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Diffstat (limited to 'src/templating/mustach.h')
| -rw-r--r-- | src/templating/mustach.h | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/templating/mustach.h b/src/templating/mustach.h new file mode 100644 index 000000000..ad952275c --- /dev/null +++ b/src/templating/mustach.h @@ -0,0 +1,241 @@ +/* + Author: José Bollo <jobol@nonadev.net> + Author: José Bollo <jose.bollo@iot.bzh> + + https://gitlab.com/jobol/mustach + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +*/ + +#ifndef _mustach_h_included_ +#define _mustach_h_included_ + +struct mustach_sbuf; /* see below */ + +/** + * Current version of mustach and its derivates + */ +#define MUSTACH_VERSION 99 +#define MUSTACH_VERSION_MAJOR (MUSTACH_VERSION / 100) +#define MUSTACH_VERSION_MINOR (MUSTACH_VERSION % 100) + +/** + * Maximum nested imbrications supported + */ +#define MUSTACH_MAX_DEPTH 256 + +/** + * Maximum length of tags in mustaches {{...}} + */ +#define MUSTACH_MAX_LENGTH 1024 + +/** + * mustach_itf - interface for callbacks + * + * All of this function should return a negative value to stop + * the mustache processing. The returned negative value will be + * then returned to the caller of mustach as is. + * + * The functions enter and next should return 0 or 1. + * + * All other functions should normally return MUSTACH_OK (zero). + * If it returns a negative value, it means an error that stop + * the process and that is reported to the caller. + * + * @start: If defined (can be NULL), starts the mustach processing + * of the closure, called at the very beginning before any + * mustach processing occurs. + * + * @put: If defined (can be NULL), writes the value of 'name' + * to 'file' with 'escape' or not. + * As an extension (see NO_ALLOW_EMPTY_TAG), the 'name' can be + * the empty string. In that later case an implementation can + * return MUSTACH_ERROR_EMPTY_TAG to refuse empty names. + * If NULL and 'get' NULL the error MUSTACH_ERROR_INVALID_ITF + * is returned. + * + * @enter: Enters the section of 'name' if possible. + * Musts return 1 if entered or 0 if not entered. + * When 1 is returned, the function 'leave' will always be called. + * Conversely 'leave' is never called when enter returns 0 or + * a negative value. + * When 1 is returned, the function must activate the first + * item of the section. + * + * @next: Activates the next item of the section if it exists. + * Musts return 1 when the next item is activated. + * Musts return 0 when there is no item to activate. + * + * @leave: Leaves the last entered section + * + * @partial: If defined (can be NULL), returns in 'sbuf' the content of the + * partial of 'name'. @see mustach_sbuf + * If NULL but 'get' not NULL, 'get' is used instead of partial. + * If NULL and 'get' NULL and 'put' not NULL, 'put' is called with + * a true FILE. + * + * @emit: If defined (can be NULL), writes the 'buffer' of 'size' with 'escape'. + * If NULL the standard function 'fwrite' is used with a true FILE. + * If not NULL that function is called instead of 'fwrite' to output + * text. + * It implies that if you define either 'partial' or 'get' callback, + * the meaning of 'FILE *file' is abstract for mustach's process and + * then you can use 'FILE*file' pass any kind of pointer (including NULL) + * to the function 'fmustach'. An example of a such behaviour is given by + * the implementation of 'umustach_json_c'. + * + * @get: If defined (can be NULL), returns in 'sbuf' the value of 'name'. + * As an extension (see NO_ALLOW_EMPTY_TAG), the 'name' can be + * the empty string. In that later case an implementation can + * return MUSTACH_ERROR_EMPTY_TAG to refuse empty names. + * If NULL and 'put' NULL the error MUSTACH_ERROR_INVALID_ITF + * is returned. + * + * @stop: If defined (can be NULL), stops the mustach processing + * of the closure, called at the very end after all mustach + * processing occurerd. The status returned by the processing + * is passed to the stop. + * + * The array below summarize status of callbacks: + * + * FULLY OPTIONAL: start partial + * MANDATORY: enter next leave + * COMBINATORIAL: put emit get + * + * Not definig a MANDATORY callback returns error MUSTACH_ERROR_INVALID_ITF. + * + * For COMBINATORIAL callbacks the array below summarize possible combinations: + * + * combination : put : emit : get : abstract FILE + * -------------+---------+---------+---------+----------------------- + * HISTORIC : defined : NULL : NULL : NO: standard FILE + * MINIMAL : NULL : NULL : defined : NO: standard FILE + * CUSTOM : NULL : defined : defined : YES: abstract FILE + * DUCK : defined : NULL : defined : NO: standard FILE + * DANGEROUS : defined : defined : any : YES or NO, depends on 'partial' + * INVALID : NULL : any : NULL : - + * + * The DUCK case runs on one leg. 