rebase: add tracing support

[gtk-doc.git] / TODO

The TODO list for the gtk-doc project is at Bugzilla,
the bugtracking system of the GNOME project.

Visit
 http://bugzilla.gnome.org/buglist.cgi?product=gtk-doc&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED
to see what is allready requested, or where you can help. :-)

To put an other request on the TODO list, visit
 http://bugzilla.gnome.org/enter_bug.cgi?product=gtk-doc

Also have a look at
 http://live.gnome.org/DocumentationProject/GtkDocFuture
and join discussion about future features.


Developers can also add items here :)

= Less files to manually edit =
The goal is that we configure gtk-doc in configure.ac and Makefile.am and
document the code in the sources. Right no we also have to edit a bunch of extra
files:
 * $(DOC_MODULE).types
 * $(DOC_MODULE)-docs.xml
 * $(DOC_MODULE)-sections.txt

== .types ==

* using SCAN_OPTION="--rebuild-types" can be used to avoid maintaining the types
  file
* we need to check if this works well for all kind of _types (e.g. boxed)
  https://bugzilla.gnome.org/show_bug.cgi?id=605025
  
== -section.txt ==
https://bugzilla.gnome.org/show_bug.cgi?id=646094

* using SCAN_OPTION="--rebuild-sections" can be used to use the audogenerated
  sections file
* when scanning a header file, everything of the header and the respective .c 
  file will be put to one section
* symbols can be hidden using __GTK_DOC_IGNORE__

* we need comment markup to override the section
  e.g.: " * InSection: xxxx"
  this needs gtkdoc-mkdb::ScanSourceFile to understand a new tag, which
  otherwise would appear as verbatim in the sources
* if one has "@InSection: xxxx" in a section comment we could patch the
  main.xml file and insert then xi:include line (would possibly rely on a
  special comment-pair there, we might also need to rewrite these
  auto-generated xi:includes everytime as the placements could have been
  changed, or we have a xi:inlcude for each chapter, that we regenerate).
* we need a way to specify subsections (Standart, Private)
  this could be done in the SECTION comment
  e.g.: "@HideSymbols: <list-of-symbols-to-hide>
  * we could allow to have a SUBSECTION:xxx comment block too
    but then we list all the symbols here to override the auto-section placement
* if we want to avoid the "InSection in symbol docs we could also have
  e.g.: "@ExtraSymbols: <list-of-symbols-to-include>
* documented symbols that are in a file without section comment and do not
  appear in "@ExtraSymbols", "@HideSymbols" would go to unused.txt
  * shall we deprecated the unused sub-sections?
* can we have both at the same time (for migration)
  * yes, read section-file first and add/override from inline comments


= More abbreviations =
* expand urls (needds more work, see gtkdoc-mkdb : ExpandAbbreviations)


= Testing =
cd test/gobject
diff -u --exclude="Makefile*" docs docs-tmpl | diffstat


= Running =
gtk-doc is using a makefile with several targets to get from sources to docs. It
uses makefile variables for configuration.
It might be easier to have a gtk-doc tool that can run the other gtk-doc tools
in the right order (ev. by importing them as modules). This could handle a few
things nicer that the makefiles don't do well. This would also make it easy to
run it manually or integrate into other build systems.

= Issues =
* gtkdoc-fixxref makefile targets use $HTML_DIR
  * HTML_DIR: The directory where gtk-doc generated documentation is installed
    it comes from gtk-doc.m4 (--with-html-dir) but has no default
  * automake exports $htmldir which is by default:
    ${prefix}/share/doc/${PACKAGE_TARNAME}
  * the Makefile uses $(DESTDIR)$(TARGET_DIR)
    where TARGET_DIR = $(HTML_DIR)/$(DOC_MODULE)
    http://www.gnu.org/software/libtool/manual/automake/DESTDIR.html
* gtkdoc does not know about module versions
  * this is causing troubles when multiple library versions are installed
    (gtk+-{2,3}, gstreamer-{0.8,0.10,1.0}
  * right now gtk-doc is xreffing against any <module>/index.sgml found
  * just using the one with a higher number won't work


= Extensibility =
We'd like to extend gtk-doc to understand conventions/features of gobject libs.
Ideally libs register their extension hooks, so that other libs that use these
libs can benefit from the extensions too.

