Refactor WASM binding directory structure

* All tests moved into wasm/codegen/tests folder
* Merged wasm/codegen/helpers/ into wasm/codegen/generators/

PiperOrigin-RevId: 829471173
Change-Id: I2dbc5d9351771817ec260c7ddf87c31e66a9eabe

wasm/codegen/generators/common.py

@@ -0,0 +1,66 @@
+# Copyright 2025 DeepMind Technologies Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Utility functions for code generation."""
+
+import os
+
+
+def write_to_file(filepath: str, content: str) -> None:
+  """Writes content to a file."""
+  output_dir = os.path.dirname(filepath)
+
+  try:
+    if output_dir:
+      os.makedirs(output_dir, exist_ok=True)
+    with open(filepath, "w") as f:
+      chars = f.write(content)
+      print(f"wrote {chars} characters to file '{filepath}'")
+  except IOError as e:
+    print(f"Error writing to output file: {filepath} - {e}")
+
+
+def lowercase_first_letter(input_string: str) -> str:
+  """Lowercases the first letter of a string."""
+  return input_string[:1].lower() + input_string[1:]
+
+
+def uppercase_first_letter(input_string: str) -> str:
+  """Uppercases the first letter of a string."""
+  return input_string[:1].upper() + input_string[1:]
+
+
+def replace_lines_containing_marker(
+    lines: list[str],
+    marker: str,
+    content: list[str],
+) -> list[str]:
+  """Replaces lines containing a specific marker with new content."""
+  for i, line in enumerate(lines):
+    if marker in line:
+      indent = line[: len(line) - len(line.lstrip(" "))]
+      replacement_lines = []
+      for text in content:
+        if text.strip():
+          # Prepend indent to ensure the first replacement line matches the
+          # indentation of the marker and also ensure that text containing
+          # newlines is also indented correctly.
+          # TODO(matijak): This is working around an upstream problem, we should
+          # make it a precondition that content elements do not contain newlines
+          # and fix callers to ensure that.
+          replacement_lines.append(
+              indent + text.replace("\n", f"\n{indent}") + "\n"
+          )
+      return lines[:i] + replacement_lines + lines[i + 1 :]
+  return lines