Compatibility plugin for SquirrelMail
=====================================
Ver 2.0.14, 2009/01/01


Copyright (c) 2004-2009 Paul Lesniewski <paul@squirrelmail.org>



Description
===========

This plugin allows any other plugin access to the functions
and special variables needed to make it backward (and forward) 
compatible with most versions of SM in wide use.  This eliminates 
the need for duplication of certain functions throughout many plugins.

It also provides functionality that helps check that plugins 
have been installed and set up correctly.



License
=======

This plugin is released under the GNU General Public 
License (see the file COPYING for details).



Donations
=========

If you or your company make regular use of this software, please
consider supporting Open Source development by donating to the authors
or inquire about hiring them to consult on other projects.  Donation/
wish list links for the author(s) are as follows:

Paul Lesniewski: https://sourceforge.net/donate/index.php?user_id=508228



Requirements
============

  * None



Troubleshooting
===============

  * If you experience errors that look similar to the following:

       Fatal error: Call to undefined function php_self() in .../compatibility/includes/1.5.0/global.php on line 25
    
    You have a plugin installed that requires version 1.x of the
    Compatibility plugin.  There is a list of plugins that have
    this requirement here:

       http://www.squirrelmail.org/wiki/CompatibilityDependencies

    Note that you generally cannot use plugins that require
    Compatibility 1.x with ones that require Compatibility 2.x.
    The best approach to solving this problem is to contact the
    plugin author of the outdated plugin and work with them to
    update that code.



Help Requests
=============

Before looking for help elsewhere, please try to help yourself:

  * Read the Troubleshooting section herein.

  * Look to see if others have already asked about the same issue.
    There are tips and links for the best places to do this in
    the SquirrelMail mailing list posting guidelines:
    http://squirrelmail.org/wiki/MailingListPostingGuidelines
    You should also try Google or some other search engine.

  * If you cannot find any information about your issue, please
    first mail your help request to the squirrelmail-plugins
    mailing list.  Information about it can be found here:
    http://lists.sourceforge.net/mailman/listinfo/squirrelmail-plugins
    You MUST read the mailing list posting guidelines (see above)
    and include as much information about your issue (and your
    system) as possible.  Including configtest output, any debug
    output, the plugin configuration settings you've made and
    anything else you can think of to make it easier to diagnose
    your problem will get you the most useful responses.  Inquiries
    that do not comply with the posting guidelines are liable to
    be ignored.

  * If you don't get any replies on the mailing list, you are
    welcome to send a help request to the authors' personal
    address(es), but please be patient with the mailing list.



Usage (Plugin Authors' Guide)
=============================

As of version 2.0 of this plugin, no special action is required
on the part of plugin developers to make their plugin backward
compatible via the Compatibility Plugin.  However, any custom pages
(such as option pages) provided by a plugin should always start 
with the following code:


   // set up SquirrelMail environment
   //
   if (file_exists('../../include/init.php'))
      include_once('../../include/init.php');
   else if (file_exists('../../include/validate.php'))
   {
      define('SM_PATH', '../../');
      include_once(SM_PATH . 'include/validate.php');
   }
   else
   {
      chdir('..');
      define('SM_PATH', '../');
      include_once(SM_PATH . 'src/validate.php');
   }


   // make sure plugin is activated!
   //
   global $plugins;
   if (!in_array('plugin_name', $plugins))
      exit;


Otherwise, developers should just use the most up-to-date SquirrelMail 
API and expect that their plugins will in most cases work with most
versions of SquirrelMail as long as users of older versions have 
downloaded this plugin and applied its patch if necessary.  If a 
function is found that a certain plugin uses that is not included 
in the Compatibility Plugin, please ask to have it added.  

Authors who want to avoid getting support requests for simple setup
problems (such as when the person installing the plugin neglects to 
create a configuration file) can use one of these functionalities:

   load_config('my_plugin', array('config.php'));

   check_plugin_setup('my_plugin', array('config.php'));

The first of these functions will load (include) any and all 
configuration files given (in the order given) and will trigger an 
error (that is a bit more helpful for novice administrators who can't 
find or understand PHP errors) if none of them are found.

The second function checks for the existence of any configuration 
files you specify (it does not load (include) them, however - this
function is only intended as a configuration test.  It can be handy
in combination with the "configtest" hook which is available in 
SquirrelMail 1.4.10 and above and 1.5.2 and above.

