Handle the DataCount section (#264)

This is a relatively recent addition to the bulk-memory-ops proposal

src/elements/module.rs

@@ -253,7 +253,7 @@ impl Module {
 			}
 		}
 		let insert_before = self.sections().iter().enumerate()
-			.filter_map(|(i, s)| if s.id() > 0x8 { Some(i) } else { None })
+			.filter_map(|(i, s)| if s.order() > 0x8 { Some(i) } else { None })
 			.next()
 			.unwrap_or(0);
 		self.sections_mut().insert(insert_before, Section::Start(new_start));
@@ -482,20 +482,20 @@ impl Deserialize for Module {
 			return Err(Error::UnsupportedVersion(version));
 		}
 
-		let mut last_section_id = 0;
+		let mut last_section_order = 0;
 
 		loop {
 			match Section::deserialize(reader) {
 				Err(Error::UnexpectedEof) => { break; },
 				Err(e) => { return Err(e) },
 				Ok(section) => {
-					if section.id() != 0 {
-						if last_section_id > section.id() {
+					if section.order() != 0 {
+						if last_section_order > section.order() {
 							return Err(Error::SectionsOutOfOrder);
-						} else if last_section_id == section.id() {
-							return Err(Error::DuplicatedSections(last_section_id));
+						} else if last_section_order == section.order() {
+							return Err(Error::DuplicatedSections(last_section_order));
 						}
-						last_section_id = section.id();
+						last_section_order = section.order();
 					}
 					sections.push(section);
 				}
@@ -837,22 +837,22 @@ mod integration_tests {
         module.set_start_section(0);
         assert_eq!(module.start_section().expect("Did not find any start section"), 0);
 
-        let sections = module.sections().iter().map(|s| s.id()).collect::<Vec<_>>();
-        assert_eq!(sections, vec![1, 2, 3, 6, 7, 8, 9, 10, 11]);
+        let sections = module.sections().iter().map(|s| s.order()).collect::<Vec<_>>();
+        assert_eq!(sections, vec![1, 2, 3, 6, 7, 8, 9, 11, 12]);
     }
 
     #[test]
     fn add_start_custom() {
         let mut module = deserialize_file("./res/cases/v1/start_add_custom.wasm").expect("failed to deserialize");
 
-        let sections = module.sections().iter().map(|s| s.id()).collect::<Vec<_>>();
-        assert_eq!(sections, vec![1, 2, 3, 6, 7, 9, 10, 11, 0]);
+        let sections = module.sections().iter().map(|s| s.order()).collect::<Vec<_>>();
+        assert_eq!(sections, vec![1, 2, 3, 6, 7, 9, 11, 12, 0]);
 
         assert!(module.start_section().is_none());
         module.set_start_section(0);
-        assert_eq!(module.start_section().expect("Did not find any start section"), 0);
+        assert_eq!(module.start_section().expect("Dorder not find any start section"), 0);
 
-        let sections = module.sections().iter().map(|s| s.id()).collect::<Vec<_>>();
-        assert_eq!(sections, vec![1, 2, 3, 6, 7, 8, 9, 10, 11, 0]);
+        let sections = module.sections().iter().map(|s| s.order()).collect::<Vec<_>>();
+        assert_eq!(sections, vec![1, 2, 3, 6, 7, 8, 9, 11, 12, 0]);
     }
 }

src/elements/section.rs

@@ -60,6 +60,8 @@ pub enum Section {
 	Start(u32),
 	/// Elements section.
 	Element(ElementSection),
+	/// Number of passive data entries in the data section
+	DataCount(u32),
 	/// Function bodies section.
 	Code(CodeSection),
 	/// Data definition section.
@@ -127,6 +129,12 @@ impl Deserialize for Section {
 				11 => {
 					Section::Data(DataSection::deserialize(reader)?)
 				},
+				12 => {
+					let mut section_reader = SectionReader::new(reader)?;
+					let count = VarUint32::deserialize(&mut section_reader)?;
+					section_reader.close()?;
+					Section::DataCount(count.into())
+				},
 				invalid_id => {
 					return Err(Error::InvalidSectionId(invalid_id))
 				},
@@ -182,6 +190,12 @@ impl Serialize for Section {
 				VarUint32::from(index).serialize(&mut counted_writer)?;
 				counted_writer.done()?;
 			},
+			Section::DataCount(count) => {
+				VarUint7::from(0x0c).serialize(writer)?;
+				let mut counted_writer = CountedWriter::new(writer);
+				VarUint32::from(count).serialize(&mut counted_writer)?;
+				counted_writer.done()?;
+			},
 			Section::Element(element_section) => {
 				VarUint7::from(0x09).serialize(writer)?;
 				element_section.serialize(writer)?;
@@ -212,7 +226,7 @@ impl Serialize for Section {
 }
 
 impl Section {
-	pub(crate) fn id(&self) -> u8 {
+	pub(crate) fn order(&self) -> u8 {
 		match *self {
 			Section::Custom(_) => 0x00,
 			Section::Unparsed { .. } => 0x00,
@@ -225,8 +239,9 @@ impl Section {
 			Section::Export(_) => 0x7,
 			Section::Start(_) => 0x8,
 			Section::Element(_) => 0x9,
-			Section::Code(_) => 0x0a,
-			Section::Data(_) => 0x0b,
+			Section::DataCount(_) => 0x0a,
+			Section::Code(_) => 0x0b,
+			Section::Data(_) => 0x0c,
 			Section::Name(_) => 0x00,
 			Section::Reloc(_) => 0x00,
 		}