Add copy_directory rule

[kormide]

Following up on the discussion in @alexeagle's PR (#323) to add a new copy_directory rule.

[kormide]

@tetromino do you have any feedback on this PR?

[tetromino]

@kormide,please ask one of the other maintainers for review - I will have very limited availability until July (paternity leave).

[kormide]

@kormide,please ask one of the other maintainers for review - I will have very limited availability until July (paternity leave).

Yes, no problem. And congratulations! 🎉

[kormide]

@brandjon Do you have any feedback on this PR?

[kormide]

@comius, @hvadehra, or @c-mita do you have any feedback on this PR?

[comius]

@hvadehra can you review this one?

[hvadehra]

Looks good to me, thanks!

[kormide]

Are we ready to merge, or does this require further review?

[kkpattern]

copy_directory is very useful to us, thanks for implementing it!

Maybe we can add another copy_files_to_directory?

The difference between copy_files_to_directory with copy_directory is that only seletced files will be copied and they don't have to be in the same source directroy.

The difference between copy_files_to_directory with copy_file is that we can use filegroup to copy multiple files at the same time. Something like:

filegroup(
    name = "files_to_copy",
    srcs = glob(["a/*.h", "b/*.h"]),
)

copy_files_to_directory(
    name = "copy_files",
    srcs = [":files_to_copy"],
    output = "path/to/target/directory",
)

I found a related copy_filegroup_to_package implementation here from a StackOverflow question.

[kormide]

copy_directory is very useful to us, thanks for implementing it!

Maybe we can add another copy_files_to_directory?

The difference between copy_files_to_directory with copy_directory is that only seletced files will be copied and they don't have to be in the same source directroy.

The difference between copy_files_to_directory with copy_file is that we can use filegroup to copy multiple files at the same time. Something like:

filegroup(
    name = "files_to_copy",
    srcs = glob(["a/*.h", "b/*.h"]),
)

copy_files_to_directory(
    name = "copy_files",
    srcs = [":files_to_copy"],
    output = "path/to/target/directory",
)

I found a related copy_filegroup_to_package implementation here from a StackOverflow question.

@kkpattern Something like this copy_to_directory rule that we wrote?

[kkpattern]

@kkpattern Something like this copy_to_directory rule that we wrote?

Yes! Looks like exactly what we need.