Currently, for each `Disconnect()` call, we spawn a coroutine, but every
one of them is just usesless, except the first one. However, since all
`Disconnect()` usages share the same asio strand and cannot interfere
with each other, spawning another coroutine within `Disconnect()` isn't
even necessary. When a coroutine calls `Disconnect()` now, it will
immediately initiate an async shutdown of the socket, potentially causing
the coroutine to yield and allowing the others to resume. Therefore, the
`m_ShuttingDown` flag is still required by the coroutines to be checked
regularly.
When a HTTP connection dies prematurely while the response is sent,
`http::async_write()` sets the error code to something like broken pipe for
example. When calling `async_flush()` afterwards, it sometimes happens that
this never returns. This results in a resource leak as the coroutine isn't
cleaned up. This commit makes the individual functions throw exceptions instead
of silently ignoring the errors, resulting in the function terminating early
and also resulting in an error being logged as well.
Boost.Beast changed the signature of the previously used generic `set`
method so that it no longer accepts integer types, however there is
alreay a more specific method for setting the Content-Length header, so
use this one instead.
This is required to
- catch all exceptions and wrap them into Boost exceptions. They
are the only ones allowed with Boost.Coroutine.
- set a dedicated coroutine stack size for Windows.
refs #7431
Throwing local exceptions unnecessarily pollutes the exception
stack with immediate unwinding. Avoid this pattern at all cost within
Boost.Coroutines. MSVC may handle exceptions differently and cause
problems with stack unwinding.
refs #7431
refs #7351
Exceptions in Disconnect() might be thrown (this has been reworked
into error_code locally) which are swallowed inside the Destructor
for being dangerous. On the other hand, swallowing them may
corrupt the stack unwinding operation from the coroutine layer.
The best is to avoid Defer inside lib/remote and call Disconnect()
directly after breaking from other operations.
refs #7351
refs #7431
When run within a coroutine, exceptions on Windows may influence
bad behaviour here. Instead, we'll check for the error code
and extract the message from memory. In contrast to exceptions
which are stored on the stack frame and then return, this costs
a little more memory but simplifies the logic.
This doesn't fix the linked issue, but is related to the analysis.
refs #7431
Yonas Habteab
Julian Brost
Alexander Aleksandrovič Klimov
Michael Friedrich