1:
2: /*
3: * Copyright (c) 2001-2002 Packet Design, LLC.
4: * All rights reserved.
5: *
6: * Subject to the following obligations and disclaimer of warranty,
7: * use and redistribution of this software, in source or object code
8: * forms, with or without modifications are expressly permitted by
9: * Packet Design; provided, however, that:
10: *
11: * (i) Any and all reproductions of the source or object code
12: * must include the copyright notice above and the following
13: * disclaimer of warranties; and
14: * (ii) No rights are granted, in any manner or form, to use
15: * Packet Design trademarks, including the mark "PACKET DESIGN"
16: * on advertising, endorsements, or otherwise except as such
17: * appears in the above copyright notice or in the software.
18: *
19: * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
20: * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
21: * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
22: * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
23: * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
24: * OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
25: * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
26: * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
27: * RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
28: * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
29: * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
30: * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
31: * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
32: * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
33: * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
35: * THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
36: * THE POSSIBILITY OF SUCH DAMAGE.
37: *
38: * Author: Archie Cobbs <archie@freebsd.org>
39: */
40:
41: #ifndef _PDEL_TMPL_TMPL_H_
42: #define _PDEL_TMPL_TMPL_H_
43:
44: /*
45: * This code supports a simple text template language. An input file
46: * is scanned for special function tags. A function tag is an at sign
47: * ('@') followed by a contiguous sequence of letters, digits, and
48: * underscores, followed by parentheses containing zero or more
49: * function arguments.
50: *
51: * Function arguments may be either other function tags (the argument
52: * to the outer function is the result of the inner function invocation),
53: * or constant literal strings in double quotes (the argument is the
54: * value of the string). Note this means that all function arguments
55: * begin with either an at sign or a double quote character. Function
56: * arguments are enclosed in parentheses, separated by commas, and
57: * may have whitespace around them.
58: *
59: * When processed, function tags result in a function invocation
60: * which returns some text which is then substituted into the output
61: * stream. Special control flow function tags control input processing
62: * and return the empty string.
63: *
64: * Non-function tag text input is passed through unaltered.
65: *
66: * Constant literal strings (enclosed in double quotes) respect the
67: * normal C backslash escapes.
68: *
69: * Built-in functions that take no arguments do not require parentheses,
70: * but parentheses may be included for separation purposes.
71: *
72: * User-supplied functions may return NULL and set errno to indicate
73: * an error, in which case the corresponding error string is substituted,
74: * after being formatted by the caller-supplied error formatter.
75: *
76: * The predefined functions are:
77: *
78: * @while(x) ... @endwhile
79: * The text in between is repeated as long as x is true
80: * (x is true if it is an integer whose value is non-zero).
81: *
82: * @loop(numloops) ... @endloop
83: * The text in between is repeated 'numloops' times, which
84: * must be an integer value.
85: *
86: * @loopindex(i)
87: * Returns the loop index (counting from zero) of the loop
88: * that is 'i' loops out from the innermost loop, else -1.
89: * If argument is omitted it is assumed to be zero.
90: *
91: * @if(x) ... [ @elif ... [ @elif ... ] ] [ @else ... ] @endif
92: * Conditional execution depending on the truth value of x.
93: *
94: * @define(name) ... @enddef
95: * Defines a run-time function. The text in between is executed
96: * whenever @name(...) is subsequently invoked. During this execution,
97: * the variables "argc" and "arg0", "arg1", ... are set to the
98: * function argument count and arguments, respectively (the function
99: * name itself is always the value of "arg0".
100: *
101: * @break
102: * Break out of the nearest enclosing @loop or @while loop.
103: *
104: * @continue
105: * Continue with the next iteration of the nearest enclosing
106: * @loop or @while loop.
107: *
108: * @return
109: * Return from within a run-time function.
110: *
111: * @equal(x,y)
112: * Returns "1" if x and y are identical, else "0".
113: *
114: * @not(x)
115: * Returns "1" unless x is an integer whose value is non-zero.
116: *
117: * @and(arg1, arg2, ...)
118: * Returns logical "and" of the truth values of the arguments.
119: *
120: * @or(arg1, arg2, ...)
121: * Returns logical "or" of the truth values of the arguments.
122: *
123: * @add(arg1, ...)
124: * Returns sum of the numerical values of the arguments.
