| // Copyright 2019 The Bazel Authors. All rights reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| |
| package com.google.devtools.build.lib.bazel.rules.ninja.file; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * Finds the border between two different Ninja declarations. |
| * |
| * <p>The Ninja declaration consists of several text lines; if the line is a part of the previous |
| * declaration, it starts with some amount of spaces or tabs. If the line is the beginning of the |
| * new declaration, it starts with non-space symbol. Dollar symbol '$' escapes the newline, i.e. |
| * "$\nsomething" does not contain a separator. |
| * |
| * <p>We support '\r\n' separators in Ninja files and throw {@link IncorrectSeparatorException} in |
| * case an incorrect separator '\r' is used. |
| */ |
| public class NinjaSeparatorFinder { |
| private static final byte DOLLAR_BYTE = '$'; |
| private static final byte LINEFEED_BYTE = '\r'; |
| private static final byte NEWLINE_BYTE = '\n'; |
| private static final byte SPACE_BYTE = ' '; |
| private static final byte TAB_BYTE = '\t'; |
| |
| private NinjaSeparatorFinder() {} |
| |
| public static int findNextSeparator(FileFragment fragment, int startingFrom, int untilExcluded) |
| throws IncorrectSeparatorException { |
| Preconditions.checkState(startingFrom < fragment.length()); |
| Preconditions.checkState(untilExcluded < 0 || untilExcluded <= fragment.length()); |
| |
| boolean escaped = DOLLAR_BYTE == fragment.byteAt(startingFrom); |
| int endExcl = untilExcluded > 0 ? untilExcluded : fragment.length(); |
| for (int i = startingFrom + 1; i < endExcl - 1; i++) { |
| byte current = fragment.byteAt(i); |
| byte next = fragment.byteAt(i + 1); |
| byte afterNextOrSpace = i < (endExcl - 2) ? fragment.byteAt(i + 2) : SPACE_BYTE; |
| if (LINEFEED_BYTE == current && NEWLINE_BYTE != next) { |
| throw new IncorrectSeparatorException( |
| "Wrong newline separators: \\r should be followed by \\n."); |
| } |
| if (!escaped |
| && SPACE_BYTE != afterNextOrSpace |
| && TAB_BYTE != afterNextOrSpace |
| && LINEFEED_BYTE == current) { |
| // To do not introduce the length of the separator, let us point to the last symbol of it. |
| return i + 1; |
| } |
| if (!escaped && SPACE_BYTE != next && TAB_BYTE != next && NEWLINE_BYTE == current) { |
| return i; |
| } |
| if (escaped && LINEFEED_BYTE == current) { |
| // Jump over the whole escaped linefeed + newline. |
| ++i; |
| escaped = false; |
| } else { |
| escaped = DOLLAR_BYTE == current; |
| } |
| } |
| return -1; |
| } |
| } |