The notifications are used for notifying on connected blocks and on
warning and fatal error conditions.
The user of the C header may define callbacks that gets passed to the
internal notification object in the
`kernel_NotificationInterfaceCallbacks` struct.
Each of the callbacks take a `user_data` argument that gets populated
from the `user_data` value in the struct. It can be used to recreate the
structure containing the callbacks on the user's side, or to give the
callbacks additional contextual information.
As a first option, add the chainparams. For now these can only be
instantiated with default values. In future they may be expanded to take
their own options for regtest and signet configurations.
This commit also introduces a unique pattern for setting the option
values when calling the `*_set(...)` function.
The context introduced here holds the objects that will be required for
running validation tasks, such as the chosen chain parameters, callbacks
for validation events, and interrupt handling. These will be used by the
chainstate manager introduced in subsequent commits.
This commit also introduces conventions for defining option objects. A
common pattern throughout the C header will be:
```
options = object_option_create();
object = object_create(options);
```
This allows for more consistent usage of a "builder pattern" for
objects where options can be configured independently from
instantiation.
Exposing logging in the kernel library allows users to follow
operations. Users of the C header can use
`kernel_logging_connection_create(...)` to pass a callback function to
Bitcoin Core's internal logger. Additionally the level and category can
be globally configured.
By default, the logger buffers messages until
`kernel_loggin_connection_create(...)` is called. If the user does not
want any logging messages, it is recommended that
`kernel_disable_logging()` is called, which permanently disables the
logging and any buffering of messages.
Co-authored-by: stringintech <stringintech@gmail.com>
As a first step, implement the equivalent of what was implemented in the
now deprecated libbitcoinconsensus header. Also add a test binary to
exercise the header and library.
Unlike the deprecated libbitcoinconsensus the kernel library can now use
the hardware-accelerated sha256 implementations thanks for its
statically-initialzed context. The functions kept around for
backwards-compatibility in the libbitcoinconsensus header are not ported
over. As a new header, it should not be burdened by previous
implementations. Also add a new error code for handling invalid flag
combinations, which would otherwise cause a crash.
The macros used in the new C header were adapted from the libsecp256k1
header.
To make use of the C header from C++ code, a C++ header is also
introduced for wrapping the C header. This makes it safer and easier to
use from C++ code.
Co-authored-by: stickies-v <stickies-v@protonmail.com>