== custom get_types collector ==
- the default method takes the types from a type file
- gstreamer plugin docs take a list of types from the gst plugin registry

== custom properties ==
- gtk has style and child properties

== extra gobject property flags ==
- gstreamer has 'controllable' properties

= Output =
* http://sagehill.net/docbookxsl/index.html
* multipage-html
  * would be good to be able to have page titles as a concatenation of document
    name and page name (gtk+:GtkWIdget)
* formats
  http://bugzilla.gnome.org/show_bug.cgi?id=531572 : html-single
  http://bugzilla.gnome.org/show_bug.cgi?id=466535 : pdf
  http://bugzilla.gnome.org/show_bug.cgi?id=467488 : man
  we need more configure options in gtk-doc.m4:
  --(enable|disable)-gtk-doc-(html|pdf|man|html-single|rtf)
  - html : enabled by default
  - html-single : is single page html
* validation
    xmllint --noout --xinclude --postvalid tester-docs.xml
    xmllint --noout --postvalid tester-docs.fo --dtdvalid file://$HOME/download/fo.dtd
    - fo.dtd : http://www.renderx.com/Tests/validator/fo.zip
* single page
  xsltproc  --nonet --xinclude -o gtk-docs.html /home/ensonic/projects/gtk-doc/gtk-doc-single.xsl  gtk-docs.sgml
  * need to check if we can pass the style-sheet class as a parameter (--stringparam gtkdoc.stylesheet=(chunk|docbook))
  * we might also need to reflow some things, as gtk-doc.xsl also runs the devhelp/devhelp2 generation
    - but then the urls in the devhelp file, refer to the chunked html anyway

= Warnings =
Bugzilla has some requests for extra warnings. We should support a common
commandline option(s) in all tools to enable/disable the warnings. The makefiles
should pass the flags from an env-var (GTKDOC_OPTIONS). The env-var should be
used after the regular flags, so that the env-var can override hardcoded
settings (in Makefile.am).

Lets take this warning for the example:
  "Symbol name not found at the start of the comment block."

Version 1: (template "warn-xxx!, warn-yyy!")
--warn-missing-symbol-at-comment-start
--no-warn-missing-symbol-at-comment-start

Version 2: (template "warn:s@")
-Wmissing-symbol-at-comment-start
-Wno-missing-symbol-at-comment-start
-warn missing-symbol-at-comment-start
-warn no-missing-symbol-at-comment-start

more warnings:
  - 'deprecated' deprecating 'features'
  - 'dummy-docs' check if symbol docs are very short and repeat mainly words
    from the symbol.
  - possible xrefs (e.g. adding a # or () would make it a successful xref)

= GIR =
== scanning ==
* ideas
  * use gir files
    1) replace gtkdoc-scan/gtkdoc-scangobject by gtkdoc-gir and output the classical files or
       patch gtkdoc-scan/gtkdoc-scangobject to output gir files
    2) patch gtkdoc-mkdb to read stuff from gir instead of classical files
  * if gir-files would have the comments too (they are getting this now):
    * we could even drop scanning the sources
    * IDEs could use the gir-files to show doc-tooltips for symbols
  * we might need yet another makefile flavour to use gir files
* perl and xml
  * http://www.xml.com/pub/a/2001/04/18/perlxmlqstart1.html

== binding docs ==
* simmillar workflow to gettext
* add gtkdoc-mk??? to generate binding doc templates
  * have c-comments there as comments
  * when updating templates, mark sections that have changed as fuzzy
* add options to gtkdoc-mkdb to build docbook from those templates
* questions
  * could we use the tmpl file mechanism?
  * directory structure?
    * we need to list the languages like ALL_LINGUAS for translations
    * we need to create subdirs for binding docs, ideally we use one for 'C' as well
* devhelp
  * devhelp files need a language attribute in the book-tag
    language={C,C++,JavaScript,Perl,Python,...}
  * devhelp could show a selector for the language
  * need to get existing python/~mm docs to use it, gtk-doc could output
    language=C for own docs