'get' is not used if 'partial' is defined + * but is used for 'partial' if 'partial' is NULL. Thus for clarity, do not use + * it that way but define 'partial' and let 'get' NULL. + * + * The DANGEROUS case is special: it allows abstract FILE if 'partial' is defined + * but forbids abstract FILE when 'partial' is NULL. + * + * The INVALID case returns error MUSTACH_ERROR_INVALID_ITF. + */ +struct mustach_itf { + int (*start)(void *closure); + int (*put)(void *closure, const char *name, int escape, FILE *file); + int (*enter)(void *closure, const char *name); + int (*next)(void *closure); + int (*leave)(void *closure); + int (*partial)(void *closure, const char *name, struct mustach_sbuf *sbuf); + int (*emit)(void *closure, const char *buffer, size_t size, int escape, FILE *file); + int (*get)(void *closure, const char *name, struct mustach_sbuf *sbuf); + void (*stop)(void *closure, int status); +}; + +/** + * mustach_sbuf - Interface for handling zero terminated strings + * + * That structure is used for returning zero terminated strings -in 'value'- + * to mustach. The callee can provide a function for releasing the returned + * 'value'. Three methods for releasing the string are possible. + * + * 1. no release: set either 'freecb' or 'releasecb' with NULL (done by default) + * 2. release without closure: set 'freecb' to its expected value + * 3. release with closure: set 'releasecb' and 'closure' to their expected values + * + * @value: The value of the string. That value is not changed by mustach -const-. + * + * @freecb: The function to call for freeing the value without closure. + * For convenience, signature of that callback is compatible with 'free'. + * Can be NULL. + * + * @releasecb: The function to release with closure. + * Can be NULL. + * + * @closure: The closure to use for 'releasecb'. + */ +struct mustach_sbuf { + const char *value; + union { + void (*freecb)(void*); + void (*releasecb)(const char *value, void *closure); + }; + void *closure; +}; + +/* + * Definition of error codes returned by mustach + */ +#define MUSTACH_OK 0 +#define MUSTACH_ERROR_SYSTEM -1 +#define MUSTACH_ERROR_UNEXPECTED_END -2 +#define MUSTACH_ERROR_EMPTY_TAG -3 +#define MUSTACH_ERROR_TAG_TOO_LONG -4 +#define MUSTACH_ERROR_BAD_SEPARATORS -5 +#define MUSTACH_ERROR_TOO_DEEP -6 +#define MUSTACH_ERROR_CLOSING -7 +#define MUSTACH_ERROR_BAD_UNESCAPE_TAG -8 +#define MUSTACH_ERROR_INVALID_ITF -9 +#define MUSTACH_ERROR_ITEM_NOT_FOUND -10 +#define MUSTACH_ERROR_PARTIAL_NOT_FOUND -11 + +/* You can use definition below for user specific error */ +#define MUSTACH_ERROR_USER_BASE -100 +#define MUSTACH_ERROR_USER(x) (MUSTACH_ERROR_USER_BASE-(x)) + +/** + * fmustach - Renders the mustache 'template' in 'file' for 'itf' and 'closure'. + * + * @template: the template string to instantiate + * @itf: the interface to the functions that mustach calls + * @closure: the closure to pass to functions called + * \@file: the file where to write the result + * + * Returns 0 in case of success, -1 with errno set in case of system error + * a other negative value in case of error. + */ +extern int fmustach(const char *template, struct mustach_itf *itf, void *closure, FILE *file); + +/** + * fmustach - Renders the mustache 'template' in 'fd' for 'itf' and 'closure'. + * + * @template: the template string to instantiate + * @itf: the interface to the functions that mustach calls + * @closure: the closure to pass to functions called + * @fd: the file descriptor number where to write the result + * + * Returns 0 in case of success, -1 with errno set in case of system error + * a other negative value in case of error. + */ +extern int fdmustach(const char *template, struct mustach_itf *itf, void *closure, int fd); + +/** + * fmustach - Renders the mustache 'template' in 'result' for 'itf' and 'closure'. + * + * @template: the template string to instantiate + * @itf: the interface to the functions that mustach calls + * @closure: the closure to pass to functions called + * @result: the pointer receiving the result when 0 is returned + * @size: the size of the returned result + * + * Returns 0 in case of success, -1 with errno set in case of system error + * a other negative value in case of error. + */ +extern int mustach(const char *template, struct mustach_itf *itf, void *closure, char **result, size_t *size); + +#endif + |