aboutsummaryrefslogtreecommitdiff
path: root/en_US.ISO8859-1/books/fdp-primer/doc-build/chapter.sgml
blob: bb03eb46df5d5ba2cc55ff7271e3436a063af4b9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
<?xml version="1.0" encoding="ISO8859-1" standalone="no"?>
<!-- Copyright (c) 1999 Neil Blakey-Milner, All rights reserved.

     Redistribution and use in source (SGML DocBook) and 'compiled' forms
     (SGML HTML, PDF, PostScript, RTF and so forth) with or without
     modification, are permitted provided that the following conditions
     are met:

      1. Redistributions of source code (SGML DocBook) must retain the above
         copyright notice, this list of conditions and the following
         disclaimer as the first lines of this file unmodified.

      2. Redistributions in compiled form (transformed to other DTDs,
         converted to PDF, PostScript, RTF and other formats) must reproduce
         the above copyright notice, this list of conditions and the
         following disclaimer in the documentation and/or other materials
         provided with the distribution.

     THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     DISCLAIMED. IN NO EVENT SHALL NIK CLAYTON BE LIABLE FOR ANY DIRECT,
     INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
     ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE
     POSSIBILITY OF SUCH DAMAGE.

     $FreeBSD$
-->

<chapter id="doc-build">
  <title>The Documentation Build Process</title>

  <para>This chapter's main purpose is to clearly explain
    <emphasis>how the documentation build process is
      organized</emphasis>, and <emphasis>how to affect modifications
      to this process</emphasis>.</para>

  <para>After you have finished reading this chapter you
    should:</para>

  <itemizedlist>
    <listitem>
      <para>Know what you need to build the FDP documentation, in
	addition to those mentioned in the
	<link linkend="tools">XML tools chapter</link>.</para>
    </listitem>

    <listitem>
      <para>Be able to read and understand the
	<application>make</application> instructions that are present
	in each document's <filename>Makefile</filename>s, as well as
	an overview of the <filename>doc.project.mk</filename>
	includes.</para>
    </listitem>

    <listitem>
      <para>Be able to customize the build process by using
	<application>make</application> variables and
	<application>make</application> targets.</para>
    </listitem>
  </itemizedlist>

  <sect1 id="doc-build-toolset">
    <title>The FreeBSD Documentation Build Toolset</title>

    <para>Here are your tools.  Use them every way you can.</para>

    <itemizedlist>
      <listitem>
	<para>The primary build tool you will need is
	  <application>make</application>, but specifically
	  <application>Berkeley Make</application>.</para>
      </listitem>

      <listitem>
	<para>Package building is handled by FreeBSD's
	  <application>pkg_create</application>.  If you are not using
	  FreeBSD, you will either have to live without packages, or
	  compile the source yourself.</para>
      </listitem>

      <listitem>
	<para><application>gzip</application> is needed to create
	  compressed versions of the document.
	  <application>bzip2</application> compression and
	  <application>zip</application> archives are also supported.
	  <application>tar</application> is supported, but package
	  building demands it.</para>
      </listitem>

      <listitem>
	<para><application>install</application> is the default method
	  to install the documentation.  There are alternatives,
	  however.</para>
      </listitem>
    </itemizedlist>

    <note>
      <para>It is unlikely you will have any trouble finding these
	last two, they are mentioned for completeness only.</para>
    </note>
  </sect1>

  <sect1 id="doc-build-makefiles">

    <title>Understanding <filename>Makefile</filename>s in the
      Documentation Tree</title>

    <para>There are three main types of <filename>Makefile</filename>s
      in the FreeBSD Documentation Project tree.</para>

    <itemizedlist>
      <listitem>
	<para><link linkend="sub-make">Subdirectory
	    <filename>Makefile</filename>s</link> simply pass
	  commands to those directories below them.</para>
      </listitem>

      <listitem>
	<para><link linkend="doc-make">Documentation
	    <filename>Makefile</filename>s</link> describe the
	  document(s) that should be produced from this
	  directory.</para>
      </listitem>

      <listitem>
	<para><link
	    linkend="make-includes"><application>Make</application>
	  includes</link> are the glue that perform the document
	  production, and are usually of the form
	  <filename>doc.<replaceable>xxx</replaceable>.mk</filename>.</para>
      </listitem>
    </itemizedlist>

