Fix unity pointer paths on mono v2/v3 that have generic classes#132
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mitchell-merry wants to merge 11 commits into
Open
Fix unity pointer paths on mono v2/v3 that have generic classes#132mitchell-merry wants to merge 11 commits into
mitchell-merry wants to merge 11 commits into
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mitchell-merry
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May 10, 2026
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| // See https://github.com/mono/mono/blob/337052f86112fc0dc8435c5c4a2de43b399a14bb/mono/metadata/class-internals.h#L327 | ||
| Version::V2 => { | ||
| // TODO I feel like I'm doing this very poorly | ||
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| let byte = | ||
| process.read::<u8>(self.class + module.offsets.class.class_kind)? & 0x7u8; | ||
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| if !MonoTypeKind::is_valid_bit_pattern(&byte) { | ||
| return Err(Error {}); | ||
| } | ||
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| // SAFETY: We just checked if this was valid | ||
| let kind: MonoTypeKind = unsafe { (&raw const byte).cast::<MonoTypeKind>().read() }; | ||
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| Ok(kind) | ||
| } |
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Er, my rust noob-ness is showing here. I'm trying to read just these three bits into a MonoTypeKind, but I suspect this can be done much simpler than I've done it here... could use help on that
Maybe I should drop the enum and just use a u8?
mitchell-merry
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May 10, 2026
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| class_kind: 0x1E, | ||
| generic_class: 0x94, |
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These are the untested offsets
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Why, what is the context?
Trying to fetch field offsets on generic classes in mono v2/v3, e.g.
class MyClass : Singleton<MyClass>doesn't work since the field count logic is different on for generic classes in those versions.What?
Add v2/v3 logic, which fetches the class kind and then if it's GINST fetches the generic container class.
This logic is stolen from a variety of places, but in particular asl-help does this: https://github.com/just-ero/asl-help/blob/9a17c5ec7108aba1fe1932358703f4e6adaa6b2c/src/Unity/Mono/Managers/MonoV2Manager.cs#L16 and I also had a look at the mono source to verify it: https://github.com/mono/mono/blob/0f53e9e151d92944cacab3e24ac359410c606df6/mono/metadata/class-accessors.c#L216
Testing
I tested this on:
Additional thoughts
Not exactly sure what the best practice is in rust for this, but I think we should be using some sort of strategy pattern similar to what asl-help does. Having these
match (mono version)cases everywhere is going to get convoluted, and in this case I've even had to include offsets that don't even exist in mono v1 (and thus I've defaulted them to 0x0).