On Sat, 22 Jan 2005 14:00:42 +0100, Sven Neumann <sven@xxxxxxxx> wrote: > Raphaël Quinet <quinet@xxxxxxxxxx> writes: > > [...] I am worried about the configuration parameters that could > > be used by more than one plug-in. > > > Of course plug-ins must not access gimprc directly. gimprc is the core > rc file and must only be read and written by the core. I was rather > thinking of letting each plug-in use it's own config file, located in > the ~/.gimp-2.x directory. I expected this suggestion, which is why I wrote that I was worried about the parameters the could be used by more than one plug-in. If each plug-in uses its own config file, then it will become tricky for two plug-ins to share some config settings. This could happen if the load and save plug-ins for some file format want to share some settings, or for parameters that could be shared by many plug-ins, such as some metadata (default author, default copyright/license, etc.) or color profile information, whether some conversions should be done automatically, ... Some of these things could be handled by the GIMP and stored into global parasites as we already have the default comment but that would only solve a part of the problem. Besides, I would prefer to get rid of the default-comment parasite and move that to a proper GimpConfig object instead of having to add several new global parasites for the configurable defaults of some other parts of the metadata (author, copyright, etc.). So we still have a problem for the settings that are used by more than one plug-in. If two plug-ins (or a plug-in and the core) want to save some settings into the same file (gimprc or some other shared file) and do it at the same time, then you don't know if you will only get the settings from one, from both, or if you will get garbage. Although the race conditions would not occur too often and we could decide to ignore them, there are some situations that make them more likely. For example, when you have several images open and you save them all before quitting the GIMP. > Regarding concurrent writes, I should probably note that > GimpConfigWriter writes to a temporary file and moves it to the final > destination when done. This is a good thing and that prevents the "garbage" case from happening. But there is still a problem if two plug-ins want to update some config settings stored in the same file: you will only get the updates from one plug-in (or from the core), but you don't know which one. Of course, if both plug-ins want to update the same settings, then the user will only get what he deserves. But if they want to update different settings (no conflict) then one of them will be lost. This could be avoided if all GimpConfig updates were serialized through the PDB. -Raphaël
