c_Generator *c_Generator::Clone(ObjectData* obj) {
auto thiz = static_cast<c_Generator*>(obj);
auto fp = thiz->actRec();
c_Generator* cont = Create(fp, thiz->resumable()->resumeAddr(),
thiz->resumable()->resumeOffset());
cont->copyVars(fp);
cont->setState(thiz->getState());
cont->m_index = thiz->m_index;
cellSet(thiz->m_key, cont->m_key);
cellSet(thiz->m_value, cont->m_value);
return cont;
}
void c_AsyncFunctionWaitHandle::resume() {
auto const child = m_children[0].getChild();
assert(getState() == STATE_READY);
assert(child->isFinished());
setState(STATE_RUNNING);
if (LIKELY(child->isSucceeded())) {
// child succeeded, pass the result to the async function
g_context->resumeAsyncFunc(resumable(), child, child->getResult());
} else {
// child failed, raise the exception inside the async function
g_context->resumeAsyncFuncThrow(resumable(), child,
child->getException());
}
}
void delete_AsyncFunctionWaitHandle(ObjectData* od, const Class*) {
auto const waitHandle = static_cast<c_AsyncFunctionWaitHandle*>(od);
auto const size = waitHandle->resumable()->size();
auto const base = (char*)(waitHandle + 1) - size;
waitHandle->~c_AsyncFunctionWaitHandle();
MM().objFreeLogged(base, size);
}
void delete_AsyncGenerator(ObjectData* od, const Class*) {
auto const gen = static_cast<c_AsyncGenerator*>(od);
auto const size = gen->resumable()->size();
auto const base = (char*)(gen + 1) - size;
gen->~c_AsyncGenerator();
MM().objFreeLogged(base, size);
}
void delete_Generator(ObjectData* od, const Class*) {
auto const cont = static_cast<c_Generator*>(od);
auto const size = cont->resumable()->size();
auto const base = (char*)(cont + 1) - size;
cont->~c_Generator();
MM().objFreeLogged(base, size);
}
static ActRec* getPrevActRec(const ActRec* fp, Offset* prevPc) {
if (fp && fp->func() && fp->resumed() && fp->func()->isAsyncFunction()) {
c_WaitableWaitHandle* currentWaitHandle = frame_afwh(fp);
if (currentWaitHandle->isFinished()) {
/*
* It's possible in very rare cases (it will return a truncated stack):
* 1) async function which WaitHandle is not referenced by anything
* else finishes
* 2) its return value is an object with destructor
* 3) this destructor gets called as part of destruction of the
* WaitHandleobject, which happens right before FP is adjusted
*/
return nullptr;
}
auto const contextIdx = currentWaitHandle->getContextIdx();
while (currentWaitHandle != nullptr) {
auto p = currentWaitHandle->getParentChain().firstInContext(contextIdx);
if (p == nullptr) break;
if (p->getKind() == c_WaitHandle::Kind::AsyncFunction) {
auto wh = p->asAsyncFunction();
*prevPc = wh->resumable()->resumeOffset();
return wh->actRec();
}
currentWaitHandle = p;
}
*prevPc = 0;
return AsioSession::Get()->getContext(contextIdx)->getSavedFP();
}
return g_context->getPrevVMState(fp, prevPc);
}
// Get the line number on which execution will proceed when execution resumes.
int c_AsyncFunctionWaitHandle::getLineNumber() {
if (isFinished()) {
return -1;
}
always_assert(!isRunning());
return actRec()->func()->unit()->getLineNumber(resumable()->resumeOffset());
}
void c_Generator::suspend(JIT::TCA resumeAddr, Offset resumeOffset,
const Cell& value) {
assert(getState() == Running);
resumable()->setResumeAddr(resumeAddr, resumeOffset);
cellSet(make_tv<KindOfInt64>(++m_index), m_key);
cellSet(value, m_value);
setState(Started);
}
// Get the next execution offset
Offset c_AsyncFunctionWaitHandle::getNextExecutionOffset() {
if (isFinished()) {
return InvalidAbsoluteOffset;
}
always_assert(!isRunning());
return resumable()->resumeOffset();
}
void c_AsyncFunctionWaitHandle::resume() {
// may happen if scheduled in multiple contexts
if (getState() != STATE_SCHEDULED) {
decRefObj(this);
return;
}
assert(getState() == STATE_SCHEDULED);
assert(m_child->isFinished());
setState(STATE_RUNNING);
if (LIKELY(m_child->isSucceeded())) {
// child succeeded, pass the result to the async function
g_context->resumeAsyncFunc(resumable(), m_child, m_child->getResult());
} else {
// child failed, raise the exception inside the async function
g_context->resumeAsyncFuncThrow(resumable(), m_child,
m_child->getException());
}
}
void c_AsyncFunctionWaitHandle::await(Offset resumeOffset,
c_WaitableWaitHandle* child) {
// Prepare child for establishing dependency. May throw.
