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| 1 | +/* |
| 2 | + * Copyright 2016 DiffPlug |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | +package com.diffplug.spotless.extra.integration; |
| 17 | + |
| 18 | +import java.io.ByteArrayOutputStream; |
| 19 | +import java.io.IOException; |
| 20 | +import java.nio.ByteBuffer; |
| 21 | +import java.nio.CharBuffer; |
| 22 | +import java.nio.charset.CharacterCodingException; |
| 23 | +import java.nio.charset.Charset; |
| 24 | + |
| 25 | +import org.bouncycastle.util.Arrays; |
| 26 | +import org.eclipse.jgit.diff.Edit; |
| 27 | +import org.eclipse.jgit.diff.EditList; |
| 28 | +import org.eclipse.jgit.diff.RawText; |
| 29 | +import org.eclipse.jgit.util.IntList; |
| 30 | +import org.eclipse.jgit.util.RawParseUtils; |
| 31 | + |
| 32 | +/** |
| 33 | + * Formats the diff in Git-like style, however it makes whitespace visible for |
| 34 | + * edit-like diffs (when one fragment is replaced with another). |
| 35 | + */ |
| 36 | +class WriteSpaceAwareDiffFormatter { |
| 37 | + private static final int CONTEXT_LINES = 3; |
| 38 | + private static final String MIDDLE_DOT = "\u00b7"; |
| 39 | + private static final String CR = "\u240d"; |
| 40 | + private static final String LF = "\u240a"; |
| 41 | + private static final String TAB = "\u21e5"; |
| 42 | + private static final byte[] ONE_SPACE = new byte[]{' '}; |
| 43 | + private static final byte[] CR_SIMPLE = new byte[]{'\\', 'r'}; |
| 44 | + private static final byte[] LF_SIMPLE = new byte[]{'\\', 'n'}; |
| 45 | + private static final byte[] TAB_SIMPLE = new byte[]{'\\', 't'}; |
| 46 | + |
| 47 | + private final ByteArrayOutputStream out; |
| 48 | + private final byte[] middleDot; |
| 49 | + private final byte[] cr; |
| 50 | + private final byte[] lf; |
| 51 | + private final byte[] tab; |
| 52 | + |
| 53 | + /** |
| 54 | + * Creates the formatter. |
| 55 | + * @param out output stream for the resulting diff. The diff would have \n line endings |
| 56 | + * @param charset the charset for the text to use |
| 57 | + */ |
| 58 | + public WriteSpaceAwareDiffFormatter(ByteArrayOutputStream out, Charset charset) { |
| 59 | + this.out = out; |
| 60 | + this.middleDot = replacementFor(MIDDLE_DOT, charset, ONE_SPACE); |
| 61 | + this.cr = replacementFor(CR, charset, CR_SIMPLE); |
| 62 | + this.lf = replacementFor(LF, charset, LF_SIMPLE); |
| 63 | + this.tab = replacementFor(TAB, charset, TAB_SIMPLE); // \u2409 is missing in lots of the fonts |
| 64 | + } |
| 65 | + |
| 66 | + private static byte[] replacementFor(String value, Charset charset, byte[] defaultValue) { |
| 67 | + try { |
| 68 | + ByteBuffer buffer = charset.newEncoder() |
| 69 | + .replaceWith(ONE_SPACE) |
| 70 | + .encode(CharBuffer.wrap(value)); |
| 71 | + return Arrays.copyOf(buffer.array(), buffer.remaining()); |
| 72 | + } catch (CharacterCodingException e) { |
| 73 | + return defaultValue; |
| 74 | + } |
| 75 | + } |
| 76 | + |
| 77 | + /** |
| 78 | + * Formats the diff. |
| 79 | + * @param edits the list of edits to format |
| 80 | + * @param a input text a, with \n line endings |
| 81 | + * @param b input text b, with \n line endings |
| 82 | + * @throws IOException if formatting fails |
| 83 | + */ |
| 84 | + public void format(EditList edits, RawText a, RawText b) throws IOException { |
| 85 | + IntList linesA = RawParseUtils.lineMap(a.getRawContent(), 0, a.getRawContent().length); |
| 86 | + IntList linesB = RawParseUtils.lineMap(b.getRawContent(), 0, b.getRawContent().length); |
| 87 | + boolean firstLine = true; |
| 88 | + for (int i = 0; i < edits.size(); i++) { |
| 89 | + Edit edit = edits.get(i); |
| 90 | + int lineA = Math.max(0, edit.getBeginA() - CONTEXT_LINES); |
| 91 | + int lineB = Math.max(0, edit.getBeginB() - CONTEXT_LINES); |
| 92 | + |
| 93 | + final int endIdx = findCombinedEnd(edits, i); |
| 94 | + final Edit endEdit = edits.get(endIdx); |
| 95 | + |
