1 //===- unittests/Rewrite/RewriteBufferTest.cpp - RewriteBuffer tests ------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "clang/Rewrite/Core/RewriteBuffer.h"
10 #include "gtest/gtest.h"
11 
12 using namespace llvm;
13 using namespace clang;
14 
15 namespace {
16 
17 #define EXPECT_OUTPUT(Buf, Output) EXPECT_EQ(Output, writeOutput(Buf))
18 
19 static std::string writeOutput(const RewriteBuffer &Buf) {
20   std::string Result;
21   raw_string_ostream OS(Result);
22   Buf.write(OS);
23   OS.flush();
24   return Result;
25 }
26 
27 static void tagRange(unsigned Offset, unsigned Len, StringRef tagName,
28                      RewriteBuffer &Buf) {
29   std::string BeginTag;
30   raw_string_ostream(BeginTag) << '<' << tagName << '>';
31   std::string EndTag;
32   raw_string_ostream(EndTag) << "</" << tagName << '>';
33 
34   Buf.InsertTextAfter(Offset, BeginTag);
35   Buf.InsertTextBefore(Offset+Len, EndTag);
36 }
37 
38 TEST(RewriteBuffer, TagRanges) {
39   StringRef Input = "hello world";
40   const char *Output = "<outer><inner>hello</inner></outer> ";
41 
42   RewriteBuffer Buf;
43   Buf.Initialize(Input);
44   StringRef RemoveStr = "world";
45   size_t Pos = Input.find(RemoveStr);
46   Buf.RemoveText(Pos, RemoveStr.size());
47 
48   StringRef TagStr = "hello";
49   Pos = Input.find(TagStr);
50   tagRange(Pos, TagStr.size(), "outer", Buf);
51   tagRange(Pos, TagStr.size(), "inner", Buf);
52 
53   EXPECT_OUTPUT(Buf, Output);
54 }
55 
56 TEST(RewriteBuffer, DISABLED_RemoveLineIfEmpty_XFAIL) {
57   StringRef Input = "def\n"
58                     "ghi\n"
59                     "jkl\n";
60   RewriteBuffer Buf;
61   Buf.Initialize(Input);
62 
63   // Insert "abc\n" at the start.
64   Buf.InsertText(0, "abc\n");
65   EXPECT_OUTPUT(Buf, "abc\n"
66                      "def\n"
67                      "ghi\n"
68                      "jkl\n");
69 
70   // Remove "def\n".
71   //
72   // After the removal of "def", we have:
73   //
74   //   "abc\n"
75   //   "\n"
76   //   "ghi\n"
77   //   "jkl\n"
78   //
79   // Because removeLineIfEmpty=true, RemoveText has to remove the "\n" left on
80   // the line.  This happens correctly for the rewrite buffer itself, so the
81   // next check below passes.
82   //
83   // However, RemoveText's implementation incorrectly records the delta for
84   // removing the "\n" using the rewrite buffer offset, 4, where it was
85   // supposed to use the original input offset, 3.  Interpreted as an original
86   // input offset, 4 points to "g" not to "\n".  Thus, any future modifications
87   // at the original input's "g" will incorrectly see "g" as having become an
88   // empty string and so will map to the next character, "h", in the rewrite
89   // buffer.
90   StringRef RemoveStr0 = "def";
91   Buf.RemoveText(Input.find(RemoveStr0), RemoveStr0.size(),
92                  /*removeLineIfEmpty*/ true);
93   EXPECT_OUTPUT(Buf, "abc\n"
94                      "ghi\n"
95                      "jkl\n");
96 
97   // Try to remove "ghi\n".
98   //
99   // As discussed above, the original input offset for "ghi\n" incorrectly
100   // maps to the rewrite buffer offset for "hi\nj", so we end up with:
101   //
102   //   "abc\n"
103   //   "gkl\n"
104   //
105   // To show that removeLineIfEmpty=true is the culprit, change true to false
106   // and append a newline to RemoveStr0 above.  The test then passes.
107   StringRef RemoveStr1 = "ghi\n";
108   Buf.RemoveText(Input.find(RemoveStr1), RemoveStr1.size());
109   EXPECT_OUTPUT(Buf, "abc\n"
110                      "jkl\n");
111 }
112 
113 } // anonymous namespace
114