WJElement Schema

WJElement provides selection and validation using json-schema.

Note:
Json-schema draft 3 is fully supported.
Draft 4 support is in-progress and partially working. (Patches are welcome!)

Callbacks:

typedef WJElement (* WJESchemaLoadCB)(const char *name, void *client, const char *file, const int line);
typedef void (* WJESchemaFreeCB)(WJElement schema, void *client);
typedef void (* WJESchemaMatchCB)(WJElement schema, const char *selector, void *client);
typedef void (* WJEErrCB)(void *client, const char *format, ...);

WJESchemaLoadCB callbacks are used to fetch schema as needed. WJESchemaFreeCB are called when schema is no longer needed.

WJESchemaValidate - Validate a document against a given schema.

XplBool WJESchemaValidate(WJElement schema, WJElement document,
                          WJEErrCB err, WJESchemaLoadCB load,
                          WJESchemaFreeCB freecb, void *client);

Additional schema will be loaded via the load callback if needed. Any validation errors will be reported, printf-style, to errcb.

If a the load callback is used to acquire schema but a NULL free callback is provided, WJECloseDocument will be used internally to release it.

WJESchemaIsType - Determine if a document implements a specific schema.

XplBool WJESchemaIsType(WJElement document, const char *type,
                        WJESchemaLoadCB loadcb, WJESchemaFreeCB freecb,
                        void *client);

Additional schema will be loaded via the load callback if needed.

If a load callback is not provided then the object type will still be checked but it will not be considered a match if it is a type that extends the specifed type.

WJESchemaNameIsType - variation of WJESchemaIsType which acts on schema name instead of a document

XplBool WJESchemaNameIsType(const char *describedby, const char *type,
                            WJESchemaLoadCB loadcb,
                            WJESchemaFreeCB freecb, void *client);

WJESchemaGetSelectors - find type/format-matching properties

void WJESchemaGetSelectors(WJElement document,
                           char *type, char *format,
                           WJESchemaLoadCB load,
                           WJESchemaFreeCB freecb,
                           WJESchemaMatchCB matchcb, void *client);

WJESchemaGetSelectors calls back matchcb for each WJElement selector which will fetch a property of a given type and format, from a given document. The load callback will be used to load all necessary schema, starting with the document's "describedby". stripat-type wildcards may be used; "Date*" will find "date" and "date-time".

WJESchemaGetAllSelectors - variation of WJESchemaGetSelectors which provides selectors that could exist in objects of the given "describedby" schema name

void WJESchemaGetAllSelectors(char *describedby,
                              char *type, char *format,
                              WJESchemaLoadCB load,
                              WJESchemaFreeCB freecb,
                              WJESchemaMatchCB matchcb, void *client);

WJESchemaFindBacklink - find "backlink" property by schema

char * WJESchemaFindBacklink(WJElement document, const char *format,
                             WJESchemaLoadCB loadcb, WJESchemaFreeCB freecb,
                             void *client);

WJESchemaNameFindBacklink - find "backlink" property by name

char * WJESchemaNameFindBacklink(char *describedby, const char *format,
                                 WJESchemaLoadCB loadcb, WJESchemaFreeCB freecb,
                                 void *client);

WJESchemaFreeBacklink - clean up a previously-found backlink

void WJESchemaFreeBacklink(char *backlink);