file: Add LOCK subcommand to do file and directory locking

Provide options to fail without blocking or to block up to a timeout.
Provide options to specify the scope containing the lock so it can be
released automatically at the end of a function, file, or process.

Extend the RunCMake.file test with cases covering the file(LOCK) command
usage and error cases.

1 files changed, 111 insertions, 0 deletions

diff --git a/Source/cmFileLockResult.cxx b/Source/cmFileLockResult.cxx
new file mode 100644
index 0000000..045e7ee
--- /dev/null
+++ b/Source/cmFileLockResult.cxx
@@ -0,0 +1,111 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  Copyright 2014 Ruslan Baratov
+
+  Distributed under the OSI-approved BSD License (the "License");
+  see accompanying file Copyright.txt for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even the
+  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the License for more information.
+============================================================================*/
+
+#include "cmFileLockResult.h"
+
+#include <errno.h>
+
+cmFileLockResult cmFileLockResult::MakeOk()
+{
+  return cmFileLockResult(OK, 0);
+}
+
+cmFileLockResult cmFileLockResult::MakeSystem()
+{
+#if defined(_WIN32)
+  const Error lastError = GetLastError();
+#else
+  const Error lastError = errno;
+#endif
+  return cmFileLockResult(SYSTEM, lastError);
+}
+
+cmFileLockResult cmFileLockResult::MakeTimeout()
+{
+  return cmFileLockResult(TIMEOUT, 0);
+}
+
+cmFileLockResult cmFileLockResult::MakeAlreadyLocked()
+{
+  return cmFileLockResult(ALREADY_LOCKED, 0);
+}
+
+cmFileLockResult cmFileLockResult::MakeInternal()
+{
+  return cmFileLockResult(INTERNAL, 0);
+}
+
+cmFileLockResult cmFileLockResult::MakeNoFunction()
+{
+  return cmFileLockResult(NO_FUNCTION, 0);
+}
+
+bool cmFileLockResult::IsOk() const
+{
+  return this->Type == OK;
+}
+
+std::string cmFileLockResult::GetOutputMessage() const
+{
+  switch (this->Type)
+    {
+    case OK:
+      return "0";
+    case SYSTEM:
+#if defined(_WIN32)
+      {
+      char* errorText = NULL;
+
+      // http://stackoverflow.com/a/455533/2288008
+      DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM |
+          FORMAT_MESSAGE_ALLOCATE_BUFFER |
+          FORMAT_MESSAGE_IGNORE_INSERTS;
+      ::FormatMessageA(
+          flags,
+          NULL,
+          this->ErrorValue,
+          MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+          (LPSTR)&errorText,
+          0,
+          NULL
+      );
+
+      if (errorText != NULL)
+        {
+        const std::string message = errorText;
+        ::LocalFree(errorText);
+        return message;
+        }
+      else
+        {
+        return "Internal error (FormatMessageA failed)";
+        }
+      }
+#else
+      return strerror(this->ErrorValue);
+#endif
+    case TIMEOUT:
+      return "Timeout reached";
+    case ALREADY_LOCKED:
+      return "File already locked";
+    case NO_FUNCTION:
+      return "'GUARD FUNCTION' not used in function definition";
+    case INTERNAL:
+    default:
+      return "Internal error";
+    }
+}
+
+cmFileLockResult::cmFileLockResult(ErrorType typeValue, Error errorValue):
+    Type(typeValue), ErrorValue(errorValue)
+{
+}