Difference between revisions of "Coding Guidelines for Rivendell"

Revision as of 23:44, 23 February 2018

These are the CODINGSTYLE guidelines for the Rivendell package.

OVERVIEW

Rivendell is a Free Software project to develop a radio broadcast automation system. This file, CODINGSTYLE, describes how to get the Rivendell code, coding style guidelines for writing new code, how to submit patches to be incorporated into the official Rivendell CVS repository, and other code related information. General info on the Rivendell project can be found at the http://www.rivendellaudio.org/ web page and also in the README and INSTALLATION files.

CODING STYLE GUIDELINES

Please try to write code that fits with the formating style already present. Some good basic guidelines:

  LINE LENGTH -- Should be short enough to fit onto an eighty character line
                 without wrapping.  This applies to ChangeLog 
                 entries too!  While it's not always possible to follow this 
                 rule (quoted literal strings being one place in particular 
                 where it is sometimes necessary to violate it), sticking 
                 with it wherever possible makes life much easier for those 
                 using character mode editing sessions.

  INDENTATION -- Should be two characters per level.

  CLASS NAMES -- Should have the initial letter of each word capitalized, 
                 e.g. 'ThisIsMyClass'.  If the class is part of librd, the
                 name should be prefaced with the uppercase letters 'RD', 
                 e.g. 'RDThisIsMyClass'.

 METHOD NAMES -- Names of class methods should follow the general style used
                 by Qt.  A special convention for Rivendell is to reserve
                 names beginning with an uppercase letter for private classes
                 only.

 VARIABLE NAMES -- Class variables should be prefaced with a short base name 
                 that is common to all, followed by an underscore.  For
                 example, the class 'MyClass' might use 'myclass_', as 
                 in 'myclass_foo1', 'myclass_foo2', etc.  *All* variables
                 should be lowercase only, with uppercase being reserved for
                 class and method names.

Doxygen is the code documenting system in place. Doxygen style comments placed in header files can then be processed to generate friendly code documentation. More information on doxygen can be found here ( http://www.stack.nl/~dimitri/doxygen/ ).

FIXME: doxygen code samples

CVS GENERAL INFO

CVS allows multiple developers to work simultaneously on a project. CVS does this by keeping a master version of the source code in a central repository on the cvs.rivendellaudio.org server. Each developer "checks out" a copy of the source code to their personal workspace. This local copy of the source is called a sandbox. Developers test and work on the source in their sandboxes until they reach a mile-point, such as implementing a new feature or fixing a bug. Developers can then create a patch or commit their changes back to the central repository. The CVS server auto-magically merges changes from multiple developers together. Other developers periodically update their sandboxes to merge changes others have committed to the server.

Conflicts normally are prevented by developers communicating and by working on different areas of the source code. It is important that only working code is committed back into the repository.

Though CVS has one main program, cvs, that program has a lot of functionality which is accessed by giving the program different commands. The general syntax of the cvs program is:

cvs CVS_OPTIONS COMMAND COMMAND_OPTIONS

A brief overview of CVS can be found online here ( http://techweb.rfa.org/grauf/cvs.html ).

CVS READ

Any user can get anonymous read-only access to the CVS repository using the pserver protocol. The module one wishes to check out must be specified as the module-name (ex: rivendell). cvs.rivendellaudio.org is configured with the username "cvs" and the password "cvs". Access via the pserver protocol requires that a user login/logout.

cvs -d:pserver:cvs@cvs.rivendellaudio.org:/home/cvs/cvsroot login
cvs -d:pserver:cvs@cvs.rivendellaudio.org:/home/cvs/cvsroot checkout rivendell
cvs -d:pserver:cvs@cvs.rivendellaudio.org:/home/cvs/cvsroot logout

SUBMITTING PATCHES

Contributions of patches with fixes or enhancements are welcome. Posting a patch to the rivendell programmer mailing list ( rivendell-prog@rivendellaudio.org http://www.rivendellaudio.org/mailman/listinfo/rivendell-prog ) is the best approach for anyone to contribute to the project. Established Rivendell programmers can then review the patch and apply it to the official CVS tree. Users who contribute significant patches over time may earn the privilege of CVS write access.

The cvs diff command may be used to generate patches from a CVS sandbox. This allows for a user to checkout a cvs sandbox and make changes as needed by directly editing the files checked out. When done making changes, the cvs utility can generate the differences, in patch file format, of the sandbox version to the repository version of a file. Run the following commands from within the sandbox.

# see changes made to sandbox against what was checked out from the
# repository
cvs diff FILE

# see the difference between two versions of a file in the repository
cvs diff -rVERSION_NUMBER -rVERSION_NUMBER FILE

Additional flags, such as "-u" can be added to produce a "unified context" style diff. Similarly the output redirector can be used to send the patch to a file (which can then be emailed to the mailing list). A sample command follows:

cvs diff -u FILE > /tmp/FILE_bugfix_2007.03.26.patch

CVS WRITE

Contributors who have write access to the Rivendell CVS repository must use Secure Shell (ssh) as the secure transport for all non-anonymous CVS access.

To get this set up, you will need to generate a public key and send it to Federico Grau <grauf@rfa.org> and the sysadmin team <sysadmins@rfa.org> at Radio Free Asia (RFA), along with the username one wishes to use. As an example of how to create a public key, use the following command:

ssh-keygen -t dsa

This should prompt you for the base filename to put the public and private keys in, as well as a passphrase (be sure to use a secure one). Assuming that the default filenames were accepted, you should then have the following two files in '~/.ssh/':

• id_dsa
• id_dsa.pub

The 'id_dsa.pub' file is the one that gets sent to don Fede. The other is your secret key, and should be guarded accordingly. You will need this key every time you access the CVS archive using your selected username. Once (RFA) has set up your account, all you will need to do is change the CVSROOT string in your environment or set the cvs command to point to the new server. The form of the environment string and a sample checkout command follow:

export CVSROOT=:ext:<username>@cvs.rivendellaudio.org:/home/cvs/cvsroot
cvs checkout rivendell

A sample checkout command that does not use the environment variable follows:

cvs -d:ext:<username>@cvs.rivendellaudio.org:/home/cvs/cvsroot checkout rivendell

You should now be able to checkout, update and commit material as before, the only difference being that CVS will prompt you for the passphrase of your private key each time you access the archive. As a convenience the ssh-agent(1) and ssh-add(1) utilities can be used to securely hold private keys used for public key authentication without repeatedly prompting for passphrases.

CVS WRITE COMMIT CHECKLIST

Before committing changes back to the Rivendell CVS repository the following guidelines should be completed:

1.) Successful update of CVS without conflicts.

2.) Successful compile of CVS without errors.

3.) Update the ChangeLog file at the base of the Rivendell source code tree. The format of the ChangeLog file has the most recent changes at the bottom of the file. Entries start with a date stamp and have a format like:

YYYY-MM-DD [HH:MM TIMEZONE] NAME <EMAIL>
* Description of change

A couple examples follow:

2007-01-09 19:00 EST Federico Grau <grauf@rfa.org> <donfede@casagrau.org>
  * lib/rdcart.cpp lib/rdcut.cpp rdcatch/rdcatch.cpp; corrected i18n bug by
  replacing use of QT shortDayName() with libradio RGetShortDayNameEN()
  which will always return english day names regardless of configured
  locale.

2007-02-23 Fred Gleason <fredg@paravelsystems.com>
  * Modified the code in 'lib/rdimport_audio.cpp' to use the
  'RDCart::setMetadata()' and 'RDCut::setMetadata()' methods.

4.) CVS Commit of the files changed using the ChangeLog snippet.