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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);
int /*long*/ 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;
int /*long*/ hMem = stgmedium.unionField;
try {
int /*long*/ 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);
}
}