feature: pool with wildcard

[evgfedotov]

Some MVP PR to demonstrate #114

[vmg]

I think we'd be better set by using the standard library's path.Match, since the GoImportPath here contains slashes, it'd be good if our wildcard function was slash-aware.

Also, why the composition with Sprintf here? Doesn't protogen.GoIdent have a String method? Pretty sure it does.

[evgfedotov]

Agreed, should use path.Match instead.

protogen.GoIdent have String method. But uses quoted GoImportPath part.
(https://github.com/protocolbuffers/protobuf-go/blob/master/compiler/protogen/protogen.go#L1226)

[vmg]

This is not great, and won't work once we use path.Match because those wildcards also support ?. I think we should assume that all patterns are wildcards and just attempt matching accordingly.

[vmg]

Is this a feature we really need? I'd rather drop this flag. It should always be able to write a more careful pattern for Poolable to make sure it doesn't match any unnecessary structs.

[vmg]

The new matching looks good but I still don't like poolable-exclude. I'd prefer to keep the CLI surface smaller. Thanks!

[evgfedotov]

@vmg Hi! Thanks for your comments.

Sorry for the long answer.

Looks like in cases where wee need multiple deep pathes with differend structures like:

pool=github.com/my/awesome/repo/path/to/proto/one/example.Message
pool=github.com/my/awesome/repo/path/two/to/proto/two/example.Message

where I actually need

pool=github.com/my/awesome/repo/*

usage of path.Match wildcards requires following of full directory depth. For example:

pool=github.com/my/awesome/repo/path/*/*/*/*
pool=github.com/my/awesome/repo/path/*/*/*/*/*

I thinking about usage something like https://github.com/bmatcuk/doublestar. Which provides opportunity for represent different path depths with ** wildcard. Then next example would be:

pool=github.com/my/awesome/repo/**

[evgfedotov]

And I'm still not sure about removing poolable-exclude because it could give more flexible api. For example, for proto with a large number of messages from whom I want to remove generating pool feature for one of them. That leads to enumerate every message excep one.