为多个项目设置Perforce软件仓库

Question

Summary: Want help to figure out how to setup the depot and my development environment so that I can support multiple, related projects.

Details: Until now I've had a depot which had in it only one project - ProjectA - robot version A.

I am starting to work on a new version (ProjectB) which has some differences in HW - I/O port mappings and timers have changed. I would like to continue to develop code for both projects.

This means that ProjectB will share some files with the ProjectA and some files will be different.

Since the differences are HW related items what I'm thinking of doing is creating a common area and then project specific areas where the common area is for device independent code and project specific area is for device dependent code.

The differences are big enough that I don't want to do #ifdef within files. Some differences are simple - different I/O port mapping and some are completely new modules.

To make maintainance easier, I would like to be able to compare differences between device dependent code and propagate selected changes.

Finally, to minimize my burden during comparisons, I would like to mark differences that I know are okay so that in future comparisons they don't show up.

Help!

Answer 1

Your instincts are good -- you're trying to Not Duplicate Code. This is the core of good design & engineering.

As for the file layout, it's always annoying to have your directories too deep, but that's MUCH better than too shallow. Maybe:

<root>
  main/
    projects/
       robot1/...
       robot2/...
       shared1/
       shared2/

(Big repositories are much deeper than that, even.)

As for how you make shared code -- you could have different setup.h or constants.h that drive what the various shared libraries do. Alternatively, build your shared libraries so they are parameterized at runtime.

SetupDrivers(0x80020); // address of PIO registers

And lastly -- if the projects really are different, decide if sharing the code really is the right thing. Usually yes, but everything is a choice. If you hope to manually "diff" your files to look for differences, it's really up to you to keep the structures close enough to diff. The "different config.h file for each project" idea mentioned above would help.

If you roll your own diff tool (in python or whatever) you could use special comments to flag "expected different lines".