Workaround for P/Invoke AccessViolationException

Summary:
The issue is on ARM builds for Windows UWP. For the C# P/Invoke API wrapper, any native method that returns the YogaValue struct throws the AccessViolationException. The issue is not with structs in general, as returning the YogaSize / YGSize struct works fine. The issue seems to be limited to structs that have an enum member.

I tried a number of things to resolve the issue without changing the underlying native API for Windows. I read the ARM documentation and saw reference to variable enum sizes based on the number of enum members, so I tried to use a number of different UnmanagedType values in a [MarsalAs()] attribute on the enum member of the C# struct declaration.

What ultimately worked was to return a pointer to the location of the struct, and use the System.Runtime.InteropServices.PtrToStructure API to read the struct data from that pointer. I added a few new macros that will return the struct address on Windows only, other builds are not affected.

Note, I have not tested the impact of this ch
Closes https://github.com/facebook/yoga/pull/459

Reviewed By: emilsjolander

Differential Revision: D4652278

Pulled By: splhack

fbshipit-source-id: bf7ada4da1781e3f813b3ba331974b7bded476d9
This commit is contained in:
Eric Rozell 2017-03-06 11:29:52 -08:00 committed by Facebook Github Bot
parent b87f4abf78
commit dd5798b57b
3 changed files with 11 additions and 3 deletions

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@ -23,6 +23,14 @@
#define WIN_EXPORT
#endif
#ifdef WINARMDLL
#define WIN_STRUCT(type) type*
#define WIN_STRUCT_REF(value) &value
#else
#define WIN_STRUCT(type) type
#define WIN_STRUCT_REF(value) value
#endif
#ifndef FB_ASSERTIONS_ENABLED
#define FB_ASSERTIONS_ENABLED 1
#endif

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@ -613,8 +613,8 @@ static inline const YGValue *YGNodeResolveFlexBasisPtr(const YGNodeRef node) {
} \
} \
\
type YGNodeStyleGet##name(const YGNodeRef node, const YGEdge edge) { \
return node->style.instanceName[edge]; \
WIN_STRUCT(type) YGNodeStyleGet##name(const YGNodeRef node, const YGEdge edge) { \
return WIN_STRUCT_REF(node->style.instanceName[edge]); \
}
#define YG_NODE_STYLE_EDGE_PROPERTY_IMPL(type, name, paramName, instanceName) \

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@ -141,7 +141,7 @@ WIN_EXPORT void YGNodeCopyStyle(const YGNodeRef dstNode, const YGNodeRef srcNode
WIN_EXPORT void YGNodeStyleSet##name##Percent(const YGNodeRef node, \
const YGEdge edge, \
const float paramName); \
WIN_EXPORT type YGNodeStyleGet##name(const YGNodeRef node, const YGEdge edge);
WIN_EXPORT WIN_STRUCT(type) YGNodeStyleGet##name(const YGNodeRef node, const YGEdge edge);
#define YG_NODE_STYLE_EDGE_PROPERTY_UNIT_AUTO(type, name) \
WIN_EXPORT void YGNodeStyleSet##name##Auto(const YGNodeRef node, const YGEdge edge);