upipe/upipe_helper_output.h header reference

Upipe helper functions for output More

• upipe/ubase.h
• upipe/ulist.h
• upipe/uref.h
• upipe/uref_flow.h
• upipe/urequest.h
• upipe/upipe.h

• enum upipe_helper_output_state

• UPIPE_HELPER_OUTPUT

It allows to deal with flow definitions, output requests, and output pipes.

This macro is declared in upipe/upipe_helper_output.h source file, line 184.

This macro declares functions dealing with the output of a pipe, and an associated uref which is the flow definition on the output.

You must add four members to your private upipe structure, for instance:

You must also declare UPIPE_HELPER_UPIPE prior to using this macro.

Supposing the name of your structure is upipe_foo, it declares:

• void upipe_foo_init_output(struct upipe *upipe)

  Typically called in your upipe_foo_alloc() function.

• void upipe_foo_output(struct upipe *upipe, struct uref *uref,
struct upump **upump_p)

  Called whenever you need to send a packet to your output. It takes care of sending the flow definition if necessary.

• int upipe_foo_register_output_request(struct upipe *upipe,
struct urequest *urequest)

  Registers a request on the output. The request will be replayed if the output changes. If there is no output, the request is sent via a probe.

• int upipe_foo_unregister_output_request(struct upipe *upipe,
struct urequest *urequest)

  Unregisters a request on the output.

• int upipe_foo_provide_output_proxy(struct urequest *urequest, va_list args)

  Internal function used to receive answers to proxy requests.

• int upipe_foo_alloc_output_proxy(struct upipe *upipe,
struct urequest *urequest)

  Allocates a proxy request to forward a request downstream.

• int upipe_foo_free_output_proxy(struct upipe *upipe,
struct urequest *urequest)

  Frees a proxy request.

• void upipe_foo_store_flow_def(struct upipe *upipe, struct uref *flow_def)

  Called whenever you change the flow definition on this output.

• int upipe_foo_get_flow_def(struct upipe *upipe, struct uref **p)

  Typically called from your upipe_foo_control() handler, such as:

  case UPIPE_GET_FLOW_DEF: {
struct uref **p = va_arg(args, struct uref **);
return upipe_foo_get_flow_def(upipe, p);
}
• int upipe_foo_get_output(struct upipe *upipe, struct upipe **p)

  Typically called from your upipe_foo_control() handler, such as:

  case UPIPE_GET_OUTPUT: {
struct upipe **p = va_arg(args, struct upipe **);
return upipe_foo_get_output(upipe, p);
}
• int upipe_foo_set_output(struct upipe *upipe, struct upipe *output)

  Typically called from your upipe_foo_control() handler, such as:

  case UPIPE_SET_OUTPUT: {
struct upipe *output = va_arg(args, struct upipe *);
return upipe_foo_set_output(upipe, output);
}
• int upipe_foo_control_output(struct upipe *upipe,
int command, va_list args)

  This function handles the output helper control commands (upipe_foo_get_flow_def, upipe_foo_get_output, upipe_foo_set_output, ...). Typically called from your upipe_foo_control() handler, such as:

  int upipe_foo_control(struct upipe *upipe, int command, va_list args)
{
...
UBASE_HANDLED_RETURN(upipe_foo_control_output(upipe, command, args));
...
}
• void upipe_foo_clean_output(struct upipe *upipe)

  Typically called from your upipe_foo_free() function.

Parameter list:

• STRUCTURE: name of your private upipe structure
• OUTPUT: name of the struct upipe * field of your private upipe structure
• FLOW_DEF: name of the struct uref * field of your private upipe structure
• OUTPUT_STATE: name of the enum upipe_helper_output_state field of your private upipe structure
• REQUEST_LIST: name of the struct uchain field of your private upipe structure

This macro is declared in upipe/upipe_helper_output.h source file, line 32.

This enum is declared in upipe/upipe_helper_output.h source file, line 49.

This enum represents the state of the output.