commit | 6a6a7e5d862a0b8a2258bd0d2d1f182ca830946c | [log] [tgz] |
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author | Atneya Nair <atneya@google.com> | Fri Feb 11 18:18:23 2022 -0500 |
committer | Atneya Nair <atneya@google.com> | Fri Feb 25 14:25:54 2022 -0500 |
tree | ee89f7653c1a6eb91ec4380bd7483cf5de67325c | |
parent | 542f384c6652ee020977c6583fc3ed814df4fc91 [diff] |
Disambiguate OkOrFail conversion sequences - OkOrFail<Result<T,E>> fails to convert to the desired type when using OR_RETURN, and the returning function expects a Result<U, E> and E is implicitly convertible to U. - Added test cases for various ambiguous conversion seq - OkOrFail now only converts to the underlying code type and Result types - Add explicit specializations for numeric types. This is necessary since user defined conversions can be succeeded by numeric conversions - Store only the error, so we can use with non-copyable types For results where the value type is constructible via universal ref AND this construction is valid from the underlying code type, it is not possible to disambiguate while retaining the implicit conversion to code. In this case, if we are compiling with cpp20 concepts, we utilize them to solve the issue. If not, the caller will receive a compile error. Bug: 219580167 Test: atest result_test.cpp Test: atest libbase_result_constraint_test Merged-In: I4bdb25fddea3093635811bf2df25cdb5b2cbe530 Change-Id: I97b4ea523f0a3c753c5d7609758e37e3dd919370
This library is a collection of convenience functions to make common tasks easier and less error-prone.
In this context, “error-prone” covers both “hard to do correctly” and “hard to do with good performance”, but as a general purpose library, libbase's primary focus is on making it easier to do things easily and correctly when a compromise has to be made between “simplest API” on the one hand and “fastest implementation” on the other. Though obviously the ideal is to have both.
The intention is to cover the 80% use cases, not be all things to all users.
If you have a routine that‘s really useful in your project, congratulations. But that doesn’t mean it should be here rather than just in your project.
The question for libbase is “should everyone be doing this?”/“does this make everyone's code cleaner/safer?”. Historically we've considered the bar for inclusion to be “are there at least three unrelated projects that would be cleaned up by doing so”.
If your routine is actually something from a future C++ standard (that isn‘t yet in libc++), or it’s widely used in another library, that helps show that there's precedent. Being able to say “so-and-so has used this API for n years” is a good way to reduce concerns about API choices.
Unlike most Android code, code in libbase has to build for Mac and Windows too.
Code here is also expected to have good test coverage.
By its nature, it‘s difficult to change libbase API. It’s often best to start using your routine just in your project, and let it “graduate” after you're certain that the API is solid.