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, 100 insertions, 0 deletions

diff --git a/Source/cmFileLockPool.h b/Source/cmFileLockPool.h
new file mode 100644
index 0000000..a63540c
--- /dev/null
+++ b/Source/cmFileLockPool.h
@@ -0,0 +1,100 @@
+/*============================================================================
+  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.
+============================================================================*/
+#ifndef cmFileLockPool_h
+#define cmFileLockPool_h
+
+#include "cmStandardIncludes.h"
+
+class cmFileLockResult;
+class cmFileLock;
+
+class cmFileLockPool
+{
+ public:
+  cmFileLockPool();
+  ~cmFileLockPool();
+
+  //@{
+  /**
+    * @brief Function scope control.
+    */
+  void PushFunctionScope();
+  void PopFunctionScope();
+  //@}
+
+  //@{
+  /**
+    * @brief File scope control.
+    */
+  void PushFileScope();
+  void PopFileScope();
+  //@}
+
+  //@{
+  /**
+    * @brief Lock the file in given scope.
+    * @param timeoutSec Lock timeout. If -1 try until success or fatal error.
+    */
+  cmFileLockResult LockFunctionScope(
+      const std::string& filename, unsigned timeoutSec
+  );
+  cmFileLockResult LockFileScope(
+      const std::string& filename, unsigned timeoutSec
+  );
+  cmFileLockResult LockProcessScope(
+      const std::string& filename, unsigned timeoutSec
+  );
+  //@}
+
+  /**
+    * @brief Unlock the file explicitly.
+    */
+  cmFileLockResult Release(const std::string& filename);
+
+ private:
+  cmFileLockPool(const cmFileLockPool&);
+  cmFileLockPool& operator=(const cmFileLockPool&);
+
+  bool IsAlreadyLocked(const std::string& filename) const;
+
+  class ScopePool
+  {
+   public:
+    ScopePool();
+    ~ScopePool();
+
+    cmFileLockResult Lock(const std::string& filename, unsigned timeoutSec);
+    cmFileLockResult Release(const std::string& filename);
+    bool IsAlreadyLocked(const std::string& filename) const;
+
+   private:
+    ScopePool(const ScopePool&);
+    ScopePool& operator=(const ScopePool&);
+
+    typedef std::list<cmFileLock*> List;
+    typedef List::iterator It;
+    typedef List::const_iterator CIt;
+
+    List Locks;
+  };
+
+  typedef std::list<ScopePool*> List;
+
+  typedef List::iterator It;
+  typedef List::const_iterator CIt;
+
+  List FunctionScopes;
+  List FileScopes;
+  ScopePool ProcessScope;
+};
+
+#endif // cmFileLockPool_h