=== installation ===
* need to install each book with a prefix
* would be good to have a language attribute in book tag to allow filter by language
* look at /usr/share/gtk-doc/html/pygobject/index.html


= external processors =
We need parametric, user definable macros.
|[ ... ]| - programlistings
|macro(arg1,arg2,...)[ ... ]| - call macro
  - pass args as parameters (on the commandline)
  - pass some gtk-doc vars in environment
    (gtk-doc version, module, srcdir, buildir)
  - content of [] on stdin or as a file
  - get output on stdout or file
  - and replace the macro with it
The changes could be made in gtkdoc-mkdb::ExpandAbbreviations()
== example macros ==
|highlight(c)[...]| - highlight source code for a specific language (c)
  - what will this output? preformatted html to be xincluded?
  - we could have macros for each format, the docbook xml macro would leave
    enough traces in the html so that a html macro can continue
|dot(svg)[...]| - format dot graph and include result as mediaobject (in svg format)
|ditta(svg)[...]| - parse ascii art and include result as mediaobject (in svg format)
  - we need to generate a filename for the image or use anoter parameter

== where to define macros ==
* system wide and with the package, <prefix>/share/gtk-doc/macros, $(srcdir)
* prefix for custom macros?
* we could require stdin for input and stdout for output, the wrapper for the
  actual tool can ensure the convention


= styling =
=== process html ===
if we highlight to html we get colors, we need to check what tags we should process though:
<pre class="programlisting"> is used for all code boxes.
<div class="informalexample"><pre class="programlisting"> is used for examples.
problems:
* in html we don't know the language anymore
  * add another div
* with source-highlight, constants and types are not markedup.
  for types we might need to build an own lang file dynamically and include
  /usr/share/source-highlight/c.lang
=== |[ ... ]| does not allow setting the language ===
* check for vi/emacs/jedit modelines
  jedit: http://www.jedit.org/users-guide/buffer-local.html
  vim: http://vim.wikia.com/wiki/Modeline_magic
  emacs: http://www.delorie.com/gnu/docs/emacs/emacs_486.html
* allow <!-- language="C" --> comments after |[
* we need to catch those when processing the docbook and expanding the |[
* require new macro syntax

== show inherited api ==
could we write small html files for each object for methods, signals and properties and then use iframes to combine those at runtime like in javadoc?
could we do that using javascript and some other magic?


= Markup =
== tags ==
* to document the api-life cycle we have: since, deprecated and stability:
* other things we might want to specify:
  * multi-threading safety: mt-safe, use-with-lock <lock>

== protected scope ==
* we can have /* < protected > */ in classes
* we can have <SUBSECTION Protected> in -section.txt
* ideally we have Scope: {Public, Protected, Private} supported in doc comments
* there is a bug for gir, https://bugzilla.gnome.org/show_bug.cgi?id=594125

== wildcards in symbol names ==
Sometimes one defines a set of function and macros with very similar purpose, e.g.
READ_INT8, READ_INT16, READ_INT32. It would be great to allow documenting a symbol
READ_INT* instead of 3 docs which are copy'n'pasted anyway. In the output we will have
all matching declarations in one source listing. Multiple wildcards are okay.


= documentation best practises #518427 =
* we'd like offer a more complete skelleton
  * structure
  * docbook markup (part/chapter structure)
* structure
  Suggested structure for api-docs.
  Idea is to have more content that api reference. It would be good to have a
  gnome-platform document in devhelp, so that we could xref that instead of
  explaining 100 times how to use pkg-config.

