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