$Date: 2012-02-05 12:39:18 -0800 (Sun, 05 Feb 2012) $
NOTE: Please improve this list!
Dear (new) GRASS Developer,
When submitting C code to GRASS SVN repository, please take care of
following rules:
[ see SUBMITTING_SCRIPTS for shell script hints ]
[ see SUBMITTING_TCLTK for tcl and tk hints ]
[ see SUBMITTING_DOCS for documentation ]
[ see SUBMITTING_PYTHON for Python code hints ]
1. Get and read the GRASS 6 Programmer's Manual here:
http://grass.osgeo.org/programming6/
or generate it from this source code (the programmer's manual is
integrated in the source code in doxygen style):
make htmldocs
make pdfdocs
2. Use the directory structure to place your module appropriately into
the source tree
- libes go into lib/
- raster goes into raster/
- vector goes into vector/
- ...
Consider to take a look at "GNU Coding Standards"
http://www.gnu.org/prep/standards.html
In future, there will be a centralized contribution directory.
3. Add a header section to each file you submit and make sure you include
the copyright. The purpose section is meant to contain a general
overview of the code in the file to assist other programmers that will
need to make changes to your code. If you are modifying an existing
file you may under no circumstances remove prior copyright or licensing
text that is not your own, even for a major rewrite. If any original
code or code that is in part derived from another's original work
remains, it must be properly cited.
Example (ficticious header for a file called color.c) :
/****************************************************************************
*
* MODULE: d.rast (or new higher level module name (eg GRASS core))
* AUTHOR(S): Original author unknown - probably CERL
* John Doe <jdoe at somewhere org>
* PURPOSE: To provide storage and manipulation of colors used for
* rendering the raster. The colors are stored in a doubly linked
* list which must be initialized with InitColors() before it can
* be used. Note that most linked list functionality (add,
* remove, get) is supported, but there is no sorting
* functionality.
* COPYRIGHT: (C) 2010 by the GRASS Development Team
*
* This program is free software under the GNU General Public
* License (>=v2). Read the COPYING file that comes with GRASS
* for details.
*
*****************************************************************************/
The copyright protects your rights according to GNU General Public
License (www.gnu.org).
4. - deleted.
We don't want the $ID$ in source code any more as it causes problems
for the SVN branches.
5. To ensure that the software system continues to work, please include
#include <grass/config.h>
in your files and make use of the various system dependencies
contained therein. As one example of this, see lib/gmath/fft.c.
Please refrain from declaring system functions within the
software; include the proper header files (conditionally dependent
on config.h macros if necessary) instead.
6. Order of include headers
In general, headers should be included in the order:
1. Core system headers (stdio.h, ctype.h, ...)
2. Headers for non-core system components (X11, libraries).
3. Headers for core systems of the package being compiled (grass/gis.h, grass/glocale.h, ...)
4. Headers for the specific library/program being compiled (geodesic.h, ...)
Each class of header has an obligation to be compatible with those
above it in the list, but not those below it.
7. Always specify the return type for ALL functions including those that
return type "void", and insert return statements for any function
which returns a value.
Also, use ANSI C prototypes to declare your functions.
For module return values, see "Exit status" below.
Examples:
void G_something(void);
int G_something_else(int, int);
void G_something(void)
{
/* Snipped out code */
}
int G_something_else(int x, int y)
{
/* Snipped out code */
return 0;
}
8. Module exit status is defined as EXIT_SUCCESS or EXIT_FAILURE, e.g.
{
...
if (G_parser (argc, argv))
exit (EXIT_FAILURE);
...
exit (EXIT_SUCCESS);
}
9. Use fprintf instead of printf. But:
For errors and warnings please use the G_fatal_error() and
G_warning() functions. General messages for the user should use
G_message() while debug messages should use G_debug() whenever
possible. There are two variants to G_message(): G_verbose_message()
which will only display the message if in verbose mode, and
G_important_message() which will always show the message unless
the module is running in --quiet mode. G_fatal_error() and
G_warning() will always be displayed regardless of verbosity setting.
Messages sent to any of these functions will be printed to stderr.
G_message() output is not expected to be sent to pipe or file.
Always use the gettext macros with _("") for user messages,
example:
G_fatal_error(_("Vector map <%s> not found"), name);
Pipe/file data output:
For data output redirected to pipe or file, please use fprintf() and
specify the stdout stream as follows:
fprintf(stdout, ...);
fflush(stdout);
fflush(stdout) always required when using fprintf(stdout, ...).
