Add toBytes() and BufferProtocol

VoidPtr:
Add toBytes() method that return a char* representation
of the void* pointer.

QByteArray:
The current implementation only provided the Buffer Protocol
for Python2, this patch includes the getbuffer implementation
for Python3.

Having a BufferProtocol implementation for Python3 allows the
initialization of VoidPtr to get access to the internal content,
so one can go back and forward with the representation of it:

    ba = QByteArray(b"Hello World")
    vp = VoidPtr(ba, ba.size())
    vp.toBytes() # b"Hello World"

The BufferProtocol was also changed for Python2 including the new
buffer protocol (Py_TPFLAGS_HAVE_NEWBUFFER) function `bf_getbuffer`.

A test case was included.

Fixes: PYSIDE-934
Change-Id: I8936966da91b2dcc879c582cfc35e6a35f7a60b6
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

2 files changed, 54 insertions, 10 deletions

diff --git a/sources/pyside2/PySide2/glue/qtcore.cpp b/sources/pyside2/PySide2/glue/qtcore.cpp
index 629484458..6259724c3 100644
--- a/sources/pyside2/PySide2/glue/qtcore.cpp
+++ b/sources/pyside2/PySide2/glue/qtcore.cpp
@@ -965,13 +965,33 @@ if (PyIndex_Check(_key)) {
 // @snippet qbytearray-msetitem
 
 // @snippet qbytearray-bufferprotocol
-#if PY_VERSION_HEX < 0x03000000
-
+extern "C" {
 // QByteArray buffer protocol functions
 // see: http://www.python.org/dev/peps/pep-3118/
 
-extern "C" {
+static int SbkQByteArray_getbufferproc(PyObject* obj, Py_buffer *view, int flags)
+{
+    if (!view || !Shiboken::Object::isValid(obj))
+        return -1;
+
+    QByteArray* cppSelf = %CONVERTTOCPP[QByteArray*](obj);
+    view->obj = obj;
+    view->buf = reinterpret_cast<void*>(cppSelf->data());
+    view->len = cppSelf->size();
+    view->readonly = 0;
+    view->itemsize = 1;
+    view->format = const_cast<char*>("c");
+    view->ndim = 1;
+    view->shape = NULL;
+    view->strides = &view->itemsize;
+    view->suboffsets = NULL;
+    view->internal = NULL;
+
+    Py_XINCREF(obj);
+    return 0;
+}
 
+#if PY_VERSION_HEX < 0x03000000
 static Py_ssize_t SbkQByteArray_segcountproc(PyObject* self, Py_ssize_t* lenp)
 {
     if (lenp)
@@ -993,12 +1013,18 @@ PyBufferProcs SbkQByteArrayBufferProc = {
     /*bf_getreadbuffer*/  &SbkQByteArray_readbufferproc,
     /*bf_getwritebuffer*/ (writebufferproc) &SbkQByteArray_readbufferproc,
     /*bf_getsegcount*/    &SbkQByteArray_segcountproc,
-    /*bf_getcharbuffer*/  (charbufferproc) &SbkQByteArray_readbufferproc
+    /*bf_getcharbuffer*/  (charbufferproc) &SbkQByteArray_readbufferproc,
+    /*bf_getbuffer*/  (getbufferproc)SbkQByteArray_getbufferproc,
 };
+#else
 
-}
+static PyBufferProcs SbkQByteArrayBufferProc = {
+    /*bf_getbuffer*/  (getbufferproc)SbkQByteArray_getbufferproc,
+    /*bf_releasebuffer*/ (releasebufferproc)0,
+};
 
 #endif
+}
 // @snippet qbytearray-bufferprotocol
 
 // @snippet qbytearray-operatorplus-1
@@ -1110,8 +1136,14 @@ if (PyBytes_Check(%PYARG_1)) {
 
 // @snippet qbytearray-py3
 #if PY_VERSION_HEX < 0x03000000
-    Shiboken::SbkType<QByteArray>()->tp_as_buffer = &SbkQByteArrayBufferProc;
-    Shiboken::SbkType<QByteArray>()->tp_flags |= Py_TPFLAGS_HAVE_GETCHARBUFFER;
+Shiboken::SbkType<QByteArray>()->tp_as_buffer = &SbkQByteArrayBufferProc;
+Shiboken::SbkType<QByteArray>()->tp_flags |= Py_TPFLAGS_HAVE_NEWBUFFER;
+#else
+#ifdef Py_LIMITED_API
+PepType_AS_BUFFER(Shiboken::SbkType<QByteArray>()) = &SbkQByteArrayBufferProc;
+#else
+Shiboken::SbkType<QByteArray>()->tp_as_buffer = &SbkQByteArrayBufferProc;
+#endif
 #endif
 // @snippet qbytearray-py3
 
diff --git a/sources/pyside2/tests/support/voidptr_test.py b/sources/pyside2/tests/support/voidptr_test.py
index 330788c63..c04022489 100644
--- a/sources/pyside2/tests/support/voidptr_test.py
+++ b/sources/pyside2/tests/support/voidptr_test.py
@@ -38,9 +38,21 @@ class PySide2Support(unittest.TestCase):
         # a C++ object, a wrapped Shiboken Object type,
         # an object implementing the Python Buffer interface,
         # or another VoidPtr object.
-        ba = QByteArray(b"Hello world")
-        voidptr = VoidPtr(ba)
-        self.assertIsInstance(voidptr, shiboken.VoidPtr)
+
+        # Original content
+        b = b"Hello world"
+        ba = QByteArray(b)
+        vp = VoidPtr(ba, ba.size())
+        self.assertIsInstance(vp, shiboken.VoidPtr)
+
+        # Create QByteArray from voidptr byte interpretation
+        nba = QByteArray.fromRawData(vp.toBytes())
+        # Compare original bytes to toBytes()
+        self.assertTrue(b, vp.toBytes())
+        # Compare original with new QByteArray data
+        self.assertTrue(b, nba.data())
+        # Convert original and new to str
+        self.assertTrue(str(b), str(nba))
 
 if __name__ == '__main__':
     unittest.main()