1 files changed, 80 insertions, 0 deletions
diff --git a/Source/cmDefinitions.h b/Source/cmDefinitions.h
new file mode 100644
index 0000000..528b157
--- /dev/null
+++ b/Source/cmDefinitions.h
@@ -0,0 +1,80 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#ifndef cmDefinitions_h
+#define cmDefinitions_h
+
+#include "cmConfigure.h" // IWYU pragma: keep
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "cmLinkedTree.h"
+
+/** \class cmDefinitions
+ * \brief Store a scope of variable definitions for CMake language.
+ *
+ * This stores the state of variable definitions (set or unset) for
+ * one scope.  Sets are always local.  Gets search parent scopes
+ * transitively and save results locally.
+ */
+class cmDefinitions
+{
+  typedef cmLinkedTree<cmDefinitions>::iterator StackIter;
+
+public:
+  static const char* Get(const std::string& key, StackIter begin,
+                         StackIter end);
+
+  static void Raise(const std::string& key, StackIter begin, StackIter end);
+
+  static bool HasKey(const std::string& key, StackIter begin, StackIter end);
+
+  /** Set (or unset if null) a value associated with a key.  */
+  void Set(const std::string& key, const char* value);
+
+  std::vector<std::string> UnusedKeys() const;
+
+  static std::vector<std::string> ClosureKeys(StackIter begin, StackIter end);
+
+  static cmDefinitions MakeClosure(StackIter begin, StackIter end);
+
+private:
+  // String with existence boolean.
+  struct Def : public std::string
+  {
+  private:
+    typedef std::string std_string;
+
+  public:
+    Def()
+      : std_string()
+      , Exists(false)
+      , Used(false)
+    {
+    }
+    Def(const char* v)
+      : std_string(v ? v : "")
+      , Exists(v ? true : false)
+      , Used(false)
+    {
+    }
+    Def(const std_string& v)
+      : std_string(v)
+      , Exists(true)
+      , Used(false)
+    {
+    }
+    bool Exists;
+    bool Used;
+  };
+  static Def NoDef;
+
+  typedef std::unordered_map<std::string, Def> MapType;
+  MapType Map;
+
+  static Def const& GetInternal(const std::string& key, StackIter begin,
+                                StackIter end, bool raise);
+};
+
+#endif