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construct/include/ircd/m/vm.h

126 lines
4.1 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_M_VM_H
/// Matrix Virtual Machine
///
namespace ircd::m::vm
{
IRCD_M_EXCEPTION(m::error, VM_ERROR, http::INTERNAL_SERVER_ERROR);
IRCD_M_EXCEPTION(VM_ERROR, VM_FAULT, http::BAD_REQUEST);
enum fault :uint;
struct front;
struct eval;
using closure = std::function<void (const event &)>;
using closure_bool = std::function<bool (const event &)>;
using dbs::cursor;
extern struct log::log log;
extern struct fronts fronts;
extern uint64_t current_sequence;
extern ctx::view<const event> inserted;
event::id::buf commit(json::iov &event);
event::id::buf commit(json::iov &event, const json::iov &content);
}
/// Event Evaluation Device
///
/// This object conducts the evaluation of an event or a tape of multiple
/// events. An event is evaluated in an attempt to execute it. Events which
/// fail during evaluation won't be executed; such is the case for events which
/// have already been executed, or events which are invalid or lead to invalid
/// transitions or actions of the machine etc.
///
struct ircd::m::vm::eval
{
struct opts;
struct opts static const default_opts;
const struct opts *opts {&default_opts};
db::txn txn{*dbs::events};
uint64_t cs{0};
fault operator()(const event &);
eval(const event &, const struct opts & = default_opts);
eval(const struct opts &);
eval() = default;
friend string_view reflect(const fault &);
};
/// Evaluation Options
struct ircd::m::vm::eval::opts
{
};
/// Individual evaluation state
///
/// Evaluation faults. These are reasons which evaluation has halted but may
/// continue after the user defaults the fault. They are basically types of
/// interrupts and traps, which are recoverable. Only the GENERAL protection
/// fault (#gp) is an abort and is not recoverable. An exception_ptr will be
/// set; aborts are otherwise just thrown as exceptions from eval. If any
/// fault isn't handled properly that is an abort.
///
enum ircd::m::vm::fault
:uint
{
ACCEPT, ///< No fault.
DEBUGSTEP, ///< Debug step. (#db)
BREAKPOINT, ///< Debug breakpoint. (#bp)
GENERAL, ///< General protection fault. (#gp)
EVENT, ///< Eval requires addl events in the ef register (#ef)
STATE, ///< Required state is missing (#st)
};
/// The "event front" for a graph. This holds all of the childless events
/// for a room. Each childless event may exist at a different depth, but
/// we track the highest depth to increment it for issuing the next event.
/// The contents of the front will then be used as the prev references for
/// that new event. The front is then replaced by the new event. This is
/// managed by the vm core.
///
struct ircd::m::vm::front
{
int64_t top {0};
std::map<std::string, uint64_t, std::less<std::string_view>> map;
};
/// Singleton iface to all "event fronts" - the top depth in an active graph
///
/// This extern singleton is a fundamental structure which holds the highest
/// depth events in a graph which have no children. The fronts collection
/// itself is a map of rooms by ID, and one 'front' is held in RAM for each
/// room. Each front is a collection of those events, which ideally, will
/// become the prev references for the next event this server issues in the
/// room.
///
/// This is managed by the vm core. The fronts interface is the root of the
/// RAM footprint for a room known to IRCd. In other words, all room data is
/// stored in the database except what is reachable through here.
///
struct ircd::m::vm::fronts
{
std::map<std::string, front, std::less<std::string_view>> map;
friend front &fetch(const room::id &, front &, const event &);
public:
front &get(const room::id &, const event &);
front &get(const room::id &);
};