125: *
126: * @mul(arg1, ...)
127: * Returns product of the numerical values of the arguments.
128: *
129: * @div(arg1, arg2)
130: * Returns the first argument divided by the second.
131: *
132: * @mod(arg1, arg2)
133: * Returns the first argument modulo by the second.
134: *
135: * @lt(arg1, arg2)
136: * @gt(arg1, arg2)
137: * @le(arg1, arg2)
138: * @ge(arg1, arg2)
139: * Returns "0" or "1" as arg1 is <, >, <=, or >= arg2.
140: *
141: * @sub(arg1, ...)
142: * Returns subtraction of the numerical values of the second
143: * and subsequent arguments from the first.
144: *
145: * @error(arg)
146: * Output the argument using the caller's error formatting.
147: *
148: * @eval(arg)
149: * The argument itself is processed. Embedded function tags
150: * are processed normally, while the rest is passed unaltered.
151: *
152: * @funcname(arg1, arg2, ...)
153: * Invoke the generic user-supplied function handler.
154: *
155: * @@
156: * Expands to ``@''
157: *
158: * @cat(arg1, arg2, ...)
159: * Returns concatentated arguments.
160: *
161: * @set(var, value)
162: * Sets run-time variable 'var' to have value 'value'. Variables
163: * are global and live until tmpl_process() returns. Returns the
164: * empty string.
165: *
166: * @get(var)
167: * Retrieves the value of run-time variable 'var'.
168: * Returns the empty string if 'var' is not set.
169: *
170: * @urlencode(arg)
171: * Expands and URL-encodes the argument.
172: *
173: * @htmlencode(arg)
174: * Expands and HTML-encodes the first argument.
175: *
176: * @output(arg)
177: * Outputs the argument directly to the output stream. That is,
178: * if this function is invoked from within a user-defined function,
179: * the argument goes directly to the template output rather than
180: * being concatenated to the return value of the function.
181: *
182: * @flush()
183: * Flushes the template output.
184: *
185: * @foobar(...)
186: * If "foobar" is not defined as a run-time function, then this
187: * invokes the supplied handler for user-defined functions.
188: * Here "foobar" is any name other than the above function names,
189: * consisting of only letters, digits, and underscores.
190: *
191: */
192:
193: struct tmpl;
194: struct tmpl_ctx;
195:
196: #define TMPL_FUNCTION_CHARACTER '@'
197:
198: /***********************************************************************
199: CALLBACK FUNCTION TYPES
200: ***********************************************************************/
201:
202: /*
203: * Generic function handler type. Should return a malloc'd string (allocated
204: * with the same memory type as passed to tmpl_ctx_create()), or else return
205: * NULL and either set errno or set *errmsgp to point to a malloc'd string
206: * (same memory type) containing an error message. *errmsgp will be NULL
207: * initially.
208: *
209: * The first argument is the function name. Subsequent arguments are the
210: * (evaluated) arguments passed to the function. Note that this means "argc"
211: * is always >= 1. argv[argc] is NOT guaranteed to be NULL.
212: */
213: typedef char *tmpl_handler_t(struct tmpl_ctx *ctx, char **errmsgp,
214: int argc, char **argv);
215:
216: /*
217: * Error formatter type. This should format the error message string
218: * using whatever formatting is desired and return the result in a
219: * malloc'd buffer (note: just returning 'errmsg' is wrong; use
220: * strdup(3) instead). Return NULL and set errno if there is an error.
221: * The "arg" parameter is the same "arg" passed to tmpl_ctx_create().
222: */
223: typedef char *tmpl_errfmtr_t(struct tmpl_ctx *ctx, const char *errmsg);
224:
225: /***********************************************************************
226: PUBLIC FUNCTIONS
227: ***********************************************************************/
228:
229: __BEGIN_DECLS
230:
231: /*
232: * Create template object by parsing "input". The input stream must
233: * be seekable, and is not used again after this function returns.
234: *
235: * If num_errors != NULL, it will be set to the number of parse
236: * errors encountered while parsing the input.
237: *
238: * Returns NULL and sets errno on failure.
239: */
240: extern struct tmpl *tmpl_create(FILE *input,
241: int *num_errors, const char *mtype);
242:
243: /*
244: * Similar to tmpl_create(), but memory map the file so that its
245: * contents don't have to be stored in heap memory. However, the
246: * file contents must not change or else subsequent executions will
247: * give garbled output.