prepareChild(child);
// Suspend the async function.
resumable()->setResumeAddr(nullptr, resumeOffset);
// Set up the dependency.
setState(STATE_BLOCKED);
m_children[0].setChild(child);
}
void c_Generator::suspend(JIT::TCA resumeAddr, Offset resumeOffset,
const Cell& key, const Cell& value) {
assert(getState() == Running);
resumable()->setResumeAddr(resumeAddr, resumeOffset);
cellSet(key, m_key);
cellSet(value, m_value);
if (m_key.m_type == KindOfInt64) {
int64_t new_index = m_key.m_data.num;
m_index = new_index > m_index ? new_index : m_index;
}
setState(Started);
}
c_AsyncGeneratorWaitHandle*
AsyncGenerator::await(Offset resumeOffset, c_WaitableWaitHandle* child) {
assert(isRunning());
resumable()->setResumeAddr(nullptr, resumeOffset);
if (m_waitHandle) {
// Resumed execution.
m_waitHandle->await(child);
return nullptr;
}
// Eager executon.
m_waitHandle = c_AsyncGeneratorWaitHandle::Create(this, child);
return m_waitHandle.get();
}
Generator& Generator::operator=(const Generator& other) {
auto const fp = other.actRec();
const size_t numSlots = fp->func()->numSlotsInFrame();
const size_t frameSz = Resumable::getFrameSize(numSlots);
const size_t genSz = genSize(sizeof(Generator), frameSz);
resumable()->initialize<true>(fp,
other.resumable()->resumeAddr(),
other.resumable()->resumeOffset(),
frameSz,
genSz);
copyVars(fp);
setState(other.getState());
m_index = other.m_index;
cellSet(other.m_key, m_key);
cellSet(other.m_value, m_value);
return *this;
}
ObjectData*
AsyncGenerator::Create(const ActRec* fp, size_t numSlots,
jit::TCA resumeAddr, Offset resumeOffset) {
assert(fp);
assert(!fp->resumed());
assert(fp->func()->isAsyncGenerator());
const size_t frameSz = Resumable::getFrameSize(numSlots);
const size_t genSz = genSize(sizeof(AsyncGenerator), frameSz);
auto const obj = BaseGenerator::Alloc<AsyncGenerator>(s_class, genSz);
auto const genData = new (Native::data<AsyncGenerator>(obj)) AsyncGenerator();
genData->resumable()->initialize<false>(fp,
resumeAddr,
resumeOffset,
frameSz,
genSz);
genData->setState(State::Created);
return obj;
}
void c_Generator::yield(Offset resumeOffset,
const Cell* key, const Cell& value) {
assert(getState() == State::Running);
resumable()->setResumeAddr(nullptr, resumeOffset);
if (key) {
cellSet(*key, m_key);
tvRefcountedDecRefNZ(*key);
if (m_key.m_type == KindOfInt64) {
int64_t new_index = m_key.m_data.num;
m_index = new_index > m_index ? new_index : m_index;
}
} else {
cellSet(make_tv<KindOfInt64>(++m_index), m_key);
}
cellSet(value, m_value);
tvRefcountedDecRefNZ(value);
setState(State::Started);
}
static ActRec* getPrevActRec(
const ActRec* fp, Offset* prevPc,
folly::small_vector<c_WaitableWaitHandle*, 64>& visitedWHs) {
if (fp && fp->func() && fp->resumed() && fp->func()->isAsyncFunction()) {
c_WaitableWaitHandle* currentWaitHandle = frame_afwh(fp);
if (currentWaitHandle->isFinished()) {
/*
* It's possible in very rare cases (it will return a truncated stack):
* 1) async function which WaitHandle is not referenced by anything
* else finishes
* 2) its return value is an object with destructor
* 3) this destructor gets called as part of destruction of the
* WaitHandleobject, which happens right before FP is adjusted
*/
return nullptr;
}
auto const contextIdx = currentWaitHandle->getContextIdx();
while (currentWaitHandle != nullptr) {
auto p = currentWaitHandle->getParentChain().firstInContext(contextIdx);
if (p == nullptr ||
UNLIKELY(std::find(visitedWHs.begin(), visitedWHs.end(), p)
!= visitedWHs.end())) {
// If the parent exists in our backtrace, it means we have detected a
// cycle. Fall back to savedFP in that case.
