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type inspection support on coroutines (with context as common base type)

master
Daniel Kolesa 2017-03-17 02:38:37 +01:00
parent 75e4ac1cb7
commit 959f319318
3 changed files with 112 additions and 46 deletions
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16
examples/coroutine2.cc
View File

@ -14,6 +14,22 @@ int main() {
for (int i: generator<int>{f}) {
writefln("generated: %s", i);
}
generator<int> x{f};
/* coroutine_context exists as a base type for any coroutine */
coroutine_context &ctx = x;
writefln(
"generator is coroutine<int()>: %s",
bool(ctx.coroutine<coroutine<int()>>())
);
writefln(
"generator is generator<int>: %s",
bool(ctx.coroutine<generator<int>>())
);
generator<int> &gr = *ctx.coroutine<generator<int>>();
writefln("value of cast back generator: %s", gr.value());
}
/*

44
ostd/coroutine.hh
View File

@ -254,11 +254,11 @@ namespace detail {
} /* namespace detail */
template<typename R, typename ...A>
struct coroutine<R(A...)>: detail::coroutine_context {
struct coroutine<R(A...)>: coroutine_context {
private:
using base_t = detail::coroutine_context;
using base_t = coroutine_context;
/* necessary so that context callback can access privates */
friend struct detail::coroutine_context;
friend struct coroutine_context;
template<typename RR, typename ...AA>
struct yielder {
@ -389,6 +389,20 @@ public:
base_t::swap(other);
}
std::type_info const &target_type() const {
return p_stor.p_func.target_type();
}
template<typename F>
F *target() { return p_stor.p_func.target(); }
template<typename F>
F const *target() const { return p_stor.p_func.target(); }
std::type_info const &coroutine_type() const {
return typeid(coroutine);
}
private:
void resume_call() {
p_stor.call_helper(*this);
@ -409,10 +423,10 @@ namespace detail {
}
template<typename T>
struct generator: detail::coroutine_context {
struct generator: coroutine_context {
private:
using base_t = detail::coroutine_context;
friend struct detail::coroutine_context;
using base_t = coroutine_context;
friend struct coroutine_context;
template<typename U>
struct yielder {
@ -514,7 +528,7 @@ public:
if (this->is_dead()) {
throw coroutine_error{"dead generator"};
}
detail::coroutine_context::call();
coroutine_context::call();
}
T &value() {
@ -545,7 +559,21 @@ public:
using std::swap;
swap(p_func, other.p_func);
swap(p_result, other.p_result);
detail::coroutine_context::swap(other);
coroutine_context::swap(other);
}
std::type_info const &target_type() const {
return p_func.target_type();
}
template<typename F>
F *target() { return p_func.target(); }
template<typename F>
F const *target() const { return p_func.target(); }
std::type_info const &coroutine_type() const {
return typeid(generator);
}
private:

