Added further support for whitespace ignoring during diff

Added code to support ignoring leading, trailing, and changed
whitespace when performing a diff operation. I also added command
line options to Diff to enable the various whitespace ignoring
methods. These match the flags for git diff.

Change-Id: Ie56301aafad59ee3f0fe5de62719f5023cd702c8

3 files changed, 330 insertions, 0 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreLeadingWhitespace.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreLeadingWhitespace.java
new file mode 100644
index 0000000000..1d928766a9
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreLeadingWhitespace.java
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2009-2010, Google Inc.
+ * Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.diff;
+
+import static org.eclipse.jgit.util.RawCharUtil.trimLeadingWhitespace;
+
+/**
+ * A version of {@link RawText} that ignores leading whitespace.
+ */
+public class RawTextIgnoreLeadingWhitespace extends RawText {
+
+	/**
+	 * Create a new sequence from an existing content byte array.
+	 * <p>
+	 * The entire array (indexes 0 through length-1) is used as the content.
+	 *
+	 * @param input
+	 *            the content array. The array is never modified, so passing
+	 *            through cached arrays is safe.
+	 */
+	public RawTextIgnoreLeadingWhitespace(byte[] input) {
+		super(input);
+	}
+
+	@Override
+	public boolean equals(final int i, final Sequence other, final int j) {
+		return equals(this, i + 1, (RawText) other, j + 1);
+	}
+
+	private static boolean equals(final RawText a, final int ai,
+			final RawText b, final int bi) {
+		if (a.hashes.get(ai) != b.hashes.get(bi))
+			return false;
+
+		int as = a.lines.get(ai);
+		int bs = b.lines.get(bi);
+		int ae = a.lines.get(ai + 1);
+		int be = b.lines.get(bi + 1);
+
+		as = trimLeadingWhitespace(a.content, as, ae);
+		bs = trimLeadingWhitespace(b.content, bs, be);
+
+		if (ae - as != be - bs)
+			return false;
+
+		while (as < ae) {
+			if (a.content[as++] != b.content[bs++])
+				return false;
+		}
+		return true;
+	}
+
+	@Override
+	protected int hashLine(final byte[] raw, int ptr, int end) {
+		int hash = 5381;
+		ptr = trimLeadingWhitespace(raw, ptr, end);
+		for (; ptr < end; ptr++) {
+			hash = (hash << 5) ^ (raw[ptr] & 0xff);
+		}
+		return hash;
+	}
+}
\ No newline at end of file
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreTrailingWhitespace.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreTrailingWhitespace.java
new file mode 100644
index 0000000000..b9095940cf
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreTrailingWhitespace.java
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2009-2010, Google Inc.
+ * Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.diff;
+
+import static org.eclipse.jgit.util.RawCharUtil.trimTrailingWhitespace;
+
+/**
+ * A version of {@link RawText} that ignores trailing whitespace.
+ */
+public class RawTextIgnoreTrailingWhitespace extends RawText {
+
+	/**
+	 * Create a new sequence from an existing content byte array.
+	 * <p>
+	 * The entire array (indexes 0 through length-1) is used as the content.
+	 *
+	 * @param input
+	 *            the content array. The array is never modified, so passing
+	 *            through cached arrays is safe.
+	 */
+	public RawTextIgnoreTrailingWhitespace(byte[] input) {
+		super(input);
+	}
+
+	@Override
+	public boolean equals(final int i, final Sequence other, final int j) {
+		return equals(this, i + 1, (RawText) other, j + 1);
+	}
+
+	private static boolean equals(final RawText a, final int ai,
+			final RawText b, final int bi) {
+		if (a.hashes.get(ai) != b.hashes.get(bi))
+			return false;
+
+		int as = a.lines.get(ai);
+		int bs = b.lines.get(bi);
+		int ae = a.lines.get(ai + 1);
+		int be = b.lines.get(bi + 1);
+
+		ae = trimTrailingWhitespace(a.content, as, ae);
+		be = trimTrailingWhitespace(b.content, bs, be);
+
+		if (ae - as != be - bs)
+			return false;
+
+		while (as < ae) {
+			if (a.content[as++] != b.content[bs++])
+				return false;
+		}
+		return true;
+	}
+
+	@Override
+	protected int hashLine(final byte[] raw, int ptr, int end) {
+		int hash = 5381;
+		end = trimTrailingWhitespace(raw, ptr, end);
+		for (; ptr < end; ptr++) {
+			hash = (hash << 5) ^ (raw[ptr] & 0xff);
+		}
+		return hash;
+	}
+}
\ No newline at end of file
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreWhitespaceChange.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreWhitespaceChange.java
new file mode 100644
index 0000000000..399f038bca
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RawTextIgnoreWhitespaceChange.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2009-2010, Google Inc.
+ * Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.diff;
+
+import static org.eclipse.jgit.util.RawCharUtil.isWhitespace;
+import static org.eclipse.jgit.util.RawCharUtil.trimTrailingWhitespace;
+import static org.eclipse.jgit.util.RawCharUtil.trimLeadingWhitespace;
+
+/**
+ * A version of {@link RawText} that ignores changes in the amount of
+ * whitespace, as well as trailing whitespace.
+ */
+public class RawTextIgnoreWhitespaceChange extends RawText {
+
+	/**
+	 * Create a new sequence from an existing content byte array.
+	 * <p>
+	 * The entire array (indexes 0 through length-1) is used as the content.
+	 *
+	 * @param input
+	 *            the content array. The array is never modified, so passing
+	 *            through cached arrays is safe.
+	 */
+	public RawTextIgnoreWhitespaceChange(byte[] input) {
+		super(input);
+	}
+
+	@Override
+	public boolean equals(final int i, final Sequence other, final int j) {
+		return equals(this, i + 1, (RawText) other, j + 1);
+	}
+
+	private static boolean equals(final RawText a, final int ai,
+			final RawText b, final int bi) {
+		if (a.hashes.get(ai) != b.hashes.get(bi))
+			return false;
+
+		int as = a.lines.get(ai);
+		int bs = b.lines.get(bi);
+		int ae = a.lines.get(ai + 1);
+		int be = b.lines.get(bi + 1);
+
+		ae = trimTrailingWhitespace(a.content, as, ae);
+		be = trimTrailingWhitespace(b.content, bs, be);
+
+		while (as < ae && bs < be) {
+			byte ac = a.content[as];
+			byte bc = b.content[bs];
+
+			if (ac != bc)
+				return false;
+
+			if (isWhitespace(ac))
+				as = trimLeadingWhitespace(a.content, as, ae);
+			else
+				as++;
+
+			if (isWhitespace(bc))
+				bs = trimLeadingWhitespace(b.content, bs, be);
+			else
+				bs++;
+		}
+		return as == ae && bs == be;
+	}
+
+	@Override
+	protected int hashLine(final byte[] raw, int ptr, int end) {
+		int hash = 5381;
+		end = trimTrailingWhitespace(raw, ptr, end);
+		while (ptr < end) {
+			byte c = raw[ptr];
+			hash = (hash << 5) ^ (c & 0xff);
+			if (isWhitespace(c))
+				ptr = trimLeadingWhitespace(raw, ptr, end);
+			else
+				ptr++;
+		}
+		return hash;
+	}
+}
\ No newline at end of file