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Workaround for P/Invoke AccessViolationException

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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 62f47190fb
commit 5bc0197c78
9 changed files with 102 additions and 78 deletions
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4
yoga/Yoga.c
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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) \