I'm developing a Rust script that I need to convert to WebAssembly (WASM). In this script, I'm using the BlakeTwo256 hasher, which is imported from the sp_runtime crate. However, I'm unable to compile the code(cargo build --release) with sp_runtime in a no_std environment. I need to enable the std feature to compile it, but this prevents the code from being converted to WASM. What alternative can I use to BlakeTwo256 that will work in a no_std environment?
use crate::{Decode, Encode, DispatchError};
use sp_std::vec::Vec;
use sp_trie::{
trie_types::{TrieDBBuilder, TrieDBMutBuilderV0},
LayoutV0, MemoryDB, Recorder, Trie, TrieMut, EMPTY_PREFIX,
};
/// A trait for creating a merkle trie for checking and generating merkle proofs.
pub trait ProvingTrie<Hashing, Hash, Key, Value>
where
Self: Sized,
{
/// Create a new instance of a `ProvingTrie` using an iterator of key/value pairs.
fn generate_for<I>(items: I) -> Result<Self, DispatchError>
where
I: IntoIterator<Item = (Key, Value)>;
}
/// A basic trie implementation for checking and generating proofs for a key / value pair.
pub struct BasicProvingTrie<Hashing, Hash, Key, Value>
where
Hashing: sp_core::Hasher<Out = Hash>,
{
db: MemoryDB<Hashing>,
root: Hash,
_phantom: core::marker::PhantomData<(Key, Value)>,
}
impl<Hashing, Hash, Key, Value> ProvingTrie<Hashing, Hash, Key, Value>
for BasicProvingTrie<Hashing, Hash, Key, Value>
where
Hashing: sp_core::Hasher<Out = Hash>,
Hash: Default + Send + Sync,
Key: Encode,
Value: Encode + Decode,
{
fn generate_for<I>(items: I) -> Result<Self, DispatchError>
where
I: IntoIterator<Item = (Key, Value)>,
{
let mut db = MemoryDB::default();
let mut root = Default::default();
{
let mut trie = TrieDBMutBuilderV0::new(&mut db, &mut root).build();
for (key, value) in items.into_iter() {
key.using_encoded(|k| value.using_encoded(|v| trie.insert(k, v)))
.map_err(|_| "failed to insert into trie")?;
}
}
Ok(Self { db, root, _phantom: Default::default() })
}
}
This is where I'm calling generate_for()
type BalanceTrie = BasicProvingTrie<BlakeTwo256, H256, String, u128>;
let trie = BalanceTrie::generate_for(map).expect("Root not generated");
Cargo.toml
[dependencies]
csv = { version = "1.3.0", default-features = false }
hex = { version = "0.4.3", default-features = false }
log = { version = "0.4.22", default-features = false }
sp-core = { version = "34.0.0", default-features = false }
sp-runtime = { version = "39.0.0", default-features = false }
codec = { version = "3.6.12", default-features = false, package = "parity-scale-codec" }
sp-std = { version = "14.0.0", default-features = false }
sp-trie = { version = "37.0.0", default-features = false }
anyhow = "1.0.86"
If i run cargo build --release with the above code then I'm getting this error:
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
--> /Users/deepak/.cargo/registry/src/index.crates.io-6f17d22bba15001f/sp-runtime-interface-28.0.0/src/impls.rs:45:1
|
45 | assert_eq_size!(usize, u32);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: source type: `usize` (64 bits)
= note: target type: `u32` (32 bits)
= note: this error originates in the macro `assert_eq_size` (in Nightly builds, run with -Z macro-backtrace for more info)
error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
--> /Users/deepak/.cargo/registry/src/index.crates.io-6f17d22bba15001f/sp-runtime-interface-28.0.0/src/impls.rs:47:1
|
47 | assert_eq_size!(*const u8, u32);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: source type: `*const u8` (64 bits)
= note: target type: `u32` (32 bits)
= note: this error originates in the macro `assert_eq_size` (in Nightly builds, run with -Z macro-backtrace for more info)
But If I add std in cargo.toml, then it is compiling successfully.
[features]
default = ["std"]
std = [
"sp-runtime/std",
]
