diff options
author | toma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da> | 2009-11-25 17:56:58 +0000 |
---|---|---|
committer | toma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da> | 2009-11-25 17:56:58 +0000 |
commit | ce4a32fe52ef09d8f5ff1dd22c001110902b60a2 (patch) | |
tree | 5ac38a06f3dde268dc7927dc155896926aaf7012 /kconf_update/README.kconf_update | |
download | tdelibs-ce4a32fe52ef09d8f5ff1dd22c001110902b60a2.tar.gz tdelibs-ce4a32fe52ef09d8f5ff1dd22c001110902b60a2.zip |
Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.
BUG:215923
git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdelibs@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
Diffstat (limited to 'kconf_update/README.kconf_update')
-rw-r--r-- | kconf_update/README.kconf_update | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/kconf_update/README.kconf_update b/kconf_update/README.kconf_update new file mode 100644 index 000000000..14d50ad66 --- /dev/null +++ b/kconf_update/README.kconf_update @@ -0,0 +1,251 @@ +README kconf_update + +Version: 1.1 +Author: Waldo Bastian <bastian@kde.org>, <bastian@suse.com> + +What it does +============ + +kconf_update is a tool designed to update config files. Over time applications +sometimes need to rearrange the way configuration options are stored. Since +such an update shouldn't influence the configuration options that the user +has selected, the application must take care that the options stored in the +old way will still be honored. + +What used to happen is that the application looks up both the old and the +new configuration option and then decides which one to use. This method has +several drawbacks: +* The application may need to read more configuration files than strictly +needed, resulting in a slower startup. +* The application becomes bigger with code that will only be used once. + +kconf_update addresses these problems by offering a framework to update +configuration files without adding code to the application itself. + + +How it works +============ + +Applications can install so called "update files" under +$KDEDIR/share/apps/kconf_update. An update file has ".upd" as extension and +contains instructions for transferring/converting configuration information +from one place to another. + +Updating the configuration happens automatically, either when KDE gets started +or when kded detects a new update file in the above mentioned location. + +Update files are separated into sections. Each section has an Id. When a +section describing a configuration change has been applied, the Id will be +stored in the file "kconf_updaterc". This information is used to make sure +that a configuration update is only performed once. + +If you overwrite an existing update file with a new version that contains a +new section, only the update instructions from this extra section will be +performed. + +File format of the update file +============================== + +Empty lines or lines that start with '#' are considered comments. +Commas (,) are used to seperate fields and may not occur as part +of any field and all of the keywords are case-sensitive, i.e. you +cannot say "key" instead of "Key" for example. + +For the rest the file is parsed and executed sequentially from top to bottom. +Each line can contain one entry. The following entries are recognized: + + +Id=<id> + +With <id> identifying the group of update entries that follows. Once a group +of entries have been applied, their <id> is stored and this group of entries +will not be applied again. + + +File=<oldfile>,<newfile> +File=<oldfile> + +Specifies that configuration information is read from <oldfile> and written +to <newfile>. If you only specify <oldfile>, the information is read from +as well as written to <oldfile>. + +Script=<script>[,<interpreter>] + +All entries from <oldfile> are piped into <script>. The output of script +is used as new entries for <newfile>. Existing entries can be deleted by +adding lines with "# DELETE [group]key" in the output of the script. +To delete a whole group use "# DELETEGROUP [group]". + +<script> should be installed into $(kde_datadir)/kconf_update, or +kconf_update will not be able to find it. It is not portable to install +binary applications in $kde_datadir, so you have to stick with interpreted +scripts like sh or perl scripts. From KDE 3.2 onwards it's also possible +to install kconf_update applications in $(kde_bindir)/kconf_update_bin, +which opens the door to kconf_update applications that are written in C++ +and use Qt's powerful string API instead. + +A workaround for KDE 3.1.x and older is to install a .sh script in +$(kde_datadir) that contains a simple exec: + + exec "`kde-config --prefix`/bin/kconf_update_bin/my_update_app" + +This is equivalent to what KDE 3.2 can do directly, but of course the .upd +file now points to the .sh script instead of the binary application. + +If Script was issued after a "Group" command the behavior is slightly +different: +All entries from <oldfile>/<oldgroup> are piped into <script>. The output +of script is used as new entries for <newfile>/<newgroup>, unless a different +group is specified with "[group]". Existing entries can be deleted from +<oldgroup> by adding lines with "# DELETE key" in the output of the script. +To delete <oldgroup> use "# DELETEGROUP". + +<interpreter> can be something