clang/unittests/Rewrite/RewriteBufferTest.cpp

   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