(v) - - // The visitor also needs to read back the - // list of segments: for this it needs to - // know what jpeg splitter it's attached to, - // so give it a pointer to the splitter. - v.js = js - - // Jpeg visitor's 'split' function - // satisfies bufio.SplitFunc{}. - scanner.Split(js.Split) - - go scanAndClose(scanner, writer) - return nil -} - -func terminateWebp(scanner *bufio.Scanner, writer *io.PipeWriter) error { - v := &webpVisitor{ - writer: writer, - } - - // Webp visitor's 'split' function - // satisfies bufio.SplitFunc{}. - scanner.Split(v.split) - - go scanAndClose(scanner, writer) - return nil -} - -func terminatePng(scanner *bufio.Scanner, writer *io.PipeWriter) error { - ps := pngstructure.NewPngSplitter() - - // Don't bother checking CRC; - // we're overwriting it anyway. - ps.DoCheckCrc(false) - - v := &pngVisitor{ - ps: ps, - writer: writer, - lastWrittenChunk: -1, - } - - // Png visitor's 'split' function - // satisfies bufio.SplitFunc{}. - scanner.Split(v.split) - - go scanAndClose(scanner, writer) - return nil -} - -// scanAndClose scans through the given scanner until there's -// nothing left to scan, and then closes the writer so that the -// reader on the other side of the pipe knows that we're done. -// -// Any error encountered when scanning will be logged by terminator. -// -// Due to the nature of io.Pipe, writing won't actually work -// until the pipeReader starts being read by the caller, which -// is why this function should always be called asynchronously. -func scanAndClose(scanner *bufio.Scanner, writer *io.PipeWriter) { - var err error - - defer func() { - // Always close writer, using returned - // scanner error (if any). If err is nil - // then the standard io.EOF will be used. - // (this will not overwrite existing). - writer.CloseWithError(err) - }() - - for scanner.Scan() { - } - - // Set error on return. - err = scanner.Err() -} |