Add diff formatter that generates a list of style ranges

This class will be used for a general purpose diff
viewer available as a tab in the commit viewer.

Bug: 343000
Change-Id: Ic2eb3e178f5a049154bd5744da3010fa791a9933
Signed-off-by: Kevin Sawicki <kevin@github.com>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

2 files changed, 287 insertions, 0 deletions

diff --git a/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/test/commit/DiffStyleRangeFormatterTest.java b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/test/commit/DiffStyleRangeFormatterTest.java
new file mode 100644
index 0000000000..64cc3ba8d2
--- /dev/null
+++ b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/test/commit/DiffStyleRangeFormatterTest.java
@@ -0,0 +1,79 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  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:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.egit.ui.test.commit;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+
+import org.eclipse.egit.core.Activator;
+import org.eclipse.egit.ui.common.LocalRepositoryTestCase;
+import org.eclipse.egit.ui.internal.commit.DiffStyleRangeFormatter;
+import org.eclipse.egit.ui.internal.commit.DiffStyleRangeFormatter.DiffStyleRange;
+import org.eclipse.jface.text.Document;
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link DiffStyleRangeFormatter}
+ */
+public class DiffStyleRangeFormatterTest extends LocalRepositoryTestCase {
+
+	private static Repository repository;
+
+	private static RevCommit commit;
+
+	@BeforeClass
+	public static void setup() throws Exception {
+		File repoFile = createProjectAndCommitToRepository();
+		assertNotNull(repoFile);
+		repository = Activator.getDefault().getRepositoryCache()
+				.lookupRepository(repoFile);
+		assertNotNull(repository);
+
+		RevWalk walk = new RevWalk(repository);
+		try {
+			commit = walk.parseCommit(repository.resolve(Constants.HEAD));
+			assertNotNull(commit);
+			walk.parseBody(commit.getParent(0));
+		} finally {
+			walk.release();
+		}
+	}
+
+	@Test
+	public void testRanges() throws Exception {
+		IDocument document = new Document();
+		DiffStyleRangeFormatter formatter = new DiffStyleRangeFormatter(
+				document);
+		formatter.setRepository(repository);
+		formatter.format(commit.getTree(), commit.getParent(0).getTree());
+		assertTrue(document.getLength() > 0);
+		DiffStyleRange[] ranges = formatter.getRanges();
+		assertNotNull(ranges);
+		assertTrue(ranges.length > 0);
+		for (DiffStyleRange range : ranges) {
+			assertNotNull(range);
+			assertNotNull(range.diffType);
+			assertTrue(range.start >= 0);
+			assertTrue(range.length >= 0);
+			assertTrue(range.start < document.getLength());
+		}
+
+	}
+
+}
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/commit/DiffStyleRangeFormatter.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/commit/DiffStyleRangeFormatter.java
new file mode 100644
index 0000000000..98559e1e86
--- /dev/null
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/commit/DiffStyleRangeFormatter.java
@@ -0,0 +1,208 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  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:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.egit.ui.internal.commit;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.eclipse.egit.ui.internal.CompareUtils;
+import org.eclipse.egit.ui.internal.commit.DiffStyleRangeFormatter.DiffStyleRange.Type;
+import org.eclipse.egit.ui.internal.history.FileDiff;
+import org.eclipse.jface.text.BadLocationException;
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jgit.diff.DiffFormatter;
+import org.eclipse.jgit.diff.RawText;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.swt.custom.StyleRange;
+import org.eclipse.swt.graphics.Color;
+
+/**
+ * Diff style range formatter class that builds up a list of
+ * {@link DiffStyleRange} instances as each {@link FileDiff} is being written to
