1 /****************************************************************************
2 * Copyright (c) 2008-2016,2018 Free Software Foundation, Inc. *
4 * Permission is hereby granted, free of charge, to any person obtaining a *
5 * copy of this software and associated documentation files (the *
6 * "Software"), to deal in the Software without restriction, including *
7 * without limitation the rights to use, copy, modify, merge, publish, *
8 * distribute, distribute with modifications, sublicense, and/or sell *
9 * copies of the Software, and to permit persons to whom the Software is *
10 * furnished to do so, subject to the following conditions: *
12 * The above copyright notice and this permission notice shall be included *
13 * in all copies or substantial portions of the Software. *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
18 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
21 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
23 * Except as contained in this notice, the name(s) of the above copyright *
24 * holders shall not be used in advertising or otherwise to promote the *
25 * sale, use or other dealings in this Software without prior written *
27 ****************************************************************************/
29 /***************************************************************************
31 * Author : Juergen Pfeifer *
33 ***************************************************************************/
35 #include "form.priv.h"
37 MODULE_ID("$Id: fty_generic.c,v 1.8 2018/12/16 00:14:02 tom Exp $")
40 * This is not a full implementation of a field type, but adds some
41 * support for higher level languages with some restrictions to interop
42 * with C language. Especially the collection of arguments for the
43 * various fieldtypes is not based on the vararg C mechanism, but on a
44 * iterator based callback mechanism that allowes the high level language
45 * to provide the arguments as a structure. Most languages have mechanisms
46 * to layout structures so that they can be passed to C.
47 * The languages can register a new generic fieldtype dynamically and store
48 * a handle (key) to the calling object as an argument. Together with that
49 * it can register a freearg callback, so that the high level language
50 * remains in control of the memory management of the arguments they pass.
51 * The design idea is, that the high-level language - typically a OO
52 * language like C# or Java, uses it's own dispatching mechanisms
53 * (polymorphism) to call the proper check routines responsible for the
54 * argument type. So these language implement typically only one generic
55 * fieldtype they register with the forms library using this call.
57 * For that purpose we have extended the fieldtype struc by a new element
58 * that gets the arguments from a single struct passed by the caller.
61 #if NCURSES_INTEROP_FUNCS
63 /*---------------------------------------------------------------------------
65 | Function : static void *Generic_This_Type( void * arg )
67 | Description : We interpret the passed arg just as a handle the
68 | calling language uses to keep track of its allocated
69 | argument structures. We can simply copy it back.
71 | Return Values : Pointer to argument structure
72 +--------------------------------------------------------------------------*/
74 Generic_This_Type(void *arg)
79 /*---------------------------------------------------------------------------
81 | Function : FIELDTYPE *_nc_generic_fieldtype(
82 | bool (* const field_check)(FIELD *,const void *),
83 | bool (* const char_check) (int, const void *),
84 | bool (*const next)(FORM*,FIELD*,const void*),
85 | bool (*const prev)(FORM*,FIELD*,const void*),
86 | void (*freecallback)(void*))
88 | Description : Create a new fieldtype. The application programmer must
89 | write a field_check and a char_check function and give
90 | them as input to this call. A callback to allow the
91 | release of the allocated memory must also be provided.
92 | For generic field types, we provide some more
93 | information about the field as parameters.
