xref: /aosp_15_r20/external/ktfmt/core/src/main/java/com/facebook/ktfmt/kdoc/Escaping.kt (revision 5be3f65c8cf0e6db0a7e312df5006e8e93cdf9ec)
1 /*
2  * Copyright (c) Meta Platforms, Inc. and affiliates.
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 com.facebook.ktfmt.kdoc
18 
19 object Escaping {
20 
21   private const val SLASH_STAR_ESCAPE = "\u0004\u0005"
22 
23   private const val STAR_SLASH_ESCAPE = "\u0005\u0004"
24 
indexOfCommentEscapeSequencesnull25   fun indexOfCommentEscapeSequences(s: String) =
26       s.indexOfAny(listOf(SLASH_STAR_ESCAPE, STAR_SLASH_ESCAPE))
27 
28   /**
29    * kotlin-compiler's KDoc lexer doesn't correctly handle nested slash-star comments, so we escape
30    * them into tombstones, format, then unescape.
31    */
32   fun escapeKDoc(s: String): String {
33     val startMarkerIndex = s.indexOf("/*")
34     val endMarkerIndex = s.lastIndexOf("*/")
35 
36     if (startMarkerIndex == -1 || endMarkerIndex == -1) {
37       throw RuntimeException("KDoc with no /** and/or */")
38     }
39 
40     return s.substring(0, startMarkerIndex + 3) +
41         s.substring(startMarkerIndex + 3, endMarkerIndex)
42             .replace("/*", SLASH_STAR_ESCAPE)
43             .replace("*/", STAR_SLASH_ESCAPE) +
44         s.substring(endMarkerIndex)
45   }
46 
47   /** See [escapeKDoc]. */
unescapeKDocnull48   fun unescapeKDoc(s: String): String =
49       s.replace(SLASH_STAR_ESCAPE, "/*").replace(STAR_SLASH_ESCAPE, "*/")
50 }
51