JBR-5857 Wayland: implement clipboard support

src/java.desktop/unix/classes/sun/awt/wl/WLDataTransferer.java

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+/*
+ * Copyright 2023 JetBrains s.r.o.
+ * 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 sun.awt.wl;
+
+import sun.awt.datatransfer.DataTransferer;
+import sun.awt.datatransfer.ToolkitThreadBlockedHandler;
+import sun.datatransfer.DataFlavorUtil;
+import sun.util.logging.PlatformLogger;
+
+import javax.imageio.ImageIO;
+import javax.imageio.ImageReadParam;
+import javax.imageio.ImageReader;
+import javax.imageio.ImageTypeSpecifier;
+import javax.imageio.ImageWriter;
+import javax.imageio.spi.ImageWriterSpi;
+import javax.imageio.stream.ImageInputStream;
+import java.awt.Graphics2D;
+import java.awt.Image;
+import java.awt.datatransfer.DataFlavor;
+import java.awt.image.BufferedImage;
+import java.awt.image.ColorModel;
+import java.awt.image.WritableRaster;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.HashMap;
+import java.util.Objects;
+
+/**
+ * Facilitates data conversion between formats for the use with the clipboard.
+ * Some terminology:
+ * "native" format - the format understood by Wayland; MIME with some deviations
+ * "long" format - an arbintrary number assigned to some native format;
+ *                 once established, this mapping never changes
+ */
+public class WLDataTransferer extends DataTransferer {
+    private static final PlatformLogger log = PlatformLogger.getLogger("sun.awt.wl.WLDataTransferer");
+
+    private static ImageTypeSpecifier defaultImageSpec = null;
+
+    // Maps the "native" format (MIME) to its numeric ID
+    private final Map<String, Long> nameToLong = new HashMap<>();
+
+    // Maps the numeric ID of a format to its native (MIME) representation
+    private final Map<Long, String> longToName = new HashMap<>();
+
+    private final Map<Long, Boolean> imageFormats = new HashMap<>();
+    private final Map<Long, Boolean> textFormats = new HashMap<>();
+
+    private static class HOLDER {
+        static WLDataTransferer instance = new WLDataTransferer();
+    }
+
+    static WLDataTransferer getInstanceImpl() {
+        return HOLDER.instance;
+    }
+
+    @Override
+    public String getDefaultUnicodeEncoding() {
+        return "UTF-8";
+    }
+
+    @Override
+    public boolean isLocaleDependentTextFormat(long format) {
+        return false;
+    }
+
+    @Override
+    public boolean isFileFormat(long format) {
+        String nat = getNativeForFormat(format);
+        return "FILE_NAME".equals(nat);
+    }
+
+    @Override
+    public boolean isImageFormat(long format) {
+        synchronized (this) {
+            return imageFormats.computeIfAbsent(format, f -> isMimeFormat(f, "image"));
+        }
+    }
+
+    @Override
+    public boolean isTextFormat(long format) {
+        synchronized (this) {
+            return textFormats.computeIfAbsent(
+                    format,
+                    f -> super.isTextFormat(format)
+                            || isMimeFormat(format, "text"));
+        }
+    }
+
+    /**
+     * @return true if the given format ID corresponds to a MIME format
+     *         with the given primary type
+     */
+    private boolean isMimeFormat(long format, String primaryType) {
+        String nat = getNativeForFormat(format);
+        if (nat != null) {
+            try {
+                DataFlavor df = new DataFlavor(nat);
+                if (primaryType.equals(df.getPrimaryType())) {
+                    return true;
+                }
+            } catch (Exception ignored) { /* Not MIME */ }
+        }
+        return false;
+    }
+
+    @Override
+    protected Long getFormatForNativeAsLong(String formatName) {
+        Objects.requireNonNull(formatName);
+        synchronized (this) {
+            Long thisID = nameToLong.get(formatName);
+            if (thisID == null) {
+                // Some apps request data in a format that only differs from
+                // the advertised in the case of some of the letters.
+                // IMO we can ignore the case and find an equivalent.
+                var matchingKey = nameToLong.keySet().stream()
+                        .filter(formatName::equalsIgnoreCase).findAny()
+                        .orElse(null);
+                if (matchingKey != null) {
+                    thisID = nameToLong.get(matchingKey);
+                } else {
+                    long nextID = nameToLong.size();
+                    thisID = nextID;
+                    longToName.put(thisID, formatName);
+                }
+                nameToLong.put(formatName, thisID);
+            }
+
+            return thisID;
+        }
+    }
+
+    @Override
+    protected String getNativeForFormat(long format) {
+        synchronized (this) {
+            return longToName.get(format);
+        }
+    }
+
+    @Override
+    protected ByteArrayOutputStream convertFileListToBytes(ArrayList<String> fileList) {
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        for (int i = 0; i < fileList.size(); i++) {
+            byte[] bytes = fileList.get(i).getBytes();
+            if (i != 0) bos.write(0);
+            bos.write(bytes, 0, bytes.length);
+        }
+        return bos;
+    }
+
+    @Override
+    protected String[] dragQueryFile(byte[] bytes) {
+        // TODO
+        log.info("Unimplemented");
+        return new String[0];
+    }
+
+    @Override
+    protected Image platformImageBytesToImage(byte[] bytes, long format) throws IOException {
+        DataFlavor df = getImageDataFlavorForFormat(format);
+        final String baseType = df.getPrimaryType() + "/" + df.getSubType();
+        Iterator<ImageReader> readers = ImageIO.getImageReadersByMIMEType(baseType);
+        BufferedImage bi = null;
+        if (readers.hasNext()) {
+            ImageReader reader = readers.next();
+            ImageReadParam param = reader.getDefaultReadParam();
+            ByteArrayInputStream byteStream = new ByteArrayInputStream(bytes);
