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#ifndef GREENLET_STACK_STATE_CPP
#define GREENLET_STACK_STATE_CPP
#include "TGreenlet.hpp"
namespace greenlet {
#ifdef GREENLET_USE_STDIO
#include <iostream>
using std::cerr;
using std::endl;
std::ostream& operator<<(std::ostream& os, const StackState& s)
{
os << "StackState(stack_start=" << (void*)s._stack_start
<< ", stack_stop=" << (void*)s.stack_stop
<< ", stack_copy=" << (void*)s.stack_copy
<< ", stack_saved=" << s._stack_saved
<< ", stack_prev=" << s.stack_prev
<< ", addr=" << &s
<< ")";
return os;
}
#endif
StackState::StackState(void* mark, StackState& current)
: _stack_start(nullptr),
stack_stop((char*)mark),
stack_copy(nullptr),
_stack_saved(0),
/* Skip a dying greenlet */
stack_prev(current._stack_start
? ¤t
: current.stack_prev)
{
}
StackState::StackState()
: _stack_start(nullptr),
stack_stop(nullptr),
stack_copy(nullptr),
_stack_saved(0),
stack_prev(nullptr)
{
}
StackState::StackState(const StackState& other)
// can't use a delegating constructor because of
// MSVC for Python 2.7
: _stack_start(nullptr),
stack_stop(nullptr),
stack_copy(nullptr),
_stack_saved(0),
stack_prev(nullptr)
{
this->operator=(other);
}
StackState& StackState::operator=(const StackState& other)
{
if (&other == this) {
return *this;
}
if (other._stack_saved) {
throw std::runtime_error("Refusing to steal memory.");
}
//If we have memory allocated, dispose of it
this->free_stack_copy();
this->_stack_start = other._stack_start;
this->stack_stop = other.stack_stop;
this->stack_copy = other.stack_copy;
this->_stack_saved = other._stack_saved;
this->stack_prev = other.stack_prev;
return *this;
}
inline void StackState::free_stack_copy() noexcept
{
PyMem_Free(this->stack_copy);
this->stack_copy = nullptr;
this->_stack_saved = 0;
}
inline void StackState::copy_heap_to_stack(const StackState& current) noexcept
{
/* Restore the heap copy back into the C stack */
if (this->_stack_saved != 0) {
memcpy(this->_stack_start, this->stack_copy, this->_stack_saved);
this->free_stack_copy();
}
StackState* owner = const_cast<StackState*>(¤t);
if (!owner->_stack_start) {
owner = owner->stack_prev; /* greenlet is dying, skip it */
}
while (owner && owner->stack_stop <= this->stack_stop) {
// cerr << "\tOwner: " << owner << endl;
owner = owner->stack_prev; /* find greenlet with more stack */
}
this->stack_prev = owner;
// cerr << "\tFinished with: " << *this << endl;
}
inline int StackState::copy_stack_to_heap_up_to(const char* const stop) noexcept
{
/* Save more of g's stack into the heap -- at least up to 'stop'
g->stack_stop |________|
| |
| __ stop . . . . .
| | ==> . .
|________| _______
| | | |
| | | |
g->stack_start | | |_______| g->stack_copy
*/
intptr_t sz1 = this->_stack_saved;
intptr_t sz2 = stop - this->_stack_start;
assert(this->_stack_start);
if (sz2 > sz1) {
char* c = (char*)PyMem_Realloc(this->stack_copy, sz2);
if (!c) {
PyErr_NoMemory();
return -1;
}
memcpy(c + sz1, this->_stack_start + sz1, sz2 - sz1);
this->stack_copy = c;
this->_stack_saved = sz2;
}
return 0;
}
inline int StackState::copy_stack_to_heap(char* const stackref,
const StackState& current) noexcept
{
/* must free all the C stack up to target_stop */
const char* const target_stop = this->stack_stop;
StackState* owner = const_cast<StackState*>(¤t);
assert(owner->_stack_saved == 0); // everything is present on the stack
if (!owner->_stack_start) {
owner = owner->stack_prev; /* not saved if dying */
}
else {
owner->_stack_start = stackref;
}
while (owner->stack_stop < target_stop) {
/* ts_current is entierely within the area to free */
if (owner->copy_stack_to_heap_up_to(owner->stack_stop)) {
return -1; /* XXX */
}
owner = owner->stack_prev;
}
if (owner != this) {
if (owner->copy_stack_to_heap_up_to(target_stop)) {
return -1; /* XXX */
}
}
return 0;
}
inline bool StackState::started() const noexcept
{
return this->stack_stop != nullptr;
}
inline bool StackState::main() const noexcept
{
return this->stack_stop == (char*)-1;
}
inline bool StackState::active() const noexcept
{
return this->_stack_start != nullptr;
}
inline void StackState::set_active() noexcept
{
assert(this->_stack_start == nullptr);
this->_stack_start = (char*)1;
}
inline void StackState::set_inactive() noexcept
{
this->_stack_start = nullptr;
// XXX: What if we still have memory out there?
// That case is actually triggered by
// test_issue251_issue252_explicit_reference_not_collectable (greenlet.tests.test_leaks.TestLeaks)
// and
// test_issue251_issue252_need_to_collect_in_background
// (greenlet.tests.test_leaks.TestLeaks)
//
// Those objects never get deallocated, so the destructor never
// runs.
// It *seems* safe to clean up the memory here?
if (this->_stack_saved) {
this->free_stack_copy();
}
}
inline intptr_t StackState::stack_saved() const noexcept
{
return this->_stack_saved;
}
inline char* StackState::stack_start() const noexcept
{
return this->_stack_start;
}
inline StackState StackState::make_main() noexcept
{
StackState s;
s._stack_start = (char*)1;
s.stack_stop = (char*)-1;
return s;
}
StackState::~StackState()
{
if (this->_stack_saved != 0) {
this->free_stack_copy();
}
}
void StackState::copy_from_stack(void* vdest, const void* vsrc, size_t n) const
{
char* dest = static_cast<char*>(vdest);
const char* src = static_cast<const char*>(vsrc);
if (src + n <= this->_stack_start
|| src >= this->_stack_start + this->_stack_saved
|| this->_stack_saved == 0) {
// Nothing we're copying was spilled from the stack
memcpy(dest, src, n);
return;
}
if (src < this->_stack_start) {
// Copy the part before the saved stack.
// We know src + n > _stack_start due to the test above.
const size_t nbefore = this->_stack_start - src;
memcpy(dest, src, nbefore);
dest += nbefore;
src += nbefore;
n -= nbefore;
}
// We know src >= _stack_start after the before-copy, and
// src < _stack_start + _stack_saved due to the first if condition
size_t nspilled = std::min<size_t>(n, this->_stack_start + this->_stack_saved - src);
memcpy(dest, this->stack_copy + (src - this->_stack_start), nspilled);
dest += nspilled;
src += nspilled;
n -= nspilled;
if (n > 0) {
// Copy the part after the saved stack
memcpy(dest, src, n);
}
}
}; // namespace greenlet
#endif // GREENLET_STACK_STATE_CPP
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