From f6ba9364c2e7c8adc05e08ec305249e5031b8fbe Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@k1024.org>
Date: Wed, 11 Dec 2019 20:50:55 +0100
Subject: [PATCH] Implement creating an ACL directly from serialised form

---
 NEWS               |  4 ++++
 acl.c              | 21 +++++++++++++++++++++
 tests/test_acls.py | 13 +++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/NEWS b/NEWS
index 94e5183..a6a0df1 100644
--- a/NEWS
+++ b/NEWS
@@ -40,6 +40,10 @@ Important API changes/bug fixes:
 
 Minor improvements:
 
+- Added a `data` keyword argument to `ACL()`, which allows restoring an
+  ACL directly from a serialised form (as given by `__getstate__()`),
+  which should simplify some uses cases (`a = ACL(); a.__set
+  state__(…)`).
 - When available, add the file path to I/O error messages, which should
   lead to easier debugging.
 - The test suite has changed to `pytest`, which allows increased
diff --git a/acl.c b/acl.c
index 2bd05d8..99f3e9a 100644
--- a/acl.c
+++ b/acl.c
@@ -133,11 +133,17 @@ static int ACL_init(PyObject* obj, PyObject* args, PyObject *keywds) {
     static char *kwlist[] = { "file", "fd", "text", "acl", "filedef",
 #ifdef HAVE_LINUX
                               "mode",
+#endif
+#ifdef HAVE_ACL_COPY_EXT
+                              "data",
 #endif
                               NULL };
     char *format = "|O&OsO!O&"
 #ifdef HAVE_LINUX
       "i"
+#endif
+#ifdef HAVE_ACL_COPY_EXT
+      "y#"
 #endif
       ;
     int mode = -1;
@@ -146,6 +152,8 @@ static int ACL_init(PyObject* obj, PyObject* args, PyObject *keywds) {
     char *text = NULL;
     PyObject *fd = NULL;
     ACL_Object* thesrc = NULL;
+    const void *buf = NULL;
+    Py_ssize_t bufsize;
 
     if(!PyTuple_Check(args) || PyTuple_Size(args) != 0 ||
        (keywds != NULL && PyDict_Check(keywds) && PyDict_Size(keywds) > 1)) {
@@ -159,6 +167,9 @@ static int ACL_init(PyObject* obj, PyObject* args, PyObject *keywds) {
                                     PyUnicode_FSConverter, &filedef
 #ifdef HAVE_LINUX
                                     , &mode
+#endif
+#ifdef HAVE_ACL_COPY_EXT
+                                    , &buf, &bufsize
 #endif
                                     ))
         return -1;
@@ -192,6 +203,14 @@ static int ACL_init(PyObject* obj, PyObject* args, PyObject *keywds) {
 #ifdef HAVE_LINUX
     else if(mode != -1)
         self->acl = acl_from_mode(mode);
+#endif
+#ifdef HAVE_ACL_COPY_EXT
+    else if(buf != NULL) {
+      if((self->acl = acl_copy_int(buf)) == NULL) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return -1;
+      }
+    }
 #endif
     else
         self->acl = acl_init(0);
@@ -1259,6 +1278,8 @@ static char __ACL_Type_doc__[] =
     "    (e.g. ``mode=0644``); this is valid only when the C library\n"
     "    provides the ``acl_from_mode call``, and\n"
     "    note that no validation is done on the given value.\n"
+    ":param bytes data: creates an ACL from a serialised form,\n"
+    "    as provided by calling ``__getstate__()`` on an existing ACL\n"
     "\n"
     "If no parameters are passed, an empty ACL will be created; this\n"
     "makes sense only when your OS supports ACL modification\n"
diff --git a/tests/test_acls.py b/tests/test_acls.py
index 8de6aa2..28f55c9 100644
--- a/tests/test_acls.py
+++ b/tests/test_acls.py
@@ -492,6 +492,19 @@ class TestAclExtensions:
         with pytest.raises(TypeError):
             a.__setstate__(None)
 
+    @require_copy_ext
+    def test_acl_init_copy_ext(self):
+        a = posix1e.ACL(text=BASIC_ACL_TEXT)
+        b = posix1e.ACL()
+        c = posix1e.ACL(data=a.__getstate__())
+        assert c != b
+        assert c == a
+
+    @require_copy_ext
+    def test_acl_init_copy_ext_invalid(self):
+        with pytest.raises(IOError):
+            posix1e.ACL(data=b"foobar")
+
 
 class TestWrite:
     """Write tests"""
-- 
2.39.5