Display.withCrLf() is producing wrong line breaks on Windows

Replacing all line breaks on windows with CrLf using regex, which is much safer.

Fixes #1557

Author: Christopher-Hermann

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java

@@ -5152,85 +5152,16 @@ String wrapText (String text, long handle, int width) {
 }
 
 static String withCrLf (String string) {
-
-	/* If the string is empty, return the string. */
-	int length = string.length ();
-	if (length == 0) return string;
-
-	/*
-	* Check for an LF or CR/LF and assume the rest of
-	* the string is formated that way.  This will not
-	* work if the string contains mixed delimiters.
-	*/
-	int i = string.indexOf ('\n', 0);
-	if (i == -1) return string;
-	if (i > 0 && string.charAt (i - 1) == '\r') {
+	if (string == null) {
 		return string;
 	}
-
-	/*
-	* The string is formatted with LF.  Compute the
-	* number of lines and the size of the buffer
-	* needed to hold the result
-	*/
-	i++;
-	int count = 1;
-	while (i < length) {
-		if ((i = string.indexOf ('\n', i)) == -1) break;
-		count++; i++;
-	}
-	count += length;
-
-	/* Create a new string with the CR/LF line terminator. */
-	i = 0;
-	StringBuilder result = new StringBuilder (count);
-	while (i < length) {
-		int j = string.indexOf ('\n', i);
-		if (j == -1) j = length;
-		result.append (string.substring (i, j));
-		if ((i = j) < length) {
-			result.append ("\r\n"); //$NON-NLS-1$
-			i++;
-		}
-	}
-	return result.toString ();
+	// Replace \r\n, \r, or \n with \r\n
+	return string.replaceAll("(\r\n|\r|\n)", "\r\n");
 }
 
 static char [] withCrLf (char [] string) {
-	/* If the string is empty, return the string. */
-	int length = string.length;
-	if (length == 0) return string;
-
-	/*
-	* Check for an LF or CR/LF and assume the rest of
-	* the string is formated that way.  This will not
-	* work if the string contains mixed delimiters.
-	* Also, compute the number of lines.
-	*/
-	int count = 0;
-	for (int i = 0; i < string.length; i++) {
-		if (string [i] == '\n') {
-			count++;
-			if (count == 1 && i > 0 && string [i - 1] == '\r') return string;
-		}
-	}
-	if (count == 0) return string;
-
-	/*
-	* The string is formatted with LF.
-	*/
-	count += length;
-
-	/* Create a new string with the CR/LF line terminator. */
-	char [] result = new char [count];
-	for (int i = 0, j = 0; i < length && j < count; i++) {
-		if (string [i] == '\n') {
-			result [j++] = '\r';
-		}
-		result [j++] = string [i];
-	}
-
-	return result;
+	String withCrLf = withCrLf(new String(string));
+	return withCrLf.toCharArray();
 }
 
 static boolean isActivateShellOnForceFocus() {

tests/org.eclipse.swt.tests.win32/JUnit Tests/org/eclipse/swt/tests/win32/widgets/Test_org_eclipse_swt_widgets_Display.java

@@ -13,26 +13,52 @@
  *******************************************************************************/
 package org.eclipse.swt.tests.win32.widgets;
 
+import static org.junit.Assert.assertEquals;
+
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 
+import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Shell;
+import org.eclipse.swt.widgets.Text;
+import org.junit.After;
+import org.junit.Before;
 import org.junit.Test;
 
 public class Test_org_eclipse_swt_widgets_Display {
 
+	private Display display;
+	private Shell shell;
+
+	@Before
+	public void setup() {
+		display = new Display();
+		shell = new Shell(display);
+	}
+
+	@After
+	public void teardown() {
+		shell.dispose();
+		display.dispose();
+	}
+
 	@Test
 	public void test_isXMouseActive() throws NoSuchMethodException, SecurityException, IllegalAccessException,
 			IllegalArgumentException, InvocationTargetException {
-		Display display = new Display();
-		try {
-			Method method = display.getClass().getDeclaredMethod("isXMouseActive");
-			method.setAccessible(true);
-
-			boolean xMouseActive = (boolean) method.invoke(display);
-			System.out.println("org.eclipse.swt.widgets.Display.isXMouseActive(): " + xMouseActive);
-		} finally {
-			display.dispose();
-		}
+		Method method = display.getClass().getDeclaredMethod("isXMouseActive");
+		method.setAccessible(true);
+
+		boolean xMouseActive = (boolean) method.invoke(display);
+		System.out.println("org.eclipse.swt.widgets.Display.isXMouseActive(): " + xMouseActive);
+	}
+
+	@Test
+	public void test_mixedLfAndCrfl() {
+		//Use text control for testing since Display.withCrLf() is package private
+		Text text = new Text(shell, SWT.None);
+
+		text.setText("First Line \n second line \r\n third line");
+		assertEquals("First Line \r\n second line \r\n third line", text.getText());
 	}
 }