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function executed by resume_with() has to return a continuation

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olk committed Aug 10, 2017
1 parent 8346fbf commit 420554fe9ac01482990e8ae314f4f7ba81010c9a
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@@ -176,6 +176,7 @@ return `void`.
c=c.resume_with([&data](ctx::continuation && c){
std::cout << "f2: entered: " << data << std::endl;
data=-1;
return std::move( c);
});
std::cout << "f1: returned third time" << std::endl;
@@ -221,6 +222,7 @@ an exception.
c = c.resume_with(
[](ctx::continuation && c){
throw my_exception(std::move(c),"abc");
return std::move( c);
});
output:
@@ -527,11 +529,11 @@ e.g. ['continuation::operator bool()] returns `true`.]]
[variablelist
[[Effects:] [Captures current continuation and resumes `*this`.
The function `resume_with`, is used to execute function `fn` in continuation
The function `resume_with`, is used to execute function `fn` in the execution context of
`*this` (e.g. the stack frame of `fn` is allocated on stack of `*this`).]]
[[Returns:] [The continuation representing the continuation that has been
suspended.]]
[[Note:] [Function `fn` needs to return void.]]
[[Note:] [Function `fn` needs to return `continuation`.]]
[[Note:] [The returned continuation indicates if the suspended continuation has
terminated (return from context-function) via `bool operator()`.]]
]
View
@@ -32,6 +32,7 @@ int main() {
c = c.resume_with( [&data](ctx::continuation && c){
std::cout << "f2: entered: " << data << std::endl;
data = -1;
return std::move( c);
});
std::cout << "f1: returned third time" << std::endl;
std::cout << "main: done" << std::endl;
View
@@ -21,8 +21,9 @@ ctx::continuation f1( ctx::continuation && c) {
return std::move( c);
}
void f2( ctx::continuation && c) {
ctx::continuation f2( ctx::continuation && c) {
std::cout << "f2: entered" << std::endl;
return std::move( c);
}
int main() {
View
@@ -38,6 +38,7 @@ int main() {
c = c.resume_with(
[](ctx::continuation && c){
throw my_exception(std::move( c), "abc");
return std::move( c);
});
std::cout << "main: done" << std::endl;
@@ -95,7 +95,7 @@ transfer_t context_ontop( transfer_t t) {
t.data = nullptr;
Ctx c{ t.fctx };
// execute function, pass continuation via reference
fn( std::move( c) );
c = fn( std::move( c) );
#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
return { exchange( c.fctx_, nullptr), nullptr };
#else
@@ -84,18 +84,18 @@ static void entry_func( void * data) noexcept {
struct BOOST_CONTEXT_DECL activation_record {
thread_local static activation_record * current_rec;
ucontext_t uctx{};
stack_context sctx{};
bool main_ctx{ true };
activation_record * from{ nullptr };
std::function< void(activation_record*&) > ontop{};
bool terminated{ false };
bool force_unwind{ false };
ucontext_t uctx{};
stack_context sctx{};
bool main_ctx{ true };
activation_record * from{ nullptr };
std::function< activation_record*(activation_record*&) > ontop{};
bool terminated{ false };
bool force_unwind{ false };
#if defined(BOOST_USE_ASAN)
void * fake_stack{ nullptr };
void * stack_bottom{ nullptr };
std::size_t stack_size{ 0 };
bool started{ false };
void * fake_stack{ nullptr };
void * stack_bottom{ nullptr };
std::size_t stack_size{ 0 };
bool started{ false };
#endif
static activation_record *& current() noexcept;
@@ -168,20 +168,30 @@ struct BOOST_CONTEXT_DECL activation_record {
current()->ontop = std::bind(
[](typename std::decay< Fn >::type & fn, activation_record *& ptr){
Ctx c{ ptr };
fn( std::move( c) );
c = fn( std::move( c) );
if ( ! c) {
ptr = nullptr;
}
#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
return exchange( c.ptr_, nullptr);
#else
return std::exchange( c.ptr_, nullptr);
#endif
},
std::forward< Fn >( fn),
std::placeholders::_1);
#else
current()->ontop = [fn=std::forward<Fn>(fn)](activation_record *& ptr){
Ctx c{ ptr };
fn( std::move( c) );
c = fn( std::move( c) );
if ( ! c) {
ptr = nullptr;
}
