This adds the infrastructure required to process validation events. For
now the external validation interface only has support for the
`BlockChecked` , `NewPoWValidBlock`, `BlockConnected`, and
`BlockDisconnected` callback. Support for the other internal
validation interface methods can be added in the future.
The validation interface follows an architecture for defining its
callbacks and ownership that is similar to the notifications.
The task runner is created internally with a context, which itself
internally creates a unique ValidationSignals object. When the user
creates a new chainstate manager the validation signals are internally
passed to the chainstate manager through the context.
A validation interface can register for validation events with a
context. Internally the passed in validation interface is registerd with
the validation signals of a context.
The callbacks block any further validation execution when they are
called. It is up to the user to either multiplex them, or use them
otherwise in a multithreaded mechanism to make processing the validation
events non-blocking.
I.e. for a synchronous mechanism, the user executes instructions
directly at the end of the callback function:
```mermaid
sequenceDiagram
participant V as Validation
participant C as Callback
V->>C: Call callback
Note over C: Process event (blocks)
C-->>V: Return
Note over V: Validation resumes
```
To avoid blocking, the user can submit the data to e.g. a worker thread
or event manager, so processing happens asynchronously:
```mermaid
sequenceDiagram
participant V as Validation
participant C as Callback
participant W as Worker Thread
V->>C: Call callback
C->>W: Submit to worker thread
C-->>V: Return immediately
Note over V: Validation continues
Note over W: Process event async
```
Add `btck_import_blocks` to import block data and rebuild indexes. The
function can either reindex all existing block files if the indexes were
previously wiped through the chainstate manager options, or import
blocks from specified file paths.
This allows a user to run the kernel without creating on-disk files for
the block tree and chainstate indexes. This is potentially useful in
scenarios where the user needs to do some ephemeral validation
operations.
One specific use case is when linearizing the blocks on disk. The block
files store blocks out of order, so a program may utilize the library
and its header to read the blocks with one chainstate manager, and then
write them back in order, and without orphans, with another chainstate
maanger. To save disk resources and if the indexes are not required once
done, it may be beneficial to keep the indexes in memory for the
chainstate manager that writes the blocks back again.
Adds options for wiping the chainstate and block tree indexes to the
chainstate manager options. In combination and once the
`*_import_blocks(...)` function is added in a later commit, this
triggers a reindex. For now, it just wipes the existing data.
The added function allows the user process and validate a given block
with the chainstate manager. The *_process_block(...) function does some
preliminary checks on the block before passing it to
`ProcessNewBlock(...)`. These are similar to the checks in the
`submitblock()` rpc.
Richer processing of the block validation result will be made available
in the following commits through the validation interface.
The commits also adds a utility for deserializing a `CBlock`
(`kernel_block_create()`) that may then be passed to the library for
processing.
The tests exercise the function for both mainnet and regtest. The
commit also adds the data of 206 regtest blocks (some blocks also
contain transactions).
This is the main driver class for anything validation related, so expose
it here.
Creating the chainstate manager options will currently also trigger the
creation of their respectively configured directories.
The chainstate manager and block manager options are consolidated into a
single object. The kernel might eventually introduce a separate block
manager object for the purposes of being a light-weight block store
reader.
The chainstate manager will associate with the context with which it was
created for the duration of its lifetime and it keeps it in memory with
a shared pointer.
The tests now also create dedicated temporary directories. This is
similar to the behaviour in the existing unit test framework.
Co-authored-by: stickies-v <stickies-v@protonmail.com>
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>
