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 // Copyright (c) 2007, Google Inc.

 // All rights reserved.

 //

 // Redistribution and use in source and binary forms, with or without

 // modification, are permitted provided that the following conditions are

 // met:

 //

 //     * Redistributions of source code must retain the above copyright

 // notice, this list of conditions and the following disclaimer.

 //     * Redistributions in binary form must reproduce the above

 // copyright notice, this list of conditions and the following disclaimer

 // in the documentation and/or other materials provided with the

 // distribution.

 //     * Neither the name of Google Inc. nor the names of its

 // contributors may be used to endorse or promote products derived from

 // this software without specific prior written permission.

 //

 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 #include <mach/mach.h>

 #include <servers/bootstrap.h>

 #include <stdio.h>

 #include <stdlib.h>

 #include <sys/stat.h>

 #include <unistd.h>

 //==============================================================================

 // class OnDemandServer :

 //    A basic on-demand server launcher supporting a single named service port

 //

 // Example Usage :

 //

 //  kern_return_t result;

 //  OnDemandServer *server = OnDemandServer::Create("/tmp/myserver",

 //                                                  "com.MyCompany.MyServiceName",

 //                                                  true,

 //                                                  &result);

 //

 //  if (server) {

 //    server->LaunchOnDemand();

 //    mach_port_t service_port = GetServicePort();

 //

 //    // Send a mach message to service_port and "myserver" will be launched

 //  }

 //

 //

 //                  ---- Now in the server code ----

 //

 //  // "myserver" should get the service port and read the message which

 //  // launched it:

 //  mach_port_t service_rcv_port_;

 //  kern_return_t kr = bootstrap_check_in(bootstrap_port,

 //                                      "com.MyCompany.MyServiceName",

 //                                      &service_rcv_port_);

 //  // mach_msg() read service_rcv_port_ ....

 //

 //  ....

 //

 //  // Later "myserver" may want to unregister the service if it doesn't

 //  // want its bootstrap service to stick around after it exits.

 //

 //  // DO NOT use mach_port_deallocate() here -- it will fail and the

 //  // following bootstrap_register() will also fail leaving our service

 //  // name hanging around forever (until reboot)

 //  kern_return_t kr = mach_port_destroy(mach_task_self(), service_rcv_port_);

 //

 //  kr = bootstrap_register(bootstrap_port,

 //                          "com.MyCompany.MyServiceName",

 //                          MACH_PORT_NULL);

 class OnDemandServer {

  public:

   // must call Initialize() to be useful

   OnDemandServer()

     : server_port_(MACH_PORT_NULL),

       service_port_(MACH_PORT_NULL),

       unregister_on_cleanup_(true) {

   }

   // Creates the bootstrap server and service

   kern_return_t Initialize(const char *server_command,

                            const char *service_name,

                            bool unregister_on_cleanup);

   // Returns an OnDemandServer object if successful, or NULL if there's

   // an error.  The error result will be returned in out_result.

   //

   //    server_command : the full path name including optional command-line

   //      arguments to the executable representing the server

   //

   //    service_name : represents service name

   //      something like "com.company.ServiceName"

   //

   //    unregister_on_cleanup : if true, unregisters the service name

   //      when the OnDemandServer is deleted -- unregistering will

   //      ONLY be possible if LaunchOnDemand() has NOT been called.

   //      If false, then the service will continue to be registered

   //      even after the current process quits.

   //

   //    out_result : if non-NULL, returns the result

   //      this value will be KERN_SUCCESS if Create() returns non-NULL

   //

   static OnDemandServer *Create(const char *server_command,

                                 const char *service_name,

                                 bool unregister_on_cleanup,

                                 kern_return_t *out_result);

   // Cleans up and if LaunchOnDemand() has not yet been called then

   // the bootstrap service will be unregistered.

   ~OnDemandServer();

   // This must be called if we intend to commit to launching the server

   // by sending a mach message to our service port.  Do not call it otherwise

   // or it will be difficult (impossible?) to unregister the service name.

   void LaunchOnDemand();

   // This is the port we need to send a mach message to after calling

   // LaunchOnDemand().  Sending a message causing an immediate launch

   // of the server

   mach_port_t GetServicePort() { return service_port_; };

  private:

   // Disallow copy constructor

   OnDemandServer(const OnDemandServer&);

   // Cleans up and if LaunchOnDemand() has not yet been called then

   // the bootstrap service will be unregistered.

   void Unregister();

   name_t      service_name_;

   mach_port_t server_port_;

   mach_port_t service_port_;

   bool        unregister_on_cleanup_;

 };