ui/android/java/src/org/chromium/ui/base/Clipboard.java - chromium/src - Git at Google

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 package org.chromium.ui.base;

 import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;

 import org.chromium.base.ContextUtils;
 import org.chromium.base.Log;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.SuppressFBWarnings;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.ui.R;
 import org.chromium.ui.widget.Toast;

 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;

 /**
  * Simple proxy that provides C++ code with an access pathway to the Android clipboard.
  */
 @JNINamespace("ui")
 public class Clipboard implements ClipboardManager.OnPrimaryClipChangedListener {
     private static Clipboard sInstance;

     private static final String TAG = "Clipboard";

     // Necessary for coercing clipboard contents to text if they require
     // access to network resources, etceteras (e.g., URI in clipboard)
     private final Context mContext;

     private final ClipboardManager mClipboardManager;

     // A message hasher that's used to hash clipboard contents so we can tell
     // when a clipboard changes without storing the full contents.
     private MessageDigest mMd5Hasher;
     // The hash of the current clipboard.
     // TODO(mpearson): unsuppress this warning once saving and restoring
     // the hash from prefs is added.
     @SuppressFBWarnings("URF_UNREAD_FIELD")
     private byte[] mClipboardMd5;
     // The time when the clipboard was last updated.  Set to 0 if unknown.
     private long mClipboardChangeTime;

     /**
      * Get the singleton Clipboard instance (creating it if needed).
      */
     @CalledByNative
     public static Clipboard getInstance() {
         if (sInstance == null) {
             sInstance = new Clipboard();
         }
         return sInstance;
     }

     private Clipboard() {
         mContext = ContextUtils.getApplicationContext();
         mClipboardManager =
                 (ClipboardManager) ContextUtils.getApplicationContext().getSystemService(
                         Context.CLIPBOARD_SERVICE);
         mClipboardManager.addPrimaryClipChangedListener(this);
         try {
             mMd5Hasher = MessageDigest.getInstance("MD5");
             mClipboardMd5 = weakMd5Hash();
         } catch (NoSuchAlgorithmException e) {
             Log.e(TAG,
                     "Unable to construct MD5 MessageDigest: %s; assume "
                             + "clipboard last update time is start of epoch.",
                     e);
             mMd5Hasher = null;
             mClipboardMd5 = new byte[] {};
         }
         RecordHistogram.recordBooleanHistogram("Clipboard.ConstructedHasher", mMd5Hasher != null);
         mClipboardChangeTime = 0;
     }

     /**
      * Emulates the behavior of the now-deprecated
      * {@link android.text.ClipboardManager#getText()} by invoking
      * {@link android.content.ClipData.Item#coerceToText(Context)} on the first
      * item in the clipboard (if any) and returning the result as a string.
      * <p>
      * This is quite different than simply calling {@link Object#toString()} on
      * the clip; consumers of this API should familiarize themselves with the
      * process described in
      * {@link android.content.ClipData.Item#coerceToText(Context)} before using
      * this method.
      *
      * @return a string representation of the first item on the clipboard, if
      *         the clipboard currently has an item and coercion of the item into
      *         a string is possible; otherwise, <code>null</code>
      */
     @SuppressWarnings("javadoc")
     @CalledByNative
     private String getCoercedText() {
         // getPrimaryClip() has been observed to throw unexpected exceptions for some devices (see
         // crbug.com/654802 and b/31501780)
         try {
             return mClipboardManager.getPrimaryClip()
                     .getItemAt(0)
                     .coerceToText(mContext)
                     .toString();
         } catch (Exception e) {
             return null;
         }
     }

     /**
      * Gets the HTML text of top item on the primary clip on the Android clipboard.
      *
      * @return a Java string with the html text if any, or null if there is no html
      *         text or no entries on the primary clip.
      */
     @CalledByNative
     private String getHTMLText() {
         // getPrimaryClip() has been observed to throw unexpected exceptions for some devices (see
         // crbug/654802 and b/31501780)
         try {
             return mClipboardManager.getPrimaryClip().getItemAt(0).getHtmlText();
         } catch (Exception e) {
             return null;
         }
     }

