Make av/descriptor pure

Author: WyattBlue

av/descriptor.py

@@ -0,0 +1,75 @@
+import cython
+import cython.cimports.libav as lib
+from cython.cimports.av.option import (
+    Option,
+    OptionChoice,
+    wrap_option,
+    wrap_option_choice,
+)
+
+_cinit_sentinel = cython.declare(object, object())
+
+
+@cython.cfunc
+def wrap_avclass(ptr: cython.pointer[cython.const[lib.AVClass]]) -> Descriptor | None:
+    if ptr == cython.NULL:
+        return None
+    obj: Descriptor = Descriptor(_cinit_sentinel)
+    obj.ptr = ptr
+    return obj
+
+
+@cython.cclass
+class Descriptor:
+    def __cinit__(self, sentinel):
+        if sentinel is not _cinit_sentinel:
+            raise RuntimeError("Cannot construct av.Descriptor")
+
+    @property
+    def name(self):
+        return self.ptr.class_name if self.ptr.class_name else None
+
+    @property
+    def options(self):
+        ptr: cython.pointer[cython.const[lib.AVOption]] = self.ptr.option
+        choice_ptr: cython.pointer[cython.const[lib.AVOption]]
+        option: Option
+        option_choice: OptionChoice
+        choice_is_default: cython.bint
+        if self._options is None:
+            options: list = []
+            ptr = self.ptr.option
+            while ptr != cython.NULL and ptr.name != cython.NULL:
+                if ptr.type == lib.AV_OPT_TYPE_CONST:
+                    ptr += 1
+                    continue
+                choices: list = []
+                if (
+                    ptr.unit != cython.NULL
+                ):  # option has choices (matching const options)
+                    choice_ptr = self.ptr.option
+                    while choice_ptr != cython.NULL and choice_ptr.name != cython.NULL:
+                        if (
+                            choice_ptr.type != lib.AV_OPT_TYPE_CONST
+                            or choice_ptr.unit != ptr.unit
+                        ):
+                            choice_ptr += 1
+                            continue
+                        choice_is_default = (
+                            choice_ptr.default_val.i64 == ptr.default_val.i64
+                            or ptr.type == lib.AV_OPT_TYPE_FLAGS
+                            and choice_ptr.default_val.i64 & ptr.default_val.i64
+                        )
+                        option_choice = wrap_option_choice(
+                            choice_ptr, choice_is_default
+                        )
+                        choices.append(option_choice)
+                        choice_ptr += 1
+                option = wrap_option(tuple(choices), ptr)
+                options.append(option)
+                ptr += 1
+            self._options = tuple(options)
+        return self._options
+
+    def __repr__(self):
+        return f"<{self.__class__.__name__} {self.name} at 0x{id(self):x}>"