Annotation of mandoc/mandoc_html.3, Revision 1.10
1.10 ! schwarze 1: .\" $Id: mandoc_html.3,v 1.9 2017/07/14 16:06:44 schwarze Exp $
1.1 schwarze 2: .\"
1.3 schwarze 3: .\" Copyright (c) 2014, 2017 Ingo Schwarze <schwarze@openbsd.org>
1.1 schwarze 4: .\"
5: .\" Permission to use, copy, modify, and distribute this software for any
6: .\" purpose with or without fee is hereby granted, provided that the above
7: .\" copyright notice and this permission notice appear in all copies.
8: .\"
9: .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10: .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11: .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12: .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13: .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14: .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15: .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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1.10 ! schwarze 17: .Dd $Mdocdate: July 14 2017 $
1.1 schwarze 18: .Dt MANDOC_HTML 3
19: .Os
20: .Sh NAME
21: .Nm mandoc_html
22: .Nd internals of the mandoc HTML formatter
23: .Sh SYNOPSIS
24: .In "html.h"
25: .Ft void
26: .Fn print_gen_decls "struct html *h"
27: .Ft void
28: .Fn print_gen_head "struct html *h"
29: .Ft struct tag *
30: .Fo print_otag
31: .Fa "struct html *h"
32: .Fa "enum htmltag tag"
1.2 schwarze 33: .Fa "const char *fmt"
34: .Fa ...
1.1 schwarze 35: .Fc
36: .Ft void
37: .Fo print_tagq
38: .Fa "struct html *h"
39: .Fa "const struct tag *until"
40: .Fc
41: .Ft void
42: .Fo print_stagq
43: .Fa "struct html *h"
44: .Fa "const struct tag *suntil"
45: .Fc
46: .Ft void
47: .Fo print_text
48: .Fa "struct html *h"
49: .Fa "const char *word"
50: .Fc
1.7 schwarze 51: .Ft char *
52: .Fo html_make_id
53: .Fa "const struct roff_node *n"
54: .Fc
55: .Ft int
56: .Fo html_strlen
57: .Fa "const char *cp"
58: .Fc
1.1 schwarze 59: .Sh DESCRIPTION
60: The mandoc HTML formatter is not a formal library.
61: However, as it is compiled into more than one program, in particular
62: .Xr mandoc 1
63: and
64: .Xr man.cgi 8 ,
65: and because it may be security-critical in some contexts,
66: some documentation is useful to help to use it correctly and
67: to prevent XSS vulnerabilities.
68: .Pp
69: The formatter produces HTML output on the standard output.
70: Since proper escaping is usually required and best taken care of
71: at one central place, the language-specific formatters
72: .Po
73: .Pa *_html.c ,
74: see
75: .Sx FILES
76: .Pc
77: are not supposed to print directly to
78: .Dv stdout
79: using functions like
80: .Xr printf 3 ,
81: .Xr putc 3 ,
82: .Xr puts 3 ,
83: or
84: .Xr write 2 .
85: Instead, they are expected to use the output functions declared in
86: .Pa html.h
87: and implemented as part of the main HTML formatting engine in
88: .Pa html.c .
89: .Ss Data structures
90: These structures are declared in
91: .Pa html.h .
92: .Bl -tag -width Ds
93: .It Vt struct html
94: Internal state of the HTML formatter.
95: .It Vt struct tag
96: One entry for the LIFO stack of HTML elements.
97: Members are
98: .Fa "enum htmltag tag"
99: and
100: .Fa "struct tag *next" .
101: .El
102: .Ss Private interface functions
103: The function
104: .Fn print_gen_decls
105: prints the opening
106: .Ao Pf \&? Ic xml ? Ac
107: and
108: .Aq Pf \&! Ic DOCTYPE
109: declarations required for the current document type.
110: .Pp
111: The function
112: .Fn print_gen_head
113: prints the opening
114: .Aq Ic META
115: and
116: .Aq Ic LINK
117: elements for the document
118: .Aq Ic HEAD ,
119: using the
120: .Fa style
121: member of
122: .Fa h
123: unless that is
124: .Dv NULL .
