Support backref for wasm

src/serde/ser_br.rs

@@ -7,6 +7,7 @@ use super::object_cache::{serialized_length, treehash, ObjectCache};
 use super::read_cache_lookup::ReadCacheLookup;
 use super::write_atom::write_atom;
 use crate::allocator::{Allocator, NodePtr, SExp};
+use crate::serde::ser::LimitedWriter;
 
 const BACK_REFERENCE: u8 = 0xfe;
 const CONS_BOX_MARKER: u8 = 0xff;
@@ -77,10 +78,45 @@ pub fn node_to_stream_backrefs<W: io::Write>(
     Ok(())
 }
 
+pub fn node_to_bytes_backrefs_limit(
+    a: &Allocator,
+    node: NodePtr,
+    limit: usize,
+) -> io::Result<Vec<u8>> {
+    let buffer = Cursor::new(Vec::new());
+    let mut writer = LimitedWriter::new(buffer, limit);
+    node_to_stream_backrefs(a, node, &mut writer)?;
+    let vec = writer.into_inner().into_inner();
+    Ok(vec)
+}
+
 pub fn node_to_bytes_backrefs(a: &Allocator, node: NodePtr) -> io::Result<Vec<u8>> {
-    let mut buffer = Cursor::new(Vec::new());
+    node_to_bytes_backrefs_limit(a, node, 2000000)
+}
 
-    node_to_stream_backrefs(a, node, &mut buffer)?;
-    let vec = buffer.into_inner();
-    Ok(vec)
+#[test]
+fn test_serialize_limit() {
+    let mut a = Allocator::new();
+
+    let leaf = a.new_atom(&[1, 2, 3, 4, 5]).unwrap();
+    let l1 = a.new_pair(leaf, leaf).unwrap();
+    let l2 = a.new_pair(l1, l1).unwrap();
+    let l3 = a.new_pair(l2, l2).unwrap();
+
+    let expected = &[255, 255, 255, 133, 1, 2, 3, 4, 5, 254, 2, 254, 2, 254, 2];
+
+    {
+        assert_eq!(node_to_bytes_backrefs(&a, l3).unwrap(), expected);
+    }
+
+    {
+        assert_eq!(node_to_bytes_backrefs_limit(&a, l3, 15).unwrap(), expected);
+    }
+
+    {
+        assert_eq!(
+            node_to_bytes_backrefs_limit(&a, l3, 14).unwrap_err().kind(),
+            io::ErrorKind::OutOfMemory
+        );
+    }
 }

wasm/src/flags.rs

@@ -0,0 +1,3 @@
+// when this flag is set, the block generator serialization is allowed to
+// contain back-references
+pub const ALLOW_BACKREFS: u32 = 0x2000000;

wasm/src/lazy_node.rs

@@ -1,9 +1,11 @@
-use clvmr::allocator::{Allocator, NodePtr, SExp};
-use std::rc::Rc;
-
 use js_sys::Array;
+use std::rc::Rc;
 use wasm_bindgen::prelude::*;
 
+use crate::flags::ALLOW_BACKREFS;
+use clvmr::allocator::{Allocator, NodePtr, SExp};
+use clvmr::serde::{node_to_bytes, node_to_bytes_backrefs};
+
 #[wasm_bindgen]
 #[derive(Clone)]
 pub struct LazyNode {
@@ -35,6 +37,16 @@ impl LazyNode {
             _ => None,
         }
     }
+
+    #[wasm_bindgen]
+    pub fn to_bytes(&self, flag: u32) -> Option<Vec<u8>> {
+        let serializer = if (flag & ALLOW_BACKREFS) != 0 {
+            node_to_bytes_backrefs
+        } else {
+            node_to_bytes
+        };
+        serializer(&self.allocator, self.node).ok()
+    }
 }
 
 impl LazyNode {

wasm/src/lib.rs

@@ -1,5 +1,7 @@
-pub mod api;
+pub mod flags;
 pub mod lazy_node;
+pub mod run_program;
+pub mod serialize;
 
 #[cfg(test)]
 pub mod tests;

wasm/src/api.rs → wasm/src/run_program.rs

@@ -2,13 +2,14 @@ use js_sys::Array;
 use std::rc::Rc;
 use wasm_bindgen::prelude::*;
 