#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
return exchange( c.ptr_, nullptr);
#else
return std::exchange( c.ptr_, nullptr);
#endif
};
#endif
#if defined(BOOST_USE_SEGMENTED_STACKS)
@@ -408,7 +418,7 @@ class BOOST_CONTEXT_DECL continuation {
if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
throw detail::forced_unwind{ ptr};
} else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
detail::activation_record::current()->ontop( ptr);
ptr = detail::activation_record::current()->ontop( ptr);
detail::activation_record::current()->ontop = nullptr;
}
return continuation{ ptr };
@@ -426,7 +436,7 @@ class BOOST_CONTEXT_DECL continuation {
if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
throw detail::forced_unwind{ ptr};
} else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
detail::activation_record::current()->ontop( ptr);
ptr = detail::activation_record::current()->ontop( ptr);
detail::activation_record::current()->ontop = nullptr;
}
return continuation{ ptr };
@@ -65,13 +65,13 @@ static VOID WINAPI entry_func( LPVOID data) noexcept {
struct BOOST_CONTEXT_DECL activation_record {
thread_local static activation_record * current_rec;
LPVOID fiber{ nullptr };
stack_context sctx{};
bool main_ctx{ true };
activation_record * from{ nullptr };
std::function< void(activation_record*&) > ontop{};
bool terminated{ false };
bool force_unwind{ false };
LPVOID fiber{ nullptr };
stack_context sctx{};
bool main_ctx{ true };
activation_record * from{ nullptr };
std::function< activation_record*(activation_record*&) > ontop{};
bool terminated{ false };
bool force_unwind{ false };
static activation_record *& current() noexcept;
@@ -142,20 +142,30 @@ struct BOOST_CONTEXT_DECL activation_record {
current()->ontop = std::bind(
[](typename std::decay< Fn >::type & fn, activation_record *& ptr){
Ctx c{ ptr };
fn( std::move( c) );
c = fn( std::move( c) );
if ( ! c) {
ptr = nullptr;
}
#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
return exchange( c.ptr_, nullptr);
#else
return std::exchange( c.ptr_, nullptr);
#endif
},
std::forward< Fn >( fn),
std::placeholders::_1);
#else
current()->ontop = [fn=std::forward<Fn>(fn)](activation_record *& ptr){
Ctx c{ ptr };
fn( std::move( c) );
c = fn( std::move( c) );
if ( ! c) {
ptr = nullptr;
}
#if defined(BOOST_NO_CXX14_STD_EXCHANGE)
return exchange( c.ptr_, nullptr);
#else
return std::exchange( c.ptr_, nullptr);
#endif
};
#endif
// context switch
@@ -336,7 +346,7 @@ class BOOST_CONTEXT_DECL continuation {
if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
throw detail::forced_unwind{ ptr};
} else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
detail::activation_record::current()->ontop( ptr);
ptr = detail::activation_record::current()->ontop( ptr);
detail::activation_record::current()->ontop = nullptr;
}
return continuation{ ptr };
@@ -354,7 +364,7 @@ class BOOST_CONTEXT_DECL continuation {
if ( BOOST_UNLIKELY( detail::activation_record::current()->force_unwind) ) {
throw detail::forced_unwind{ ptr};
} else if ( BOOST_UNLIKELY( nullptr != detail::activation_record::current()->ontop) ) {
detail::activation_record::current()->ontop( ptr);
ptr = detail::activation_record::current()->ontop( ptr);
detail::activation_record::current()->ontop = nullptr;
}
return continuation{ ptr };
View
@@ -252,6 +252,7 @@ void test_ontop() {
c = c.resume_with(
[&i](ctx::continuation && c){
i -= 10;
return std::move( c);
});
BOOST_CHECK( c);
BOOST_CHECK_EQUAL( i, 200);
@@ -266,6 +267,7 @@ void test_ontop() {
c = c.resume_with(
[&c1](ctx::continuation && c){
c1 = std::move( c);
return std::move( c);
});
}
}
@@ -290,7 +292,8 @@ void test_ontop_exception() {
const char * what = "hello world";
c.resume_with(
[what](ctx::continuation && c){
throw my_exception( std::move( c), what);
throw my_exception( std::move( c), what);
return std::move( c);
});
BOOST_CHECK_EQUAL( 3, value1);
BOOST_CHECK_EQUAL( std::string( what), value2);

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