    <sect2 id="sub-make">
      <title>Subdirectory <filename>Makefile</filename>s</title>

      <para>These <filename>Makefile</filename>s usually take the form
	of:</para>

      <programlisting>SUBDIR =articles
SUBDIR+=books

COMPAT_SYMLINK = en

DOC_PREFIX?= ${.CURDIR}/..
.include "${DOC_PREFIX}/share/mk/doc.project.mk"</programlisting>

      <para>In quick summary, the first four non-empty lines define
	the <application>make</application> variables,
	<makevar>SUBDIR</makevar>, <makevar>COMPAT_SYMLINK</makevar>,
	and <makevar>DOC_PREFIX</makevar>.</para>

      <para>The first <makevar>SUBDIR</makevar> statement, as well as
	the <makevar>COMPAT_SYMLINK</makevar> statement, shows how to
	assign a value to a variable, overriding any previous
	value.</para>

      <para>The second <makevar>SUBDIR</makevar> statement shows how a
	value is appended to the current value of a variable.  The
	<makevar>SUBDIR</makevar> variable is now <literal>articles
	  books</literal>.</para>

      <para>The <makevar>DOC_PREFIX</makevar> assignment shows how a
	value is assigned to the variable, but only if it is not
	already defined.  This is useful if
	<makevar>DOC_PREFIX</makevar> is not where this
	<filename>Makefile</filename> thinks it is - the user can
	override this and provide the correct value.</para>

      <para>Now what does it all mean?  <makevar>SUBDIR</makevar>
	mentions which subdirectories below this one the build process
	should pass any work on to.</para>

      <para><makevar>COMPAT_SYMLINK</makevar> is specific to
	compatibility symlinks (amazingly enough) for languages to
	their official encoding (<filename>doc/en</filename> would
	point to <filename>en_US.ISO-8859-1</filename>).</para>

      <para><makevar>DOC_PREFIX</makevar> is the path to the root of
	the FreeBSD Document Project tree.  This is not always that
	easy to find, and is also easily overridden, to allow for
	flexibility.  <makevar>.CURDIR</makevar> is a
	<application>make</application> builtin variable with the path
	to the current directory.</para>

      <para>The final line includes the FreeBSD Documentation
	Project's project-wide <application>make</application> system
	file <filename>doc.project.mk</filename> which is the glue
	which converts these variables into build instructions.</para>
    </sect2>

    <sect2 id="doc-make">
      <title>Documentation <filename>Makefile</filename>s</title>

      <para>These <filename>Makefile</filename>s set a bunch of
	<application>make</application> variables that describe how to
	build the documentation contained in that directory.</para>

      <para>Here is an example:</para>

      <programlisting>MAINTAINER=nik@FreeBSD.org

DOC?= book

FORMATS?= html-split html

INSTALL_COMPRESSED?= gz
INSTALL_ONLY_COMPRESSED?=

# SGML content
SRCS=  book.sgml

DOC_PREFIX?= ${.CURDIR}/../../..

.include "$(DOC_PREFIX)/share/mk/docproj.docbook.mk"</programlisting>

      <para>The <makevar>MAINTAINER</makevar> variable is a very
	important one.  This variable provides the ability to claim
	ownership over a document in the FreeBSD Documentation
	Project, whereby you gain the responsibility for maintaining
	it.</para>

      <para><makevar>DOC</makevar> is the name (sans the
	<filename>.sgml</filename> extension) of the main document
	created by this directory.  <makevar>SRCS</makevar> lists all
	the individual files that make up the document.  This should
	also include important files in which a change should result
	in a rebuild.</para>

      <para><makevar>FORMATS</makevar> indicates the default formats
	that should be built for this document.
	<makevar>INSTALL_COMPRESSED</makevar> is the default list of
	compression techniques that should be used in the document
	build.  <makevar>INSTALL_ONLY_COMPRESS</makevar>, empty by
	default, should be non-empty if only compressed documents are
	desired in the build.</para>

      <note>
	<para>We covered optional variable assignments in the
	  <link linkend="sub-make">previous section</link>.</para>
      </note>

      <para>The <makevar>DOC_PREFIX</makevar> and include statements
	should be familiar already.</para>
    </sect2>
  </sect1>