10. Use the GRASS library function G_asprintf() instead of the
standard C functions asprintf(), vsnprintf() and snprintf(). These
functions are not portable or have other issues. Example:
char *msg;
G_asprintf(&msg, "%s", parameters);
do_something_with_msg();
G_free(msg);
Note that you should free memory when G_asprintf() is used.
11. Use the following GRASS library functions instead of the standard C
functions. The reason for this is that the following functions ensure
good programming practice (e.g. always checking if memory was allocated)
and/or improves portability. PLEASE refer to the programmers manual
for the proper use (e.g. determining if any casts are needed for arguments
or return values) of these library functions. They may perform a task
slightly different from their corresponding C library function, and thus,
their use may not be the same.
G_malloc() instead of malloc()
G_calloc() instead of calloc()
G_realloc() instead of realloc()
G_free() instead of free()
G_getenv() instead of getenv()
G_setenv() instead of setenv()
G_unsetenv() instead of unsetenv()
G_sleep() instead of sleep()
G_system() instead of system()
Could somebody please add others (please verify that they are
useful and safe first)
12. Use function names which fulfill the official GNU naming convention.
http://www.gnu.org/prep/standards/html_node/Names.html#Names
Instead of naming a function like: MyNewFunction() use underscores
for seperation and lower case letters: my_new_function().
13. Don't use the C++ comment style! This confuses several compilers.
Use instead:
/* C-comments */
If you want to comment code portions, use
#ifdef notdef
portion_to_be_commented;
#endif
This is safe comparing to nested /* comments */
Functions in the library must be documented in doxygen style to
get them into the programmer's manual (generate with
make pdfdocs or
make htmldocs
). See lib/gis/*.c for examples.
14. PLEASE take the time to add comments throughout your code explaining what
the code is doing. It will save a HUGE amount of time and frustration for
other programmers that may have to change your code in the future.
15. To promote a consistent coding style, please use the "indent" program
on all new C modules using the following switches:
$ indent -bad -bap -bbb -br -bli0 -bls -cli0 -ncs -fc1 -hnl -i4 \
-nbbo -nbc -nbfda -nbfde -ncdb -ncdw -nce -nfca -npcs -nprs \
-npsl -nsc -nsob -saf -sai -saw -sbi0 -ss -ts8 -ut main.c
Existing code should not be re-indented except in extreme cases, as this
will make "diff" comparisons with older versions impossible. If indent is
needed, do not check in any changes other than the indentation in the same
commit! Do add the indent switches and any indent warning messages to the
SVN log. Any change or fix mixed in with an indent is very hard to track
making it hard for others to follow the change or fix any new bugs.
For your convenience use the tools/grass_indent.sh script.
16. Platform dependent code:
Do not remove #ifdef __CYGWIN__ and/or #ifndef __CYGWIN__ lines and
their encapsulated lines from source code (one example was that someone
removed drand48 definition.)
17. Suggested compiler flags:
We suggest to use very strict compiler flags to capture errors
at the very beginning. Here our list of flags, please use them
to configure you development version of GRASS:
GNU/Linux:
MYCFLAGS="-g -Wall -Werror-implicit-function-declaration -fno-common"
MYCXXFLAGS="-g -Wall"
CFLAGS="$MYCFLAGS" CXXFLAGS="$MYCXXFLAGS" ./configure ...
MacOSX: [to be suggested]
MS-Windows: [to be suggested]
18. Make sure a new line is at the end of each file and UNIX style newlines
are used (\n).
19. When writing Makefiles, use the current standard.
If you have to use commands, please check for:
avoid | use instead
------------------+---------------
make target | $(MAKE) target
mkdir target | $(MKDIR) target
cp (executable) | $(INSTALL) -m 755 file target
cp (normal file) | $(INSTALL) -m 644 file target
ar | $(AR)
rm: be VERY careful with recursive remove. Also beware of
removing $(FOO)* if $(FOO) has any chance of being empty.
Examples: see below examples or others
raster/r.info/Makefile
vector/v.digit/Makefile
If you are unsure, please ask on the GRASS Developers list.
20. Have a look at ./INSTALL
21. Have a function included in your module which writes to the history
file of the map (e.g. command line, parameters etc.). See e.g.
raster/r.patch/main.c
(the same applies to vector and g3d modules!)
22. Standard parser options: use G_define_standard_option() whenever possible
to define standard module command line options. This will save you time,
create fewer bugs, and make things easier on the translators.
See lib/gis/parser.c for details of the function definition.
