Merge pull request #55 from ewasm/eth2-phase2

Eth 2 Phase 2 methods

Author: axic

Cargo.toml

@@ -17,3 +17,4 @@ default = ["std", "wee_alloc"]
 std = []
 debug = []
 experimental = []
+eth2 = []

circle.yml

@@ -41,3 +41,5 @@ jobs:
              cargo build --release --no-default-features --features experimental
              cargo build --release --features experimental,debug
              cargo build --release --no-default-features --features experimental,debug
+             cargo build --release --features eth2
+             cargo build --release --no-default-features --features eth2

src/eth2.rs

@@ -0,0 +1,68 @@
+//! This is the work in progress interface for Eth 2 Phase 2.
+//!
+//! Please check Ewasm [Scout](https://github.com/ewasm/scout) for more details.
+
+use super::*;
+
+mod native {
+    extern "C" {
+        pub fn eth2_loadPreStateRoot(offset: *const u32);
+        pub fn eth2_blockDataSize() -> u32;
+        pub fn eth2_blockDataCopy(outputOfset: *const u32, offset: u32, length: u32);
+        pub fn eth2_savePostStateRoot(offset: *const u32);
+        pub fn eth2_pushNewDeposit(offset: *const u32, length: u32);
+    }
+}
+
+/// Load current state root.
+pub fn load_pre_state_root() -> Bytes32 {
+    let mut ret = Bytes32::default();
+
+    unsafe { native::eth2_loadPreStateRoot(ret.bytes.as_mut_ptr() as *const u32) }
+
+    ret
+}
+
+/// Returns the length of the "block data" supplied with the current block.
+pub fn block_data_size() -> usize {
+    unsafe { native::eth2_blockDataSize() as usize }
+}
+
+/// Copies a slices from the "block data", but does not check for overflow.
+pub fn unsafe_block_data_copy(from: usize, length: usize, ret: &mut [u8]) {
+    unsafe {
+        native::eth2_blockDataCopy(ret.as_mut_ptr() as *const u32, from as u32, length as u32);
+    }
+}
+
+#[cfg(feature = "std")]
+/// Returns a vector containing the entire "block data".
+pub fn acquire_block_data() -> Vec<u8> {
+    let length = block_data_size();
+
+    let mut ret: Vec<u8> = unsafe_alloc_buffer(length);
+    unsafe_block_data_copy(0, length, &mut ret);
+    ret
+}
+
+/// Returns the segment of "block data" beginning at `from`, and continuing for `length` bytes.
+pub fn block_data_copy(from: usize, length: usize, ret: &mut [u8]) -> Result<(), Error> {
+    let size = block_data_size();
+
+    if (size < from) || ((size - from) < length) || (ret.len() < length) {
+        Err(Error::OutOfBoundsCopy)
+    } else {
+        unsafe_block_data_copy(from, length, ret);
+        Ok(())
+    }
+}
+
+/// Push new deposit receipt.
+pub fn push_new_deposit(deposit: &[u8]) {
+    unsafe { native::eth2_pushNewDeposit(deposit.as_ptr() as *const u32, deposit.len() as u32) }
+}
+
+/// Save new state root.
+pub fn save_post_state_root(state: Bytes32) {
+    unsafe { native::eth2_savePostStateRoot(state.bytes.as_ptr() as *const u32) }
+}

src/lib.rs

@@ -53,6 +53,9 @@ pub mod debug;
 #[cfg(feature = "experimental")]
 pub mod bignum;
 
+#[cfg(feature = "eth2")]
+pub mod eth2;
+
 #[cfg(not(feature = "std"))]
 pub mod convert;