| 96 | + int endA = Math.min(a.size(), endEdit.getEndA() + CONTEXT_LINES); |
| 97 | + int endB = Math.min(b.size(), endEdit.getEndB() + CONTEXT_LINES); |
| 98 | + |
| 99 | + if (firstLine) { |
| 100 | + firstLine = false; |
| 101 | + } else { |
| 102 | + out.write('\n'); |
| 103 | + } |
| 104 | + header(lineA, endA, lineB, endB); |
| 105 | + |
| 106 | + boolean showWhitespace = edit.getType() == Edit.Type.REPLACE; |
| 107 | + |
| 108 | + while (lineA < endA || lineB < endB) { |
| 109 | + if (lineA < edit.getBeginA()) { |
| 110 | + // Common part before the diff |
| 111 | + line(' ', a, lineA, linesA, false); |
| 112 | + lineA++; |
| 113 | + lineB++; |
| 114 | + } else if (lineA < edit.getEndA()) { |
| 115 | + line('-', a, lineA, linesA, showWhitespace); |
| 116 | + lineA++; |
| 117 | + } else if (lineB < edit.getEndB()) { |
| 118 | + line('+', b, lineB, linesB, showWhitespace); |
| 119 | + lineB++; |
| 120 | + } else { |
| 121 | + // Common part after the diff |
| 122 | + line(' ', a, lineA, linesA, false); |
| 123 | + lineA++; |
| 124 | + lineB++; |
| 125 | + } |
| 126 | + |
| 127 | + if (lineA == edit.getEndA() && lineB == edit.getEndB() && i < endIdx) { |
| 128 | + i++; |
| 129 | + edit = edits.get(i); |
| 130 | + showWhitespace = edit.getType() == Edit.Type.REPLACE; |
| 131 | + } |
| 132 | + } |
| 133 | + } |
| 134 | + } |
| 135 | + |
| 136 | + /** |
| 137 | + * There might be multiple adjacent diffs, so we need to figure out the latest one in the group. |
| 138 | + * @param edits list of edits |
| 139 | + * @param i starting edit |
| 140 | + * @return the index of the latest edit in the group |
| 141 | + */ |
| 142 | + private int findCombinedEnd(EditList edits, int i) { |
| 143 | + for (; i < edits.size() - 1; i++) { |
| 144 | + Edit current = edits.get(i); |
| 145 | + Edit next = edits.get(i + 1); |
| 146 | + if (current.getEndA() - next.getBeginA() > 2 * CONTEXT_LINES && |
| 147 | + current.getEndB() - next.getBeginB() > 2 * CONTEXT_LINES) { |
| 148 | + break; |
| 149 | + } |
| 150 | + } |
| 151 | + return i; |
| 152 | + } |
| 153 | + |
| 154 | + private void header(int lineA, int endA, int lineB, int endB) { |
| 155 | + out.write('@'); |
| 156 | + out.write('@'); |
| 157 | + range('-', lineA + 1, endA - lineA); |
| 158 | + range('+', lineB + 1, endB - lineB); |
| 159 | + out.write(' '); |
| 160 | + out.write('@'); |
| 161 | + out.write('@'); |
| 162 | + } |
| 163 | + |
| 164 | + private void range(char prefix, int begin, int length) { |
| 165 | + out.write(' '); |
| 166 | + out.write(prefix); |
| 167 | + if (length == 0) { |
| 168 | + writeInt(begin - 1); |
| 169 | + out.write(','); |
| 170 | + out.write('0'); |
| 171 | + } else { |
| 172 | + writeInt(begin); |
| 173 | + if (length > 1) { |
| 174 | + out.write(','); |
| 175 | + writeInt(length); |
| 176 | + } |
| 177 | + } |
| 178 | + } |
| 179 | + |
| 180 | + private void writeInt(int num) { |
| 181 | + String str = Integer.toString(num); |
| 182 | + for (int i = 0, len = str.length(); i < len; i++) { |
| 183 | + out.write(str.charAt(i)); |
| 184 | + } |
| 185 | + } |
| 186 | + |
| 187 | + private void line(char prefix, RawText a, int lineA, IntList lines, boolean showWhitespace) throws IOException { |
| 188 | + out.write('\n'); |
| 189 | + out.write(prefix); |
| 190 | + if (!showWhitespace) { |
| 191 | + a.writeLine(out, lineA); |
| 192 | + return; |
| 193 | + } |
| 194 | + byte[] bytes = a.getRawContent(); |
| 195 | + for (int i = lines.get(lineA + 1), end = lines.get(lineA + 2); i < end; i++) { |
| 196 | + byte b = bytes[i]; |
| 197 | + if (b == ' ') { |
| 198 | + out.write(middleDot); |
| 199 | + } else if (b == '\t') { |
| 200 | + out.write(tab); |
| 201 | + } else if (b == '\r') { |
| 202 | + out.write(cr); |
| 203 | + } else if (b == '\n') { |
| 204 | + out.write(lf); |
| 205 | + } else { |
| 206 | + out.write(b); |
| 207 | + } |
| 208 | + } |
| 209 | + } |
| 210 | +} |
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