Status: Add class to hold an OS-specific status of a system operation

CMakeLists.txt

@@ -142,6 +142,7 @@ if(KWSYS_STANDALONE OR CMake_SOURCE_DIR)
   set(KWSYS_USE_MD5 1)
   set(KWSYS_USE_Process 1)
   set(KWSYS_USE_RegularExpression 1)
+  set(KWSYS_USE_Status 1)
   set(KWSYS_USE_System 1)
   set(KWSYS_USE_SystemTools 1)
   set(KWSYS_USE_CommandLineArguments 1)
@@ -630,7 +631,7 @@ set(KWSYS_HXX_FILES Configure String)
 # Add selected C++ classes.
 set(cppclasses
   Directory DynamicLoader Encoding Glob RegularExpression SystemTools
-  CommandLineArguments FStream SystemInformation ConsoleBuf
+  CommandLineArguments FStream SystemInformation ConsoleBuf Status
   )
 foreach(cpp ${cppclasses})
   if(KWSYS_USE_${cpp})
@@ -963,6 +964,7 @@ if(KWSYS_STANDALONE OR CMake_SOURCE_DIR)
     # C++ tests
     set(KWSYS_CXX_TESTS ${KWSYS_CXX_TESTS}
       testConfigure.cxx
+      testStatus.cxx
       testSystemTools.cxx
       testCommandLineArguments.cxx
       testCommandLineArguments1.cxx

Status.cxx

+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing#kwsys for details.  */
+#include "kwsysPrivate.h"
+#include KWSYS_HEADER(Status.hxx)
+
+// Work-around CMake dependency scanning limitation.  This must
+// duplicate the above list of headers.
+#if 0
+#  include "Status.hxx.in"
+#endif
+
+#include <cerrno>
+#include <cstring>
+#include <string>
+
+#if defined(_WIN32)
+#  include <windows.h>
+#endif
+
+namespace KWSYS_NAMESPACE {
+
+Status Status::POSIX_errno()
+{
+  return Status::POSIX(errno);
+}
+
+#ifdef _WIN32
+Status Status::Windows_GetLastError()
+{
+  return Status::Windows(GetLastError());
+}
+#endif
+
+std::string Status::GetString() const
+{
+  std::string err;
+  switch (this->Kind_) {
+    case Kind::Success:
+      err = "Success";
+      break;
+    case Kind::POSIX:
+      err = strerror(this->POSIX_);
+      break;
+#ifdef _WIN32
+    case Kind::Windows: {
+      LPSTR message = NULL;
+      DWORD size = FormatMessageA(
+        FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+          FORMAT_MESSAGE_IGNORE_INSERTS,
+        NULL, this->Windows_, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+        (LPSTR)&message, 0, NULL);
+      err = std::string(message, size);
+      LocalFree(message);
+    } break;
+#endif
+  };
+  return err;
+}
+
+} // namespace KWSYS_NAMESPACE

Status.hxx.in

+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing#kwsys for details.  */
+#ifndef @KWSYS_NAMESPACE@_Status_hxx
+#define @KWSYS_NAMESPACE@_Status_hxx
+
+#include <@KWSYS_NAMESPACE@/Configure.hxx>
+
+#include <string>
+
+namespace @KWSYS_NAMESPACE@ {
+
+/** \class Status
+ * \brief OS-specific status of a system operation.
+ */
+class @KWSYS_NAMESPACE@_EXPORT Status
+{
+public:
+  enum class Kind
+  {
+    Success,
+    POSIX,
+#ifdef _WIN32
+    Windows,
+#endif
+  };
+
+  /** Construct with kind "Success".  */
+  Status() = default;
+
+  /** Construct with kind "Success".  */
+  static Status Success() { return Status(); }
+
+  /** Construct with kind "POSIX" using given errno-style value.  */
+  static Status POSIX(int e)
+  {
+    Status s(Kind::POSIX);
+    s.POSIX_ = e;
+    return s;
+  }
+
+  /** Construct with kind "POSIX" using errno.  */
+  static Status POSIX_errno();
+
+#ifdef _WIN32
+  /** Construct with kind "Windows" using given GetLastError()-style value.  */
+  static Status Windows(unsigned int e)
+  {
+    Status s(Kind::Windows);
+    s.Windows_ = e;
+    return s;
+  }
+
+  /** Construct with kind "Windows" using GetLastError().  */
+  static Status Windows_GetLastError();
+#endif
+
+  /** Return true on "Success", false otherwise.  */
+  explicit operator bool() const { return this->Kind_ == Kind::Success; }
+
+  /** Return the kind of status.  */
+  Kind GetKind() const { return this->Kind_; }
+
+  /** If the kind is "POSIX", returns the errno-style value.
+      Otherwise, returns 0.  */
+  int GetPOSIX() const
+  {
+    return this->Kind_ == Kind::POSIX ? this->POSIX_ : 0;
+  }
+
+#ifdef _WIN32
+  /** If the kind is "Windows", returns the GetLastError()-style value.
+      Otherwise, returns 0.  */
+  int GetWindows() const
+  {
+    return this->Kind_ == Kind::Windows ? this->Windows_ : 0;
+  }
+#endif
+
+  /** Return a human-readable description of the status.  */
+  std::string GetString() const;
+
+private:
+  Status(Kind kind)
+    : Kind_(kind)
+  {
+  }
+
+  Kind Kind_ = Kind::Success;
+
+  union
+  {
+    int POSIX_;
+#ifdef _WIN32
+    unsigned int Windows_;
+#endif
+  };
+};
+
+} // namespace @KWSYS_NAMESPACE@
+
+#endif

