unittests/Support/ReplaceFileTest.cpp

   1 //===- llvm/unittest/Support/ReplaceFileTest.cpp - unit 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/Support/Errc.h"
  10 #include "llvm/Support/ErrorHandling.h"
  11 #include "llvm/Support/FileSystem.h"
  12 #include "llvm/Support/MemoryBuffer.h"
  13 #include "llvm/Support/Path.h"
  14 #include "llvm/Support/Process.h"
  15 #include "gtest/gtest.h"
  16
  17 using namespace llvm;
  18 using namespace llvm::sys;
  19
  20 #define ASSERT_NO_ERROR(x)                                                 \
  21   do {                                                                     \
  22     if (std::error_code ASSERT_NO_ERROR_ec = x) {                          \
  23       errs() << #x ": did not return errc::success.\n"                     \
  24              << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"     \
  25              << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n"; \
  26     }                                                                      \
  27   } while (false)
  28
  29 namespace {
  30 std::error_code CreateFileWithContent(const SmallString<128> &FilePath,
  31                                       const StringRef &content) {
  32   int FD = 0;
  33   if (std::error_code ec = fs::openFileForWrite(FilePath, FD))
  34     return ec;
  35
  36   const bool ShouldClose = true;
  37   raw_fd_ostream OS(FD, ShouldClose);
  38   OS << content;
  39
  40   return std::error_code();
  41 }
  42
  43 class ScopedFD {
  44   int FD;
  45
  46   ScopedFD(const ScopedFD &) = delete;
  47   ScopedFD &operator=(const ScopedFD &) = delete;
  48
  49  public:
  50   explicit ScopedFD(int Descriptor) : FD(Descriptor) {}
  51   ~ScopedFD() { Process::SafelyCloseFileDescriptor(FD); }
  52 };
  53
  54 bool FDHasContent(int FD, StringRef Content) {
  55   auto Buffer =
  56       MemoryBuffer::getOpenFile(sys::fs::convertFDToNativeFile(FD), "", -1);
  57   assert(Buffer);
  58   return Buffer.get()->getBuffer() == Content;
  59 }
  60
  61 bool FileHasContent(StringRef File, StringRef Content) {
  62   int FD = 0;
  63   auto EC = fs::openFileForRead(File, FD);
  64   (void)EC;
  65   assert(!EC);
  66   ScopedFD EventuallyCloseIt(FD);
  67   return FDHasContent(FD, Content);
  68 }
  69
  70 TEST(rename, FileOpenedForReadingCanBeReplaced) {
  71   // Create unique temporary directory for this test.
  72   SmallString<128> TestDirectory;
  73   ASSERT_NO_ERROR(fs::createUniqueDirectory(
  74       "FileOpenedForReadingCanBeReplaced-test", TestDirectory));
  75
  76   // Add a couple of files to the test directory.
  77   SmallString<128> SourceFileName(TestDirectory);
  78   path::append(SourceFileName, "source");
  79
  80   SmallString<128> TargetFileName(TestDirectory);
  81   path::append(TargetFileName, "target");
  82
  83   ASSERT_NO_ERROR(CreateFileWithContent(SourceFileName, "!!source!!"));
  84   ASSERT_NO_ERROR(CreateFileWithContent(TargetFileName, "!!target!!"));
  85
  86   {
  87     // Open the target file for reading.
  88     int ReadFD = 0;
  89     ASSERT_NO_ERROR(fs::openFileForRead(TargetFileName, ReadFD));
  90     ScopedFD EventuallyCloseIt(ReadFD);
  91
  92     // Confirm we can replace the file while it is open.
  93     EXPECT_TRUE(!fs::rename(SourceFileName, TargetFileName));
  94
  95     // We should still be able to read the old data through the existing
  96     // descriptor.
  97     EXPECT_TRUE(FDHasContent(ReadFD, "!!target!!"));
  98
  99     // The source file should no longer exist
 100     EXPECT_FALSE(fs::exists(SourceFileName));
 101   }
 102
 103   // If we obtain a new descriptor for the target file, we should find that it
 104   // contains the content that was in the source file.
 105   EXPECT_TRUE(FileHasContent(TargetFileName, "!!source!!"));
 106
 107   // Rename the target file back to the source file name to confirm that rename
 108   // still works if the destination does not already exist.
 109   EXPECT_TRUE(!fs::rename(TargetFileName, SourceFileName));
 110   EXPECT_FALSE(fs::exists(TargetFileName));
 111   ASSERT_TRUE(fs::exists(SourceFileName));
 112
 113   // Clean up.
 114   ASSERT_NO_ERROR(fs::remove(SourceFileName));
 115   ASSERT_NO_ERROR(fs::remove(TestDirectory.str()));
 116 }
 117
 118 TEST(rename, ExistingTemp) {
 119   // Test that existing .tmpN files don't get deleted by the Windows
 120   // sys::fs::rename implementation.
 121   SmallString<128> TestDirectory;
 122   ASSERT_NO_ERROR(
 123       fs::createUniqueDirectory("ExistingTemp-test", TestDirectory));
 124
 125   SmallString<128> SourceFileName(TestDirectory);
 126   path::append(SourceFileName, "source");
 127
 128   SmallString<128> TargetFileName(TestDirectory);
 129   path::append(TargetFileName, "target");
 130
 131   SmallString<128> TargetTmp0FileName(TestDirectory);
 132   path::append(TargetTmp0FileName, "target.tmp0");
 133
 134   SmallString<128> TargetTmp1FileName(TestDirectory);
 135   path::append(TargetTmp1FileName, "target.tmp1");
 136
 137   ASSERT_NO_ERROR(CreateFileWithContent(SourceFileName, "!!source!!"));
 138   ASSERT_NO_ERROR(CreateFileWithContent(TargetFileName, "!!target!!"));
 139   ASSERT_NO_ERROR(CreateFileWithContent(TargetTmp0FileName, "!!target.tmp0!!"));
 140
 141   {
 142     // Use mapped_file_region to make sure that the destination file is mmap'ed.
 143     // This will cause SetInformationByHandle to fail when renaming to the
 144     // destination, and we will follow the code path that tries to give target
 145     // a temporary name.
 146     int TargetFD;
 147     std::error_code EC;
 148     ASSERT_NO_ERROR(fs::openFileForRead(TargetFileName, TargetFD));
 149     ScopedFD X(TargetFD);
 150     sys::fs::mapped_file_region MFR(sys::fs::convertFDToNativeFile(TargetFD),
 151                                     sys::fs::mapped_file_region::readonly, 10,
 152                                     0, EC);
 153     ASSERT_FALSE(EC);
 154
 155     ASSERT_NO_ERROR(fs::rename(SourceFileName, TargetFileName));
 156
 157 #ifdef _WIN32
 158     // Make sure that target was temporarily renamed to target.tmp1 on Windows.
 159     // This is signified by a permission denied error as opposed to no such file
 160     // or directory when trying to open it.
 161     int Tmp1FD;
 162     EXPECT_EQ(errc::permission_denied,
 163               fs::openFileForRead(TargetTmp1FileName, Tmp1FD));
 164 #endif
 165   }
 166
 167   EXPECT_TRUE(FileHasContent(TargetTmp0FileName, "!!target.tmp0!!"));
 168
 169   ASSERT_NO_ERROR(fs::remove(TargetFileName));
 170   ASSERT_NO_ERROR(fs::remove(TargetTmp0FileName));
 171   ASSERT_NO_ERROR(fs::remove(TestDirectory.str()));
 172 }
 173
 174 }  // anonymous namespace