+ * an {@link IDocument}.
+ */
+public class DiffStyleRangeFormatter extends DiffFormatter {
+
+	/**
+	 * Diff style range
+	 */
+	public static class DiffStyleRange extends StyleRange {
+
+		/**
+		 * Diff type
+		 */
+		public enum Type {
+
+			/**
+			 * Added line
+			 */
+			ADD,
+
+			/**
+			 * Removed line
+			 */
+			REMOVE,
+
+			/**
+			 * Hunk line
+			 */
+			HUNK,
+
+			/**
+			 * Other line
+			 */
+			OTHER,
+
+		}
+
+		/**
+		 * Diff type
+		 */
+		public Type diffType = Type.OTHER;
+
+		/**
+		 * Line background
+		 */
+		public Color lineBackground = null;
+
+		public boolean similarTo(StyleRange style) {
+			return super.similarTo(style) && style instanceof DiffStyleRange
+					&& diffType == ((DiffStyleRange) style).diffType;
+		}
+	}
+
+	private static class DocumentOutputStream extends OutputStream {
+
+		private String charset;
+
+		private IDocument document;
+
+		private int offset;
+
+		public DocumentOutputStream(IDocument document, int offset) {
+			this.document = document;
+			this.offset = offset;
+		}
+
+		private void write(String content) throws IOException {
+			try {
+				this.document.replace(this.offset, 0, content);
+				this.offset += content.length();
+			} catch (BadLocationException e) {
+				throw new IOException(e);
+			}
+		}
+
+		public void write(byte[] b, int off, int len) throws IOException {
+			if (charset == null)
+				write(new String(b, off, len));
+			else
+				write(new String(b, off, len, charset));
+		}
+
+		public void write(byte[] b) throws IOException {
+			write(b, 0, b.length);
+		}
+
+		public void write(int b) throws IOException {
+			write(new byte[] { (byte) b });
+		}
+	}
+
+	private DocumentOutputStream stream;
+
+	private List<DiffStyleRange> ranges = new ArrayList<DiffStyleRange>();
+
+	/**
+	 * @param document
+	 * @param offset
+	 */
+	public DiffStyleRangeFormatter(IDocument document, int offset) {
+		super(new DocumentOutputStream(document, offset));
+		this.stream = (DocumentOutputStream) getOutputStream();
+	}
+
+	/**
+	 * @param document
+	 */
+	public DiffStyleRangeFormatter(IDocument document) {
+		this(document, document.getLength());
+	}
+
+	/**
+	 * Write diff
+	 *
+	 * @param repository
+	 * @param diff
+	 * @return this formatter
+	 * @throws IOException
+	 */
+	public DiffStyleRangeFormatter write(Repository repository, FileDiff diff)
+			throws IOException {
+		this.stream.charset = CompareUtils.getResourceEncoding(repository,
+				diff.getPath());
+		diff.outputDiff(null, repository, this, true);
+		flush();
+		return this;
+	}
+
+	/**
+	 * Get diff style ranges
+	 *
+	 * @return non-null but possibly empty array
+	 */
+	public DiffStyleRange[] getRanges() {
+		return this.ranges.toArray(new DiffStyleRange[this.ranges.size()]);
+	}
+
+	/**
+	 * Create and add diff style range
+	 *
+	 * @param type
+	 * @return added range
+	 */
+	protected DiffStyleRange addRange(Type type) {
+		DiffStyleRange range = new DiffStyleRange();
+		range.start = stream.offset;
+		range.diffType = type;
+		ranges.add(range);
+		return range;
+	}
+
+	/**
+	 * @see org.eclipse.jgit.diff.DiffFormatter#writeHunkHeader(int, int, int,
+	 *      int)
+	 */
+	protected void writeHunkHeader(int aStartLine, int aEndLine,
+			int bStartLine, int bEndLine) throws IOException {
+		DiffStyleRange range = addRange(Type.HUNK);
+		super.writeHunkHeader(aStartLine, aEndLine, bStartLine, bEndLine);
+		range.length = stream.offset - range.start;
+	}
+
+	/**
+	 * @see org.eclipse.jgit.diff.DiffFormatter#writeLine(char,
+	 *      org.eclipse.jgit.diff.RawText, int)
+	 */
+	protected void writeLine(char prefix, RawText text, int cur)
+			throws IOException {
+		if (prefix == ' ')
+			super.writeLine(prefix, text, cur);
+		else {
+			DiffStyleRange range = addRange(prefix == '+' ? Type.ADD
+					: Type.REMOVE);
+			super.writeLine(prefix, text, cur);
+			range.length = stream.offset - range.start;
+		}
+	}
+}