testStatus.cxx

+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+file Copyright.txt or https://cmake.org/licensing#kwsys for details.  */
+#include "kwsysPrivate.h"
+#include KWSYS_HEADER(Status.hxx)
+
+// Work-around CMake dependency scanning limitation.  This must
+// duplicate the above list of headers.
+#if 0
+#  include "Status.hxx.in"
+#endif
+
+#include <cerrno>
+#include <iostream>
+
+#ifdef _WIN32
+#  include <windows.h>
+#endif
+
+int testStatus(int, char* [])
+{
+  bool res = true;
+  {
+    kwsys::Status status;
+    if (status.GetKind() != kwsys::Status::Kind::Success) {
+      std::cerr << "Status default constructor does not produce Success\n";
+      res = false;
+    }
+
+    status = kwsys::Status::Success();
+    if (status.GetKind() != kwsys::Status::Kind::Success) {
+      std::cerr << "Status Success constructor does not produce Success\n";
+      res = false;
+    }
+    if (!status) {
+      std::cerr << "Status Success kind is not true\n";
+      res = false;
+    }
+    if (status.GetPOSIX() != 0) {
+      std::cerr << "Status Success kind does not return POSIX 0\n";
+      res = false;
+    }
+#ifdef _WIN32
+    if (status.GetWindows() != 0) {
+      std::cerr << "Status Success kind does not return Windows 0\n";
+      res = false;
+    }
+#endif
+    if (status.GetString() != "Success") {
+      std::cerr << "Status Success kind does not return \"Success\" string\n";
+      res = false;
+    }
+
+    status = kwsys::Status::POSIX(EINVAL);
+    if (status.GetKind() != kwsys::Status::Kind::POSIX) {
+      std::cerr << "Status POSIX constructor does not produce POSIX\n";
+      res = false;
+    }
+    if (status) {
+      std::cerr << "Status POSIX kind is not false\n";
+      res = false;
+    }
+    if (status.GetPOSIX() != EINVAL) {
+      std::cerr << "Status POSIX kind does not preserve POSIX value\n";
+      res = false;
+    }
+#ifdef _WIN32
+    if (status.GetWindows() != 0) {
+      std::cerr << "Status POSIX kind does not return Windows 0\n";
+      res = false;
+    }
+#endif
+    if (status.GetString().empty()) {
+      std::cerr << "Status POSIX kind returns empty string\n";
+      res = false;
+    }
+    errno = ENOENT;
+    status = kwsys::Status::POSIX_errno();
+    if (status.GetPOSIX() != ENOENT) {
+      std::cerr << "Status POSIX_errno did not use errno\n";
+      res = false;
+    }
+    errno = 0;
+
+#ifdef _WIN32
+    status = kwsys::Status::Windows(ERROR_INVALID_PARAMETER);
+    if (status.GetKind() != kwsys::Status::Kind::Windows) {
+      std::cerr << "Status Windows constructor does not produce Windows\n";
+      res = false;
+    }
+    if (status) {
+      std::cerr << "Status Windows kind is not false\n";
+      res = false;
+    }
+    if (status.GetWindows() != ERROR_INVALID_PARAMETER) {
+      std::cerr << "Status Windows kind does not preserve Windows value\n";
+      res = false;
+    }
+    if (status.GetPOSIX() != 0) {
+      std::cerr << "Status Windows kind does not return POSIX 0\n";
+      res = false;
+    }
+    if (status.GetString().empty()) {
+      std::cerr << "Status Windows kind returns empty string\n";
+      res = false;
+    }
+
+    SetLastError(ERROR_FILE_NOT_FOUND);
+    status = kwsys::Status::Windows_GetLastError();
+    if (status.GetWindows() != ERROR_FILE_NOT_FOUND) {
+      std::cerr << "Status Windows_GetLastError did not use GetLastError()\n";
+      res = false;
+    }
+    SetLastError(ERROR_SUCCESS);
+#endif
+  }
+  return res ? 0 : 1;
+}