[−][src]Function holochain_wasmer_guest::host_call
pub fn host_call<'a, I: 'a, O>(
f: unsafe extern "C" fn(_: GuestPtr) -> Len,
payload: &'a I
) -> Result<O, WasmError> where
SerializedBytes: TryFrom<&'a I, Error = SerializedBytesError>,
O: TryFrom<SerializedBytes, Error = SerializedBytesError>,
Given an extern that we expect the host to provide, that takes a GuestPtr and returns a Len:
- Serialize the payload by reference, according to its SerializedBytes implementation
- Write the bytes into a new allocation
- Call the host function and pass it the pointer to our allocation full of serialized data
- Deallocate the serialized bytes when the host function completes
- Allocate empty bytes of the length that the host tells us the result is
- Ask the host to write the result into the allocated empty bytes
- Deserialize and deallocate whatever bytes the host has written into the result allocation
- Return a Result of the deserialized output type O