Blinker

@@ -75,6 +75,16 @@

       e.g. <code>18x8-1/256</code> for 18 pixels width, 8 pixels height

       in 256 grayscales.

     </p>

+    <h3>Locking</h3>

+    <p>

+      It is possible to interlock different games among each other,

+      i.e., to make sure that only one of the those games can be started at the

+      same time.

+      If the file <code>lockName</code> exists, it defines the name of a

+      mutual exclusion lock that is acquired when the game is started.

+      If the lock with this name is already taken by another game, the game

+      will not start.

+    </p>

     <h3>Maximum Scrore</h3>

     <p>

       The file <code>maxScore</code> configures at which score the game ends.

@@ -0,0 +1 @@

+only_one_game

@@ -0,0 +1 @@

+only_one_game

@@ -15,6 +15,7 @@

 #include "Format.h"

 #include "FormatFile.h"

 #include "Game.h"

+#include "LockNameFile.h"

 #include "Mgrs.h"

 #include "Module.h"

 #include "NameFile.h"

@@ -35,6 +36,7 @@ Game::Game(const std::string &name, Mgrs &mgrs, const Directory &dirBase):

   m_fileBackgroundColor(dirBase.getFile("backgroundColor")),

   m_fileOutStream(dirBase.getFile("outstream"), mgrs.m_streamMgr),

   m_height(0), m_width(0), m_channels(0), m_imgBuf(), m_backgroundColor(),

+  m_fileLockName(dirBase.getFile("lockName"), mgrs.m_lockMgr),

   m_haveTimeStep(false), m_timeStepTime(), m_opConnSounds(), m_opConnsClose()

 {

 }

@@ -72,6 +74,9 @@ void Game::updateConfig()

     m_fileOutStream.update();

   }

+  // process lock name updates

+  m_fileLockName.updateIfModified();

+

   // check config update of derived game

   updateConfigGame(doReinit, doRedraw);

@@ -110,19 +115,40 @@ void Game::timeCall()

   planTimeCall();

 }

-/// activate game: set up image buffer, call redraw()

-void Game::activate()

+/**

+ * @brief check if game can be actiavted: if interlock is free

+ * @return whether game can be activated (activate() might still fail)

+ */

+bool Game::canActivate()

 {

+  return m_fileLockName.isfree();

+}

+

+/**

+ * @brief activate game:

+ *        take interlock, set up image buffer, call redraw()

+ * @return whether game could be activated

+ */

+bool Game::activate()

+{

+  if (! m_fileLockName.take()) {

+    return false;

+  }

   createImgBuf();

   reinitialize();

   redraw();

+  return true;

 }

-/// deactivate game: tear down image buffer, deactivate output

+/**

+ * @brief deactivate game:

+ *        tear down image buffer, deactivate output, release interlock

+ */

 void Game::deactivate()

 {

   destroyImgBuf();

   sendFrame();

+  m_fileLockName.release();

 }

 /// check if game is active

@@ -18,6 +18,7 @@

 #include "File.h"

 #include "Format.h"

 #include "FormatFile.h"

+#include "LockNameFile.h"

 #include "Mgrs.h"

 #include "Module.h"

 #include "NameFile.h"

@@ -93,10 +94,23 @@ protected:

   /// process next time step of game

   virtual void timeStep() = 0;

-  /// activate game: set up image buffer, call redraw()

-  void activate();

+  /**

+   * @brief check if game can be actiavted: if interlock is free

+   * @return whether game can be activated (activate() might still fail)

+   */

+  bool canActivate();

-  /// deactivate game: tear down image buffer, deactivate output

+  /**

+   * @brief activate game:

+   *        take interlock, set up image buffer, call redraw()

+   * @return whether game could be activated

+   */

+  bool activate();

+

+  /**

+   * @brief deactivate game:

+   *        tear down image buffer, deactivate output, release interlock

+   */

   void deactivate();

   /// check if game is active

@@ -235,6 +249,7 @@ protected:

   ColorData     m_backgroundColor;     ///< background color

 private:

+  LockNameFile m_fileLockName; ///< lock name file for game interlock

   bool         m_haveTimeStep; ///< if a time step is pending

   Time         m_timeStepTime; ///< time of next time step

   OpConnSounds m_opConnSounds; ///< sound to play on operator connections

@@ -118,6 +118,10 @@ void Pong::updateConfigGame(bool &doReinit, bool &doRedraw)

  */

 bool Pong::acceptNewOpConn(const std::string &name)

 {

+  // game cannot be activates -> reject connection

+  if (! canActivate()) {

+    return false;

+  }

   // left player can join if none there yet

   if (name == m_name + c_opConnSuffixLeft && ! m_pConnLeft) {

     return true;

@@ -159,9 +163,14 @@ void Pong::newOpConn(const std::string &name, OpConn *pConn)

   if (isActive()) {

     redraw(); // player color is different for phone / computer

   }

-  // first player joined

+  // first player joined -> activate

   else {

-    activate();

+    if (! activate()) {

+      // activation failed (interlock), close connection as soon as possible

+      requestOpConnClose(pConn);

+      m_pConnLeft = nullptr;

+      m_pConnRight = nullptr;

+    }

   }

 }

@@ -104,8 +104,8 @@ bool Tetris::acceptNewOpConn(const std::string &name)

 {

   (void)name;

-  // accept player if no one there yet

-  return ! m_pConn;

+  // accept player if no one there yet and game can be activated

+  return ! m_pConn && canActivate();

 }

 /**

@@ -121,14 +121,17 @@ void Tetris::newOpConn(const std::string &name, OpConn *pConn)

   // player arrives and starts game

   if (! m_pConn) {

+    if (activate()) {

       m_pConn = pConn;

       requestOpConnSound(m_pConn, m_fileStartSound);

-    activate();

+    } else {

+      // activation failed (interlock), close connection as soon as possible

+      requestOpConnClose(pConn);

     }

-  // close imcoming connection as soon as possible, nothing else happens

+  }

+  // close imcoming connection as soon as possible

   else {

     requestOpConnClose(pConn);

-    return;

   }

 }