Graph Utility

Classes
struct	MMAL_GRAPH_T

Typedefs
typedef struct MMAL_GRAPH_T	MMAL_GRAPH_T
typedef void(*	MMAL_GRAPH_EVENT_CB) (MMAL_GRAPH_T *graph, MMAL_PORT_T *port, MMAL_BUFFER_HEADER_T *buffer, void *cb_data)

Enumerations
enum	MMAL_GRAPH_TOPOLOGY_T { MMAL_GRAPH_TOPOLOGY_ALL = 0, MMAL_GRAPH_TOPOLOGY_STRAIGHT, MMAL_GRAPH_TOPOLOGY_CUSTOM, MMAL_GRAPH_TOPOLOGY_MAX }

Functions
MMAL_STATUS_T	mmal_graph_create (MMAL_GRAPH_T **graph, unsigned int userdata_size)
MMAL_STATUS_T	mmal_graph_add_component (MMAL_GRAPH_T *graph, MMAL_COMPONENT_T *component)
MMAL_STATUS_T	mmal_graph_component_topology (MMAL_GRAPH_T *graph, MMAL_COMPONENT_T *component, MMAL_GRAPH_TOPOLOGY_T topology, int8_t *input, unsigned int input_num, int8_t *output, unsigned int output_num)
MMAL_STATUS_T	mmal_graph_add_port (MMAL_GRAPH_T *graph, MMAL_PORT_T *port)
MMAL_STATUS_T	mmal_graph_add_connection (MMAL_GRAPH_T *graph, MMAL_CONNECTION_T *connection)
MMAL_STATUS_T	mmal_graph_new_component (MMAL_GRAPH_T *graph, const char *name, MMAL_COMPONENT_T **component)
MMAL_STATUS_T	mmal_graph_new_connection (MMAL_GRAPH_T *graph, MMAL_PORT_T *out, MMAL_PORT_T *in, uint32_t flags, MMAL_CONNECTION_T **connection)
MMAL_STATUS_T	mmal_graph_enable (MMAL_GRAPH_T *graph, MMAL_GRAPH_EVENT_CB cb, void *cb_data)
MMAL_STATUS_T	mmal_graph_disable (MMAL_GRAPH_T *graph)
MMAL_PORT_T *	mmal_graph_find_port (MMAL_GRAPH_T *graph, const char *name, MMAL_PORT_TYPE_T type, unsigned index)
MMAL_STATUS_T	mmal_graph_build (MMAL_GRAPH_T *ctx, const char *name, MMAL_COMPONENT_T **component)
MMAL_STATUS_T	mmal_graph_component_constructor (const char *name, MMAL_COMPONENT_T *component)
MMAL_STATUS_T	mmal_graph_destroy (MMAL_GRAPH_T *ctx)

Detailed Description

The graph utility functions allows one to easily create graphs of MMAL components.

Typedef Documentation

MMAL_GRAPH_EVENT_CB

typedef void(* MMAL_GRAPH_EVENT_CB) (MMAL_GRAPH_T *graph, MMAL_PORT_T *port, MMAL_BUFFER_HEADER_T *buffer, void *cb_data)

Definition of the callback used by a graph to send events to the client.

Parameters

graph	the graph sending the event
port	the port which generated the event
buffer	the buffer header containing the event data
cb_data	data passed back to the client when the callback is invoked

Definition at line 181 of file mmal_graph.h.

MMAL_GRAPH_T

typedef struct MMAL_GRAPH_T MMAL_GRAPH_T

Structure describing a graph

Enumeration Type Documentation

MMAL_GRAPH_TOPOLOGY_T

enum MMAL_GRAPH_TOPOLOGY_T

List of topology types

Enumerator
MMAL_GRAPH_TOPOLOGY_ALL	All input ports and output ports are linked
MMAL_GRAPH_TOPOLOGY_STRAIGHT	Input ports and output ports of the same index are linked
MMAL_GRAPH_TOPOLOGY_CUSTOM	Custom defined topology
MMAL_GRAPH_TOPOLOGY_MAX

Definition at line 45 of file mmal_graph.h.

Function Documentation

mmal_graph_add_component()

MMAL_STATUS_T mmal_graph_add_component	(	MMAL_GRAPH_T *	graph,
		MMAL_COMPONENT_T *	component
	)

Add a component to a graph. Allows the client to add a component to the graph.

Parameters

graph	instance of the graph
component	component to add to a graph

Returns

MMAL_SUCCESS on success

mmal_graph_add_connection()

MMAL_STATUS_T mmal_graph_add_connection	(	MMAL_GRAPH_T *	graph,
		MMAL_CONNECTION_T *	connection
	)

Add a connection to a graph. Allows the client to add an internal connection to a graph.

