KWSys 2019-01-24 (b9dd1636)

Code extracted from:

    https://gitlab.kitware.com/utils/kwsys.git

at commit b9dd1636e50ea43cd33bed8c6ffbbe7161618b54 (master).

Upstream Shortlog
-----------------

Ben Boeckel (1):
      28db6989 cmake: add an option for building with PIC

Taylor Braun-Jones (1):
      3f35954d SystemTools: Add TextFilesDiffer method

Tobias Kloss (1):
      aa1f7f7c SystemTools: Fix FileIsSymlink with Windows data deduplication

CMakeLists.txt

@@ -454,6 +454,10 @@ ELSE()
   SET(KWSYS_LIBRARY_TYPE STATIC)
 ENDIF()
 
+if(NOT DEFINED KWSYS_BUILD_PIC)
+  set(KWSYS_BUILD_PIC 0)
+endif()
+
 #-----------------------------------------------------------------------------
 # Configure some implementation details.
 
@@ -870,7 +874,7 @@ IF(KWSYS_C_SRCS OR KWSYS_CXX_SRCS)
     SET(KWSYS_LINK_DEPENDENCY INTERFACE)
     ADD_LIBRARY(${KWSYS_TARGET_OBJECT} OBJECT
       ${KWSYS_C_SRCS} ${KWSYS_CXX_SRCS})
-    IF(KWSYS_BUILD_SHARED)
+    IF(KWSYS_BUILD_SHARED OR KWSYS_BUILD_PIC)
       SET_PROPERTY(TARGET ${KWSYS_TARGET_OBJECT} PROPERTY
         POSITION_INDEPENDENT_CODE TRUE)
     ENDIF()
@@ -965,7 +969,7 @@ IF(KWSYS_ENABLE_C AND KWSYS_C_SRCS)
       ${KWSYS_TARGET_C_INTERFACE} ${KWSYS_TARGET_C_LINK})
     SET(KWSYS_LINK_DEPENDENCY INTERFACE)
     ADD_LIBRARY(${KWSYS_TARGET_C_OBJECT} OBJECT ${KWSYS_C_SRCS})
-    IF(KWSYS_BUILD_SHARED)
+    IF(KWSYS_BUILD_SHARED OR KWSYS_BUILD_PIC)
       SET_PROPERTY(TARGET ${KWSYS_TARGET_C_OBJECT} PROPERTY
         POSITION_INDEPENDENT_CODE TRUE)
     ENDIF()

SystemTools.cxx

@@ -2161,6 +2161,32 @@ bool SystemTools::FilesDiffer(const std::string& source,
   return false;
 }
 
+bool SystemTools::TextFilesDiffer(const std::string& path1,
+                                  const std::string& path2)
+{
+  kwsys::ifstream if1(path1.c_str());
+  kwsys::ifstream if2(path2.c_str());
+  if (!if1 || !if2) {
+    return true;
+  }
+
+  for (;;) {
+    std::string line1, line2;
+    bool hasData1 = GetLineFromStream(if1, line1);
+    bool hasData2 = GetLineFromStream(if2, line2);
+    if (hasData1 != hasData2) {
+      return true;
+    }
+    if (!hasData1) {
+      break;
+    }
+    if (line1 != line2) {
+      return true;
+    }
+  }
+  return false;
+}
+
 /**
  * Blockwise copy source to destination file
  */
@@ -2979,10 +3005,36 @@ bool SystemTools::FileIsDirectory(const std::string& inName)
 bool SystemTools::FileIsSymlink(const std::string& name)
 {
 #if defined(_WIN32)
-  DWORD attr =
-    GetFileAttributesW(Encoding::ToWindowsExtendedPath(name).c_str());
+  std::wstring path = Encoding::ToWindowsExtendedPath(name);
+  DWORD attr = GetFileAttributesW(path.c_str());
   if (attr != INVALID_FILE_ATTRIBUTES) {
-    return (attr & FILE_ATTRIBUTE_REPARSE_POINT) != 0;
+    if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) != 0) {
+      // FILE_ATTRIBUTE_REPARSE_POINT means:
+      // * a file or directory that has an associated reparse point, or
+      // * a file that is a symbolic link.
+      HANDLE hFile = CreateFileW(
+        path.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING,
+        FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, NULL);
+      if (hFile == INVALID_HANDLE_VALUE) {
+        return false;
+      }
+      byte buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+      DWORD bytesReturned = 0;
+      if (!DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0, buffer,
+                           MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &bytesReturned,
+                           NULL)) {
+        CloseHandle(hFile);
+        // Since FILE_ATTRIBUTE_REPARSE_POINT is set this file must be
+        // a symbolic link if it is not a reparse point.
+        return GetLastError() == ERROR_NOT_A_REPARSE_POINT;
+      }
+      CloseHandle(hFile);
+      ULONG reparseTag =
+        reinterpret_cast<PREPARSE_GUID_DATA_BUFFER>(&buffer[0])->ReparseTag;
+      return (reparseTag == IO_REPARSE_TAG_SYMLINK) ||
+        (reparseTag == IO_REPARSE_TAG_MOUNT_POINT);
+    }
+    return false;
   } else {
     return false;
   }

SystemTools.hxx.in

@@ -578,6 +578,13 @@ public:
   static bool FilesDiffer(const std::string& source,
                           const std::string& destination);
 
+  /**
+   * Compare the contents of two files, ignoring line ending differences.
+   * Return true if different
+   */
+  static bool TextFilesDiffer(const std::string& path1,
+                              const std::string& path2);
+
   /**
    * Return true if the two files are the same file
    */

testSystemTools.cxx

@@ -984,6 +984,50 @@ static bool CheckGetLineFromStreamLongLine()
   return true;
 }
 
+static bool writeFile(const char* fileName, const char* data)
+{
+  kwsys::ofstream out(fileName, std::ios::binary);
+  out << data;
+  if (!out) {
+    std::cerr << "Failed to write file: " << fileName << std::endl;
+    return false;
+  }
+  return true;
+}
+
+static bool CheckTextFilesDiffer()
+{
+  struct
+  {
+    const char* a;
+    const char* b;
+    bool differ;
+  } test_cases[] = { { "one", "one", false },
+                     { "one", "two", true },
+                     { "", "", false },
+                     { "\n", "\r\n", false },
+                     { "one\n", "one\n", false },
+                     { "one\r\n", "one\n", false },
+                     { "one\n", "one", false },
+                     { "one\ntwo", "one\ntwo", false },
+                     { "one\ntwo", "one\r\ntwo", false } };
+  const int num_test_cases = sizeof(test_cases) / sizeof(test_cases[0]);
+  for (int i = 0; i < num_test_cases; ++i) {
+    if (!writeFile("file_a", test_cases[i].a) ||
+        !writeFile("file_b", test_cases[i].b)) {
+      return false;
+    }
+    if (kwsys::SystemTools::TextFilesDiffer("file_a", "file_b") !=
+        test_cases[i].differ) {
+      std::cerr << "Incorrect TextFilesDiffer result for test case " << i + 1
+                << "." << std::endl;
+      return false;
+    }
+  }
+
+  return true;
+}
+
 int testSystemTools(int, char* [])
 {
   bool res = true;
@@ -1027,5 +1071,7 @@ int testSystemTools(int, char* [])
 
   res &= CheckGetFilenameName();
 
+  res &= CheckTextFilesDiffer();
+
   return res ? 0 : 1;
 }