+            ImageInputStream stream = ImageIO.createImageInputStream(byteStream);
+            reader.setInput(stream, true, true);
+            try (stream) {
+                bi = reader.read(0, param);
+            } finally {
+                reader.dispose();
+            }
+        }
+
+        return bi;
+    }
+
+    @Override
+    protected byte[] imageToPlatformBytes(Image image, long format) throws IOException {
+        int width = image.getWidth(null);
+        int height = image.getHeight(null);
+        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
+        Graphics2D g2d = bufferedImage.createGraphics();
+        g2d.drawImage(image, 0, 0, null);
+        g2d.dispose();
+
+        int numBytes = (int)(width * height * bufferedImage.getColorModel().getPixelSize() / 8.0);
+        ByteArrayOutputStream out = new ByteArrayOutputStream(numBytes);
+        DataFlavor df = getImageDataFlavorForFormat(format);
+        ImageIO.write(bufferedImage, df.getSubType(), out);
+
+        return out.toByteArray();
+    }
+
+    private DataFlavor getImageDataFlavorForFormat(long format) {
+        String nat = getNativeForFormat(format);
+        DataFlavor df = null;
+        try {
+            df = new DataFlavor(nat);
+        } catch (Exception ignored) { }
+
+        if (df == null) {
+            throw new InternalError("Native image format " + nat + " corresponding to ID "
+                    + format + " not recognized as DataFlavor");
+        }
+        return df;
+    }
+
+    @Override
+    public ToolkitThreadBlockedHandler getToolkitThreadBlockedHandler() {
+        return WLToolkitThreadBlockedHandler.getToolkitThreadBlockedHandler();
+    }
+
+    @Override
+    public LinkedHashSet<DataFlavor> getPlatformMappingsForNative(String nat) {
+        // TODO: much of this has been taken verbatim from XDataTransferer.
+        //  Worth refactoring the common stuff out?
+        LinkedHashSet<DataFlavor> flavors = new LinkedHashSet<>();
+
+        if (nat == null) {
+            return flavors;
+        }
+
+        DataFlavor df;
+        try {
+            df = new DataFlavor(nat);
+        } catch (Exception e) {
+            // The string doesn't constitute a valid MIME type.
+            return flavors;
+        }
+
+        DataFlavor value = df;
+        final String primaryType = df.getPrimaryType();
+
+        // For text formats we map natives to MIME strings instead of data
+        // flavors to enable dynamic text native-to-flavor mapping generation.
+        // See SystemFlavorMap.getFlavorsForNative() for details.
+        if ("image".equals(primaryType)) {
+            final String baseType = primaryType + "/" + df.getSubType();
+            Iterator<ImageReader> readers = ImageIO.getImageReadersByMIMEType(baseType);
+            if (readers.hasNext()) {
+                flavors.add(DataFlavor.imageFlavor);
+            }
+        }
+
+        flavors.add(value);
+
+        return flavors;
+    }
+
+    private ImageTypeSpecifier getDefaultImageTypeSpecifier() {
+        if (defaultImageSpec == null) {
+            ColorModel model = ColorModel.getRGBdefault();
+            WritableRaster raster =
+                    model.createCompatibleWritableRaster(10, 10);
+
+            BufferedImage bufferedImage =
+                    new BufferedImage(model, raster, model.isAlphaPremultiplied(),
+                            null);
+
+            defaultImageSpec = new ImageTypeSpecifier(bufferedImage);
+        }
+
+        return defaultImageSpec;
+    }
+
+    @Override
+    public LinkedHashSet<String> getPlatformMappingsForFlavor(DataFlavor df) {
+        LinkedHashSet<String> natives = new LinkedHashSet<>(1);
+
+        if (df == null) {
+            return natives;
+        }
+
+        String charset = df.getParameter("charset");
+        String baseType = df.getPrimaryType() + "/" + df.getSubType();
+        String mimeType = baseType;
+
+        if (charset != null && DataFlavorUtil.isFlavorCharsetTextType(df)) {
+            mimeType += ";charset=" + charset;
+        }
+
+        // Add a mapping to the MIME native whenever the representation class
+        // doesn't require translation.
+        if (df.getRepresentationClass() != null &&
+                (df.isRepresentationClassInputStream() ||
+                        df.isRepresentationClassByteBuffer() ||
+                        byte[].class.equals(df.getRepresentationClass()))) {
+            natives.add(mimeType);
+        }
+
+        if (DataFlavor.imageFlavor.equals(df)) {
+            String[] mimeTypes = ImageIO.getWriterMIMETypes();
+            if (mimeTypes != null) {
+                for (String mime : mimeTypes) {
+                    Iterator<ImageWriter> writers = ImageIO.getImageWritersByMIMEType(mime);
+                    while (writers.hasNext()) {
+                        ImageWriter imageWriter = writers.next();
+                        ImageWriterSpi writerSpi = imageWriter.getOriginatingProvider();
+
+                        if (writerSpi != null &&
+                                writerSpi.canEncodeImage(getDefaultImageTypeSpecifier())) {
+                            natives.add(mime);
+                            break;
+                        }
+                    }
+                }
+            }
+        } else if (DataFlavorUtil.isFlavorCharsetTextType(df)) {
+            // stringFlavor is semantically equivalent to the standard
+            // "text/plain" MIME type.
+            if (DataFlavor.stringFlavor.equals(df)) {
+                baseType = "text/plain";
+            }
+
+            for (String encoding : DataFlavorUtil.standardEncodings()) {
+                if (!encoding.equals(charset)) {
+                    natives.add(baseType + ";charset=" + encoding);
+                }
+            }
+
+            // Add a MIME format without specified charset.
+            natives.add(baseType);
+        }
+
+        return natives;
+    }
+}