Determine source roots from external builder

Hi,

In my external builder I need to access a properties file with some configuration information. By convention I know it is located in the root of the "source root" as it is called in the module settings.

Unfortunately I don't find a way to get a hold on this information.

- The code below almost gets me there but it give the path to the individuals file while I look for the top level source directory
        for (ModuleBuildTarget target : chunk.getTargets()) {
            try {
                final SourceToOutputMapping srcToOut = context.getProjectDescriptor().dataManager.getSourceToOutputMap(target);

- I read about the use of ProjectFileIndex.SERVICE in  http://devnet.jetbrains.com/message/5490787#5490787 but that does not do the trick for me

Any help would be much appreciated.

Regards,

Johan