Also make CompactPair<A, B> a literal type if A and B are literal types,
and add MaybeStorageBase that ought to be used as a basis of MaybeStorage
in a follow-up patch.
Differential Revision: https://phabricator.services.mozilla.com/D55930
This also adds an UnusedZeroEnum template to Result.h, which can be used
for specializing UnusedZero for scoped enum types.
Differential Revision: https://phabricator.services.mozilla.com/D97074
No longer reset a moved-from Result to an error state, which required
UnusedZero<E>::GetDefaultValue, which was somewhat confusing, and might
also be inefficient. Leaving Result in a valid state, which might be a
success or error state is sufficient.
Differential Revision: https://phabricator.services.mozilla.com/D91250
Among other things, there were some misuses of std::forward, and
GenericErrorResult was (presumably accidentally) instatiated with
references as the template argument type, e.g. const nsresult&,
which circumvented the check for not calling it with NS_OK in
ResultExtensions.h
Differential Revision: https://phabricator.services.mozilla.com/D90561
Among other things, there were some misuses of std::forward, and
GenericErrorResult was (presumably accidentally) instatiated with
references as the template argument type, e.g. const nsresult&,
which circumvented the check for not calling it with NS_OK in
ResultExtensions.h
Differential Revision: https://phabricator.services.mozilla.com/D90561
It seems that the clang toolchain has trouble optimizing away the tag access in
a `mozilla::Variant`. Use of a `CompactPair` seems to be better when `E` is
small (all cases where `UnusedZero<E>` is true are small right now anyway).
While this doesn't change `sizeof(Result<V, E>)` in most cases, it makes
the generated code simpler/smaller: As of now, this reduce the overall VM size
of libxul.so by ca. 59K.
Without additional effort, this requires and leads to default-construction of
a `V` even in cases where it is never accessed, so this is restricted to
trivially default-constructible `V` for now.
This could be avoided by replacing `CompactPair<V, E>` by
`CompactPair<AlignedStorage2<V>, E>`.
Differential Revision: https://phabricator.services.mozilla.com/D88393
It seems that the clang toolchain has trouble optimizing away the tag access in
a `mozilla::Variant`. Use of a `CompactPair` seems to be better when `E` is
small (all cases where `UnusedZero<E>` is true are small right now anyway).
While this doesn't change `sizeof(Result<V, E>)` in most cases, it makes
the generated code simpler/smaller: As of now, this reduce the overall VM size
of libxul.so by ca. 59K.
Without additional effort, this requires and leads to default-construction of
a `V` even in cases where it is never accessed, so this is restricted to
trivially default-constructible `V` for now.
This could be avoided by replacing `CompactPair<V, E>` by
`CompactPair<AlignedStorage2<V>, E>`.
Differential Revision: https://phabricator.services.mozilla.com/D88393
Also, remove the existing uses of Result<const nsCString, nsresult> in URLPreloader
and Result<CryptoScheme, const nsCString> in SampleIterator.
Differential Revision: https://phabricator.services.mozilla.com/D88419
The phrase "copy the error" is misleading, as the error type might not be
copyable, and it is never copied but moved. "Propagate" the error seems to
be a good term to describe this.
Differential Revision: https://phabricator.services.mozilla.com/D75093
Also adds missing includes in some files, these were previously only transivitely
included through mozilla/TypeTraits.h.
Differential Revision: https://phabricator.services.mozilla.com/D68561
--HG--
extra : moz-landing-system : lando
Adds an explicit error mapping function to Result, to simplify
using MOZ_TRY... macros.
Differential Revision: https://phabricator.services.mozilla.com/D47466
--HG--
extra : moz-landing-system : lando
Simon Giesecke
Sylvestre Ledru
Bogdan Tara
Butkovits Atila
Jan Varga
Razvan Maries
André Bargull
Tooru Fujisawa
Doug Thayer