fix(bindings/c): use ManuallyDrop instead of forget to make sure pointer is valid
#5166
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tisonkun
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Oct 7, 2024
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So this is the real reason my previous patch failed, lol.
This can be a hidden knowledge that Go binding's struct should be synced with C binding's ..
tisonkun
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tisonkun
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| drop(Vec::from_raw_parts(data_mut, (*ptr).len, (*ptr).len)); | ||
| drop(Box::from_raw(ptr)); | ||
| // transmuting `*const u8` to `*mut u8` is undefined behavior in any cases | ||
| // however, fields type of `opendal_bytes` is already related to the zig binding |
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already related to the zig binding
Do you mean that the Zig binding should use non-const pointer also?
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| // it is too weird that call `Box::new` outside `opendal_bytes::new` but dealloc it here | ||
| // also, boxing `opendal_bytes` might not be necessary | ||
| // `data` points to heap, so `opendal_bytes` could be passed as a stack value |
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Reasonable. But IIRC other bindings rely on this interface also. We can update them all in a follow-up.
Then the free method is guarded by !self.data.is_null().
ethe
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ManuallyDrop instead of forget to make sure pointer is valid
Xuanwo
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ManuallyDrop instead of forget to make sure pointer is validManuallyDrop instead of forget to make sure pointer is valid
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Which issue does this PR close?
Closes #5165.
Rationale for this change
refer to https://doc.rust-lang.org/std/mem/fn.forget.html
the implementation of
Vec::into_raw_partshttps://doc.rust-lang.org/1.81.0/src/alloc/vec/mod.rs.html#883
Also, transmute
*const _to* mut _is an undefined behavior in any cases, it is fixed in this commit.