     /**
      * Gets the time the clipboard content last changed.
      *
      * This is calculated according to the device's clock.  E.g., it continues
      * increasing when the device is suspended.  Likewise, it can be in the
      * future if the user's clock updated after this information was recorded.
      *
      * @return a Java long recording the last changed time in milliseconds since
      * epoch, or 0 if the time could not be determined.
      */
     @CalledByNative
     public long getClipboardContentChangeTimeInMillis() {
         return mClipboardChangeTime;
     }

     /**
      * Emulates the behavior of the now-deprecated
      * {@link android.text.ClipboardManager#setText(CharSequence)}, setting the
      * clipboard's current primary clip to a plain-text clip that consists of
      * the specified string.
      * @param text  will become the content of the clipboard's primary clip
      */
     @SuppressFBWarnings("UPM_UNCALLED_PRIVATE_METHOD")
     @CalledByNative
     public void setText(final String text) {
         setPrimaryClipNoException(ClipData.newPlainText("text", text));
     }

     /**
      * Writes HTML to the clipboard, together with a plain-text representation
      * of that very data.
      *
      * @param html  The HTML content to be pasted to the clipboard.
      * @param text  Plain-text representation of the HTML content.
      */
     @SuppressFBWarnings("UPM_UNCALLED_PRIVATE_METHOD")
     @CalledByNative
     private void setHTMLText(final String html, final String text) {
         setPrimaryClipNoException(ClipData.newHtmlText("html", text, html));
     }

     /**
      * Clears the Clipboard Primary clip.
      *
      */
     @SuppressFBWarnings("UPM_UNCALLED_PRIVATE_METHOD")
     @CalledByNative
     private void clear() {
         setPrimaryClipNoException(ClipData.newPlainText(null, null));
     }

     private void setPrimaryClipNoException(ClipData clip) {
         try {
             mClipboardManager.setPrimaryClip(clip);
         } catch (Exception ex) {
             // Ignore any exceptions here as certain devices have bugs and will fail.
             String text = mContext.getString(R.string.copy_to_clipboard_failure_message);
             Toast.makeText(mContext, text, Toast.LENGTH_SHORT).show();
         }
     }

     /**
      * Updates mClipboardMd5 and mClipboardChangeTime when the clipboard updates.
      *
      * Implements OnPrimaryClipChangedListener to listen for clipboard updates.
      */
     @Override
     public void onPrimaryClipChanged() {
         if (mMd5Hasher == null) return;
         RecordUserAction.record("MobileOmniboxClipboardChanged");
         mClipboardMd5 = weakMd5Hash();
         // Always update the clipboard change time even if the clipboard
         // content hasn't changed.  This is because if the user put something
         // in the clipboard recently (even if it was not necessary because it
         // was already there), that content should be considered recent.
         mClipboardChangeTime = System.currentTimeMillis();
     }

     /**
      * Returns a weak hash of getCoercedText().
      *
      * @return a Java byte[] with the weak hash.
      */
     private byte[] weakMd5Hash() {
         if (getCoercedText() == null) {
             return new byte[] {};
         }
         // Compute a hash consisting of the first 4 bytes of the MD5 hash of
         // getCoercedText().  This value is used to detect clipboard content
         // change. Keeping only 4 bytes is a privacy requirement to introduce
         // collision and allow deniability of having copied a given string.
         return Arrays.copyOfRange(mMd5Hasher.digest(getCoercedText().getBytes()), 0, 4);
     }
 }
	// Copyright 2013 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	package org.chromium.ui.base;

	import android.content.ClipData;
	import android.content.ClipboardManager;
	import android.content.Context;

	import org.chromium.base.ContextUtils;
	import org.chromium.base.Log;
	import org.chromium.base.annotations.CalledByNative;
	import org.chromium.base.annotations.JNINamespace;
	import org.chromium.base.annotations.SuppressFBWarnings;
	import org.chromium.base.metrics.RecordHistogram;
	import org.chromium.base.metrics.RecordUserAction;
	import org.chromium.ui.R;
	import org.chromium.ui.widget.Toast;

	import java.security.MessageDigest;
	import java.security.NoSuchAlgorithmException;
	import java.util.Arrays;

