8160327: Support for thumbnails present in APP1 marker for JPEG

Reviewed-by: prr

Author: mickleness

src/java.desktop/share/classes/com/sun/imageio/plugins/jpeg/ExifMarkerSegment.java

@@ -0,0 +1,294 @@
+/*
+ * Copyright (c) 2001, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code 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 General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.sun.imageio.plugins.jpeg;
+
+import com.sun.imageio.plugins.tiff.TIFFImageReader;
+
+import javax.imageio.ImageIO;
+import javax.imageio.ImageReader;
+import javax.imageio.stream.ImageInputStream;
+import javax.imageio.stream.MemoryCacheImageInputStream;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.ByteOrder;
+import java.nio.charset.StandardCharsets;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.LinkedHashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * An Exif (Exchangeable Image File Format) APP1 (Application-Specific)
+ * marker segment. This implementation only supports reading thumbnails
+ * and the image creation time.
+ */
+class ExifMarkerSegment extends MarkerSegment {
+
+    static class ImageFileDirectory implements Cloneable {
+        static class Entry implements Cloneable {
+            final int tagNumber, dataFormat;
+            final long componentCount, fieldValue;
+
+            Entry(ImageInputStream in) throws IOException {
+                tagNumber = in.readUnsignedShort();
+                dataFormat = in.readUnsignedShort();
+                componentCount = in.readUnsignedInt();
+                fieldValue = in.readUnsignedInt();
+            }
+
+            @Override
+            public String toString() {
+                return "Entry[ tagNumber: " + tagNumber +
+                        ", dataFormat: " + dataFormat +
+                        ", componentCount: " + componentCount +
+                        ", fieldValue: " + fieldValue + "]";
+            }
+        }
+        static final int[] bytesPerComponent = new int[] {1, 1, 1, 2, 4, 8, 1};
+
+        Map<Integer, Entry> entriesByTag = new LinkedHashMap<>();
+        long nextIFD;
+
+        ImageFileDirectory(ImageInputStream in, long pos) throws IOException {
+            in.seek(pos);
+            int entryCount = in.readUnsignedShort();
+            for (int a = 0; a < entryCount; a++) {
+                Entry e = new Entry(in);
+                entriesByTag.put(e.tagNumber, e);
+            }
+
+            // The next 4 bytes SHOULD be the position of the next IFD.
+
+            // However in rare cases: the position of the next IFD header is missing. We can detect
+            // this by checking to see if any of the IFD entries we just read appear where the
+            // next IFD position *should* be:
+
+            long streamPos = in.getStreamPosition();
+            for (Entry e : entriesByTag.values()) {
+                int byteLength = e.dataFormat < bytesPerComponent.length ?
+                        (int) (e.componentCount * bytesPerComponent[e.dataFormat]) :
+                        // this is an unknown data format, so let's just assume its 1 byte
+                        1;
+                if (byteLength > 4) {
+                    long valuePos = e.fieldValue;
+                    if (valuePos <= streamPos) {
+                        nextIFD = 0;
+                        return;
+                    }
+                }
+            }
+
+            nextIFD = in.readUnsignedInt();
+        }
+
+        int getTagValueAsInt(int tagID) {
+            ImageFileDirectory.Entry e = entriesByTag.get(tagID);
+            if (e == null) {
+                return NO_VALUE;
+            }
+            return (int) e.fieldValue;
+        }
+    }
+
+    private static final int NO_VALUE = -1;
+
+    private static final int TIFF_BIG_ENDIAN = 0x4d4d;
