feat: Decode with iter by default (#21)

Co-authored-by: Leigh McCulloch <[email protected]>

src/lib.rs

@@ -1,8 +1,9 @@
 mod console_error_panic_hook;
 
 use schemars::gen::SchemaSettings;
+use std::io::Cursor;
 use std::str::FromStr;
-use stellar_xdr::curr::{Limits, Type, TypeVariant, WriteXdr};
+use stellar_xdr::curr::{Limited, Limits, Type, TypeVariant, WriteXdr};
 use wasm_bindgen::prelude::*;
 
 /// Returns a list of XDR types.
@@ -44,6 +45,31 @@ pub fn guess(xdr_base64: String) -> Vec<String> {
         .collect()
 }
 
+/// Decodes a stream of XDR into an array of JSONs.
+///
+/// Returns an array of JSON strings.
+///
+/// Returns a JSON string.
+#[wasm_bindgen]
+pub fn decode_stream(type_variant: String, xdr_base64: String) -> Result<Vec<String>, String> {
+    let type_variant = TypeVariant::from_str(&type_variant).map_err(|e| format!("{e}"))?;
+
+    // Base64 when decoded will have a length at or under this len.
+    // Ref: https://datatracker.ietf.org/doc/html/rfc4648#page-5
+    let decoded_max_len = xdr_base64.len() / 4 * 3;
+    // Limit decoding attempts to within the maximum length of the known input.
+    let limits = Limits::len(decoded_max_len);
+    let mut cursor = Limited::new(Cursor::new(xdr_base64.as_bytes()), limits);
+
+    let json = Type::read_xdr_base64_iter(type_variant, &mut cursor)
+        .map(|value| {
+            serde_json::to_string(&value.map_err(|e| format!("{e}"))?).map_err(|e| format!("{e}"))
+        })
+        .collect::<Result<Vec<_>, _>>()?;
+    // TODO: Return a native JS value.
+    Ok(json)
+}
+
 /// Decodes the XDR into JSON.
 ///
 /// Accepts a XDR base64 string.

tests/tests.rs

@@ -489,6 +489,24 @@ fn decode_success() {
     );
 }
 
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+#[test]
+fn decode_iter_success() {
+    assert_eq!(
+        stellar_xdr_json::decode_stream(
+            "ScSpecEntry".to_string(),
+            "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".to_string(),
+        ),
+        Ok([r#"{"function_v0":{"doc":"","name":"initialize","inputs":[{"doc":"","name":"token_wasm_hash","type_":{"bytes_n":{"n":32}}},{"doc":"","name":"token_a","type_":"address"},{"doc":"","name":"token_b","type_":"address"}],"outputs":[]}}"#,
+            r#"{"function_v0":{"doc":"","name":"share_id","inputs":[],"outputs":["address"]}}"#,
+            r#"{"function_v0":{"doc":"","name":"deposit","inputs":[{"doc":"","name":"to","type_":"address"},{"doc":"","name":"desired_a","type_":"i128"},{"doc":"","name":"min_a","type_":"i128"},{"doc":"","name":"desired_b","type_":"i128"},{"doc":"","name":"min_b","type_":"i128"}],"outputs":[]}}"#,
+            r#"{"function_v0":{"doc":"","name":"swap","inputs":[{"doc":"","name":"to","type_":"address"},{"doc":"","name":"buy_a","type_":"bool"},{"doc":"","name":"out","type_":"i128"},{"doc":"","name":"in_max","type_":"i128"}],"outputs":[]}}"#,
+            r#"{"function_v0":{"doc":"","name":"withdraw","inputs":[{"doc":"","name":"to","type_":"address"},{"doc":"","name":"share_amount","type_":"i128"},{"doc":"","name":"min_a","type_":"i128"},{"doc":"","name":"min_b","type_":"i128"}],"outputs":[{"tuple":{"value_types":["i128","i128"]}}]}}"#,
+            r#"{"function_v0":{"doc":"","name":"get_rsrvs","inputs":[],"outputs":[{"tuple":{"value_types":["i128","i128"]}}]}}"#
+            ].iter().map(ToString::to_string).collect::<Vec<String>>()),
+    );
+}
+
 #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
 #[test]
 fn decode_length_limit_protection() {