[GStreamer] 插件编写 —— source element

Reference : 

源码(finish me)：

obtsrc.h

#pragma once

#include <gst/gst.h>
#include <gst/gstbasesrc.h>

#define VERSION 1.0
#define PACKAGE "obtplugin"

G_BEGIN_DECLS

typedef struct _GstObtSrc GstObtSrc;
typedef struct _GstObtSrcClass GstObtSrcClass;
typedef struct _GstObtSrcPrivate GstObtSrcPrivate;  //every element instance has it's own private data


/***************************************

      instance stuct
      
***************************************/
struct _GstObtSrc
{
  //parent (every element has a parent instance struct instance in it's instance struct)
  GstBaseSrc element;

  //pubic member vars
  gboolean b_working;  //work state

  //private member vars
  GstObtSrcPrivate s_priv;
};



/***************************************

      class struct
      
***************************************/
struct _GstObtSrcClass
{
  //parent class (class struct has a parent class struct instance int it's class struct)
  GstBaseSrcClass parent_class;

  //class meta vars
  gchar* s_desc;

};



/***************************************

      declare GType
      
***************************************/
GType gst_obt_src_get_type(void);



/***************************************

      boilerplate MACROs

  note:every GType has two structs, instance struct and class struct , following macros' input arg are 
     related struct pointer seperatly, eg. arg of GST_OBT_SRC should be a instance struct pointer,
     meanwhile, arg of GST_OBT_SRC_CLASS should be a class struct pointer. If pointer type is mismatch,
     MACROS return null represent error arg.
     
***************************************/
#define GST_TYPE_OBT_SRC (gst_obt_src_get_type())

//if ptr_obj point to a instance of GST_TYPE_OBT_SRC, cast ptr_obj to GstObtSrc* and return , otherwise return null
#define GST_OBT_SRC(ptr_obj) \
  (G_TYPE_CHECK_INSTANCE_CAST((ptr_obj),GST_TYPE_OBT_SRC,GstObtSrc))    

//if ptr_class point to a instance of GST_TYPE_OBT_SRC, cast ptr_obj to GstObtSrcClass* and return , otherwise return null , ptr_class is a class struct pointer
#define GST_OBT_SRC_CLASS(ptr_class) \
  (G_TYPE_CHECK_CLASS_CAST((ptr_class),GST_TYPE_OBT_SRC,GstObtSrcClass))

//if ptr_obj point to a instance of GST_TYPE_OBT_SRC, return true , otherwise return false , ptr_obj is a instance struct pointer
#define GST_IS_OBT_SRC(ptr_obj) \
  (G_TYPE_CHECK_INSTANCE_TYPE((ptr_obj),GST_TYPE_OBT_SRC))

//if ptr_class point to a instance of GST_TYPE_OBT_SRC, return ture , otherwise return false, ptr_class is a class struct pointer
#define GST_IS_OBT_SRC_CLASS(ptr_obj) \
  (G_TYPE_CHECK_CLASS_TYPE((ptr_obj),GST_TYPE_OBT_SRC))





G_END_DECLS

obtsrc.c

#include "ObtSrc.h"
#include <gst/gst.h>

static gboolean gst_obt_src_event_process(GstPad* recvpad/*pad received event*/, GstObject* parentofpad/*element that own #recvpad */, GstEvent* event);


#define gst_obt_src_parent_class parent_class

struct _GstObtSrcPrivate
{
  gboolean b_reserv;
};


/***************************************** boilerplate Funcs [START] *****************************************/

static gboolean gst_obt_src_event(GstPad* recvpad/*pad received event*/, GstObject* parentofpad/*element that own #recvpad */, GstEvent* event)
{
  gboolean ret = TRUE;
  ret = gst_obt_src_event_process();
  if(ret){
    ret = gst_pad_event_default(pad,parent,event);
  }else{
    return ret;
  }
}

static GstStateChangeReturn gst_obt_src_state_changed(GstElement* element, GstStateChange transition)
{
  GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;

  ret = GST_ELEMENT_CLASS(parent_class)->change_state(element,transition);
  if (ret == GST_STATE_CHANGE_FAILURE)
    return ret;
}

static void gst_obt_src_init(GstObtSrc* ptr_obj)
{

}

static void gst_obt_src_class_init(GstObtSrcClass* ptr_class)
{

}

/***************************************** boilerplate Funcs [END] *****************************************/

static gboolean gst_obt_src_event_process(GstPad* recvpad/*pad received event*/, GstObject* parentofpad/*element that own #recvpad */, GstEvent* event)
{
  GstObtSrc* src = GST_OBT_SRC(parentofpad);

  switch (GST_EVENT_TYPE(event)) {
  case GST_EVENT_CAPS:
    //do something
    break;
  case GST_EVENT_EOS:
    //do something
    break;
  //case ....
  //....
  default:
    //do something
    break;
  }
  
  return true;
}

/***************************************** Local Funcs [START] *****************************************/

gchar* 

/***************************************** Local Funcs [END] *****************************************/