+    private static final int TIFF_MAGIC = 42;
+    private static final int TIFF_TYPE_SHORT = 3;
+    private static final int TAG_IMAGE_WIDTH = 256;
+    private static final int TAG_IMAGE_HEIGHT = 257;
+    private static final int TAG_DATE_TIME = 306;
+    private static final int TAG_JPEG_INTERCHANGE_FORMAT = 513;
+    private static final int TAG_JPEG_INTERCHANGE_FORMAT_LENGTH = 514;
+
+    int thumbnailPos = -1;
+    int thumbnailLength = -1;
+    boolean isThumbnailJPEG;
+
+    int thumbnailWidth = -1;
+    int thumbnailHeight = -1;
+
+    final long firstIFDOffset;
+    final List<ImageFileDirectory> imageFileDirectories = new LinkedList<>();
+
+    ExifMarkerSegment(MarkerSegment originalSegment) throws IOException {
+        super(originalSegment.tag);
+        this.length = originalSegment.length;
+        this.data = originalSegment.data;
+
+        ByteArrayInputStream in = new ByteArrayInputStream(data, 6, data.length - 6);
+
+        // we aren't actually going to read anything as an image yet, but ImageInputStream
+        // has useful helper methods:
+        ImageInputStream input = new MemoryCacheImageInputStream(in);
+        input.setByteOrder(input.readUnsignedShort() == TIFF_BIG_ENDIAN ?
+                ByteOrder.BIG_ENDIAN : ByteOrder.LITTLE_ENDIAN);
+        if (input.readUnsignedShort() != TIFF_MAGIC) {
+            throw new IllegalArgumentException("Bad magic number");
+        }
+
+        firstIFDOffset = input.readUnsignedInt();
+        ImageFileDirectory ifd1 = null;
+        ImageFileDirectory ifd2 = null;
+        if (firstIFDOffset != 0) {
+            ifd1 = new ImageFileDirectory(input, firstIFDOffset);
+            imageFileDirectories.add(ifd1);
+
+            long secondIFDOffset = ifd1.nextIFD;
+            if (secondIFDOffset != 0) {
+                ifd2 = new ImageFileDirectory(input, secondIFDOffset);
+                imageFileDirectories.add(ifd2);
+            }
+        }
+
+        if (ifd2 != null) {
+            // the thumbnail should always be described in the 2nd IFD (if it exists at all)
+
+            thumbnailPos = ifd2.getTagValueAsInt(TAG_JPEG_INTERCHANGE_FORMAT);
+            thumbnailLength = ifd2.getTagValueAsInt(TAG_JPEG_INTERCHANGE_FORMAT_LENGTH);
+            if (thumbnailPos != NO_VALUE && thumbnailLength != NO_VALUE) {
+                // The `compression` tag (259) should also help inform whether we read this
+                // image as a JPEG or TIFF. But in reality this is tricky: the docs say
+                // the value for a JPEG encoding is 0x0006, but the `jdk_8160327-plastic-wrap.jpg`
+                // file shows it can also sometimes be 0x60000. I've also observed it to be
+                // undefined, 0x0007, or several variations of 0x????0006. Similarly the same
+                // tag should be 0x0001 for TIFFs, but I also observed a case where it as 0x10000.
+                isThumbnailJPEG = true;
+            } else {
+                thumbnailWidth = ifd2.getTagValueAsInt(TAG_IMAGE_WIDTH);
+                thumbnailHeight = ifd2.getTagValueAsInt(TAG_IMAGE_HEIGHT);
+                thumbnailPos = 0;
+                thumbnailLength = data.length - 6;
+                isThumbnailJPEG = false;
+            }
+        }
+    }
+
+    LocalDateTime getImageCreationTime() {
+        LocalDateTime imageCreationTime = null;
+
+        if (!imageFileDirectories.isEmpty()) {
+            ImageFileDirectory ifd = imageFileDirectories.get(0);
+            int dateTimeOffset = ifd.getTagValueAsInt(TAG_DATE_TIME);
+            if (dateTimeOffset != NO_VALUE) {
+                try {
+                    String dateTime = new String(data, dateTimeOffset + 6, 19, StandardCharsets.US_ASCII);
+                    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("uuuu:MM:dd HH:mm:ss");
+                    imageCreationTime = LocalDateTime.parse(dateTime, formatter);