  <sect1 id="make-includes">
    <title>FreeBSD Documentation Project
      <application>Make</application> Includes</title>

    <para>This is best explained by inspection of the code.  Here are
      the system include files:</para>

    <itemizedlist>
      <listitem>
	<para><filename>doc.project.mk</filename> is the main project
	  include file, which includes all the following include
	  files, as necessary.</para>
      </listitem>

      <listitem>
	<para><filename>doc.subdir.mk</filename> handles traversing of
	  the document tree during the build and install
	  processes.</para>
      </listitem>

      <listitem>
	<para><filename>doc.install.mk</filename> provides variables
	  that affect ownership and installation of documents.</para>
      </listitem>

      <listitem>
	<para><filename>doc.docbook.mk</filename> is included if
	  <makevar>DOCFORMAT</makevar> is <literal>docbook</literal>
	  and <makevar>DOC</makevar> is set.</para>
      </listitem>
    </itemizedlist>

    <sect2>
      <title><filename>doc.project.mk</filename></title>

      <para>By inspection:</para>

      <programlisting>DOCFORMAT?=	docbook
MAINTAINER?=	doc@FreeBSD.org

PREFIX?=	/usr/local
PRI_LANG?=	en_US.ISO8859-1

.if defined(DOC)
.if ${DOCFORMAT} == "docbook"
.include "doc.docbook.mk"
.endif
.endif

.include "doc.subdir.mk"
.include "doc.install.mk"</programlisting>

      <sect3>

	<title>Variables</title>

	<para><makevar>DOCFORMAT</makevar> and
	  <makevar>MAINTAINER</makevar> are assigned default values,
	  if these are not set by the document make file.</para>

	<para><makevar>PREFIX</makevar> is the prefix under which the
	  <link linkend="tools">documentation building tools</link>
	  are installed.  For normal package and port installation,
	  this is <filename>/usr/local</filename>.</para>

	<para><makevar>PRI_LANG</makevar> should be set to whatever
	  language and encoding is natural amongst users these
	  documents are being built for.  US English is the
	  default.</para>

	<note>
	  <para><makevar>PRI_LANG</makevar> in no way affects what
	    documents can, or even will, be built.  Its main use is
	    creating links to commonly referenced documents into the
	    FreeBSD documentation install root.</para>
	</note>
      </sect3>

      <sect3>
	<title>Conditionals</title>

	<para>The <literal>.if defined(DOC)</literal> line is an
	  example of a <application>make</application> conditional
	  which, like in other programs, defines behavior if some
	  condition is true or if it is false.
	  <literal>defined</literal> is a function which returns
	  whether the variable given is defined or not.</para>

	<para><literal>.if ${DOCFORMAT} == "docbook"</literal>, next,
	  tests whether the <makevar>DOCFORMAT</makevar> variable is
	  <literal>"docbook"</literal>, and in this case, includes
	  <filename>doc.docbook.mk</filename>.</para>

	<para>The two <literal>.endif</literal>s close the two above
	  conditionals, marking the end of their application.</para>
      </sect3>
    </sect2>

    <sect2>
      <title><filename>doc.subdir.mk</filename></title>

      <para>This is too long to explain by inspection, you should be
	able to work it out with the knowledge gained from the
	previous chapters, and a little help given here.</para>

      <sect3>
	<title>Variables</title>

	<itemizedlist>
	  <listitem>
	    <para><makevar>SUBDIR</makevar> is a list of
	      subdirectories that the build process should go further
	      down into.</para>
	  </listitem>

	  <listitem>
	    <para><makevar>ROOT_SYMLINKS</makevar> is the name of
	      directories that should be linked to the document
	      install root from their actual locations, if the current
	      language is the primary language (specified by
	      <makevar>PRI_LANG</makevar>).</para>
	  </listitem>

	  <listitem>
	    <para><makevar>COMPAT_SYMLINK</makevar> is described in
	      the
	      <link linkend="sub-make">Subdirectory Makefile</link>
	      section.</para>
	  </listitem>
	</itemizedlist>
      </sect3>