	/**
	* Simple proxy that provides C++ code with an access pathway to the Android clipboard.
	*/
	@JNINamespace("ui")
	public class Clipboard implements ClipboardManager.OnPrimaryClipChangedListener {
	private static Clipboard sInstance;

	private static final String TAG = "Clipboard";

	// Necessary for coercing clipboard contents to text if they require
	// access to network resources, etceteras (e.g., URI in clipboard)
	private final Context mContext;

	private final ClipboardManager mClipboardManager;

	// A message hasher that's used to hash clipboard contents so we can tell
	// when a clipboard changes without storing the full contents.
	private MessageDigest mMd5Hasher;
	// The hash of the current clipboard.
	// TODO(mpearson): unsuppress this warning once saving and restoring
	// the hash from prefs is added.
	@SuppressFBWarnings("URF_UNREAD_FIELD")
	private byte[] mClipboardMd5;
	// The time when the clipboard was last updated. Set to 0 if unknown.
	private long mClipboardChangeTime;

	/**
	* Get the singleton Clipboard instance (creating it if needed).
	*/
	@CalledByNative
	public static Clipboard getInstance() {
	if (sInstance == null) {
	sInstance = new Clipboard();
	}
	return sInstance;
	}

	private Clipboard() {
	mContext = ContextUtils.getApplicationContext();
	mClipboardManager =
	(ClipboardManager) ContextUtils.getApplicationContext().getSystemService(
	Context.CLIPBOARD_SERVICE);
	mClipboardManager.addPrimaryClipChangedListener(this);
	try {
	mMd5Hasher = MessageDigest.getInstance("MD5");
	mClipboardMd5 = weakMd5Hash();
	} catch (NoSuchAlgorithmException e) {
	Log.e(TAG,
	"Unable to construct MD5 MessageDigest: %s; assume "
	+ "clipboard last update time is start of epoch.",
	e);
	mMd5Hasher = null;
	mClipboardMd5 = new byte[] {};
	}
	RecordHistogram.recordBooleanHistogram("Clipboard.ConstructedHasher", mMd5Hasher != null);
	mClipboardChangeTime = 0;
	}

	/**
	* Emulates the behavior of the now-deprecated
	* {@link android.text.ClipboardManager#getText()} by invoking
	* {@link android.content.ClipData.Item#coerceToText(Context)} on the first
	* item in the clipboard (if any) and returning the result as a string.
	* <p>
	* This is quite different than simply calling {@link Object#toString()} on
	* the clip; consumers of this API should familiarize themselves with the
	* process described in
	* {@link android.content.ClipData.Item#coerceToText(Context)} before using
	* this method.
	*
	* @return a string representation of the first item on the clipboard, if
	* the clipboard currently has an item and coercion of the item into
	* a string is possible; otherwise, <code>null</code>
	*/
	@SuppressWarnings("javadoc")
	@CalledByNative
	private String getCoercedText() {
	// getPrimaryClip() has been observed to throw unexpected exceptions for some devices (see
	// crbug.com/654802 and b/31501780)
	try {
	return mClipboardManager.getPrimaryClip()
	.getItemAt(0)
	.coerceToText(mContext)
	.toString();
	} catch (Exception e) {
	return null;
	}
	}