+                } catch(Exception e) {
+                    // intentionally empty
+                }
+            }
+        }
+
+        return imageCreationTime;
+    }
+
+    @Override
+    void print() {
+        printTag("Exif APP1");
+        for (int a = 0; a < imageFileDirectories.size(); a++) {
+            System.out.println("ImageFileDirectory #" + a + ", offset = " + firstIFDOffset);
+            int entryCtr = 0;
+            for (ImageFileDirectory.Entry entry : imageFileDirectories.get(a).entriesByTag.values()) {
+                System.out.println("Entry #" + (entryCtr++) + ": " + entry.toString());
+            }
+            System.out.println("next directory: " + imageFileDirectories.get(a).nextIFD);
+        }
+    }
+
+    int getNumThumbnails() {
+        return thumbnailPos >= 0 && thumbnailLength > 0 ? 1 : 0;
+    }
+
+    int getThumbnailWidth() throws IOException {
+        // this should only be called if there is a thumbnail
+
+        if (thumbnailWidth == -1) {
+            populateJPEGThumbnailDimensions();
+        }
+        return thumbnailWidth;
+    }
+
+    int getThumbnailHeight() throws IOException {
+        // this should only be called if there is a thumbnail
+
+        if (thumbnailHeight == -1) {
+            populateJPEGThumbnailDimensions();
+        }
+        return thumbnailHeight;
+    }
+
+    /**
+     * Use a JPEGImageReader to identify the size of the thumbnail. This
+     * populates the `thumbnailWidth` and `thumbnailHeight` fields.
+     */
+    private void populateJPEGThumbnailDimensions() throws IOException {
+        // this method will never be invoked for TIFF thumbnails, because TIFF
+        // thumbnails clearly define their thumbnail size via IFD entries.
+        JPEGImageReader reader = new JPEGImageReader(null);
+        try {
+            reader.setInput(ImageIO.createImageInputStream(new ByteArrayInputStream(
+                    data, thumbnailPos + 6, thumbnailLength)));
+            thumbnailWidth = reader.getWidth(0);
+            thumbnailHeight = reader.getHeight(0);
+        } finally {
+            reader.dispose();
+        }
+    }
+
+    BufferedImage getThumbnail(JPEGImageReader callbackReader) throws IOException {
+        // this should only be called if there is a thumbnail
+
+        callbackReader.thumbnailStarted(0);
+        ImageReader thumbReader;
+        int imageIndex = 0;
+        if (isThumbnailJPEG) {
+            thumbReader = new JPEGImageReader(null);
+            imageIndex = 0;
+        } else {
+            thumbReader = new TIFFImageReader(null);
+            imageIndex = 1;
+        }
+        try {
+            InputStream byteIn = new ByteArrayInputStream(data, thumbnailPos + 6, thumbnailLength);
+            ImageInputStream input = new MemoryCacheImageInputStream(byteIn);
+            thumbReader.setInput(input);
+            thumbReader.addIIOReadProgressListener(new JFIFMarkerSegment.JFIFThumbJPEG.ThumbnailReadListener(callbackReader));
+            BufferedImage thumbnailImage = thumbReader.read(imageIndex);
+            thumbnailWidth = thumbnailImage.getWidth();
+            thumbnailHeight = thumbnailImage.getHeight();
+            callbackReader.thumbnailComplete();
+            return thumbnailImage;
+        } finally {
+            thumbReader.dispose();
+        }
+    }
+}

src/java.desktop/share/classes/com/sun/imageio/plugins/jpeg/JFIFMarkerSegment.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1234,7 +1234,7 @@ int getHeight() {
             return retval;
         }
 
-        private static class ThumbnailReadListener
+        static class ThumbnailReadListener
             implements IIOReadProgressListener {
             JPEGImageReader reader = null;
             ThumbnailReadListener (JPEGImageReader reader) {