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 = MemoryBuffer::getOpenFile(FD, "", -1);
  56   assert(Buffer);
  57   return Buffer.get()->getBuffer() == Content;
  58 }
  59
  60 bool FileHasContent(StringRef File, StringRef Content) {
  61   int FD = 0;
  62   auto EC = fs::openFileForRead(File, FD);
  63   (void)EC;
  64   assert(!EC);
  65   ScopedFD EventuallyCloseIt(FD);
  66   return FDHasContent(FD, Content);
  67 }
  68
  69 TEST(rename, FileOpenedForReadingCanBeReplaced) {
  70   // Create unique temporary directory for this test.
  71   SmallString<128> TestDirectory;
  72   ASSERT_NO_ERROR(fs::createUniqueDirectory(
  73       "FileOpenedForReadingCanBeReplaced-test", TestDirectory));
  74
  75   // Add a couple of files to the test directory.
  76   SmallString<128> SourceFileName(TestDirectory);
  77   path::append(SourceFileName, "source");
  78
  79   SmallString<128> TargetFileName(TestDirectory);
  80   path::append(TargetFileName, "target");
  81
  82   ASSERT_NO_ERROR(CreateFileWithContent(SourceFileName, "!!source!!"));
  83   ASSERT_NO_ERROR(CreateFileWithContent(TargetFileName, "!!target!!"));
  84
  85   {
  86     // Open the target file for reading.
  87     int ReadFD = 0;
  88     ASSERT_NO_ERROR(fs::openFileForRead(TargetFileName, ReadFD));
  89     ScopedFD EventuallyCloseIt(ReadFD);
  90
  91     // Confirm we can replace the file while it is open.
  92     EXPECT_TRUE(!fs::rename(SourceFileName, TargetFileName));
  93
  94     // We should still be able to read the old data through the existing
  95     // descriptor.
  96     EXPECT_TRUE(FDHasContent(ReadFD, "!!target!!"));
  97
  98     // The source file should no longer exist
  99     EXPECT_FALSE(fs::exists(SourceFileName));
 100   }
 101
 102   // If we obtain a new descriptor for the target file, we should find that it
 103   // contains the content that was in the source file.
 104   EXPECT_TRUE(FileHasContent(TargetFileName, "!!source!!"));
 105
 106   // Rename the target file back to the source file name to confirm that rename
 107   // still works if the destination does not already exist.
 108   EXPECT_TRUE(!fs::rename(TargetFileName, SourceFileName));
 109   EXPECT_FALSE(fs::exists(TargetFileName));
 110   ASSERT_TRUE(fs::exists(SourceFileName));
 111
 112   // Clean up.
 113   ASSERT_NO_ERROR(fs::remove(SourceFileName));
 114   ASSERT_NO_ERROR(fs::remove(TestDirectory.str()));
 115 }
 116
 117 TEST(rename, ExistingTemp) {
 118   // Test that existing .tmpN files don't get deleted by the Windows
 119   // sys::fs::rename implementation.
 120   SmallString<128> TestDirectory;
 121   ASSERT_NO_ERROR(
 122       fs::createUniqueDirectory("ExistingTemp-test", TestDirectory));
 123
 124   SmallString<128> SourceFileName(TestDirectory);
 125   path::append(SourceFileName, "source");
 126
 127   SmallString<128> TargetFileName(TestDirectory);
 128   path::append(TargetFileName, "target");
 129
 130   SmallString<128> TargetTmp0FileName(TestDirectory);
 131   path::append(TargetTmp0FileName, "target.tmp0");
 132
 133   SmallString<128> TargetTmp1FileName(TestDirectory);
 134   path::append(TargetTmp1FileName, "target.tmp1");
 135
 136   ASSERT_NO_ERROR(CreateFileWithContent(SourceFileName, "!!source!!"));
 137   ASSERT_NO_ERROR(CreateFileWithContent(TargetFileName, "!!target!!"));
 138   ASSERT_NO_ERROR(CreateFileWithContent(TargetTmp0FileName, "!!target.tmp0!!"));
 139
 140   {
 141     // Use mapped_file_region to make sure that the destination file is mmap'ed.
 142     // This will cause SetInformationByHandle to fail when renaming to the
 143     // destination, and we will follow the code path that tries to give target
 144     // a temporary name.
 145     int TargetFD;
 146     std::error_code EC;
 147     ASSERT_NO_ERROR(fs::openFileForRead(TargetFileName, TargetFD));
 148     ScopedFD X(TargetFD);
 149     sys::fs::mapped_file_region MFR(
 150         TargetFD, sys::fs::mapped_file_region::readonly, 10, 0, EC);
 151     ASSERT_FALSE(EC);
 152
 153     ASSERT_NO_ERROR(fs::rename(SourceFileName, TargetFileName));
 154
 155 #ifdef _WIN32
 156     // Make sure that target was temporarily renamed to target.tmp1 on Windows.
 157     // This is signified by a permission denied error as opposed to no such file
 158     // or directory when trying to open it.
 159     int Tmp1FD;
 160     EXPECT_EQ(errc::permission_denied,
 161               fs::openFileForRead(TargetTmp1FileName, Tmp1FD));
 162 #endif
 163   }
 164
 165   EXPECT_TRUE(FileHasContent(TargetTmp0FileName, "!!target.tmp0!!"));
 166
 167   ASSERT_NO_ERROR(fs::remove(TargetFileName));
 168   ASSERT_NO_ERROR(fs::remove(TargetTmp0FileName));
 169   ASSERT_NO_ERROR(fs::remove(TestDirectory.str()));
 170 }
 171
 172 }  // anonymous namespace