Auto generate the boilerplate code to convert python opts to c opts

gen-config.py

@@ -323,12 +323,59 @@ def generate_class(defn: Definition, loc: str) -> Tuple[str, str]:
     return class_def, '\n'.join(preamble + ['', ''] + tc_lines)
 
 
+def generate_c_conversion(loc: str, ctypes: List[Option]) -> str:
+    lines: List[str] = []
+    basic_converters = {
+        'int': 'PyLong_AsLong', 'uint': 'PyLong_AsUnsignedLong', 'bool': 'PyObject_IsTrue',
+        'float': 'PyFloat_AsFloat', 'double': 'PyFloat_AsDouble',
+        'time': 'parse_s_double_to_monotonic_t', 'time-ms': 'parse_ms_long_to_monotonic_t'
+    }
+
+    for opt in ctypes:
+        lines.append('')
+        lines.append(f'static void\nconvert_from_python_{opt.name}(PyObject *val, Options *opts) ''{')
+        is_special = opt.ctype.startswith('!')
+        if is_special:
+            func = opt.ctype[1:]
+            lines.append(f'    {func}(val, opts);')
+        else:
+            func = basic_converters.get(opt.ctype, opt.ctype)
+            lines.append(f'    opts->{opt.name} = {func}(val);')
+        lines.append('}')
+        lines.append('')
+        lines.append(f'static void\nconvert_from_opts_{opt.name}(PyObject *py_opts, Options *opts) ''{')
+        lines.append(f'    PyObject *ret = PyObject_GetAttrString(py_opts, "{opt.name}");')
+        lines.append('    if (ret == NULL) return;')
+        lines.append(f'    convert_from_python_{opt.name}(ret, opts);')
+        lines.append('    Py_DECREF(ret);')
+        lines.append('}')
+
+    lines.append('')
+    lines.append('static bool\nconvert_opts_from_python_opts(PyObject *py_opts, Options *opts) ''{')
+    for opt in ctypes:
+        lines.append(f'    convert_from_opts_{opt.name}(py_opts, opts);')
+        lines.append('    if (PyErr_Occurred()) return false;')
+    lines.append('    return true;')
+    lines.append('}')
+
+    preamble = ['// generated by gen-config.py DO NOT edit', '// vim:fileencoding=utf-8', '#pragma once', '#include "to-c.h"']
+    return '\n'.join(preamble + ['', ''] + lines)
+
+
 def write_output(loc: str, defn: Definition) -> None:
     cls, tc = generate_class(defn, loc)
     with open(os.path.join(*loc.split('.'), 'options', 'types.py'), 'w') as f:
         f.write(cls + '\n')
     with open(os.path.join(*loc.split('.'), 'options', 'parse.py'), 'w') as f:
         f.write(tc + '\n')
+    ctypes = []
+    for opt in defn.root_group.iter_all_non_groups():
+        if isinstance(opt, Option) and opt.ctype:
+            ctypes.append(opt)
+    if ctypes:
+        c = generate_c_conversion(loc, ctypes)
+        with open(os.path.join(*loc.split('.'), 'options', 'to-c-generated.h'), 'w') as f:
+            f.write(c + '\n')
 
 
 def main() -> None: