Fix new S3 API and bytes with offset (awslabs#517)

build.mjs

@@ -519,6 +519,7 @@ async function loadShims() {
     loadShim(/collect-stream-body\.js/, "collect-stream-body.js"),
     loadShim(/sdk-stream-mixin.browser\.js/, "sdk-stream-mixin.js"),
     loadShim(/stream-collector\.js/, "stream-collector.js"),
+    loadShim(/splitStream.browser\.js/, "@smithy/split-stream.js"),
   ]);
 }
 

llrt_core/src/modules/llrt/xml.rs

@@ -3,6 +3,7 @@
 use std::{collections::HashMap, rc::Rc};
 
 use quick_xml::{
+    escape::resolve_xml_entity,
     events::{BytesStart, Event},
     Reader,
 };
@@ -99,10 +100,12 @@ impl<'js> XMLParser<'js> {
             }
         }
 
+        let entities = HashMap::new();
+
         Ok(XMLParser {
             tag_value_processor,
             attribute_value_processor,
-            entities: HashMap::new(),
+            entities,
             attribute_name_prefix: attribute_name_prefix.into(),
             ignore_attributes,
             text_node_name: text_node_name.into(),
@@ -116,7 +119,8 @@ impl<'js> XMLParser<'js> {
     pub fn parse(&self, ctx: Ctx<'js>, xml: Value<'js>) -> Result<Object<'js>> {
         let bytes = get_bytes(&ctx, xml)?;
         let mut reader = Reader::from_reader(bytes.as_ref());
-        reader.config_mut().trim_text(true);
+        let config = reader.config_mut();
+        config.trim_text(true);
 
         let mut current_obj = StackObject::new(ctx.clone())?;
         current_obj.has_value = true;
@@ -186,7 +190,10 @@ impl<'js> XMLParser<'js> {
                 },
                 Ok(Event::Text(ref text)) => {
                     let tag_value = text
-                        .unescape_with(|v| self.entities.get(v).map(|x| x.as_ref()))
+                        .unescape_with(|v| {
+                            resolve_xml_entity(v)
+                                .or_else(|| self.entities.get(v).map(|x| x.as_ref()))
+                        })
                         .or_throw(&ctx)?;
                     let tag_value = tag_value.as_ref();
                     let tag_value =

llrt_utils/src/bytes.rs

@@ -42,7 +42,7 @@ pub fn get_bytes_offset_length<'js>(
         if let Some((array_buffer, source_length, source_offset)) = obj_to_array_buffer(obj)? {
             let (start, end) = get_start_end_indexes(source_length, length, offset);
             let bytes: &[u8] = array_buffer.as_ref();
-            return Ok(bytes[start + source_offset..end - source_offset].to_vec());
+            return Ok(bytes[(start + source_offset)..(end + source_offset)].to_vec());
         }
     }
 

shims/@smithy/split-stream.js

@@ -0,0 +1,5 @@
+export async function splitStream(stream) {
+  //stream is blob here
+  const typedArray = await stream.bytes();
+  return [typedArray.subarray(0, 3000), typedArray];
+}