gp_widget_json.h File Reference

A JSON parser for widget layout. More...

#include <utils/gp_json.h>
#include <utils/gp_htable.h>
#include <widgets/gp_widget.h>

Go to the source code of this file.

Data Structures
struct	gp_widget_json_addr
	A structure to pass widget callbacks. More...
struct	gp_widget_json_callbacks
	Structure to pass callbacks to the JSON loader. More...
struct	gp_widget_json_ctx
	A context to propagate values top down and bottom up. More...

Typedefs
typedef struct gp_widget_json_addr	gp_widget_json_addr
	A structure to pass widget callbacks.

Functions
gp_widget *	gp_widget_from_json (gp_json_reader *json, gp_json_val *val, gp_widget_json_ctx *ctx)
	Loads a widget layout given a JSON object.
gp_widget *	gp_widget_from_json_str (const char *str, const gp_widget_json_callbacks *const callbacks, gp_htable **uids)
	Loads a widget layout given a string with JSON layout.
gp_widget *	gp_widget_layout_json (const char *fname, const gp_widget_json_callbacks *const callbacks, gp_htable **uids)
	Loads a widget layout given a path to a JSON layout description.
void *	gp_widget_callback_addr (const char *fn_name, const gp_widget_json_ctx *ctx)
	Attempts to get a pointer to a function given it's name.
void *	gp_widget_struct_addr (const char *struct_name, const gp_widget_json_ctx *ctx)
	Attempts to get a pointer to a structure given it's name.

Detailed Description

A JSON parser for widget layout.

Widget layout can be loaded from a JSON description. The application can resolve widgets by unique id and event handlers are resolved from the application binary at runtime.

Definition in file gp_widget_json.h.

Typedef Documentation

gp_widget_json_addr

typedef struct gp_widget_json_addr gp_widget_json_addr

A structure to pass widget callbacks.

The pointers to application callbacks can either be resolved by the dynamic linker at runtime, or can be explicitly passed in this table. The table has to be sorted by id and NULL id terminted.

Example use:

 static const gp_widget_json_addr app_callbacks[] = {
        {.id = "abort", .on_event = abort_on_event},
        {.id = "file_table", .table_col_ops = file_table_ops},
        {}
};

Function Documentation

gp_widget_callback_addr()

void * gp_widget_callback_addr	(	const char *	fn_name,
		const gp_widget_json_ctx *	ctx
	)

Attempts to get a pointer to a function given it's name.

This function is used to resolve callbacks from a JSON layout.

Parameters

fn_name	A fucntion name.
ctx	A widget JSON loader context, usually passed from our caller.

Returns

A function pointer.

gp_widget_from_json()

gp_widget * gp_widget_from_json	(	gp_json_reader *	json,
		gp_json_val *	val,
		gp_widget_json_ctx *	ctx
	)

Loads a widget layout given a JSON object.

Parameters

json	A json object.
val	A json value.
ctx	A widget JSON loader context, usually passed from our caller.

Returns

A widget layout or a NULL in case of a failure.

gp_widget_from_json_str()

gp_widget * gp_widget_from_json_str	(	const char *	str,
		const gp_widget_json_callbacks *const	callbacks,
		gp_htable **	uids
	)

Loads a widget layout given a string with JSON layout.

Parameters

str	A string with a JSON layout.
callbacks	An optional NULL terminated array of application callbacks.
uids	A pointer to a hash table to store widget pointers by UIDs.

Returns

A widget layout or a NULL in case of a failure.

gp_widget_layout_json()

gp_widget * gp_widget_layout_json	(	const char *	fname,
		const gp_widget_json_callbacks *const	callbacks,
		gp_htable **	uids
	)

Loads a widget layout given a path to a JSON layout description.

Parameters

fname	A path to a JSON layout file.
callbacks	An optional NULL terminated array of application callbacks.
uids	A pointer to a hash table to store widget pointers by UIDs.

Returns

A widget layout or a NULL in case of a failure.

gp_widget_struct_addr()

void * gp_widget_struct_addr	(	const char *	struct_name,
		const gp_widget_json_ctx *	ctx
	)

Attempts to get a pointer to a structure given it's name.

This function is used to resolve structures from a JSON layout.

Parameters

struct_name	A structure name.
ctx	A widget JSON loader context, usually passed from our caller.

Returns

A structure pointer.