| // Copyright (C) 2016 The Android Open Source Project |
| // |
| // 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.gitiles.doc; |
| |
| import com.google.common.base.CharMatcher; |
| import javax.annotation.Nullable; |
| |
| class PathResolver { |
| /** |
| * Resolve a path within the repository. |
| * |
| * @param file path of the Markdown file in the repository that is making the reference. May be |
| * null. |
| * @param target destination within the repository. If {@code target} starts with {@code '/'}, |
| * {@code file} may be null and {@code target} is evaluated as from the root directory of the |
| * repository. |
| * @return resolved form of {@code target} within the repository. Null if {@code target} is not |
| * valid from {@code file}. Does not begin with {@code '/'}, even if {@code target} does. |
| */ |
| @Nullable |
| static String resolve(@Nullable String file, String target) { |
| if (target.startsWith("/")) { |
| return trimLeadingSlash(target); |
| } else if (file == null) { |
| return null; |
| } |
| |
| String dir = trimLastComponent(trimLeadingSlash(file)); |
| while (!target.isEmpty()) { |
| if (target.startsWith("../") || target.equals("..")) { |
| if (dir.isEmpty()) { |
| return null; |
| } |
| dir = trimLastComponent(dir); |
| target = target.equals("..") ? "" : target.substring(3); |
| } else if (target.startsWith("./")) { |
| target = target.substring(2); |
| } else if (target.equals(".")) { |
| target = ""; |
| } else { |
| break; |
| } |
| } |
| return trimLeadingSlash(dir + '/' + target); |
| } |
| |
| private static String trimLeadingSlash(String s) { |
| return CharMatcher.is('/').trimLeadingFrom(s); |
| } |
| |
| private static String trimLastComponent(String path) { |
| int slash = path.lastIndexOf('/'); |
| return slash < 0 ? "" : path.substring(0, slash); |
| } |
| |
| static String relative(@Nullable String requestUri, String dest) { |
| if (requestUri != null) { |
| // base is the path the browser will use for relative URLs. |
| String base = requestUri; |
| if (!base.endsWith("/")) { |
| int slash = base.lastIndexOf('/'); |
| if (slash < 0) { |
| return dest; |
| } |
| base = base.substring(0, slash + 1); |
| } |
| if (dest.startsWith(base)) { |
| return dest.substring(base.length()); |
| } |
| } |
| return dest; |
| } |
| |
| private PathResolver() {} |
| } |