like "perl". + +Since KDE 3.3 it is also possible to have a Script without specifying +<oldfile> or <newfile>. In that case the script is run but it will not be +fed any input and its output will simply be discarded. + +ScriptArguments=<arguments> + +If specified, the arguments will be passed to <script>. +IMPORTANT: It has to be specified before Script=. + +Group=<oldgroup>,<newgroup> +Group=<oldgroup> + +Specifies that configuration information is read from the group <oldgroup> +and written to <newgroup>. If you only specify <oldgroup>, the information +is read from as well as written to <oldgroup>. You can use <default> to +specify keys that are not under any group. + +RemoveGroup=<oldgroup> + +Specifies that <oldgroup> is removed entirely. This can be used +to remove obsolete entries or to force a revert to default values. + +Options=<option1>, <option2>, .... + +With this entry you can specify options that apply to the next "Script", +"Key" or "AllKeys" entry (only to the first!). Possible options are: + +- "copy" Copy the configuration item instead of moving it. This means that + the configuration item will not be deleted from <oldfile>/<oldgroup>. + +- "overwrite" Normally, a configuration item is not moved if an item with the + new name already exists. When this option is specified the old + configuration item will overwrite any existing item. + + +Key=<oldkey>,<newkey> +Key=<oldkey> + +Specifies that configuration information is read from the key <oldkey> +and written to <newkey>. If you only specify <oldkey>, the information +is read from as well as written to <oldkey>. + + +AllKeys + +Specifies that all configuration information in the selected group should +be moved (All keys). + +AllGroups + +Specifies that all configuration information from all keys in ALL +groups should be moved. + + +RemoveKey=<oldkey> + +Specifies that <oldkey> is removed from the selected group. This can be used +to remove obsolete entries or to force a revert to default values. + + +Example update file +=================== + +# This is comment +Id=kde2.2 +File=kioslaverc,kio_httprc +Group=Proxy Settings +Key=NoProxyFor +Key=UseProxy +Key=httpProxy,Proxy +Group=Cache Settings,Cache +Key=MaxCacheSize +Key=UseCache +Group=UserAgent +AllKeys +RemoveGroup=KDE +# End of file + + +The above update file extracts config information from the file "kioslaverc" +and stores it into the file "kio_httprc". + +It reads the keys "NoProxyFor", "UseProxy" and "httpProxy" from the group +"Proxy Settings" in the "kioslaverc" file. If any of these options are present +they are written to the keys "NoProxyFor", "UseProxy" and "Proxy" (!) in +the group "Proxy Settings" in the "kio_httprc" file. + +It also reads the keys "MaxCacheSize" and "UseCache" from the group +"Cache Settings" in the "kioslaverc" file and writes this information to the +keys "MaxCacheSize" and "UseCache" in the group "Cache" (!) in the +"kio_httprc" file. + +Then it takes all keys in the "UserAgent" group of the file "kioslaverc" +and moves then to the "UserAgent" group in the "kio_httprc" file. + +Finally it removes the entire "KDE" group in the kioslaverc file. + + +Debugging and testing +===================== + +If you are developing a kconf_update script and want to test or debug it you +need to make sure kconf_update runs again after each of your changes. There +are a number of ways to achieve this. + +The easiest is to not install the kconf_update script in the first place, but +manually call it through a pipe. If you want to test the update script for +your application KHello's config file khellorc, you can test by using + + cat ~/.kde/share/config/khellorc | khello_conf_update.sh + +(assuming khello_conf_update.sh is the kconf_update script and ~/.kde is your +$KDEHOME). This is easier than making install every time, but has the obvious +downside that you need to 'parse' your script's output yourself instead of +letting kconf_update do it and check the resulting output file. + +After 'make install' the kconf_update script is run by kded, but it does so +only once. This is of course the idea behind it, but while developing it can +be a problem. You can increase the revision number for each subsequent run +of 'make install' to force a new kconf_update run, but there's a better +approach that doesn't skyrocket the version number for a mediocre debug +session. + +kded doesn't really ignore scripts that it has already run right away. +Instead it checks the affected config file every time a .upd file is added +or changed. The reason it still doesn't run again on your config file lies +in the traces kconf_update leaves behind: it adds a special config group +'[$Version]' with a key 'update_info'. This key lists all kconf_update +scripts that have already been run on this config file. Just remove your +file's entry, 'make install', and kconf_update will happily run your script +again, without you having to increase the version number. + +If you want to know what kconf_update has been up to lately, have a look +at $KDEHOME/share/apps/kconf_update/update.log + + +Common Problems +=============== + +* kconf_update refuses to update an entry +If you change the value of an entry without changing the key or file, +make sure to tell kconf_update that it should overwrite the old entry +by adding "Options=overwrite". + + +Have fun, +Waldo |