The first parameter for both of these functions is the name of the 
plugin as it is known to SquirrelMail (the plugin's directory name).  
The second parameter is an array of any number of files, relative to 
the plugin's directory (or a full path, if it starts with a forward
slash, such as "/var/lib/squirrelmail/config/myplugin.conf").  Any 
number of files may be named here.  Another example for each: 

   load_config('my_plugin', array('data/config-default.php', 'data/config.php'));

   check_plugin_setup('my_plugin', array('data/config.php', 'data/admins.php'));

Note that load_config() is designed to allow you to do things such
as include a default configuration in case the administrator did
not create her own configuration file, or to include a full set of
default configuration settings, and another file that contains just
a sub-set thereof, etc.  Keep in mind that files are loaded/included
in the order given.

Note that check_plugin_setup() is best placed somewhere where it will 
not run frequently, since it is only really needed once (thus, in 
SquirrelMail versions 1.4.10 and 1.5.2 and above, use it with the 
"configtest" hook).  You may turn off that function by changing the 
$disable_config_check at the top of the functions.php file in the 
Compatibility Plugin.

A function called check_file_contents() is also available for plugins
that would like to check if the SquirrelMail source code has been
properly patched if needed by that plugin.  See that function's
documentation in the functions.php file for more information if needed.

There are also some advanced utility functions for use by plugins needing
to add, remove or re-order other plugins (or themselves) called add_plugin(),
remove_plugin(), get_current_hook_name() and reposition_plugin_on_hook().
Plugin authors needing to use these should read the function documentation
in the functions.php file in the Compatibility plugin directory.



TODO
====

  * sqsetcookie probably will break some plugins, since I'm not sure
    where the flush is happening in 1.5.1 and if it's being backported
    correctly.  should fix this or make sure it's not a problem
    (hrmph, seems to work fine for multilogin, sooo....)

  * Add broader functionality to help plugins diagnose 
    other setup/install issues?  such as what?  checking
    certain variables in the config files?...

  * Add functionality to auto-define SM_PATH?  I have
    run into real sticky issues with this and prefer to
    leave it out of this plugin... too many variables...
    but would be nice to remove this responsibilty from
    plugin authors
    Possible algorightm: 
       - globalize and check if $compatibility_sm_path is already available
       - if so, use it, define SM_PATH with it if not done already
       - iterate through getcwd contents, taking off chunks until one
         of the known SM directories is found (plugins, src, functions, include, 
         class, etc)
       - define SM_PATH and $compatibility_sm_path
       - chdir to plugins or SM_PATH dir??? (see below)
    Come to think of it, why doesn't validate.php just take 
    care of this?  Not sure it is appropriate there, but 
    maybe a plugin config file would be good (that's almost
    what this is becoming... which is handy but not sure if
    all the extra work and abstraction is worth it, at least
    from a performance angle - all we gain is allowing plugin
    authors to be dumber.  and are they that dumb?!?  ;>

  * Add functionality to auto-chdir if needed?  we are
    trying to avoid this altogether (and in fact in SM
    1.3 and up we have, unless a plugin is really whacked)
    so this is only useful for 1.2... hmmm... thing is 
    that I ran into some weird situations with plugins
    clashing with one another (address_add was one 
    very problematic one) unless some chdir'ing was done.
    again, it'd be nice to pull all this out of plugin
    author hands so it'll actually work, but it could be
    a little messy, and might need to be version dependent
    code (esp 1.2?)
    The address_add thing is a good example of how messy
    things can be... it is called by code executing somewhere
    in the src directory, so chdir'ing at that time can be
    disasterous

  * Checking for config files and whatnot should be
    moved to the configuration-time code in new SquirrelMail
    versions; it is pointless to do this every time the
    plugin is used



Change Log
==========

  v2.0.14  2009/01/01  Paul Lesniewski  <paul@squirrelmail.org>
    * Added is_ssl_secured_connection()
    * Added sq_is_writable()
    * Added sq_create_tempfile()
    * Added get_process_owner_info()
    * Update with changes in sqsetcookie() and that it was
      added to 1.4.16

  v2.0.13  2008/07/26  Paul Lesniewski <paul@squirrelmail.org>
    * Synchronized sq_send_mail() and sqauth_save_password()
      with changes in SquirrelMail
    * Synchronized get_plugin_requirement() with changes in
      SquirrelMail

  v2.0.12  2008/05/21  Paul Lesniewski  <paul@squirrelmail.org>
    * Added set_uri_vars()
    * Added check_file_contents()
    * Added $load_only_one to load_config()
    * Added include directories for 1.4.15 and 1.4.16
    * Added lame-duck stand-in for ngettext() when needed
      under SquirrelMail versions less than 1.5.1 that
      are not running at least PHP 4.2.0 with the gettext
      extension

  v2.0.11  2008/02/29  Paul Lesniewski  <paul@squirrelmail.org>
    * Moved sq_send_mail(), since it was added to SM core
    * Added debug constants from 1.5.2