125: It uses
126: .Fn print_otag
127: which takes care of properly encoding attributes,
128: which is relevant for the
129: .Fa style
130: link in particular.
131: .Pp
132: The function
133: .Fn print_otag
134: prints the start tag of an HTML element with the name
135: .Fa tag ,
1.2 schwarze 136: optionally including the attributes specified by
137: .Fa fmt .
138: If
139: .Fa fmt
140: is the empty string, no attributes are written.
141: Each letter of
142: .Fa fmt
143: specifies one attribute to write.
144: Most attributes require one
145: .Va char *
146: argument which becomes the value of the attribute.
147: The arguments have to be given in the same order as the attribute letters.
1.5 schwarze 148: If an argument is
149: .Dv NULL ,
150: the respective attribute is not written.
1.2 schwarze 151: .Bl -tag -width 1n -offset indent
152: .It Cm c
153: Print a
154: .Cm class
155: attribute.
1.6 schwarze 156: This attribute letter can optionally be followed by the modifier letter
157: .Cm T .
158: In that case, a
159: .Cm title
160: attribute with the same value is also printed.
1.2 schwarze 161: .It Cm h
162: Print a
163: .Cm href
164: attribute.
1.3 schwarze 165: This attribute letter can optionally be followed by a modifier letter.
166: If followed by
167: .Cm R ,
168: it formats the link as a local one by prefixing a
169: .Sq #
170: character.
171: If followed by
172: .Cm I ,
173: it interpretes the argument as a header file name
174: and generates a link using the
175: .Xr mandoc 1
176: .Fl O Cm includes
177: option.
178: If followed by
179: .Cm M ,
180: it takes two arguments instead of one, a manual page name and
181: section, and formats them as a link to a manual page using the
182: .Xr mandoc 1
183: .Fl O Cm man
184: option.
1.2 schwarze 185: .It Cm i
186: Print an
187: .Cm id
188: attribute.
189: .It Cm \&?
190: Print an arbitrary attribute.
191: This format letter requires two
192: .Vt char *
193: arguments, the attribute name and the value.
1.5 schwarze 194: The name must not be
195: .Dv NULL .
1.2 schwarze 196: .It Cm s
197: Print a
198: .Cm style
199: attribute.
200: If present, it must be the last format letter.
201: In contrast to the other format letters, this one does not yet
1.5 schwarze 202: print the value and does not take an argument.
1.2 schwarze 203: Instead, the rest of the format string consists of pairs of
204: argument type letters and style name letters.
205: .El
206: .Pp
1.8 schwarze 207: Argument type letters each require one argument as follows:
1.2 schwarze 208: .Bl -tag -width 1n -offset indent
209: .It Cm h
210: Requires one
211: .Vt int
212: argument, interpreted as a horizontal length in units of
213: .Dv SCALE_EN .
214: .It Cm s
215: Requires one
216: .Vt char *
217: argument, used as a style value.
218: .It Cm u
219: Requires one
220: .Vt struct roffsu *
221: argument, used as a length.
222: .It Cm w
223: Requires one
224: .Vt char *
225: argument, interpreted as an
226: .Xr mdoc 7 Ns -style
227: width specifier.
1.5 schwarze 228: If the argument is
229: .Dv NULL ,
230: nothing is printed for this pair.
1.8 schwarze 231: .Pp
232: The
233: .Cm w
1.10 ! schwarze 234: argument type letter can optionally be followed by one, two, or three
1.8 schwarze 235: modifier letters.
236: The modifier
1.10 ! schwarze 237: .Cm *
! 238: suppresses printing of the pair if the argument matches 6n.
! 239: The modifier
1.8 schwarze 240: .Cm +
1.10 ! schwarze 241: increases the width by 20% to make even bold text fit
! 242: and adds three units for padding between columns.
1.8 schwarze 243: The modifier
244: .Cm \-
245: makes the width negative by multiplying it with \-1.
