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, 78 insertions, 0 deletions

diff --git a/Source/cmFileLock.cxx b/Source/cmFileLock.cxx
new file mode 100644
index 0000000..5f75637
--- /dev/null
+++ b/Source/cmFileLock.cxx
@@ -0,0 +1,78 @@
+/*============================================================================
+  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 "cmFileLock.h"
+
+#include <assert.h>
+#include "cmFileLockResult.h"
+
+// Common implementation
+
+cmFileLock::~cmFileLock()
+{
+  if (!this->Filename.empty())
+    {
+    const cmFileLockResult result = this->Release();
+    static_cast<void>(result);
+    assert(result.IsOk());
+    }
+}
+
+cmFileLockResult cmFileLock::Lock(
+    const std::string& filename, unsigned timeout)
+{
+  if (filename.empty())
+    {
+    // Error is internal since all the directories and file must be created
+    // before actual lock called.
+    return cmFileLockResult::MakeInternal();
+    }
+
+  if (!this->Filename.empty())
+    {
+    // Error is internal since double-lock must be checked in class
+    // cmFileLockPool by the cmFileLock::IsLocked method.
+    return cmFileLockResult::MakeInternal();
+    }
+
+  this->Filename = filename;
+  cmFileLockResult result = this->OpenFile();
+  if (result.IsOk())
+    {
+    if (timeout == static_cast<unsigned>(-1))
+      {
+      result = this->LockWithoutTimeout();
+      }
+    else
+      {
+      result = this->LockWithTimeout(timeout);
+      }
+    }
+
+  if (!result.IsOk())
+    {
+    this->Filename = "";
+    }
+
+  return result;
+}
+
+bool cmFileLock::IsLocked(const std::string& filename) const
+{
+  return filename == this->Filename;
+}
+
+#if defined(_WIN32)
+# include "cmFileLockWin32.cxx"
+#else
+# include "cmFileLockUnix.cxx"
+#endif