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- /*
- * Copyright (C) 2009, 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.lib.Constants.encodeASCII;
-
- import java.io.IOException;
- import java.io.OutputStream;
- import java.util.List;
-
- import org.eclipse.jgit.patch.FileHeader;
-
- /**
- * Format an {@link EditList} as a Git style unified patch script.
- */
- public class DiffFormatter {
- private static final byte[] noNewLine = encodeASCII("\\ No newline at end of file\n");
-
- private int context;
-
- /** Create a new formatter with a default level of context. */
- public DiffFormatter() {
- setContext(3);
- }
-
- /**
- * Change the number of lines of context to display.
- *
- * @param lineCount
- * number of lines of context to see before the first
- * modification and after the last modification within a hunk of
- * the modified file.
- */
- public void setContext(final int lineCount) {
- if (lineCount < 0)
- throw new IllegalArgumentException("context must be >= 0");
- context = lineCount;
- }
-
- /**
- * Format a patch script, reusing a previously parsed FileHeader.
- * <p>
- * This formatter is primarily useful for editing an existing patch script
- * to increase or reduce the number of lines of context within the script.
- * All header lines are reused as-is from the supplied FileHeader.
- *
- * @param out
- * stream to write the patch script out to.
- * @param head
- * existing file header containing the header lines to copy.
- * @param a
- * text source for the pre-image version of the content. This
- * must match the content of {@link FileHeader#getOldId()}.
- * @param b
- * text source for the post-image version of the content. This
- * must match the content of {@link FileHeader#getNewId()}.
- * @throws IOException
- * writing to the supplied stream failed.
- */
- public void format(final OutputStream out, final FileHeader head,
- final RawText a, final RawText b) throws IOException {
- // Reuse the existing FileHeader as-is by blindly copying its
- // header lines, but avoiding its hunks. Instead we recreate
- // the hunks from the text instances we have been supplied.
- //
- final int start = head.getStartOffset();
- int end = head.getEndOffset();
- if (!head.getHunks().isEmpty())
- end = head.getHunks().get(0).getStartOffset();
- out.write(head.getBuffer(), start, end - start);
-
- formatEdits(out, a, b, head.toEditList());
- }
-
- /**
- * Formats a list of edits in unified diff format
- * @param out where the unified diff is written to
- * @param a the text A which was compared
- * @param b the text B which was compared
- * @param edits some differences which have been calculated between A and B
- * @throws IOException
- */
- public void formatEdits(final OutputStream out, final RawText a,
- final RawText b, final EditList edits) throws IOException {
- for (int curIdx = 0; curIdx < edits.size();) {
- Edit curEdit = edits.get(curIdx);
- final int endIdx = findCombinedEnd(edits, curIdx);
- final Edit endEdit = edits.get(endIdx);
-
- int aCur = Math.max(0, curEdit.getBeginA() - context);
- int bCur = Math.max(0, curEdit.getBeginB() - context);
- final int aEnd = Math.min(a.size(), endEdit.getEndA() + context);
- final int bEnd = Math.min(b.size(), endEdit.getEndB() + context);
-
- writeHunkHeader(out, aCur, aEnd, bCur, bEnd);
-
- while (aCur < aEnd || bCur < bEnd) {
- if (aCur < curEdit.getBeginA() || endIdx + 1 < curIdx) {
- writeLine(out, ' ', a, aCur);
- aCur++;
- bCur++;
-
- } else if (aCur < curEdit.getEndA()) {
- writeLine(out, '-', a, aCur++);
-
- } else if (bCur < curEdit.getEndB()) {
- writeLine(out, '+', b, bCur++);
- }
-
- if (end(curEdit, aCur, bCur) && ++curIdx < edits.size())
- curEdit = edits.get(curIdx);
- }
- }
- }
-
- private void writeHunkHeader(final OutputStream out, int aCur, int aEnd,
- int bCur, int bEnd) throws IOException {
- out.write('@');
- out.write('@');
- writeRange(out, '-', aCur + 1, aEnd - aCur);
- writeRange(out, '+', bCur + 1, bEnd - bCur);
- out.write(' ');
- out.write('@');
- out.write('@');
- out.write('\n');
- }
-
- private static void writeRange(final OutputStream out, final char prefix,
- final int begin, final int cnt) throws IOException {
- out.write(' ');
- out.write(prefix);
- switch (cnt) {
- case 0:
- // If the range is empty, its beginning number must be the
- // line just before the range, or 0 if the range is at the
- // start of the file stream. Here, begin is always 1 based,
- // so an empty file would produce "0,0".
- //
- out.write(encodeASCII(begin - 1));
- out.write(',');
- out.write('0');
- break;
-
- case 1:
- // If the range is exactly one line, produce only the number.
- //
- out.write(encodeASCII(begin));
- break;
-
- default:
- out.write(encodeASCII(begin));
- out.write(',');
- out.write(encodeASCII(cnt));
- break;
- }
- }
-
- private static void writeLine(final OutputStream out, final char prefix,
- final RawText text, final int cur) throws IOException {
- out.write(prefix);
- text.writeLine(out, cur);
- out.write('\n');
- if (cur + 1 == text.size() && text.isMissingNewlineAtEnd())
- out.write(noNewLine);
- }
-
- private int findCombinedEnd(final List<Edit> edits, final int i) {
- int end = i + 1;
- while (end < edits.size()
- && (combineA(edits, end) || combineB(edits, end)))
- end++;
- return end - 1;
- }
-
- private boolean combineA(final List<Edit> e, final int i) {
- return e.get(i).getBeginA() - e.get(i - 1).getEndA() <= 2 * context;
- }
-
- private boolean combineB(final List<Edit> e, final int i) {
- return e.get(i).getBeginB() - e.get(i - 1).getEndB() <= 2 * context;
- }
-
- private static boolean end(final Edit edit, final int a, final int b) {
- return edit.getEndA() <= a && edit.getEndB() <= b;
- }
- }
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