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4.4.1.9 Example

Here is a complete working example. It implements a shared class that has a base and an embedded interface.

These are the interface files for the `iDog' interface (the base interface of our class) and the `iName' interface (the interface embedded into our class).

File: `idog.h'

 
#include "csutil/scf.h"

// Version number of our interface.
SCF_VERSION(iDog, 0, 0, 1);

struct iDog : public iBase
{
  virtual void Walk() = 0;
  virtual void Shout(char const* Message) = 0;
};

File: `iname.h'

 
#include "csutil/scf.h"

// Version number of our interface.
SCF_VERSION(iName, 0, 0, 1);

struct iName : public iBase
{
  virtual char const* GetName() = 0;
  virtual void SetName(char const*) = 0;
};

Now here is the implementation of a class for both of the mentioned interfaces:

File: `dog.cpp'

 
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "cssysdef.h"
#include "idog.h"
#include "iname.h"

class csDog : public iDog
{
  char* Name;

  // Embedded interface.
  class csName : public iName
  {
  public:
    SCF_DECLARE_EMBEDDED_IBASE(csDog);
    virtual char const* GetName();
    virtual void SetName(char const*);
  } scfiName;
  friend class csName;

public:
  SCF_DECLARE_IBASE;
  csDog(iBase* Parent);
  virtual ~csDog();
  virtual void Walk();
  virtual void Shout(char const*);
};

//---------- Implementation ---------

SCF_IMPLEMENT_FACTORY(csDog)

SCF_IMPLEMENT_IBASE(csDog)
  SCF_IMPLEMENTS_INTERFACE(iDog)
  SCF_IMPLEMENTS_EMBEDDED_INTERFACE(iName)
SCF_IMPLEMENT_IBASE_END

SCF_IMPLEMENT_EMBEDDED_IBASE(csDog::csName)
  SCF_IMPLEMENTS_INTERFACE(iName)
SCF_IMPLEMENT_EMBEDDED_IBASE_END

csDog::csDog(iBase* Parent)
{
  SCF_CONSTRUCT_IBASE(Parent);
  SCF_CONSTRUCT_EMBEDDED_IBASE(scfiName);
  Name = strdup("<noname>");
}

csDog::~csDog()
{
  free(Name);
  SCF_DESTRUCT_EMBEDDED_IBASE(scfiName);
  SCF_DESTRUCT_IBASE();
}

void csDog::Walk()
{
  printf("%s: I'm walking\n", Name);
}

void csDog::Shout(char const* Message)
{
  printf("I'm %s: shout, shout, %s\n", Name, Message);
}

// iName interface for dog.

char const* csDog::csName::GetName()
{
  return scfParent->Name;
}

void csDog::csName::SetName(char const* NewName)
{
  if (scfParent->Name != 0)
    free(scfParent->Name);
  scfParent->Name = strdup(NewName != 0 ? NewName : "");
}

Since this is a plugin module, it requires a meta-information resource. Here is the meta-information for the example plugin:

File: `dog.csplugin'

 
<?xml version="1.0"?>
<!-- dog.csplugin -->
<plugin>
  <scf>
    <classes>
      <class>
        <name>dog</name>
        <implementation>csDog</implementation>
        <description>A rather unusual dog</description>
      </class>
    </classes>
  </scf>
</plugin>

The above files should be built to get a plugin module named `dog.so' (Unix) or `dog.dll' (Windows). The plugin module will export the csDog_Create() function which is implemented by the SCF_IMPLEMENT_FACTORY() macro, and it will publish the meta-information contained in `dog.csplugin'.

Finally, here is the source code for a simple client application that uses the `csDog' plugin.

File: `doggy.cpp'

 
#include <stdio.h>

#include "cssysdef.h"
#include "csutil/scf.h"
#include "csutil/cfgfile.h"
#include "idog.h"
#include "iname.h"

static void test_dog()
{
  csRef<iDog> dog = SCF_CREATE_INSTANCE("csDog", iDog);
  if (!dog)
    fprintf(stderr, "No csDog shared class!\n");
  else
  {
    csRef<iName> name = SCF_QUERY_INTERFACE(dog, iName);
    if (!name)
      fprintf(stderr,
        "Dog does not support iName interface!\n");
    else
    {
      name->SetName("Droopy");
      dog->Walk();
      dog->Shout("hello!");
      printf("Dog's name is %s\n", name->GetName());
    }
  }
}

int main (int argc, char const* argv[])
{
  scfInitialize(argc, argv);
  test_dog();
  iSCF::SCF->Finish();
}
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