Add JavaScript bindings and WASM support

Co-authored-by: Matija Kecman <matijak@google.com>
Co-authored-by: Sebastian Noreña Rendón <sebas.norena@creativa77.com.ar>
Co-authored-by: Kyle Bayes <kylebayes@google.com>
PiperOrigin-RevId: 826479070
Change-Id: I25acf36e6c20b091d8492e10798d028ae66f6733

wasm/codegen/helpers/common.py

@@ -0,0 +1,128 @@
+# 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
+import pathlib
+
+from wasm.codegen.helpers import constants
+
+Path = pathlib.Path
+
+
+def get_default_output_dir() -> str:
+  """Gets the default output directory (sibling of 'generated' folder)."""
+  # Get the directory of the current file (generator/base.py)
+  current_dir = Path(__file__).parent
+  # Go up one level to the project root and then down to 'generated'
+  default_output_dir = str(current_dir.parent / "generated")
+  return default_output_dir
+
+
+def get_file_path(
+    template_dir: str, output_dir: str, filename: str
+) -> tuple[str, str]:
+  """Constructs the template and output file paths.
+
+  Args:
+      template_dir: The directory containing the template files.
+      output_dir: The directory where the generated files will be saved.
+      filename: The name of the file.
+
+  Returns:
+      A tuple containing the template file path and the output file path.
+  """
+  template_file = f"wasm/codegen/{template_dir}/{filename}"
+  output_file = f"wasm/codegen/{output_dir}/{filename}"
+  return template_file, output_file
+
+
+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 uppercase_first_letter(input_string: str) -> str:
+  """Uppercases the first letter of a string."""
+  if input_string:
+    return input_string[0].upper() + input_string[1:]
+  return input_string
+
+
+def try_cast_to_scalar_type(value: str) -> int | float | str:
+  """Tries to cast a string to an integer, then a float, otherwise returns the original string."""
+  for type_ in [int, float]:
+    try:
+      return type_(value)
+    except ValueError:
+      continue
+  return value
+
+
+def debug_print(msg: str):
+  """Prints a message to the console if STRUCT_DEBUG_MODE is enabled."""
+  if constants.STRUCT_DEBUG_MODE:
+    print(msg)
+
+
+def replace_lines_containing_marker(
+    lines: list[str],
+    marker_to_replace: str,
+    replacement_content: str | list[str],
+) -> list[str]:
+  """Replaces lines containing a specific marker with new content."""
+
+  new_lines = []
+  replaced = False
+  for line in lines:
+    if not replaced and marker_to_replace in line:
+      indentation = _get_indentation(line)
+      if isinstance(replacement_content, str):
+        new_lines.append(indentation + replacement_content)
+      elif isinstance(replacement_content, list):
+        for content_line in replacement_content:
+          if not content_line.strip():
+            continue
+          indented_line = (
+              indentation
+              + content_line.replace("\n", "\n" + indentation)
+              + "\n"
+          )
+          new_lines.append(indented_line)
+      replaced = True
+    else:
+      new_lines.append(line)
+  return new_lines
+
+
+def _get_indentation(line: str) -> str:
+  """Returns the indentation of the given line as a string of spaces."""
+
+  indentation = ""
+  for char in line:
+    if char == " ":
+      indentation += " "
+    else:
+      break
+  return indentation