248: */
249: extern struct tmpl *tmpl_create_mmap(const char *path,
250: int *num_errors, const char *mtype);
251:
252: /*
253: * Destroy and free a template file created by tmpl_create().
254: *
255: * Upon return, *tmplp is set to NULL. If *tmplp is already NULL,
256: * this does nothing.
257: */
258: extern void tmpl_destroy(struct tmpl **tmplp);
259:
260: /*
261: * Create a template execution context.
262: *
263: * For all functions that are not predefined, the function is looked up
264: * in the 'userfuncs' array (which is not copied and so must remain
265: * valid for the life of the exectution context). This array must be
266: * sorted by name and terminated with an entry having a NULL name.
267: * All userfuncs will have 'arg' passed as their first argument.
268: *
269: * All strings returned by "handler" MUST be dynamically allocated
270: * using memory type 'mtype'.
271: *
272: * The 'errfmtr' is called to specially format any generated error
273: * messages; if it is NULL, error messages are output as plain text.
274: */
275: extern struct tmpl_ctx *tmpl_ctx_create(void *arg, const char *mtype,
276: tmpl_handler_t *handler, tmpl_errfmtr_t *errfmtr);
277:
278: /*
279: * Get context argument.
280: */
281: extern void *tmpl_ctx_get_arg(struct tmpl_ctx *ctx);
282:
283: /*
284: * Get context memory type.
285: */
286: extern const char *tmpl_ctx_get_mtype(struct tmpl_ctx *ctx);
287:
288: /*
289: * Execute a template and output the result to 'output'.
290: *
291: * If a system error is encountered, execution halts and -1
292: * is returned with 'errno' set. Otherwise, zero is returned.
293: *
294: * Flags:
295: *
296: * TMPL_SKIP_NL_WHITE Skip inter-function text consisting only of
297: * one or more newlines followed by whitespace.
298: */
299: extern int tmpl_execute(struct tmpl *tmpl, struct tmpl_ctx *ctx,
300: FILE *output, int flags);
301:
302: #define TMPL_SKIP_NL_WHITE 0x0001
303:
304: /*
305: * Destroy and free a template context created by tmpl_ctx_create().
306: *
307: * Upon return, *ctxp is set to NULL. If *ctxp is already NULL,
308: * this does nothing.
309: */
310: extern void tmpl_ctx_destroy(struct tmpl_ctx **ctxp);
311:
312: /*
313: * Functions to get and set variables associated with a context.
314: */
315: extern const char *tmpl_ctx_get_var(struct tmpl_ctx *ctx, const char *name);
316: extern int tmpl_ctx_set_var(struct tmpl_ctx *ctx,
317: const char *name, const char *value);
318:
319: /*
320: * Invoke a template function and write the output to "output".
321: *
322: * Returns zero if successful, otherwise returns -1 and either
323: * sets *errmsgp to NULL and errno to the error code, or else
324: * sets *errmsgp to some appropriate error message.
325: */
326: extern int tmpl_execute_func(struct tmpl_ctx *ctx, FILE *output,
327: char **errmsgp, int argc, char **argv,
328: int flags);
329:
330: /*
331: * Reset a template context.
332: *
333: * This undoes the result of any variable assignments and run-time
334: * function definitions from a previous execution using the context.
335: * That is, the context is returned to original state as returned by
336: * tmpl_ctx_create().
337: */
338: extern void tmpl_ctx_reset(struct tmpl_ctx *ctx);
339:
340: /*
341: * Built-in handler for handling a fixed list of user functions.
342: *
343: * The 'userfuncs' array must be sorted lexicographically by name.
344: */
345:
346: /* Structure describing a user-supplied function */
347: struct tmpl_func {
348: const char *name; /* function name, null to end list */
349: u_int min_args; /* min # args (not counting name) */
350: u_int max_args; /* max # args (not counting name) */
351: tmpl_handler_t *handler; /* handler for function */
352: };
353:
354: extern char *tmpl_list_handler(struct tmpl_ctx *ctx,
355: const struct tmpl_func *userfuncs, u_int uflen,
356: char **errmsgp, int argc, char **argv);
357:
358: __END_DECLS
359:
360: #endif /* _PDEL_TMPL_TMPL_H_ */
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