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Commit 472371c6 authored by Satoshi Niwa's avatar Satoshi Niwa
Browse files

Q Upstream: Use ParcelFileDescriptor for storing large clip data. 

This patch enables copy&paste-ing large data for Q and below.
Using content URI is the idiomatic way to transfer large data,
but none of the major editor apps (Docs, Evernote, Word, Gmail, etc.)
support content URI in clipboard as of today.
We will ask app developers to use content: URI and remove this function
in API 30 (R).

Bug: 111577843
Test: ClipboardManagerTest
Test: Manualy tested copying a large HTML text
Change-Id: If1798c5abcec691f4b17a45e583ed314b1c16ac2
parent a85b4a2d

core/java/android/content/ClipData.java

+69 −2
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ import android.graphics.Bitmap; 
import android.net.Uri;

import android.os.Build;

import android.os.Parcel;

import android.os.ParcelFileDescriptor;

import android.os.Parcelable;

import android.os.StrictMode;

import android.text.Html;
@@ -170,6 +171,11 @@ public class ClipData implements Parcelable { 
    static final String[] MIMETYPES_TEXT_INTENT = new String[] {

        ClipDescription.MIMETYPE_TEXT_INTENT };



    // Constants used in {@link #writeHtmlTextToParcel}.

    static final int PARCEL_MAX_SIZE_BYTES = 800 * 1024;

    static final int PARCEL_TYPE_STRING = 0;

    static final int PARCEL_TYPE_PFD = 1;



    final ClipDescription mClipDescription;



    final Bitmap mIcon;
@@ -225,6 +231,10 @@ public class ClipData implements Parcelable { 
         * with an alternative HTML formatted representation.  You <em>must</em>

         * supply a plain text representation in addition to HTML text; coercion

         * will not be done from HTML formatted text into plain text.

         * <p class="note"><strong>Note:</strong> It is strongly recommended to

         * use content: URI for sharing large clip data. Starting on API 30,

         * ClipData.Item doesn't accept an HTML text if it's larger than 800KB.

         * </p>

         */

        public Item(CharSequence text, String htmlText) {

            mText = text;
@@ -1132,7 +1142,7 @@ public class ClipData implements Parcelable { 
        for (int i=0; i<N; i++) {

            Item item = mItems.get(i);

            TextUtils.writeToParcel(item.mText, dest, flags);

            dest.writeString(item.mHtmlText);

            writeHtmlTextToParcel(item.mHtmlText, dest, flags);

            if (item.mIntent != null) {

                dest.writeInt(1);

                item.mIntent.writeToParcel(dest, flags);
@@ -1159,7 +1169,7 @@ public class ClipData implements Parcelable { 
        final int N = in.readInt();

        for (int i=0; i<N; i++) {

            CharSequence text = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(in);

            String htmlText = in.readString();

            String htmlText = readHtmlTextFromParcel(in);

            Intent intent = in.readInt() != 0 ? Intent.CREATOR.createFromParcel(in) : null;

            Uri uri = in.readInt() != 0 ? Uri.CREATOR.createFromParcel(in) : null;

            mItems.add(new Item(text, htmlText, intent, uri));
@@ -1179,4 +1189,61 @@ public class ClipData implements Parcelable { 
                return new ClipData[size];

            }

        };



    /**

     * Helper function for writing an HTML text into a parcel.

     * If the text size is larger than 400KB, it writes the text to a file descriptor to prevent the

     * parcel from exceeding 800KB binder size limit. {@link android.os.Binder#checkParcel()}

     * Otherwise, it directly writes the text into the parcel.

     * Note: This function is a workaround for existing applications that still use HTML for sharing

     * large clip data. We will ask application developers to use content: URI instead and remove

     * this function in API 30.

     */

    private static void writeHtmlTextToParcel(String text, Parcel dest, int flags) {

        byte[] textData = (text != null) ? text.getBytes() : new byte[0];

        if (textData.length > PARCEL_MAX_SIZE_BYTES / 2

                && Build.VERSION.SDK_INT <= Build.VERSION_CODES.Q) {

            try {

                ParcelFileDescriptor pfd = ParcelFileDescriptor.fromData(textData, null);

                dest.writeInt(PARCEL_TYPE_PFD);

                dest.writeParcelable(pfd, flags);

            } catch (IOException e) {

                throw new IllegalStateException(

                        "Error creating the shared memory area: " + e.toString());

            }

        } else {

            dest.writeInt(PARCEL_TYPE_STRING);

            dest.writeString(text);

        }

    }



    /**

     * Reads a text written by writeHtmlTextToParcel.

     */

    private static String readHtmlTextFromParcel(Parcel in) {

        if (in.readInt() == PARCEL_TYPE_STRING) {

            return in.readString();

        }

        ParcelFileDescriptor pfd =

                in.readParcelable(ParcelFileDescriptor.class.getClassLoader());

        if (pfd == null) {

            throw new IllegalStateException("Error reading ParcelFileDescriptor from Parcel");

        }

        FileInputStream fis = new ParcelFileDescriptor.AutoCloseInputStream(pfd);

        InputStreamReader reader = new InputStreamReader(fis);

        StringBuilder builder = new StringBuilder();

        char[] buffer = new char[4096];

        int numRead;

        try {

            while ((numRead = reader.read(buffer)) != -1) {

                builder.append(buffer, 0, numRead);

            }

            return builder.toString();

        } catch (IOException e) {

            throw new IllegalStateException(

                    "Error reading data from ParcelFileDescriptor: "  + e.toString());

        } finally {

            IoUtils.closeQuietly(fis);

        }

    }

}