98
ostd/internal/context.hh
View File

@ -8,6 +8,7 @@
#include <exception>
#include <utility>
#include <typeinfo>
#include "ostd/types.hh"
#include "ostd/platform.hh"
@ -16,30 +17,50 @@
namespace ostd {
namespace detail {
/* from boost.fcontext */
using fcontext_t = void *;
/* from boost.fcontext */
using fcontext_t = void *;
struct transfer_t {
fcontext_t ctx;
void *data;
};
struct transfer_t {
fcontext_t ctx;
void *data;
};
extern "C" OSTD_EXPORT
transfer_t OSTD_CDECL ostd_jump_fcontext(
fcontext_t const to, void *vp
);
extern "C" OSTD_EXPORT
transfer_t OSTD_CDECL ostd_jump_fcontext(
fcontext_t const to, void *vp
);
extern "C" OSTD_EXPORT
fcontext_t OSTD_CDECL ostd_make_fcontext(
void *sp, size_t size, void (*fn)(transfer_t)
);
extern "C" OSTD_EXPORT
fcontext_t OSTD_CDECL ostd_make_fcontext(
void *sp, size_t size, void (*fn)(transfer_t)
);
extern "C" OSTD_EXPORT
transfer_t OSTD_CDECL ostd_ontop_fcontext(
fcontext_t const to, void *vp, transfer_t (*fn)(transfer_t)
);
extern "C" OSTD_EXPORT
transfer_t OSTD_CDECL ostd_ontop_fcontext(
fcontext_t const to, void *vp, transfer_t (*fn)(transfer_t)
);
} /* namespace detail */
struct coroutine_context {
virtual std::type_info const &coroutine_type() const = 0;
template<typename T>
T *coroutine() {
if (coroutine_type() == typeid(T)) {
return reinterpret_cast<T *>(this);
}
return nullptr;
}
template<typename T>
T const *coroutine() const {
if (coroutine_type() == typeid(T)) {
return reinterpret_cast<T const *>(this);
}
return nullptr;
}
protected:
coroutine_context() {}
~coroutine_context() {
@ -71,12 +92,12 @@ protected:
}
void coro_jump() {
p_coro = ostd_jump_fcontext(p_coro, this).ctx;
p_coro = detail::ostd_jump_fcontext(p_coro, this).ctx;
}
void yield_jump() {
p_state = state::HOLD;
p_orig = ostd_jump_fcontext(p_orig, nullptr).ctx;
p_orig = detail::ostd_jump_fcontext(p_orig, nullptr).ctx;
}
bool is_hold() const {
@ -108,7 +129,7 @@ protected:
size_t asize = p_stack.size -
(static_cast<byte *>(p_stack.ptr) - static_cast<byte *>(sp));
p_coro = ostd_make_fcontext(sp, asize, &context_call<C, SA>);
p_coro = detail::ostd_make_fcontext(sp, asize, &context_call<C, SA>);
new (sp) SA(std::move(sa));
}
@ -131,8 +152,8 @@ private:
}
struct forced_unwind {
fcontext_t ctx;
forced_unwind(fcontext_t c): ctx(c) {}
detail::fcontext_t ctx;
forced_unwind(detail::fcontext_t c): ctx(c) {}
};
enum class state {
@ -154,9 +175,9 @@ private:
coro_jump();
return;
}
ostd_ontop_fcontext(
detail::ostd_ontop_fcontext(
std::exchange(p_coro, nullptr), nullptr,
[](transfer_t t) -> transfer_t {
[](detail::transfer_t t) -> detail::transfer_t {
throw forced_unwind{t.ctx};
}
);
@ -165,15 +186,17 @@ private:
template<typename SA>
void finish() {
set_dead();
ostd_ontop_fcontext(p_orig, this, [](transfer_t t) -> transfer_t {
auto &self = *(static_cast<coroutine_context *>(t.data));
auto &sa = *(static_cast<SA *>(self.get_stack_ptr<SA>()));
SA dsa{std::move(sa)};
/* in case it holds any state that needs destroying */
sa.~SA();
dsa.deallocate(self.p_stack);
return { nullptr, nullptr };
});
detail::ostd_ontop_fcontext(
p_orig, this, [](detail::transfer_t t) -> detail::transfer_t {
auto &self = *(static_cast<coroutine_context *>(t.data));
auto &sa = *(static_cast<SA *>(self.get_stack_ptr<SA>()));
SA dsa{std::move(sa)};
/* in case it holds any state that needs destroying */
sa.~SA();
dsa.deallocate(self.p_stack);
return { nullptr, nullptr };
}
);
}
template<typename C, typename SA>
@ -188,7 +211,7 @@ private:
}
try {
self.resume_call();
} catch (detail::coroutine_context::forced_unwind v) {
} catch (coroutine_context::forced_unwind v) {
/* forced_unwind is unique */
self.p_orig = v.ctx;
} catch (...) {
@ -201,13 +224,12 @@ release:
}
stack_context p_stack;
fcontext_t p_coro;
fcontext_t p_orig;
detail::fcontext_t p_coro;
detail::fcontext_t p_orig;
std::exception_ptr p_except;
state p_state = state::HOLD;
};
} /* namespace detail */
} /* namespace ostd */
#endif