Function merkle_add 

pub(crate) fn merkle_add(
    ctx: FunctionEnvMut<'_, Env>,
    ptr: WasmPtr<u8>,
    len: u32,
) -> i64

Adds data to merkle tree. The tree, database connection, and new data to add is read from ptr at offset specified by len. Returns 0 on success; otherwise, returns an error-code corresponding to a darkfi_sdk::error::ContractError (defined in the SDK). See also the method merkle_add in sdk/src/merkle.rs.

Permissions: update