handle nullable buffers

Signed-off-by: Edoardo Vacchi <evacchi@users.noreply.github.com>

Author: evacchi

template/src/schema.zig.ejs

@@ -113,10 +113,20 @@ pub const Host = struct {
 			}
 			<% } -%>
 			<% } else if (p.type === 'buffer') { %>
-			const dest_<%- p.name %> = try std.heap.wasm_allocator.alloc(u8, try b64dec.calcSizeForSlice(self.<%- p.name %>));
-			try b64dec.decode(dest_<%- p.name %>, self.<%- p.name %>);
-			self.<%- p.name %> = dest_<%- p.name %>;
-			<% } %>
+				<% if (isZigOptional(schema, p)) { %>
+				if (self.aBuffer != null) {
+				<% }  /* end isZigOptional */ -%> 
+
+				const srcBuf = self.<%- p.name %><%- isZigOptional(schema, p) ? '.?' : null %>;
+				const dest_<%- p.name %> = try std.heap.wasm_allocator.alloc(u8, try b64dec.calcSizeForSlice(srcBuf));
+				try b64dec.decode(dest_<%- p.name %>, srcBuf);
+				self.<%- p.name %> = dest_<%- p.name %>;
+
+				<% if (isZigOptional(schema, p)) { %>
+				}
+				<% }  /* end isZigOptional */ -%> 
+
+			<% } /* end buffer */ %>
 			<% }) %>
 
 			return self;
@@ -137,8 +147,15 @@ pub const Host = struct {
 			}
 			<% } -%>
 			<% } else if (p.type === 'buffer') { %>
-			const dest_<%- p.name %> = try std.heap.wasm_allocator.alloc(u8, b64enc.calcSize(self.<%- p.name %>.len));
-			self.<%- p.name %> = b64enc.encode(dest_<%- p.name %>, self.<%- p.name %>);
+				<% if (isZigOptional(schema, p)) { %>
+				if (self.<%- p.name %> != null) {
+				<% } -%>
+				const srcBuf = self.<%- p.name %><%- isZigOptional(schema, p) ? '.?' : null %>;
+				const dest_<%- p.name %> = try std.heap.wasm_allocator.alloc(u8, b64enc.calcSize(srcBuf.len));
+				self.<%- p.name %> = b64enc.encode(dest_<%- p.name %>, srcBuf);
+				<% if (isZigOptional(schema, p)) { %>
+				}
+				<% }  /* end isZigOptional */ -%> 		
 			<% } %>
 			<% }) %>