I think the issue is that the *consumer* of this object checks whether certain methods (or rather, interfaces) are present, and behaves differently depending whether they are or not.
There are a whole load of public interfaces defined here: https://cs.opensource.google/go/go/+/refs/tags/go1.20.5:src/database/sql/driver/driver.go And the supplied object, which the OP is trying to wrap, could implement some arbitrary combination of these interfaces. I think that for *some* of these interfaces, it would be OK to provide dummy implementations if there is no underlying method to call: e.g. https://cs.opensource.google/go/go/+/refs/tags/go1.20.5:src/database/sql/sql.go;l=552-554 https://cs.opensource.google/go/go/+/refs/tags/go1.20.5:src/database/sql/sql.go;l=567-569 https://cs.opensource.google/go/go/+/refs/tags/go1.20.5:src/database/sql/sql.go;l=834-838 But for others it's much less clear, and it may make a semantic difference whether the the object you provide implements these interfaces or not, e.g. https://cs.opensource.google/go/go/+/refs/tags/go1.20.5:src/database/sql/sql.go;l=1865-1867 For these, I can't think of a better implementation that the OP's. It doesn't seem like the greatest API design though. On Sunday, 11 June 2023 at 08:10:01 UTC+1 Tamás Gulácsi wrote: > As Far as I See, you check all the combinations of methods in wideness > order. > Why not have a generic wrapper struct, that is filled with the underlying > driver.Conn's methods, > and use that if not nil, but use the generic implementation if not. > > Like > ``` > type wrappedConn struct { > driver.Conn > queryContext func(...) > } > func (wc wrappedConn) QueryContext(...) ... { > if wc.queryContext != nil { return wc.queryContext(...) } > return wc.Conn.Query(...) > } > ``` > > This way you only have to check for each method on driver.Conn, and fill > the wrappedConn's functions as they axist/not. > > Vasiliy Tolstov a következőt írta (2023. június 10., szombat, 12:16:34 > UTC+2): > >> I have sql driver that wraps original driver.Driver, to be able to work >> with drivers that not have ExecerContext or QuerierContext i need to return >> wrapped to that supports only needed interfaces. >> I'm to want to write all cases via handmade switch case and write >> generator that creates full combo list of methods and generate interfaces >> for this methods. >> But this brings file that contains 20K lines >> https://git.unistack.org/unistack-org/micro-wrapper-sql/src/branch/master/wrap_gen.go >> Does it possible to have smaller code that provides the same effect? >> Or I'm miss something? >> >> -- >> Vasiliy Tolstov, >> e-mail: v.to...@selfip.ru >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/4dc775df-6627-4134-8b32-e9f659e48831n%40googlegroups.com.