  * examples
    * gobject in devhelp
      * concepts / api / tools / tutorial / related tools
    * gtk in devhelp
      * overview / api / migation / tools
    * qt reference docs in qt assistant
      * classes / overview / tutorial&examples
  * recommendation
    * front-page
      * table with details (http://www.docbook.org/tdg/en/html/bookinfo.html)
        (problem: what enclosing tag)
        Logo, Module Version
        Copyright and Legalnotice
        Links
        * homepage, mailing lists, irc channel
        * repository, source releases, bugtracker
      * TOC
    * introduction - what is is about
    * concepts - explain basic ideas and terminology
    * development - how to build and run, env-vars, different platforms
    * api - classic api docs
    * tutorial & examples - integrated to keep it up-to-date and cross referenced
    * migration - how to for api changes, deprecations
    * (releated) tools - tools part of the package or recommended for development
    * indexes - api-index, depretations, new api since xxx

proposed structure in docbook xml:
<book>
  <bookinfo>
  </bookinfo>
  <preface><title>Introduction</title>
    ...
  </preface>
  <part label="I"><title>xxx Overview</title>
    <xi:include href="building.xml" />
    ...
  </part>
  <reference label="II"><title>xxx Core Reference</title>
    <xi:include href="xml/gtkmain.xml" />
    ...
  </part>
  <reference label="III"><title>xxx Object Reference</title>
    <chapter><title>Object Hierarchy</title>
      <xi:include href="xml/tree_index.sgml" />
    </chapter>
    <chapter>...
  </part>
  <index>...</index>
</book>

some things to check:
* gtk,glib: can we make a <part> for the glosary and index's (according to docbook, yes)
  should we use <appendix>? its like a chapter.
* gobject: uses a <preface> for introductions
* gobject: uses <reference> as a parent for the xi:includeed <refentry> docs


= extra link for symbols =
need options for configure:
--enable-gtk-doc-codesearch-links
--enable-gtk-doc-liveedit-links
== viewvc,cgit,... ==
- link to some online service for the code
- problem: most don't have local anchors for the symbols
- where to set the uri (in the document, like for online url)?
- what about a template URL containing a %s for the "path/file" or a special macro
  http://svn.gnome.org/viewvc/gtk-doc/trunk/tests/gobject/src/gobject.c?view=markup
  http://buzztard.svn.sourceforge.net/viewvc/buzztard/trunk/buzztard/src/lib/core/core.c?view=markup
  - unfortunately we can't link to symbols (only lines)
  - linking to files is difficult as in gtkdoc we have modules

== codesearch ==
- google (code) link : http://www.google.com/codesearch?q=g_object_unref
== live editing ==
The idea is to have an 'edit' link in an online version of the docs (build from
head development version) per doc-entry (symbols and section).
The link goes to a cgi and that gets following parameters: docmodule,symbol.
E.g. http://library.gnome.org/devel/references/edit?docmodule=glib&symbol=g_new
The cgi would need a hashmap to get from docmodule to the way to check it out
(ideally it has a recent checkout and only updates it).
problems:
- signal that this has been edited already?
- support for xi:included examples
- updating the checkout could be slow


= fix missing since docs =
cd gstreamer/gstreamer/docs/gst
gtkdoc-mkdb --module=gstreamer --source-dir=../../gst --outputsymbolswithoutsince
cd gstreamer/gstreamer/src
git bisect start
git bisect good
git bisect bad RELEASE-0_10_0
git bisect run script.sh

script:
#!/bin/sh
make ctags
grep "gst_caps_is_always_compatible" tags


= performance =
- timestamp each step
  make check >make.log
- try CFLAGS=-O0 for compiling the scanner, no need to optimize it
  CFLAGS="-O0" make check >make.log
  safes max 0.5 sec.
- xslt
  http://docbook2x.sourceforge.net/latest/doc/performance.html
  - play with xsltproc --profile --verbose --timing
    cd tests/gobject/docs/html
    time /usr/bin/xsltproc 2>xslt.log --profile --verbose --timing --path /home/ensonic/projects/gnome/gtk-doc/gtk-doc/tests/gobject/docs --nonet --xinclude --stringparam gtkdoc.bookname tester --stringparam gtkdoc.version 1.14 /home/ensonic/projects/gnome/gtk-doc/gtk-doc/gtk-doc.xsl ../tester-docs.xml
    - l10n.language is slow
      bug: https://sourceforge.net/tracker/index.php?func=detail&aid=2918673&group_id=21935&atid=373750
      see: http://www.mail-archive.com/docbook-apps@lists.oasis-open.org/msg05412.html
      - overide l10n.language
        glib/gobject
        real        user        sys
        2m15.221s   1m58.740s   0m1.456s
        >
        1m55.480s   1m44.296s   0m2.125s
      - override many template related to gentext
        real        user        sys
        0m43.327s   0m38.594s   0m4.724s
        >
        real        user        sys
        0m33.282s   0m29.266s   0m4.012s
      - removing the gentext calls for nav-bar alt tags does not help


