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, 126 insertions, 0 deletions

diff --git a/Source/cmFileLockWin32.cxx b/Source/cmFileLockWin32.cxx
new file mode 100644
index 0000000..17231ea
--- /dev/null
+++ b/Source/cmFileLockWin32.cxx
@@ -0,0 +1,126 @@
+/*============================================================================
+  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 <windows.h> // CreateFileW
+#include "cmSystemTools.h"
+
+cmFileLock::cmFileLock(): File(INVALID_HANDLE_VALUE)
+{
+}
+
+cmFileLockResult cmFileLock::Release()
+{
+  if (this->Filename.empty())
+    {
+    return cmFileLockResult::MakeOk();
+    }
+  const unsigned long len = static_cast<unsigned long>(-1);
+  static OVERLAPPED overlapped;
+  const DWORD reserved = 0;
+  const BOOL unlockResult = UnlockFileEx(
+      File,
+      reserved,
+      len,
+      len,
+      &overlapped
+  );
+
+  this->Filename = "";
+
+  if (unlockResult)
+    {
+    return cmFileLockResult::MakeOk();
+    }
+  else
+    {
+    return cmFileLockResult::MakeSystem();
+    }
+}
+
+cmFileLockResult cmFileLock::OpenFile()
+{
+  const DWORD access = GENERIC_READ | GENERIC_WRITE;
+  const DWORD shareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
+  const PSECURITY_ATTRIBUTES security = NULL;
+  const DWORD attr = 0;
+  const HANDLE templ = NULL;
+  this->File = CreateFileW(
+      cmSystemTools::ConvertToWindowsExtendedPath(this->Filename).c_str(),
+      access,
+      shareMode,
+      security,
+      OPEN_EXISTING,
+      attr,
+      templ
+  );
+  if (this->File == INVALID_HANDLE_VALUE)
+    {
+    return cmFileLockResult::MakeSystem();
+    }
+  else
+    {
+    return cmFileLockResult::MakeOk();
+    }
+}
+
+cmFileLockResult cmFileLock::LockWithoutTimeout()
+{
+  if (!this->LockFile(LOCKFILE_EXCLUSIVE_LOCK))
+    {
+    return cmFileLockResult::MakeSystem();
+    }
+  else
+    {
+    return cmFileLockResult::MakeOk();
+    }
+}
+
+cmFileLockResult cmFileLock::LockWithTimeout(unsigned seconds)
+{
+  const DWORD flags = LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY;
+  while (true)
+    {
+    const BOOL result = this->LockFile(flags);
+    if (result)
+      {
+      return cmFileLockResult::MakeOk();
+      }
+    const DWORD error = GetLastError();
+    if (error != ERROR_LOCK_VIOLATION)
+      {
+      return cmFileLockResult::MakeSystem();
+      }
+    if (seconds == 0)
+      {
+      return cmFileLockResult::MakeTimeout();
+      }
+    --seconds;
+    cmSystemTools::Delay(1000);
+    }
+}
+
+BOOL cmFileLock::LockFile(DWORD flags)
+{
+  const DWORD reserved = 0;
+  const unsigned long len = static_cast<unsigned long>(-1);
+  static OVERLAPPED overlapped;
+  return LockFileEx(
+      this->File,
+      flags,
+      reserved,
+      len,
+      len,
+      &overlapped
+  );
+}