  v2.0.10  2008/01/12  Paul Lesniewski  <paul@squirrelmail.org>
    * Note that SquirrelMail 1.4.13+ (as well as 1.5.1+)
      no longer requires a source patch.
    * Added sq_call_function_suppress_errors()
    * Added get_secured_config_value()
    * Added get_smtp_user()
    * Added sq_send_mail()

  v2.0.9  2007/07/12  Paul Lesniewski  <paul@squirrelmail.org>
    * Synchronize with addition of sqauth_read_password() to
      SM 1.4.11
    * Improve get_current_hook_name() function in SM 1.5.1+
      (no need to upgrade except for use with SM 1.5.1+)
    * Removed sq_popen() and family

  v2.0.8 2007/04/17
    * Fix mistyped function call, which should not have
      shown up unless using old or broken setups.  Thanks
      to Yoshinori Mamoto.
    * Fixed sqm_baseuri() location change that creates bug
      for versions 1.4.5 and below
    * Added sq_popen() and family
    * Added list_files()

  v2.0.7 2007/04/05
    * Added sqauth_save_password() and sqauth_read_password()
      from 1.5.1 to compatibility library
    * Added documentation note that plugin authors should not
      use checkForJavascript() under 1.4.x
    * Added get_plugin_version(), updated check_plugin_version()
    * Added sq_htmlspecialchars()
    * Added sq_change_text_domain()
    * Added get_plugin_requirement()
    * Added get_plugin_dependencies(), check_plugin_dependencies()
    * Changed internal legacy inclusion mechanism for better
      organization and easier maintenance
    * Adjusted for new SM_VERSION constant in SM 1.5.2

  v2.0.6 2007/01/17
    * Fixed issues from the last release: eval code return bug 
      that showed only under 1.5.1 and PHP notice issue when 
      used with the Multilogin plugin under 1.4.x.

  v2.0.5 2007/01/14
    * Revamped legacy mechanism; cleaned up include files and
      included functions (as mentioned in the README, if plugin
      authors find functions they need for better compatibility,
      please get in touch)
    * Added missing include in the case of errors in load_config
    * Added get_current_hook_name(), add_plugin(), remove_plugin()
      and reposition_plugin_on_hook() functions
    * Remove use of SM_PATH in functions file in case it is not
      available
    * load_config() and check_plugin_setup() can now also return 
      after an error to allow the caller to handle the error
    * Added patches through SquirrelMail version 1.4.9 and 1.5.0
      (Compatibility plugin is natively loaded in 1.5.1 and up)

  v2.0.4 2005/11/11
    * Sorry, folks.  Changed the location of the compatibility patch
      again.  When upgrading to this version, you *MUST* remove the
      patch from version 2.0.3 (to do so, just re-run the patch for
      that version *BEFORE* you unpack and install this version).
      As with before, patches from version 2.0.2 or previous will do
      no harm if left in place.  If you are using version 2.0.3,
      upgrade is especially recommended.

  v2.0.3 2005/10/24
    * Changed the location of the compatibility patch.  Everyone
      upgrading to this version will need to re-run the patch!
      The old compatibility patch becomes obsolete, but it does
      not hurt anything to be left in place.

  v2.0.2 2005/10/19
    * Added load_config function for use by other plugins
    * Added new sqsetcookie and sqsession_start functions to includes
    * Added new checkForJavascript function to includes

  v2.0.1 2005/07/14
    * Documentation change (plugins *never* need to include
      Compatibility directly)
    * Added 1.4.6 includes directory
    * Added is_plugin_enabled() up to 1.4.5 and 1.5.0

  v2.0 2005/06/16
    * Reorganized code so that plugin authors do not need
      to specifically use "compatibility_" functions.
    * Changed compatibility_check_plugin_setup() to check_plugin_setup()
 
  1.3 - Paul Lesniewski  <paul@squirrelmail.org>
   * Added compatibility_check_plugin_setup() that helps verify that
     a plugin has been installed and set up correctly
   * Added new $compatibility_sm_path variable for easier plugin coding...
   * Updated for compatibility (!) with new version reporting API

  1.2 - Paul Lesniewski  <paul@squirrelmail.org>
   * Fix for theme problem with plugins under SM 1.4

  1.1 - Paul Lesniewski  <paul@squirrelmail.org>
   * Some applications of this plugin were experiencing
     unusual include order, so added includes of the
     global.php and strings.php files to be safe.
   * Even though older versions of SquirrelMail have
     some of the functions that this plugin duplicates,
     because they have session issues, the compatibility
     version of those functions now takes precedence over
     older SquirrelMail core code.

  1.0 - Paul Lesniewski  <paul@squirrelmail.org>
   * Initial release