netsocket: socket operations return error codes via return values #4092
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…ketSet()` This instead should always throw `std::bad_alloc`. Signed-off-by: Pavel Solodovnikov <[email protected]>
`operator new` will throw a `std::bad_alloc` exception instead of returning `nullptr`, so there's no need to check for `nullptr` after trying to allocate a new `Socket` instance. Signed-off-by: Pavel Solodovnikov <[email protected]>
Signed-off-by: Pavel Solodovnikov <[email protected]>
…slation of network errors Signed-off-by: Pavel Solodovnikov <[email protected]>
Signed-off-by: Pavel Solodovnikov <[email protected]>
Signed-off-by: Pavel Solodovnikov <[email protected]>
…, std::error_code>` Plus, add the necessary dependency for the `netplay` library in order for it to find `tl::expected` header files. Signed-off-by: Pavel Solodovnikov <[email protected]>
Switch to returning socket error codes explicitly via return values
instead of using legacy functions `getSockErr()`, `setSockErr`,
`strSockError()` to get extended error context.
To facilitate that, use `tl::expected<T, std::error_code>` as the
return value type for all main socket operations: read, write, open,
listen.
Moving to this new approach has numerous benefits over the old one:
1. Instead of using POSIX constants directly, we wrap them into
`std::error_code` instances, which allows to attach custom error
categories to them. This can be used to customize error messages
and error codes mapping to platform-independent
`std::error_conditions`.
2. Calling separate `get/setSockErr()` functions is error-prone:
one can easily forget to check the error condition from
`getSockErr()` and the value will be overwritten by the next
socket function without the ability to recover the former error.
Conversely, one can forget to call `setSockErr()` to set
the proper error code for the caller to check upon.
3. As mentioned above, `std::error_code:s` can be implicitly mapped
to platform-independent `std::error_conditions`, allowing for this
code to compile successfuly:
if (errCode == std::errc::connection_reset) { ... }
This allows for very convenient and portable error checking
code, which completely hides implementation details of how
a particular error code is implemented (but, if one really needs to,
they still can extract the platform-dependent error code value
to get the extended error context).
The `getSockErr()`, `setSockErr` and `strSockError()` functions
are still used in the `netsocket.cpp` implementation, but now they are
strictly confined to this particular translation unit, meaning
they have now become an implementation detail, rather than a part of
public API contract of `netplay` library.
Signed-off-by: Pavel Solodovnikov <[email protected]>
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Oct 19, 2024
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Switch to returning socket error codes explicitly via return values instead of using legacy functions
getSockErr(),setSockErr,strSockError()to get extended error context.To facilitate that, use
tl::expected<T, std::error_code>as the return value type for all main socket operations: read, write, open, listen.Moving to this new approach has numerous benefits over the old one:
Instead of using POSIX constants directly, we wrap them into
std::error_codeinstances, which allows to attach custom error categories to them. This can be used to customize error messages and error codes mapping to platform-independentstd::error_conditions.Calling separate
get/setSockErr()functions is error-prone: one can easily forget to check the error condition fromgetSockErr()and the value will be overwritten by the next socket function without the ability to recover the former error.Conversely, one can forget to call
setSockErr()to set the proper error code for the caller to check upon.As mentioned above,
std::error_code:scan be implicitly mapped to platform-independentstd::error_conditions, allowing for this code to compile successfuly:if (errCode == std::errc::connection_reset) { ... }This allows for very convenient and portable error checking code, which completely hides implementation details of how a particular error code is implemented (but, if one really needs to, they still can extract the platform-dependent error code value to get the extended error context).
The
getSockErr(),setSockErrandstrSockError()functions are still used in thenetsocket.cppimplementation, but now they are strictly confined to this particular translation unit, meaning they have now become an implementation detail, rather than a part of public API contract ofnetplaylibrary.Signed-off-by: Pavel Solodovnikov [email protected]