parttype: add parttype class and functions

Parttype is a container for partition types in libfdisk.

In python-libfdisk, the only way to create parttype instances
is using the corresponding label-specific function:

	get_parttype_from_{code,string}

This function wraps libfdisk's label_get_parttype_from_code (lookup DOS
label parttype by hex code) and label_get_parttype_from_string (lookup
GPT parttype by type uuid)

For example, to get the parttype instance of 'EFI System'
partition type of a GPT label, with type uuid
'c12a7328-f81f-11d2-ba4b-00a0c93ec93b':

>>> import fdisk
>>> cxt = fdisk.Context('./disk.bin', readonly=False)
>>> cxt.create_disklabel('gpt')
>>> efitype = cxt.label.get_parttype_from_string("c12a7328-f81f-11d2-ba4b-00a0c93ec93b")
>>> efitype
<libfdisk.PartType object at 0x7f503e4a5270, name=EFI System>

See:

https://cdn.kernel.org/pub/linux/utils/util-linux/v2.34/libfdisk-docs/libfdisk-Partition-types.html
https://cdn.kernel.org/pub/linux/utils/util-linux/v2.34/libfdisk-docs/libfdisk-Label.html#fdisk-label-get-parttype-from-code
https://cdn.kernel.org/pub/linux/utils/util-linux/v2.34/libfdisk-docs/libfdisk-Label.html#fdisk-label-get-parttype-from-string

1 files changed, 86 insertions, 0 deletions

diff --git a/parttype.c b/parttype.c
new file mode 100644
index 0000000..e3c6238
--- /dev/null
+++ b/parttype.c
@@ -0,0 +1,86 @@
+/*
+ * (C) 2022 Soleta Consulting S.L. <info@soleta.eu>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Author: Jose M. Guisado <jguisado@soleta.eu>
+ */
+
+#include "fdisk.h"
+
+static PyMemberDef PartType_members[] = {
+	{ NULL }
+};
+
+static void PartType_dealloc(PartTypeObject *self)
+{
+	Py_TYPE(self)->tp_free((PyObject *) self);
+}
+
+static PyMethodDef PartType_methods[] = {
+	{NULL}
+};
+
+static PyObject *PartType_get_name(PartTypeObject *self)
+{
+	return PyObjectResultStr(fdisk_parttype_get_name(self->type));
+}
+static PyObject *PartType_get_code(PartTypeObject *self)
+{
+	return PyLong_FromUnsignedLong(fdisk_parttype_get_code(self->type));
+}
+static PyGetSetDef PartType_getseters[] = {
+	{"name",	(getter)PartType_get_name, NULL, "parttype human readable name", NULL},
+	{"code",	(getter)PartType_get_code, NULL, "parttype DOS code", NULL},
+	{NULL}
+};
+
+static PyObject *PartType_repr(PartTypeObject *self)
+{
+	return PyUnicode_FromFormat("<libfdisk.PartType object at %p, name=%s>",
+			self, fdisk_parttype_get_name(self->type));
+}
+
+PyTypeObject PartTypeType = {
+	PyVarObject_HEAD_INIT(NULL, 0)
+	.tp_name = "libfdisk.PartType",
+	.tp_basicsize = sizeof(PartTypeObject),
+	.tp_dealloc = (destructor)PartType_dealloc,
+	.tp_repr = (reprfunc) PartType_repr,
+	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+	/* TODO: .tp_doc = PartType_HELP, */
+	.tp_methods = PartType_methods,
+	.tp_members = PartType_members,
+	.tp_getset = PartType_getseters,
+};
+
+PyObject *PyObjectResultPartType(struct fdisk_parttype *t)
+{
+        PartTypeObject *result;
+
+        if (!t) {
+                PyErr_SetString(PyExc_AssertionError, "lb assert failed");
+                return NULL;
+        }
+
+        result = PyObject_New(PartTypeObject, &PartTypeType);
+        if (!result) {
+                PyErr_SetString(PyExc_MemoryError, "Couldn't allocate PartType object");
+                return NULL;
+        }
+
+        result->type = t;
+        return (PyObject *) result;
+}
+
+void PartType_AddModuleObject(PyObject *mod)
+{
+	if (PyType_Ready(&PartTypeType) < 0)
+		return;
+
+	Py_INCREF(&PartTypeType);
+	PyModule_AddObject(mod, "PartType", (PyObject *)&PartTypeType);
+}