1 /*
2  * Copyright (C) 2017 The Dagger Authors.
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 
17 package dagger.internal.codegen.base;
18 
19 import java.util.regex.Matcher;
20 import java.util.regex.Pattern;
21 
22 /**
23  * Utility methods for formatting diagnostics to the {@link javax.annotation.processing.Messager}.
24  */
25 public final class DiagnosticFormatting {
26 
27   /**
28    * A regular expression to match a small list of specific packages deemed to be unhelpful to
29    * display in fully qualified types in error messages.
30    *
31    * <p>Note: This should never be applied to messages themselves.
32    */
33   private static final Pattern COMMON_PACKAGE_PATTERN =
34       Pattern.compile(
35           "(?:^|[^.a-z_])" // What we want to match on but not capture.
36               + "((?:" // Start a group with a non-capturing or part
37               + "java[.]lang"
38               + "|java[.]util"
39               + "|javax[.]inject"
40               + "|dagger"
41               + "|dagger[.]multibindings"
42               + "|com[.]google[.]common[.]base"
43               + "|com[.]google[.]common[.]collect"
44               + ")[.])" // Always end with a literal .
45               + "[A-Z]"); // What we want to match on but not capture.
46 
47   /**
48    * A method to strip out common packages and a few rare type prefixes from types' string
49    * representation before being used in error messages.
50    *
51    * <p>This type assumes a String value that is a valid fully qualified (and possibly
52    * parameterized) type, and should NOT be used with arbitrary text, especially prose error
53    * messages.
54    *
55    * <p>TODO(user): Tighten these to take type representations (mirrors and elements) to avoid
56    * accidental mis-use by running errors through this method.
57    */
stripCommonTypePrefixes(String type)58   public static String stripCommonTypePrefixes(String type) {
59     // Do regex magic to remove common packages we care to shorten.
60     Matcher matcher = COMMON_PACKAGE_PATTERN.matcher(type);
61     StringBuilder result = new StringBuilder();
62     int index = 0;
63     while (matcher.find()) {
64       result.append(type.subSequence(index, matcher.start(1)));
65       index = matcher.end(1); // Skip the matched pattern content.
66     }
67     result.append(type.subSequence(index, type.length()));
68     return result.toString();
69   }
70 
DiagnosticFormatting()71   private DiagnosticFormatting() {}
72 }
73