95 | If an error occurs, errno is set to
96 | E_BAD_ARGUMENT - invalid arguments
97 | E_SYSTEM_ERROR - system error (no memory)
99 | Return Values : Fieldtype pointer or NULL if error occurred
100 +--------------------------------------------------------------------------*/
101 NCURSES_EXPORT(FIELDTYPE *)
102 _nc_generic_fieldtype(bool (*const field_check) (FORM *, FIELD *, const void *),
103 bool (*const char_check) (int, FORM *, FIELD *, const
105 bool (*const next) (FORM *, FIELD *, const void *),
106 bool (*const prev) (FORM *, FIELD *, const void *),
107 void (*freecallback) (void *))
109 int code = E_SYSTEM_ERROR;
110 FIELDTYPE *res = (FIELDTYPE *)0;
114 T((T_CALLED("_nc_generic_fieldtype(%s,%s,%s,%s,%s)"),
115 TR_FUNC_ARG(0, field_check),
116 TR_FUNC_ARG(1, char_check),
117 TR_FUNC_ARG(2, next),
118 TR_FUNC_ARG(3, prev),
119 TR_FUNC_ARG(4, freecallback)));
121 if (field_check || char_check)
123 res = typeMalloc(FIELDTYPE, 1);
127 *res = *_nc_Default_FieldType;
128 SetStatus(res, (_HAS_ARGS | _GENERIC));
129 res->fieldcheck.gfcheck = field_check;
130 res->charcheck.gccheck = char_check;
131 res->genericarg = Generic_This_Type;
132 res->freearg = freecallback;
133 res->enum_next.gnext = next;
134 res->enum_prev.gprev = prev;
139 code = E_BAD_ARGUMENT;
144 returnFieldType(res);
147 /*---------------------------------------------------------------------------
148 | Facility : libnform
149 | Function : static TypeArgument *GenericArgument(
150 | const FIELDTYPE* typ,
151 | int (*argiterator)(void**),
154 | Description : The iterator callback must browse through all fieldtype
155 | parameters that have an argument associated with the
156 | type. The iterator returns 1 if the operation to get
157 | the next element was successfull, 0 otherwise. If the
158 | iterator could move to the next argument, it fills
159 | the void* pointer representing the argument into the
160 | location provided as argument to the iterator.
161 | The err reference is used to keep track of errors.
163 | Return Values : Pointer to argument structure
164 +--------------------------------------------------------------------------*/
165 static TypeArgument *
166 GenericArgument(const FIELDTYPE *typ,
167 int (*argiterator) (void **), int *err)
169 TypeArgument *res = (TypeArgument *)0;
171 if (typ != 0 && (typ->status & _HAS_ARGS) != 0 && err != 0 && argiterator != 0)
173 if (typ->status & _LINKED_TYPE)
175 /* Composite fieldtypes keep track internally of their own memory */
176 TypeArgument *p = typeMalloc(TypeArgument, 1);
180 p->left = GenericArgument(typ->left, argiterator, err);
181 p->right = GenericArgument(typ->right, argiterator, err);
189 assert(typ->genericarg != (void *)0);
190 if (typ->genericarg == 0)
195 int valid = argiterator(&argp);
197 if (valid == 0 || argp == 0 ||
198 !(res = (TypeArgument *)typ->genericarg(argp)))
208 /*---------------------------------------------------------------------------
209 | Facility : libnform
210 | Function : int _nc_set_generic_fieldtype(
213 | int (*argiterator)(void**))
215 | Description : Assign the fieldtype to the field and use the iterator
216 | mechanism to get the arguments when a check is
219 | Return Values : E_OK if all went well
220 | E_SYSTEM_ERROR if an error occurred
221 +--------------------------------------------------------------------------*/
223 _nc_set_generic_fieldtype(FIELD *field,
225 int (*argiterator) (void **))
227 int code = E_SYSTEM_ERROR;
232 if (field && field->type)
233 _nc_Free_Type(field);
240 /* The precondition is that the iterator is reset */
241 field->arg = (void *)GenericArgument(field->type, argiterator, &err);
245 _nc_Free_Argument(field->type, (TypeArgument *)(field->arg));
246 field->type = (FIELDTYPE *)0;
247 field->arg = (void *)0;
259 field->arg = (void *)0;
266 /*---------------------------------------------------------------------------
267 | Facility : libnform
268 | Function : WINDOW* _nc_form_cursor(
270 | int *pRow, int *pCol)
272 | Description : Get the current position of the form cursor position
273 | We also return the field window
275 | Return Values : The fields Window or NULL on error
276 +--------------------------------------------------------------------------*/
277 NCURSES_EXPORT(WINDOW *)
278 _nc_form_cursor(const FORM *form, int *pRow, int *pCol)
280 int code = E_SYSTEM_ERROR;
281 WINDOW *res = (WINDOW *)0;
283 if (!(form == 0 || pRow == 0 || pCol == 0))
285 *pRow = form->currow;
286 *pCol = form->curcol;
296 extern void _nc_fty_generic(void);
298 _nc_fty_generic(void)
303 /* fty_generic.c ends here */