1 files changed, 116 insertions, 0 deletions
diff --git a/third_party/rust/parity-wasm/src/builder/export.rs b/third_party/rust/parity-wasm/src/builder/export.rs
new file mode 100644
index 0000000000..a2de79c24e
--- /dev/null
+++ b/third_party/rust/parity-wasm/src/builder/export.rs
@@ -0,0 +1,116 @@
+use alloc::{borrow::ToOwned, string::String};
+use super::invoke::{Invoke, Identity};
+use crate::elements;
+
+/// Export entry builder
+pub struct ExportBuilder<F=Identity> {
+	callback: F,
+	field: String,
+	binding: elements::Internal,
+}
+
+impl ExportBuilder {
+	/// New export builder
+	pub fn new() -> Self {
+		ExportBuilder::with_callback(Identity)
+	}
+}
+
+impl<F> ExportBuilder<F> {
+
+	/// New export entry builder in the specified chained context
+	pub fn with_callback(callback: F) -> Self {
+		ExportBuilder {
+			callback: callback,
+			field: String::new(),
+			binding: elements::Internal::Function(0),
+		}
+	}
+
+	/// Set the field name of the export entry
+	pub fn field(mut self, field: &str) -> Self {
+		self.field = field.to_owned();
+		self
+	}
+
+	/// Specify the internal module mapping for this entry
+	pub fn with_internal(mut self, external: elements::Internal) -> Self {
+		self.binding = external;
+		self
+	}
+
+	/// Start the internal builder for this export entry
+	pub fn internal(self) -> ExportInternalBuilder<Self> {
+		ExportInternalBuilder::with_callback(self)
+	}
+}
+
+impl<F> ExportBuilder<F> where F: Invoke<elements::ExportEntry> {
+	/// Finalize export entry builder spawning the resulting struct
+	pub fn build(self) -> F::Result {
+		self.callback.invoke(elements::ExportEntry::new(self.field, self.binding))
+	}
+}
+
+impl<F> Invoke<elements::Internal> for ExportBuilder<F> {
+	type Result = Self;
+	fn invoke(self, val: elements::Internal) -> Self {
+		self.with_internal(val)
+	}
+}
+
+/// Internal mapping builder for export entry
+pub struct ExportInternalBuilder<F=Identity> {
+	callback: F,
+	binding: elements::Internal,
+}
+
+impl<F> ExportInternalBuilder<F> where F: Invoke<elements::Internal> {
+	/// New export entry internal mapping for the chained context
+	pub fn with_callback(callback: F) -> Self {
+		ExportInternalBuilder{
+			callback: callback,
+			binding: elements::Internal::Function(0),
+		}
+	}
+
+	/// Map to function by index
+	pub fn func(mut self, index: u32) -> F::Result {
+		self.binding = elements::Internal::Function(index);
+		self.callback.invoke(self.binding)
+	}
+
+	/// Map to memory
+	pub fn memory(mut self, index: u32) -> F::Result {
+		self.binding = elements::Internal::Memory(index);
+		self.callback.invoke(self.binding)
+	}
+
+	/// Map to table
+	pub fn table(mut self, index: u32) -> F::Result {
+		self.binding = elements::Internal::Table(index);
+		self.callback.invoke(self.binding)
+	}
+
+	/// Map to global
+	pub fn global(mut self, index: u32) -> F::Result {
+		self.binding = elements::Internal::Global(index);
+		self.callback.invoke(self.binding)
+	}
+}
+
+/// New builder for export entry
+pub fn export() -> ExportBuilder {
+	ExportBuilder::new()
+}
+
+#[cfg(test)]
+mod tests {
+	use super::export;
+
+	#[test]
+	fn example() {
+		let entry = export().field("memory").internal().memory(0).build();
+		assert_eq!(entry.field(), "memory");
+	}
+}