1.2 schwarze 246: .El
247: .Pp
248: Style name letters decide what to do with the preceding argument:
249: .Bl -tag -width 1n -offset indent
250: .It Cm h
251: Set
252: .Cm height
253: to the given length.
254: .It Cm i
255: Set
256: .Cm text-indent
257: to the given length.
258: .It Cm l
259: Set
260: .Cm margin-left
261: to the given length.
262: .It Cm w
263: Set
264: .Cm width
265: to the given length.
266: .It Cm W
267: Set
268: .Cm min-width
269: to the given length.
270: .It Cm \&?
271: The special pair
272: .Cm s?
273: requires two
274: .Vt char *
275: arguments.
276: The first is the style name, the second its value.
1.5 schwarze 277: The style name must not be
278: .Dv NULL .
1.2 schwarze 279: .El
280: .Pp
281: .Fn print_otag
282: uses the private function
1.1 schwarze 283: .Fn print_encode
284: to take care of HTML encoding.
285: If required by the element type, it remembers in
286: .Fa h
287: that the element is open.
288: The function
289: .Fn print_tagq
290: is used to close out all open elements up to and including
291: .Fa until ;
292: .Fn print_stagq
293: is a variant to close out all open elements up to but excluding
294: .Fa suntil .
295: .Pp
296: The function
297: .Fn print_text
298: prints HTML element content.
299: It uses the private function
300: .Fn print_encode
301: to take care of HTML encoding.
302: If the document has requested a non-standard font, for example using a
303: .Xr roff 7
304: .Ic \ef
305: font escape sequence,
306: .Fn print_text
307: wraps
308: .Fa word
309: in an HTML font selection element using the
310: .Fn print_otag
311: and
312: .Fn print_tagq
313: functions.
314: .Pp
1.7 schwarze 315: The function
316: .Fn html_make_id
317: takes a node containing one or more text children
318: and returns a newly allocated string containing the concatenation
319: of the child strings, with blanks replaced by underscores.
320: If the node
321: .Fa n
322: contains any non-text child node,
323: .Fn html_make_id
324: returns
325: .Dv NULL
326: instead.
327: The caller is responsible for freeing the returned string.
328: .Pp
329: The function
330: .Fn html_strlen
331: counts the number of characters in
332: .Fa cp .
333: It is used as a crude estimate of the width needed to display a string.
334: .Pp
1.1 schwarze 335: The functions
336: .Fn print_eqn ,
337: .Fn print_tbl ,
338: and
339: .Fn print_tblclose
340: are not yet documented.
341: .Sh FILES
342: .Bl -tag -width mandoc_aux.c -compact
343: .It Pa main.h
344: declarations of public functions for use by the main program,
345: not yet documented
346: .It Pa html.h
347: declarations of data types and private functions
348: for use by language-specific HTML formatters
349: .It Pa html.c
350: main HTML formatting engine and utility functions
351: .It Pa mdoc_html.c
352: .Xr mdoc 7
353: HTML formatter
354: .It Pa man_html.c
355: .Xr man 7
356: HTML formatter
357: .It Pa tbl_html.c
358: .Xr tbl 7
359: HTML formatter
360: .It Pa eqn_html.c
361: .Xr eqn 7
362: HTML formatter
363: .It Pa out.h
364: declarations of data types and private functions
365: for shared use by all mandoc formatters,
366: not yet documented
367: .It Pa out.c
368: private functions for shared use by all mandoc formatters
369: .It Pa mandoc_aux.h
370: declarations of common mandoc utility functions, see
371: .Xr mandoc 3
372: .It Pa mandoc_aux.c
373: implementation of common mandoc utility functions
374: .El
375: .Sh SEE ALSO
376: .Xr mandoc 1 ,
377: .Xr mandoc 3 ,
378: .Xr man.cgi 8
379: .Sh AUTHORS
380: .An -nosplit
381: The mandoc HTML formatter was written by
382: .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .
1.5 schwarze 383: It is maintained by
384: .An Ingo Schwarze Aq Mt schwarze@openbsd.org ,
385: who also wrote this manual.
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