[Lldb-commits] [PATCH] D77480: Fix illegal early call to PyBuffer_Release in swig typemaps

[Lawrence D'Anna via Phabricator via lldb-commits]

lawrence_danna updated this revision to Diff 255464.
lawrence_danna added a comment.

delete operator= too


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D77480/new/

https://reviews.llvm.org/D77480

Files:
  lldb/bindings/python/python-typemaps.swig


Index: lldb/bindings/python/python-typemaps.swig
===================================================================
--- lldb/bindings/python/python-typemaps.swig
+++ lldb/bindings/python/python-typemaps.swig
@@ -488,39 +488,53 @@
     }
 }
 
+%inline %{
+
+struct Py_buffer_RAII {
+  Py_buffer buffer;
+  Py_buffer_RAII() { buffer = {}; };
+  Py_buffer &operator=(const Py_buffer_RAII &) = delete;
+  Py_buffer_RAII(const Py_buffer_RAII &) = delete;
+  ~Py_buffer_RAII() {
+    if (buffer.obj)
+      PyBuffer_Release(&buffer);
+  }
+};
+
+%}
+
 // These two pybuffer macros are copied out of swig/Lib/python/pybuffer.i,
 // and fixed so they will not crash if PyObject_GetBuffer fails.
 // https://github.com/swig/swig/issues/1640
+//
+// I've also moved the call to PyBuffer_Release to the end of the SWIG wrapper,
+// doing it right away is not legal according to the python buffer protocol.
 
 %define %pybuffer_mutable_binary(TYPEMAP, SIZE)
-%typemap(in) (TYPEMAP, SIZE) {
+%typemap(in) (TYPEMAP, SIZE) (Py_buffer_RAII view) {
   int res; Py_ssize_t size = 0; void *buf = 0;
-  Py_buffer view;
-  res = PyObject_GetBuffer($input, &view, PyBUF_WRITABLE);
+  res = PyObject_GetBuffer($input, &view.buffer, PyBUF_WRITABLE);
   if (res < 0) {
     PyErr_Clear();
     %argument_fail(res, "(TYPEMAP, SIZE)", $symname, $argnum);
   }
-  size = view.len;
-  buf = view.buf;
-  PyBuffer_Release(&view);
+  size = view.buffer.len;
+  buf = view.buffer.buf;
   $1 = ($1_ltype) buf;
   $2 = ($2_ltype) (size/sizeof($*1_type));
 }
 %enddef
 
 %define %pybuffer_binary(TYPEMAP, SIZE)
-%typemap(in) (TYPEMAP, SIZE) {
+%typemap(in) (TYPEMAP, SIZE) (Py_buffer_RAII view) {
   int res; Py_ssize_t size = 0; const void *buf = 0;
-  Py_buffer view;
-  res = PyObject_GetBuffer($input, &view, PyBUF_CONTIG_RO);
+  res = PyObject_GetBuffer($input, &view.buffer, PyBUF_CONTIG_RO);
   if (res < 0) {
     PyErr_Clear();
     %argument_fail(res, "(TYPEMAP, SIZE)", $symname, $argnum);
   }
-  size = view.len;
-  buf = view.buf;
-  PyBuffer_Release(&view);
+  size = view.buffer.len;
+  buf = view.buffer.buf;
   $1 = ($1_ltype) buf;
   $2 = ($2_ltype) (size / sizeof($*1_type));
 }


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