Bug 76936 - [console] Eclipse Console window does not handle \b, \f, and

\r 

Change ConsoleDocument to process the text String to handle \b, \f, and
\r. Updated change "\r\n" is no longer considered a sequence of control
characters.

Change-Id: I93f394a44fcdd891a6e139c7c055c67313187e0e
Signed-off-by: Philippe Marschall <philippe.marschall@netcetera.ch>

1 files changed, 147 insertions, 1 deletions

diff --git a/org.eclipse.ui.console/src/org/eclipse/ui/internal/console/ConsoleDocument.java b/org.eclipse.ui.console/src/org/eclipse/ui/internal/console/ConsoleDocument.java
index 8eb24bb79..2be213198 100644
--- a/org.eclipse.ui.console/src/org/eclipse/ui/internal/console/ConsoleDocument.java
+++ b/org.eclipse.ui.console/src/org/eclipse/ui/internal/console/ConsoleDocument.java
@@ -7,6 +7,7 @@
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
+ *     Philippe Marschall <philippe.marschall@netcetera.ch> - Bug 76936
  *******************************************************************************/
 package org.eclipse.ui.internal.console;
 
@@ -21,6 +22,24 @@ import org.eclipse.jface.text.Position;
  */
 public class ConsoleDocument extends Document {
 
+	private static final char NEW_LINE = '\n';
+
+	private static final char BACK_SPACE = '\b';
+
+	private static final char CARRIAGE_RETURN = '\r';
+
+	private static final char FORM_FEED = '\f';
+
+	static final class DelimiterInfo {
+		int delimiterIndex;
+		int delimiterLength;
+
+		DelimiterInfo(int delimiterIndex, int delimiterLength) {
+			this.delimiterIndex = delimiterIndex;
+			this.delimiterLength = delimiterLength;
+		}
+	}
+
 	/* (non-Javadoc)
 	 * @see org.eclipse.jface.text.IDocument#get(int, int)
 	 */
@@ -89,7 +108,51 @@ public class ConsoleDocument extends Document {
 	 */
 	@Override
 	public synchronized void replace(int pos, int length, String text) throws BadLocationException {
-		super.replace(pos, length, text);
+		if (containsControlCharacter(text)) {
+			int lineNumber = this.getTracker().getLineNumberOfOffset(pos);
+			boolean endsWithNewLIne = getLineDelimiter(lineNumber) != null;
+			int actualPosition;
+			StringBuilder buffer;
+			int lengthDelta;
+			if (endsWithNewLIne) {
+				// pos is the start of a new line
+				// assume form feeds are rare and therefore don't add additional
+				// capacity
+				buffer = new StringBuilder(length);
+				actualPosition = pos;
+				lengthDelta = 0;
+			} else {
+				// there already exists a line which we may have to modify
+				IRegion lineInformation = getLineInformation(lineNumber);
+				actualPosition = lineInformation.getOffset();
+				// assume form feeds are rare and therefore don't add additional
+				// capacity
+				int lineLength = lineInformation.getLength();
+				buffer = new StringBuilder(length + lineLength);
+				String line = get(lineInformation.getOffset(), lineLength);
+				buffer.append(line);
+				lengthDelta = lineLength;
+			}
+
+			int offset = 0;
+			int lineStart = 0; // start of the current line in the output buffer
+			DelimiterInfo delimiterInfo = nextDelimiterInfo(text, offset);
+			while (delimiterInfo != null) {
+				processLine(text, offset, lineStart, delimiterInfo.delimiterIndex - offset, buffer);
+				buffer.append(text, delimiterInfo.delimiterIndex, delimiterInfo.delimiterIndex + delimiterInfo.delimiterLength);
+
+				offset = delimiterInfo.delimiterIndex + delimiterInfo.delimiterLength;
+				delimiterInfo = nextDelimiterInfo(text, offset);
+				lineStart = buffer.length();
+
+			}
+			processLine(text, offset, lineStart, text.length() - offset, buffer);
+
+			String processedText = buffer.toString();
+			super.replace(actualPosition, length + lengthDelta, processedText);
+		} else {
+			super.replace(pos, length, text);
+		}
 	}
 	/* (non-Javadoc)
 	 * @see org.eclipse.jface.text.IDocument#set(java.lang.String)
@@ -127,4 +190,87 @@ public class ConsoleDocument extends Document {
 	public synchronized Position[] getPositions(String category) throws BadPositionCategoryException {
         return super.getPositions(category);
     }
+
+	private static boolean containsControlCharacter(String text) {
+		int length = text.length();
+		int i = 0;
+		while (i < length) {
+			char ch = text.charAt(i);
+			if (ch == BACK_SPACE || ch == FORM_FEED) {
+				return true;
+			}
+			if (ch == CARRIAGE_RETURN) {
+				if (i + 1 < length && text.charAt(i + 1) == NEW_LINE) {
+					// don't treat CR LF on Windows as control character
+					// skip the character after the current one since we already
+					// know it's a newline
+					i += 2;
+					continue;
+				}
+				return true;
+			}
+			i += 1;
+		}
+		return false;
+	}
+
+	private static void processLine(String text, int start, int initialLineStart, int length, StringBuilder buffer) {
+		if (length == 0) {
+			return;
+		}
+
+		// position where the next character insert should happen
+		int insertIndex = buffer.length();
+		// start index of the current line in the output buffer
+		int lineStart = initialLineStart;
+		// end index of the line in text
+		int end = start + length;
+		for (int i = start; i < end; i++) {
+			char ch = text.charAt(i);
+			if (ch == BACK_SPACE) {
+				if (insertIndex > lineStart) {
+					// can backtrack only in current line
+					insertIndex -= 1;
+				}
+			} else if (ch == CARRIAGE_RETURN) {
+				insertIndex = lineStart;
+			} else if (ch == FORM_FEED) {
+				int headPosition = insertIndex - lineStart;
+				buffer.append('\n');
+				lineStart = buffer.length();
+				for (int j = 0; j < headPosition; j++) {
+					buffer.append(' ');
+				}
+				insertIndex = lineStart + headPosition;
+			} else {
+				// other character insert at insertIndex
+				if (insertIndex == buffer.length()) {
+					buffer.append(ch);
+				} else {
+					// #charAt does not work when index == length
+					buffer.setCharAt(insertIndex, ch);
+				}
+				insertIndex += 1;
+			}
+		}
+	}
+
+	private static DelimiterInfo nextDelimiterInfo(String text, int offset) {
+		int length = text.length();
+		for (int i = offset; i < length; i++) {
+			char ch = text.charAt(i);
+			if (ch == '\r') {
+				// \r\n -> will be treated as a new line
+				// \r something else -> will be treated as \r
+				if (i + 1 < length) {
+					if (text.charAt(i + 1) == '\n') {
+						return new DelimiterInfo(i, 2);
+					}
+				}
+			} else if (ch == '\n') {
+				return new DelimiterInfo(i, 1);
+			}
+		}
+		return null;
+	}
 }