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Fix: Prevent crashes during drawable iteration when drawables are destroyed #369

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Fix: Prevent crashes during drawable iteration when drawables are destroyed #369

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25 changes: 20 additions & 5 deletions Generals/Code/GameEngine/Source/GameClient/GameClient.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -757,17 +757,32 @@ void GameClient::updateHeadless()
*/
void GameClient::iterateDrawablesInRegion( Region3D *region, GameClientFuncPtr userFunc, void *userData )
{
Drawable *draw, *nextDrawable;

for( draw = m_drawableList; draw; draw=nextDrawable )
// TheSuperHackers @bugfix Collect matching drawable IDs upfront before invoking any callbacks.
// The userFunc (e.g. drawablePostDraw) can indirectly call getShroudedStatus(), which may
// trigger ghost-object snapshot operations that destroy drawables and remove them from
// m_drawableList. Pre-fetching nextDrawable before the call is not sufficient because the
// pre-fetched pointer itself can become dangling if that drawable is also destroyed during
// the callback. By collecting IDs first and then validating each via findDrawableByID(),
// we ensure we never dereference a freed drawable pointer.
static std::vector<DrawableID> s_drawableIDs;
s_drawableIDs.clear();

for( Drawable *draw = m_drawableList; draw; draw = draw->getNextDrawable() )
{
nextDrawable = draw->getNextDrawable();

Coord3D pos = *draw->getPosition();
if( region == nullptr ||
(pos.x >= region->lo.x && pos.x <= region->hi.x &&
pos.y >= region->lo.y && pos.y <= region->hi.y &&
pos.z >= region->lo.z && pos.z <= region->hi.z) )
{
s_drawableIDs.push_back( draw->getID() );
}
}

for( Int i = 0; i < (Int)s_drawableIDs.size(); ++i )
{
Drawable *draw = findDrawableByID( s_drawableIDs[i] );
if( draw != nullptr )
{
(*userFunc)( draw, userData );
}
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25 changes: 20 additions & 5 deletions GeneralsMD/Code/GameEngine/Source/GameClient/GameClient.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -825,17 +825,32 @@ void GameClient::updateHeadless()
*/
void GameClient::iterateDrawablesInRegion( Region3D *region, GameClientFuncPtr userFunc, void *userData )
{
Drawable *draw, *nextDrawable;

for( draw = m_drawableList; draw; draw=nextDrawable )
// TheSuperHackers @bugfix Collect matching drawable IDs upfront before invoking any callbacks.
// The userFunc (e.g. drawablePostDraw) can indirectly call getShroudedStatus(), which may
// trigger ghost-object snapshot operations that destroy drawables and remove them from
// m_drawableList. Pre-fetching nextDrawable before the call is not sufficient because the
// pre-fetched pointer itself can become dangling if that drawable is also destroyed during
// the callback. By collecting IDs first and then validating each via findDrawableByID(),
// we ensure we never dereference a freed drawable pointer.
static std::vector<DrawableID> s_drawableIDs;
s_drawableIDs.clear();

for( Drawable *draw = m_drawableList; draw; draw = draw->getNextDrawable() )
{
nextDrawable = draw->getNextDrawable();

Coord3D pos = *draw->getPosition();
if( region == nullptr ||
(pos.x >= region->lo.x && pos.x <= region->hi.x &&
pos.y >= region->lo.y && pos.y <= region->hi.y &&
pos.z >= region->lo.z && pos.z <= region->hi.z) )
{
s_drawableIDs.push_back( draw->getID() );
}
}

for( Int i = 0; i < (Int)s_drawableIDs.size(); ++i )
{
Drawable *draw = findDrawableByID( s_drawableIDs[i] );
if( draw != nullptr )
{
(*userFunc)( draw, userData );
}
Expand Down
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