Added engine checker class. Added check point after parsing the command line and changing current directory.

git-svn-id: http://voip.null.ro/svn/yate@2559 acf43c95-373e-0410-b603-e72c3f656dc1

engine/Engine.cpp

@@ -209,6 +209,13 @@ static ObjList plugins;
 static ObjList* s_cmds = 0;
 static unsigned int s_runid = 0;
 
+static EngineCheck* s_engineCheck = 0;
+
+void EngineCheck::setChecker(EngineCheck* ptr)
+{
+    s_engineCheck = ptr;
+}
+
 class SLib : public String
 {
 public:
@@ -1734,6 +1741,9 @@ int Engine::main(int argc, const char** argv, const char** env, RunMode mode, bo
     if (workdir)
 	::chdir(workdir);
 
+    if (s_engineCheck && !s_engineCheck->check(s_cmds))
+	return s_haltcode;
+
 #ifdef _WINDOWS
     if ((mode == Server) && !service)
 	service = YSERV_RUN;

yatengine.h

@@ -711,6 +711,30 @@ bool UNLOAD_PLUGIN(bool unloadNow);
 #define UNLOAD_PLUGIN(arg) extern "C" bool _unload(bool arg)
 #endif
 
+/**
+ * Base class for engine running stage checkers.
+ * Descendants may check specific conditions and decide to stop the engine.
+ * There should be only one (static) instance of an engine checker
+ * @short Engine checker interface
+ */
+class YATE_API EngineCheck
+{
+public:
+    /**
+     * Check running conditions. This method is called by the engine in the initialize process
+     * @param cmds Optional list of strings containing extra command line parameters
+     *  (not parsed by the engine)
+     * @return False to stop the program
+     */
+    virtual bool check(const ObjList* cmds) = 0;
+
+    /**
+     * Set the current engine checker
+     * @param ptr The new engine checker. May be 0 to reset it
+     */
+    static void setChecker(EngineCheck* ptr = 0);
+};
+
 /**
  * This class holds global information about the engine.
  * Note: this is a singleton class.