0
0
Fork 0
mirror of https://github.com/matrix-construct/construct synced 2024-11-14 14:01:08 +01:00
construct/ircd/ctx.h

86 lines
3.3 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.
namespace ircd::ctx
{
struct stack;
struct profile;
void spawn(ctx *const c, context::function func);
}
namespace ircd::ctx::prof
{
void mark(const event &);
}
/// Internal structure aggregating any stack related state for the ctx
struct ircd::ctx::stack
{
uintptr_t base {0}; // assigned when spawned
size_t max {0}; // User given stack size
size_t at {0}; // Updated for profiling at sleep
stack(const size_t &max = 0)
:max{max}
{}
};
/// Internal context implementation
///
struct ircd::ctx::ctx
:instance_list<ctx>
{
static uint64_t id_ctr; // monotonic
uint64_t id {++id_ctr}; // Unique runtime ID
string_view name; // User given name (optional)
context::flags flags; // User given flags
int32_t notes {0}; // norm: 0 = asleep; 1 = awake; inc by others; dec by self
boost::asio::io_service::strand strand; // mutex/serializer
boost::asio::steady_timer alarm; // acting semaphore (64B)
boost::asio::yield_context *yc {nullptr}; // boost interface
continuation *cont {nullptr}; // valid when asleep; invalid when awake
list::node node; // node for ctx::list
ircd::ctx::stack stack; // stack related structure
prof::ticker profile; // prof related structure
dock adjoindre; // contexts waiting for this to join()
bool started() const; // context was ever entered
bool finished() const; // context will not be further entered.
bool interruption_point(std::nothrow_t); // Check for interrupt (and clear flag)
bool termination_point(std::nothrow_t); // Check for terminate
void interruption_point(); // throws interrupted or terminated
bool wake(); // jump to context by queueing with ios (use note())
bool note(); // properly request wake()
bool wait(); // yield context to ios queue (returns on this resume)
void jump(); // jump to context directly (returns on your resume)
void operator()(boost::asio::yield_context, const std::function<void ()>) noexcept;
ctx(const string_view &name = "<noname>"_sv,
const size_t &stack_max = DEFAULT_STACK_SIZE,
const context::flags &flags = (context::flags)0U,
boost::asio::io_service &ios = ircd::ios::get())
:name{name}
,flags{flags}
,strand{ios}
,alarm{ios}
,stack{stack_max}
{}
ctx(ctx &&) = delete;
ctx(const ctx &) = delete;
ctx &operator=(ctx &&) = delete;
ctx &operator=(const ctx &) = delete;
~ctx() noexcept;
};