      <sect3>
	<title>Targets and Macros</title>

	<para>Dependencies are described by
	  <literal><replaceable>target</replaceable>:
	      <replaceable>dependency1 dependency2
	      ...</replaceable></literal> tuples, where to build
	  <literal>target</literal>, you need to build the given
	  dependencies first.</para>

	<para>After that descriptive tuple, instructions on how to
	  build the target may be given, if the conversion process
	  between the target and its dependencies are not previously
	  defined, or if this particular conversion is not the same as
	  the default conversion method.</para>

	<para>A special dependency <literal>.USE</literal> defines
	  the equivalent of a macro.</para>

	<programlisting>_SUBDIRUSE: .USE
.for entry in ${SUBDIR}
	@${ECHO} "===&gt; ${DIRPRFX}${entry}"
	@(cd ${.CURDIR}/${entry} &amp;&amp; \
	${MAKE} ${.TARGET:S/realpackage/package/:S/realinstall/install/} DIRPRFX=${DIRPRFX}${entry}/ )
.endfor</programlisting>

	<para>In the above, <maketarget>_SUBDIRUSE</maketarget> is now
	  a macro which will execute the given commands when it is
	  listed as a dependency.</para>

	<para>What sets this macro apart from other targets?
	  Basically, it is executed <emphasis>after</emphasis> the
	  instructions given in the build procedure it is listed as a
	  dependency to, and it does not adjust
	  <makevar>.TARGET</makevar>, which is the variable which
	  contains the name of the target currently being
	  built.</para>

	<programlisting>clean: _SUBDIRUSE
	rm -f ${CLEANFILES}</programlisting>

	<para>In the above, <maketarget>clean</maketarget> will use
	  the <maketarget>_SUBDIRUSE</maketarget> macro after it has
	  executed the instruction
	  <command>rm -f ${CLEANFILES}</command>.  In effect, this
	  causes <maketarget>clean</maketarget> to go further and
	  further down the directory tree, deleting built files as it
	  goes <emphasis>down</emphasis>, not on the way back
	  up.</para>

	<sect4>
	  <title>Provided Targets</title>

	  <itemizedlist>
	    <listitem>
	      <para><maketarget>install</maketarget> and
		<maketarget>package</maketarget> both go down the
		directory tree calling the real versions of themselves
		in the subdirectories
		(<maketarget>realinstall</maketarget> and
		<maketarget>realpackage</maketarget>
		respectively).</para>
	    </listitem>

	    <listitem>
	      <para><maketarget>clean</maketarget> removes files
		created by the build process (and goes down the
		directory tree too).
		<maketarget>cleandir</maketarget> does the same, and
		also removes the object directory, if any.</para>
	    </listitem>
	  </itemizedlist>
	</sect4>
      </sect3>

      <sect3>
	<title>More on Conditionals</title>

	<itemizedlist>
	  <listitem>
	    <para><literal>exists</literal> is another condition
	      function which returns true if the given file
	      exists.</para>
	  </listitem>

	  <listitem>
	    <para><literal>empty</literal> returns true if the given
	      variable is empty.</para>
	  </listitem>

	  <listitem>
	    <para><literal>target</literal> returns true if the given
	      target does not already exist.</para>
	  </listitem>
	</itemizedlist>
      </sect3>

      <sect3>
	<title>Looping Constructs in <command>make
	    (.for)</command></title>

	<para><literal>.for</literal> provides a way to repeat a set
	  of instructions for each space-separated element in a
	  variable.  It does this by assigning a variable to contain
	  the current element in the list being examined.</para>

	<programlisting>_SUBDIRUSE: .USE
.for entry in ${SUBDIR}
	@${ECHO} "===&gt; ${DIRPRFX}${entry}"
	@(cd ${.CURDIR}/${entry} &amp;&amp; \
	${MAKE} ${.TARGET:S/realpackage/package/:S/realinstall/install/} DIRPRFX=${DIRPRFX}${entry}/ )
.endfor</programlisting>

	<para>In the above, if <makevar>SUBDIR</makevar> is empty, no
	  action is taken; if it has one or more elements, the
	  instructions between <literal>.for</literal> and
	  <literal>.endfor</literal> would repeat for every element,
	  with <makevar>entry</makevar> being replaced with the value
	  of the current element.</para>
      </sect3>
    </sect2>
  </sect1>
</chapter>