1 package com.github.searls.jasmine.io;
2
3 import org.apache.commons.lang3.StringEscapeUtils;
4 import org.apache.commons.lang3.StringUtils;
5
6 import java.io.File;
7 import java.io.IOException;
8
9 public class RelativizesFilePaths {
10
11 public String relativize(File from, File to) throws IOException {
12 String fromPath = from.getCanonicalPath();
13 String toPath = to.getCanonicalPath();
14
15 String root = StringUtils.getCommonPrefix(new String[]{fromPath, toPath});
16 StringBuffer result = new StringBuffer();
17 if (this.fromPathIsNotADirectAncestor(fromPath, root)) {
18 for (@SuppressWarnings("unused") String dir : this.divergentDirectories(root, fromPath)) {
19 result.append("..").append(File.separator);
20 }
21 }
22 result.append(this.pathAfterRoot(toPath, root));
23
24 return this.convertSlashes(this.trimLeadingSlashIfNecessary(result));
25 }
26
27 private String convertSlashes(String path) {
28 return path.replace(File.separatorChar, '/');
29 }
30
31 private boolean fromPathIsNotADirectAncestor(String fromPath, String root) {
32 return !StringUtils.equals(root, fromPath);
33 }
34
35 private String[] divergentDirectories(String root, String fullPath) {
36 return this.pathAfterRoot(fullPath, root).split(StringEscapeUtils.escapeJava(File.separator));
37 }
38
39 private String pathAfterRoot(String path, String root) {
40 return StringUtils.substringAfterLast(path, root);
41 }
42
43 private String trimLeadingSlashIfNecessary(StringBuffer result) {
44 return StringUtils.removeStart(result.toString(), File.separator);
45 }
46
47 }