23. Add/update, if required the related GUI menus:
gui/tcltk/gis.m/gmmenu.tcl
gui/wxpython/xml/menudata.xml
24. For consistency, use README rather than README.txt for any README files.
25. GRASS/Environment variables:
If you add a new variable, please follow the naming convention.
All variables are described in
lib/init/variables.html
26. Be sure to develop on top of the LATEST GRASS code (which is in our SVN
repository). You can re-check before submission with 'svn diff':
Be sure to create unified ("diff -u") format. "Plain" diffs (the default
format) are risky, because they will apply without warning to code which
has been substantially changed; they are also harder to read than unified.
Such diffs should be made from the top-level directory, e.g.
"svn diff display/d.vect/main.c"; that way, the diff will
include the pathname rather than just an ambiguous "main.c".
27. Try to use module names which describe shortly the intended purpose of the module.
The first letters for module name should be:
d. - display commands
db. - database commands
g. - general GIS management commands
i. - imagery commands
m. - miscellaneous tool commands
ps. - postscript commands
r. - raster commands
r3. - raster3D commands
v. - vector commands
Some additional naming conventions
* export modules: (type).out.(format) eg: r.out.arc, v.out.ascii
* import module: (type).in.(format) eg: r.in.arc, v.in.ascii
* conversion modules: (type).to.(type) eg: r.to.vect, v.to.rast, r3.to.rast
Avoid module names with more than two dots in the name.
Example:
instead of r.to.rast3.elev use r.to.rast3elev
28. Use the grass test suite to test your modules.
http://www-pool.math.tu-berlin.de/~soeren/grass/GRASS_TestSuite
You can easily write specific tests for your modules.
If your module is part of GRASS and you created some standard test
cases, please contact the developers to add your tests to the
default test suite. This will automatize complex test scenarios
and assure to find bugs much faster, if changes were made to your
modules or to the grass library.
Consider to subscribe to the GRASS Quality Assessment System to
get immediate notification about the code quality:
http://grass.osgeo.org/mailman/listinfo/grass-qa
29. When submitting new files to the repository set SVN properties,
usually for directory
svn:ignore : *.tmp.html
*OBJ*
or e.g. for C-file
svn:mime-type : text/x-csrc
svn:keywords : Author Date Id
svn:eol-style : native
See
http://svnbook.red-bean.com/en/1.4/svn.advanced.props.html
To set a property:
svn propset svn:keywords 'Author Date Id' <file>
svn propset svn:mime-type text/x-sh grass_shellscript.sh
To edit the svn:ignore property using your default text editor:
svn propedit svn:ignore <directory>
To set the svn:ignore property non-interactively, first create a
file containing the value:
echo "*.tmp.html" > ignore.txt
echo "*OBJ*" >> ignore.txt
then use:
svn propset -F ignore.txt svn:ignore <directory>
List of mime-type:
C++ files (.cpp): text/x-c++src
C files (.c): text/x-csrc
DTD files (.dtd): text/xml-dtd
GIF files (.gif): image/gif
Header files (.h): text/x-chdr
HTML files (.html): text/html
JPEG files (.jpg): image/jpeg
Makefiles: text/x-makefile
PNG files (.png): image/png
Python files (.py): text/x-python
Shell scripts (.sh): text/x-sh
Text files (.txt): text/plain
XML files (.xml): text/xml
(please update the list...)
30. Use doxygen style for source code documentation. It is required
for GRASS libraries, but also recommended for GRASS modules.
Do not use structural command inside documentation block since it
leads to some duplication of information (e.g. do not use \fn
command in comment blocks). The exception is \file command for
documenting a file, in this case structural command is required.
For files
/**
\file snap.c
\brief Vector library - Clean vector map (snap lines)
(C) 2001-2008 by the GRASS Development Team
This program is free software under the
GNU General Public License (>=v2).
Read the file COPYING that comes with GRASS
for details.
\author Radim Blazek
\date 2001-2008
*/
For functions
/**
\brief Snap lines in vector map to existing vertex in threshold
For details see Vect_snap_lines_list()
\param Map pointer to input vector map
\param type filter features of given type to be snap
\param thresh threshold value for snapping
\param[out] Err pointer to vector map where lines representing snap are written or NULL
\param[out] msgout file pointer where messages will be written or NULL
\return 1
*/
31. Tell the other developers about the new code using the following e-mail:
grass-dev@lists.osgeo.org
To subscribe to this mailing list, see
http://lists.osgeo.org/mailman/listinfo/grass-dev
32. In case of questions feel free to contact the developers at the above
mailing list.
http://grass.osgeo.org/devel/index.php#submission
...
[please add further hints if required]