break;
}
visitedWHs.push_back(p);
if (p->getKind() == c_WaitHandle::Kind::AsyncFunction) {
auto wh = p->asAsyncFunction();
*prevPc = wh->resumable()->resumeOffset();
return wh->actRec();
}
currentWaitHandle = p;
}
*prevPc = 0;
return AsioSession::Get()->getContext(contextIdx)->getSavedFP();
}
return g_context->getPrevVMState(fp, prevPc);
}
c_StaticWaitHandle*
AsyncGenerator::yield(Offset resumeOffset,
const Cell* key, const Cell value) {
assert(isRunning());
resumable()->setResumeAddr(nullptr, resumeOffset);
setState(State::Started);
auto keyValueTuple = make_packed_array(
key ? Variant(tvAsCVarRef(key), Variant::CellCopy()) : init_null_variant,
Variant(tvAsCVarRef(&value), Variant::CellCopy()));
auto keyValueTupleTV = make_tv<KindOfArray>(keyValueTuple.detach());
if (m_waitHandle) {
// Resumed execution.
req::ptr<c_AsyncGeneratorWaitHandle> wh(std::move(m_waitHandle));
wh->ret(*tvAssertCell(&keyValueTupleTV));
return nullptr;
}
// Eager execution.
return c_StaticWaitHandle::CreateSucceeded(keyValueTupleTV);
}
void delete_AsyncFunctionWaitHandle(ObjectData* od, const Class*) {
auto wh = static_cast<c_AsyncFunctionWaitHandle*>(od);
Resumable::Destroy(wh->resumable()->size(), wh);
}
void
c_AsyncFunctionWaitHandle::suspend(JIT::TCA resumeAddr, Offset resumeOffset,
c_WaitableWaitHandle* child) {
resumable()->setResumeAddr(resumeAddr, resumeOffset);
m_child = child;
}
void c_AsyncFunctionWaitHandle::run() {
// may happen if scheduled in multiple contexts
if (getState() != STATE_SCHEDULED) {
return;
}
try {
setState(STATE_RUNNING);
// resume async function
if (LIKELY(m_child->isSucceeded())) {
// child succeeded, pass the result to the async function
g_context->resumeAsyncFunc(resumable(), m_child, m_child->getResult());
} else if (m_child->isFailed()) {
// child failed, raise the exception inside the async function
g_context->resumeAsyncFuncThrow(resumable(), m_child,
m_child->getException());
} else {
throw FatalErrorException(
"Invariant violation: child neither succeeded nor failed");
}
retry:
// async function reached RetC, which already set m_resultOrException
if (isSucceeded()) {
m_child = nullptr;
markAsSucceeded();
return;
}
// async function reached AsyncSuspend, which already set m_child
assert(!m_child->isFinished());
assert(m_child->instanceof(c_WaitableWaitHandle::classof()));
// import child into the current context, detect cross-context cycles
try {
child()->enterContext(getContextIdx());
} catch (Object& e) {
g_context->resumeAsyncFuncThrow(resumable(), m_child, e.get());
goto retry;
}
// detect cycles
if (UNLIKELY(isDescendantOf(child()))) {
Object e(createCycleException(child()));
g_context->resumeAsyncFuncThrow(resumable(), m_child, e.get());
goto retry;
}
// on await callback
AsioSession* session = AsioSession::Get();
if (UNLIKELY(session->hasOnAsyncFunctionAwaitCallback())) {
session->onAsyncFunctionAwait(this, m_child);
}
// set up dependency
setState(STATE_BLOCKED);
blockOn(child());
} catch (const Object& exception) {
// process exception thrown by the async function
m_child = nullptr;
markAsFailed(exception);
} catch (...) {
// process C++ exception
m_child = nullptr;
markAsFailed(AsioSession::Get()->getAbruptInterruptException());
throw;
}
}
