Handle .data file for kernels that require preloading (#145)

jupyterlite_xeus/add_on.py

@@ -41,7 +41,7 @@
 
 
 def get_kernel_binaries(path):
-    """return path to the kernel binary (js and wasm) if they exist, else None"""
+    """Return paths to the kernel binaries (js, wasm, and optionally data) if they exist, else None."""
     json_file = path / "kernel.json"
     if json_file.exists():
         kernel_spec = json.loads(json_file.read_text(**UTF8))
@@ -50,9 +50,16 @@ def get_kernel_binaries(path):
 
         kernel_binary_js = Path(kernel_binary + ".js")
         kernel_binary_wasm = Path(kernel_binary + ".wasm")
+        kernel_binary_data = Path(kernel_binary + ".data")
 
         if kernel_binary_js.exists() and kernel_binary_wasm.exists():
-            return kernel_binary_js, kernel_binary_wasm
+            # Return all three, with None for .data if it doesn't exist
+            # as this might not be neccessary for all kernels.
+            return (
+                kernel_binary_js,
+                kernel_binary_wasm,
+                kernel_binary_data if kernel_binary_data.exists() else None,
+            )
         else:
             warnings.warn(f"kernel binaries not found for {path.name}")
 
@@ -61,7 +68,6 @@ def get_kernel_binaries(path):
 
     return None
 
-
 class MountPoints(List):
     def from_string(self, s):
         return s.split(",")
@@ -181,10 +187,10 @@ def copy_kernels_from_prefix(self):
         for kernel_dir in kernel_spec_path.iterdir():
             kernel_binaries = get_kernel_binaries(kernel_dir)
             if kernel_binaries:
-                kernel_js, kernel_wasm = kernel_binaries
+                kernel_js, kernel_wasm, kernel_data = kernel_binaries
                 all_kernels.append(kernel_dir.name)
                 # take care of each kernel
-                yield from self.copy_kernel(kernel_dir, kernel_wasm, kernel_js)
+                yield from self.copy_kernel(kernel_dir, kernel_wasm, kernel_js, kernel_data)
 
         # write the kernels.json file
         kernel_file = Path(self.cwd.name) / "kernels.json"
@@ -196,7 +202,7 @@ def copy_kernels_from_prefix(self):
             ],
         )
 
-    def copy_kernel(self, kernel_dir, kernel_wasm, kernel_js):
+    def copy_kernel(self, kernel_dir, kernel_wasm, kernel_js, kernel_data):
         kernel_spec = json.loads((kernel_dir / "kernel.json").read_text(**UTF8))
 
         # update kernel_executable path in kernel.json
@@ -249,6 +255,18 @@ def copy_kernel(self, kernel_dir, kernel_wasm, kernel_js):
             ],
         )
 
+        # copy the kernel.data file to the bin dir if present
+        if kernel_data:
+            yield dict(
+                name=f"copy:{kernel_dir.name}:data",
+                actions=[
+                    (
+                        self.copy_one,
+                        [kernel_data, self.xeus_output_dir / "bin" / kernel_data.name],
+                    ),
+                ],
+            )
+
         # copy the kernel.json file
         yield dict(
             name=f"copy:{kernel_dir.name}:kernel.json",

packages/xeus/src/worker.ts

@@ -106,12 +106,16 @@ export class XeusRemoteKernel {
     // location of the kernel binary on the server
     const binary_js = URLExt.join(baseUrl, kernelSpec.argv[0]);
     const binary_wasm = binary_js.replace('.js', '.wasm');
+    const binary_data = binary_js.replace('.js', '.data');
 
     importScripts(binary_js);
     globalThis.Module = await createXeusModule({
       locateFile: (file: string) => {
         if (file.endsWith('.wasm')) {
           return binary_wasm;
+        } else if (file.endsWith('.data')) {
+          // Handle the .data file if it exists
+          return binary_data;
         }
         return file;
       }