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SWT is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.

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/*******************************************************************************
 * Copyright (c) 2000, 2012 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.dnd;

import org.eclipse.swt.internal.ole.win32.*;
import org.eclipse.swt.internal.win32.*;

/**
 * The class HTMLTransfer provides a platform specific mechanism 
 * for converting text in HTML format represented as a java String 
 * to a platform specific representation of the data and vice versa.
 * 
 * 

An example of a java String containing HTML text is shown * below:

* *
 *     String htmlData = "

This is a paragraph of text.

"; *
* * @see Transfer */ public class HTMLTransfer extends ByteArrayTransfer { static HTMLTransfer _instance = new HTMLTransfer(); static final String HTML_FORMAT = "HTML Format"; //$NON-NLS-1$ static final int HTML_FORMATID = registerType(HTML_FORMAT); static final String NUMBER = "00000000"; //$NON-NLS-1$ static final String HEADER = "Version:0.9\r\nStartHTML:"+NUMBER+"\r\nEndHTML:"+NUMBER+"\r\nStartFragment:"+NUMBER+"\r\nEndFragment:"+NUMBER+"\r\n"; static final String PREFIX = ""; //$NON-NLS-1$ static final String SUFFIX = ""; //$NON-NLS-1$ static final String StartFragment = "StartFragment:"; //$NON-NLS-1$ static final String EndFragment = "EndFragment:"; //$NON-NLS-1$ private HTMLTransfer() {} /** * Returns the singleton instance of the HTMLTransfer class. * * @return the singleton instance of the HTMLTransfer class */ public static HTMLTransfer getInstance () { return _instance; } /** * This implementation of javaToNative converts HTML-formatted text * represented by a java String to a platform specific representation. * * @param object a java String containing HTML text * @param transferData an empty TransferData object that will * be filled in on return with the platform specific format of the data * * @see Transfer#nativeToJava */ public void javaToNative (Object object, TransferData transferData){ if (!checkHTML(object) || !isSupportedType(transferData)) { DND.error(DND.ERROR_INVALID_DATA); } String string = (String)object; int count = string.length(); char[] chars = new char[count + 1]; string.getChars(0, count, chars, 0); /* NOTE: CF_HTML uses UTF-8 encoding. */ int cchMultiByte = OS.WideCharToMultiByte(OS.CP_UTF8, 0, chars, -1, null, 0, null, null); if (cchMultiByte == 0) { transferData.stgmedium = new STGMEDIUM(); transferData.result = COM.DV_E_STGMEDIUM; return; } int startHTML = HEADER.length(); int startFragment = startHTML + PREFIX.length(); int endFragment = startFragment + cchMultiByte - 1; int endHTML = endFragment + SUFFIX.length(); StringBuffer buffer = new StringBuffer(HEADER); int maxLength = NUMBER.length(); //startHTML int start = buffer.toString().indexOf(NUMBER); String temp = Integer.toString(startHTML); buffer.replace(start + maxLength-temp.length(), start + maxLength, temp); //endHTML start = buffer.toString().indexOf(NUMBER, start); temp = Integer.toString(endHTML); buffer.replace(start + maxLength-temp.length(), start + maxLength, temp); //startFragment start = buffer.toString().indexOf(NUMBER, start); temp = Integer.toString(startFragment); buffer.replace(start + maxLength-temp.length(), start + maxLength, temp); //endFragment start = buffer.toString().indexOf(NUMBER, start); temp = Integer.toString(endFragment); buffer.replace(start + maxLength-temp.length(), start + maxLength, temp); buffer.append(PREFIX); buffer.append(string); buffer.append(SUFFIX); count = buffer.length(); chars = new char[count + 1]; buffer.getChars(0, count, chars, 0); cchMultiByte = OS.WideCharToMultiByte(OS.CP_UTF8, 0, chars, -1, null, 0, null, null); long /*int*/ lpMultiByteStr = OS.GlobalAlloc(OS.GMEM_FIXED | OS.GMEM_ZEROINIT, cchMultiByte); OS.WideCharToMultiByte(OS.CP_UTF8, 0, chars, -1, lpMultiByteStr, cchMultiByte, null, null); transferData.stgmedium = new STGMEDIUM(); transferData.stgmedium.tymed = COM.TYMED_HGLOBAL; transferData.stgmedium.unionField = lpMultiByteStr; transferData.stgmedium.pUnkForRelease = 0; transferData.result = COM.S_OK; return; } /** * This implementation of nativeToJava converts a platform specific * representation of HTML text to a java String. * * @param transferData the platform specific representation of the data to be converted * @return a java String containing HTML text if the conversion was successful; * otherwise null * * @see Transfer#javaToNative */ public Object nativeToJava(TransferData transferData){ if (!isSupportedType(transferData) || transferData.pIDataObject == 0) return null; IDataObject data = new IDataObject(transferData.pIDataObject); data.AddRef(); STGMEDIUM stgmedium = new STGMEDIUM(); FORMATETC formatetc = transferData.formatetc; stgmedium.tymed = COM.TYMED_HGLOBAL; transferData.result = getData(data, formatetc, stgmedium); data.Release(); if (transferData.result != COM.S_OK) return null; long /*int*/ hMem = stgmedium.unionField; try { long /*int*/ lpMultiByteStr = OS.GlobalLock(hMem); if (lpMultiByteStr == 0) return null; try { /* NOTE: CF_HTML uses UTF-8 encoding. * The MSDN documentation for MultiByteToWideChar states that dwFlags must be set to 0 for UTF-8. * Otherwise, the function fails with ERROR_INVALID_FLAGS. */ int cchWideChar = OS.MultiByteToWideChar (OS.CP_UTF8, 0, lpMultiByteStr, -1, null, 0); if (cchWideChar == 0) return null; char[] lpWideCharStr = new char [cchWideChar - 1]; OS.MultiByteToWideChar (OS.CP_UTF8, 0, lpMultiByteStr, -1, lpWideCharStr, lpWideCharStr.length); String string = new String(lpWideCharStr); int fragmentStart = 0, fragmentEnd = 0; int start = string.indexOf(StartFragment) + StartFragment.length(); int end = start + 1; while (end < string.length()) { String s = string.substring(start, end); try { fragmentStart = Integer.parseInt(s); end++; } catch (NumberFormatException e) { break; } } start = string.indexOf(EndFragment) + EndFragment.length(); end = start + 1; while (end < string.length()) { String s = string.substring(start, end); try { fragmentEnd = Integer.parseInt(s); end++; } catch (NumberFormatException e) { break; } } if (fragmentEnd <= fragmentStart || fragmentEnd > OS.strlen(lpMultiByteStr)) return null; cchWideChar = OS.MultiByteToWideChar (OS.CP_UTF8, 0, lpMultiByteStr+fragmentStart, fragmentEnd - fragmentStart, lpWideCharStr, lpWideCharStr.length); if (cchWideChar == 0) return null; String s = new String(lpWideCharStr, 0, cchWideChar); /* * Firefox includes in the fragment, so remove it. */ String foxStart = "\r\n"; //$NON-NLS-1$ int prefix = s.indexOf(foxStart); if (prefix != -1) { prefix += foxStart.length(); s = s.substring(prefix); } return s; } finally { OS.GlobalUnlock(hMem); } } finally { OS.GlobalFree(hMem); } } protected int[] getTypeIds(){ return new int[] {HTML_FORMATID}; } protected String[] getTypeNames(){ return new String[] {HTML_FORMAT}; } boolean checkHTML(Object object) { return (object != null && object instanceof String && ((String)object).length() > 0); } protected boolean validate(Object object) { return checkHTML(object); } }




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