  - try plain docbook xslt to see if maybe we have bad xslt templates in the
    customisation layer (gtk-doc.xsl)

  - we could do the xinlcude processing once and use it for both html and pdf
    time /usr/bin/xsltproc 2>../xslt4.log --path /home/ensonic/projects/gnome/gtk-doc/gtk-doc/tests/gobject/docs --nonet --xinclude --stringparam gtkdoc.bookname tester --stringparam gtkdoc.version 1.14 /home/ensonic/projects/gnome/gtk-doc/gtk-doc/gtk-doc.xsl ../tester-docs.xml
    real        user       sys
    0m4.846s    0m4.434s   0m0.147s
    0m4.842s    0m4.386s   0m0.145s


    time xmllint --nonet --xinclude ../tester-docs.xml >./tester-docs-all.xml
    real        user       sys
    0m0.596s    0m0.546s   0m0.023s

    time /usr/bin/xsltproc 2>../xslt5.log --path /home/ensonic/projects/gnome/gtk-doc/gtk-doc/tests/gobject/docs --nonet --stringparam gtkdoc.bookname tester --stringparam gtkdoc.version 1.14 /home/ensonic/projects/gnome/gtk-doc/gtk-doc/gtk-doc.xsl ./tester-docs-all.xml
    real        user       sys
    0m4.167s    0m3.834s   0m0.106s
    0m4.248s    0m3.851s   0m0.114s


    time xmllint --nonet --c14n --xinclude ../tester-docs.xml >./tester-docs-all2.xml

    real        user       sys
    0m0.700s    0m0.636s   0m0.034s

    time /usr/bin/xsltproc 2>../xslt6.log --path /home/ensonic/projects/gnome/gtk-doc/gtk-doc/tests/gobject/docs --nonet --stringparam gtkdoc.bookname tester --stringparam gtkdoc.version 1.14 /home/ensonic/projects/gnome/gtk-doc/gtk-doc/gtk-doc.xsl ./tester-docs-all2.xml

    real        user       sys
    0m3.344s    0m3.026s   0m0.109s
    0m3.372s    0m3.037s   0m0.115s


    l ../tester-docs.xml ./tester-docs-all*.xml

  - we could also try to compact the installed xslt
    xmllint --nonet --c14n --xinclude gtk-doc.xsl | sed -ne '/<!--/ { :c; /-->/! { N; b c; }; /-->/s/<!--.*-->//g }; /^  *$/!p;' | sed '/^$/d' >gtk-doc.pre.xsl
    - unfortunately there is no way to ask xsltproc to pre-transform an xslt, that could
      - strip comments
      - process xsl:import and xsl:include
  - compile xslt
    http://sourceforge.net/projects/xsltc/
    http://www.xmlhack.com/read.php?item=618
  - extra xsltproc options:
    --novalid: saves ~ 0.12 sec

- perl regexps
  - not really an issue, but we can improve by compiling the regexps
    http://stackoverflow.com/questions/550258/does-the-o-modifier-for-perl-regular-expressions-still-provide-any-benefit
  - we use $&, $', and $` in several places (comple match, pre-match and post-match).
    Those are slow and once they are used a single time perl prepares them for every match operation.
    Since perl 5.10 one can use the /p flag for matches where this is needed and then use
    ${^PREMATCH} , ${^MATCH}  and ${^POSTMATCH}
- perl profiling
  - http://blog.timbunce.org/2008/07/15/nytprof-v2-a-major-advance-in-perl-profilers/
    perl -d:NYTProf gtkdoc-mkdb ...
    nytprofhtml
    firefox nytprof/index.html