	/**
	* Gets the HTML text of top item on the primary clip on the Android clipboard.
	*
	* @return a Java string with the html text if any, or null if there is no html
	* text or no entries on the primary clip.
	*/
	@CalledByNative
	private String getHTMLText() {
	// getPrimaryClip() has been observed to throw unexpected exceptions for some devices (see
	// crbug/654802 and b/31501780)
	try {
	return mClipboardManager.getPrimaryClip().getItemAt(0).getHtmlText();
	} catch (Exception e) {
	return null;
	}
	}

	/**
	* Gets the time the clipboard content last changed.
	*
	* This is calculated according to the device's clock. E.g., it continues
	* increasing when the device is suspended. Likewise, it can be in the
	* future if the user's clock updated after this information was recorded.
	*
	* @return a Java long recording the last changed time in milliseconds since
	* epoch, or 0 if the time could not be determined.
	*/
	@CalledByNative
	public long getClipboardContentChangeTimeInMillis() {
	return mClipboardChangeTime;
	}

	/**
	* Emulates the behavior of the now-deprecated
	* {@link android.text.ClipboardManager#setText(CharSequence)}, setting the
	* clipboard's current primary clip to a plain-text clip that consists of
	* the specified string.
	* @param text will become the content of the clipboard's primary clip
	*/
	@SuppressFBWarnings("UPM_UNCALLED_PRIVATE_METHOD")
	@CalledByNative
	public void setText(final String text) {
	setPrimaryClipNoException(ClipData.newPlainText("text", text));
	}

	/**
	* Writes HTML to the clipboard, together with a plain-text representation
	* of that very data.
	*
	* @param html The HTML content to be pasted to the clipboard.
	* @param text Plain-text representation of the HTML content.
	*/
	@SuppressFBWarnings("UPM_UNCALLED_PRIVATE_METHOD")
	@CalledByNative
	private void setHTMLText(final String html, final String text) {
	setPrimaryClipNoException(ClipData.newHtmlText("html", text, html));
	}

	/**
	* Clears the Clipboard Primary clip.
	*
	*/
	@SuppressFBWarnings("UPM_UNCALLED_PRIVATE_METHOD")
	@CalledByNative
	private void clear() {
	setPrimaryClipNoException(ClipData.newPlainText(null, null));
	}

	private void setPrimaryClipNoException(ClipData clip) {
	try {
	mClipboardManager.setPrimaryClip(clip);
	} catch (Exception ex) {
	// Ignore any exceptions here as certain devices have bugs and will fail.
	String text = mContext.getString(R.string.copy_to_clipboard_failure_message);
	Toast.makeText(mContext, text, Toast.LENGTH_SHORT).show();
	}
	}

	/**
	* Updates mClipboardMd5 and mClipboardChangeTime when the clipboard updates.
	*
	* Implements OnPrimaryClipChangedListener to listen for clipboard updates.
	*/
	@Override
	public void onPrimaryClipChanged() {
	if (mMd5Hasher == null) return;
	RecordUserAction.record("MobileOmniboxClipboardChanged");
	mClipboardMd5 = weakMd5Hash();
	// Always update the clipboard change time even if the clipboard
	// content hasn't changed. This is because if the user put something
	// in the clipboard recently (even if it was not necessary because it
	// was already there), that content should be considered recent.
	mClipboardChangeTime = System.currentTimeMillis();
	}

	/**
	* Returns a weak hash of getCoercedText().
	*
	* @return a Java byte[] with the weak hash.
	*/
	private byte[] weakMd5Hash() {
	if (getCoercedText() == null) {
	return new byte[] {};
	}
	// Compute a hash consisting of the first 4 bytes of the MD5 hash of
	// getCoercedText(). This value is used to detect clipboard content
	// change. Keeping only 4 bytes is a privacy requirement to introduce
	// collision and allow deniability of having copied a given string.
	return Arrays.copyOfRange(mMd5Hasher.digest(getCoercedText().getBytes()), 0, 4);
	}
	}