Parameters

graph	instance of the graph
connection	connection to add to the graph

Returns

MMAL_SUCCESS on success

mmal_graph_add_port()

MMAL_STATUS_T mmal_graph_add_port	(	MMAL_GRAPH_T *	graph,
		MMAL_PORT_T *	port
	)

Add a port to a graph. Allows the client to add an input or output port to a graph. The given port will effectively become an end point for the graph.

Parameters

graph	instance of the graph
port	port to add to the graph

Returns

MMAL_SUCCESS on success

mmal_graph_build()

MMAL_STATUS_T mmal_graph_build	(	MMAL_GRAPH_T *	ctx,
		const char *	name,
		MMAL_COMPONENT_T **	component
	)

Create an instance of a component from a graph. The newly created component will expose input and output ports to the client. Not that all the exposed ports will be in a disabled state by default.

Parameters

graph	graph to create the component from
name	name of the component to create
component	returned component

Returns

MMAL_SUCCESS on success

mmal_graph_component_constructor()

MMAL_STATUS_T mmal_graph_component_constructor	(	const char *	name,
		MMAL_COMPONENT_T *	component
	)

Component constructor for a graph. FIXME: private function

Parameters

name	name of the component to create
component	component

Returns

MMAL_SUCCESS on success

mmal_graph_component_topology()

MMAL_STATUS_T mmal_graph_component_topology	(	MMAL_GRAPH_T *	graph,
		MMAL_COMPONENT_T *	component,
		MMAL_GRAPH_TOPOLOGY_T	topology,
		int8_t *	input,
		unsigned int	input_num,
		int8_t *	output,
		unsigned int	output_num
	)

Describe the topology of the ports of a component. Allows the client to describe the topology of a component. This information is used by the graph to choose which action to perform when enabling / disabling / committing / flushing a port exposed by the graph. Note that by default the topology of a component is set to MMAL_GRAPH_TOPOLOGY_ALL.

Parameters

graph	instance of the graph
component	component to describe
topology	type of topology used by this component
input	output index (or -1 if sink) linked to each input port
input_num	number of indexes in the input list
output	input index (or -1 if source) linked to each output port
output_num	number of indexes in the output list

Returns

MMAL_SUCCESS on success

mmal_graph_create()

MMAL_STATUS_T mmal_graph_create	(	MMAL_GRAPH_T **	graph,
		unsigned int	userdata_size
	)

Create an instance of a graph. The newly created graph will need to be populated by the client.

Parameters

graph	returned graph
userdata_size	size to be allocated for the userdata field

Returns

MMAL_SUCCESS on success

mmal_graph_destroy()

MMAL_STATUS_T mmal_graph_destroy

(

MMAL_GRAPH_T *

ctx

)

Destroy a previously created graph

Parameters

graph

graph to destroy

Returns

MMAL_SUCCESS on success

mmal_graph_disable()

MMAL_STATUS_T mmal_graph_disable

(

MMAL_GRAPH_T *

graph

)

mmal_graph_enable()

MMAL_STATUS_T mmal_graph_enable	(	MMAL_GRAPH_T *	graph,
		MMAL_GRAPH_EVENT_CB	cb,
		void *	cb_data
	)

Enable the graph and start processing.

Parameters

graph	the graph to enable
cb	the callback to invoke when an event occurs on any of the internal control ports
cb_data	data passed back to the client when the callback is invoked

Returns

MMAL_SUCCESS on success

mmal_graph_find_port()

MMAL_PORT_T* mmal_graph_find_port	(	MMAL_GRAPH_T *	graph,
		const char *	name,
		MMAL_PORT_TYPE_T	type,
		unsigned	index
	)

Find a port in the graph.

Parameters

graph	graph instance
name	name of the component of interest
type	type of port (in/out)
index	which port index within the component

Returns

port, or NULL if not found

mmal_graph_new_component()

MMAL_STATUS_T mmal_graph_new_component	(	MMAL_GRAPH_T *	graph,
		const char *	name,
		MMAL_COMPONENT_T **	component
	)

Create a new component and add it to a graph. Allows the client to create and add a component to the graph.

Parameters

graph	instance of the graph
name	name of the component to create
component	if not NULL, will contain a pointer to the created component

Returns

MMAL_SUCCESS on success

mmal_graph_new_connection()

MMAL_STATUS_T mmal_graph_new_connection	(	MMAL_GRAPH_T *	graph,
		MMAL_PORT_T *	out,
		MMAL_PORT_T *	in,
		uint32_t	flags,
		MMAL_CONNECTION_T **	connection
	)

Create and add a connection to a graph. Allows the client to create and add an internal connection to a graph.

Parameters

graph	instance of the graph
out	the output port to use for the connection
in	the input port to use for the connection
flags	the flags specifying which type of connection should be created
connection	if not NULL, will contain a pointer to the created connection

Returns

MMAL_SUCCESS on success