+use crate::flags::ALLOW_BACKREFS;
 use crate::lazy_node::LazyNode;
 use clvmr::allocator::Allocator;
 use clvmr::chia_dialect::ChiaDialect;
 use clvmr::chia_dialect::NO_UNKNOWN_OPS as _no_unknown_ops;
 use clvmr::cost::Cost;
 use clvmr::run_program::run_program;
-use clvmr::serde::{node_from_bytes, node_to_bytes, serialized_length_from_bytes};
+use clvmr::serde::{node_from_bytes, node_from_bytes_backrefs, node_to_bytes};
 
 // When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
 // allocator.
@@ -25,31 +26,28 @@ impl Flag {
     pub fn no_unknown_ops() -> u32 {
         _no_unknown_ops
     }
-}
 
-#[wasm_bindgen]
-pub fn serialized_length(program: &[u8]) -> Result<u64, String> {
-    match serialized_length_from_bytes(program) {
-        Ok(length) => Ok(length),
-        Err(err) => Err(err.to_string()),
+    #[wasm_bindgen]
+    pub fn allow_backrefs() -> u32 {
+        ALLOW_BACKREFS
     }
 }
 
 #[wasm_bindgen]
-pub fn run_clvm(program: &[u8], args: &[u8]) -> Vec<u8> {
+pub fn run_clvm(program: &[u8], args: &[u8], flag: u32) -> Vec<u8> {
     let max_cost: Cost = 1_000_000_000_000_000;
 
     let mut allocator = Allocator::new();
-    let program = node_from_bytes(&mut allocator, program).unwrap();
-    let args = node_from_bytes(&mut allocator, args).unwrap();
+    let deserializer = if (flag & ALLOW_BACKREFS) != 0 {
+        node_from_bytes_backrefs
+    } else {
+        node_from_bytes
+    };
+    let program = deserializer(&mut allocator, program).unwrap();
+    let args = deserializer(&mut allocator, args).unwrap();
+    let dialect = ChiaDialect::new(flag);
 
-    let r = run_program(
-        &mut allocator,
-        &ChiaDialect::new(0),
-        program,
-        args,
-        max_cost,
-    );
+    let r = run_program(&mut allocator, &dialect, program, args, max_cost);
     match r {
         Ok(reduction) => node_to_bytes(&allocator, reduction.1).unwrap(),
         Err(_eval_err) => format!("{:?}", _eval_err).into(),
@@ -64,8 +62,13 @@ pub fn run_chia_program(
     flag: u32,
 ) -> Result<Array, String> {
     let mut allocator = Allocator::new();
-    let program = node_from_bytes(&mut allocator, program).unwrap();
-    let args = node_from_bytes(&mut allocator, args).unwrap();
+    let deserializer = if (flag & ALLOW_BACKREFS) != 0 {
+        node_from_bytes_backrefs
+    } else {
+        node_from_bytes
+    };
+    let program = deserializer(&mut allocator, program).unwrap();
+    let args = deserializer(&mut allocator, args).unwrap();
     let dialect = ChiaDialect::new(flag);
 
     let r = run_program(&mut allocator, &dialect, program, args, max_cost);

wasm/src/serialize.rs

@@ -0,0 +1,24 @@
+use std::rc::Rc;
+use wasm_bindgen::prelude::wasm_bindgen;
+
+use crate::flags::ALLOW_BACKREFS;
+use crate::lazy_node::LazyNode;
+use clvmr::serde::{node_from_bytes, node_from_bytes_backrefs, serialized_length_from_bytes};
+use clvmr::Allocator;
+
+#[wasm_bindgen]
+pub fn serialized_length(program: &[u8]) -> Result<u64, String> {
+    serialized_length_from_bytes(program).map_err(|x| x.to_string())
+}
+
+#[wasm_bindgen]
+pub fn sexp_from_bytes(b: &[u8], flag: u32) -> Result<LazyNode, String> {
+    let mut allocator = Allocator::new();
+    let deserializer = if (flag & ALLOW_BACKREFS) != 0 {
+        node_from_bytes_backrefs
+    } else {
+        node_from_bytes
+    };
+    let node = deserializer(&mut allocator, b).map_err(|e| e.to_string())?;
+    Ok(LazyNode::new(Rc::new(allocator), node))
+}