From: Tom Tromey <tom@tromey.com>
To: gdb-patches@sourceware.org
Cc: Tom Tromey <tom@tromey.com>
Subject: [RFA 01/14] Introduce py-ref.h
Date: Mon, 07 Nov 2016 05:48:00 -0000 [thread overview]
Message-ID: <1478497656-11832-2-git-send-email-tom@tromey.com> (raw)
In-Reply-To: <1478497656-11832-1-git-send-email-tom@tromey.com>
This patch introduces class gdbpy_reference, which is a sort of smart
pointer that owns a single Python reference to a PyObject. This class
acts a bit like unique_ptr, but also a bit like shared_ptr (in that
copies do what you might expect); I considered going solely with
unique_ptr but it seemed quite strange to have a unique_ptr that
actually manages a shared resource.
Subsequent patches use this new class to simplify logic in the Python
layer.
2016-11-06 Tom Tromey <tom@tromey.com>
* python/py-ref.h: New file.
---
gdb/ChangeLog | 4 ++
gdb/python/py-ref.h | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 146 insertions(+)
create mode 100644 gdb/python/py-ref.h
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8e173a7..b46e26a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2016-11-06 Tom Tromey <tom@tromey.com>
+
+ * python/py-ref.h: New file.
+
2016-10-29 Manish Goregaokar <manish@mozilla.com>
* rust-exp.y: Parse `sizeof(exp)` as `UNOP_SIZEOF`
diff --git a/gdb/python/py-ref.h b/gdb/python/py-ref.h
new file mode 100644
index 0000000..1b1f1d2
--- /dev/null
+++ b/gdb/python/py-ref.h
@@ -0,0 +1,142 @@
+/* Python reference-holding class
+
+ Copyright (C) 2016 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef GDB_PYTHON_REF_H
+#define GDB_PYTHON_REF_H
+
+/* An instance of this class holds a reference to a PyObject. When
+ the object is destroyed, the PyObject is decref'd.
+
+ Normally an instance is constructed using a PyObject*. This sort
+ of initialization lets this class manage the lifetime of that
+ reference.
+
+ Assignment and copy construction will make a new reference as
+ appropriate. Assignment from a plain PyObject* is disallowed to
+ avoid confusion about whether this acquires a new reference;
+ instead use the "reset" method -- which, like the PyObject*
+ constructor, transfers ownership.
+*/
+class gdbpy_reference
+{
+ public:
+
+ /* Create a new NULL instance. */
+ gdbpy_reference ()
+ : m_obj (NULL)
+ {
+ }
+
+ /* Create a new NULL instance. */
+ gdbpy_reference (nullptr_t)
+ : m_obj (NULL)
+ {
+ }
+
+ /* Create a new instance. OBJ is a reference, management of which
+ is now transferred to this class. */
+ explicit gdbpy_reference (PyObject *obj)
+ : m_obj (obj)
+ {
+ }
+
+ /* Copy another instance. */
+ gdbpy_reference (const gdbpy_reference &other)
+ : m_obj (other.m_obj)
+ {
+ if (m_obj != NULL)
+ Py_INCREF (m_obj);
+ }
+
+ /* Transfer ownership from another instance. */
+ gdbpy_reference (gdbpy_reference &&other)
+ : m_obj (other.m_obj)
+ {
+ other.m_obj = NULL;
+ }
+
+ /* Destroy this instance. */
+ ~gdbpy_reference ()
+ {
+ Py_XDECREF (m_obj);
+ }
+
+ /* Copy another instance. */
+ gdbpy_reference &operator= (const gdbpy_reference &other)
+ {
+ Py_XDECREF (m_obj);
+ m_obj = other.m_obj;
+ if (m_obj != NULL)
+ Py_INCREF (m_obj);
+ return *this;
+ }
+
+ /* Transfer ownership from another instance. */
+ gdbpy_reference &operator= (gdbpy_reference &&other)
+ {
+ Py_XDECREF (m_obj);
+ m_obj = other.m_obj;
+ other.m_obj = NULL;
+ return *this;
+ }
+
+ /* Change this instance's referent. OBJ is a reference, management
+ of which is now transferred to this class. */
+ void reset (PyObject *obj)
+ {
+ Py_XDECREF (m_obj);
+ m_obj = obj;
+ }
+
+ /* Return this instance's referent. In Python terms this is a
+ borrowed pointer. */
+ PyObject *get ()
+ {
+ return m_obj;
+ }
+
+ /* Return this instance's referent, and stop managing this
+ reference. The caller is now responsible for the ownership of
+ the reference. */
+ PyObject *release ()
+ {
+ PyObject *result = m_obj;
+
+ m_obj = NULL;
+ return result;
+ }
+
+ /* Equality. */
+ bool operator== (const PyObject *other) const
+ {
+ return m_obj == other;
+ }
+
+ /* Inequality. */
+ bool operator!= (const PyObject *other) const
+ {
+ return m_obj != other;
+ }
+
+ private:
+
+ PyObject *m_obj;
+};
+
+#endif /* GDB_PYTHON_REF_H */
--
2.7.4
next prev parent reply other threads:[~2016-11-07 5:47 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-07 6:00 [RFA 00/14] add a smart pointer for PyObject* Tom Tromey
2016-11-07 5:48 ` [RFA 10/14] Use gdbpy_reference in call_doc_function Tom Tromey
2016-11-07 5:48 ` [RFA 12/14] Use gdbpy_reference in python.c Tom Tromey
2016-11-07 5:48 ` [RFA 07/14] Use gdbpy_reference in gdbpy_breakpoints Tom Tromey
2016-11-07 5:48 ` [RFA 13/14] Use gdbpy_reference in py-value.c Tom Tromey
2016-11-07 5:48 ` [RFA 06/14] Use gdbpy_reference in gdbpy_inferiors Tom Tromey
2016-11-07 5:48 ` [RFA 04/14] Use gdbpy_reference in gdbpy_string_to_argv Tom Tromey
2016-11-07 5:48 ` Tom Tromey [this message]
2016-11-07 7:45 ` [RFA 01/14] Introduce py-ref.h Jan Kratochvil
2016-11-07 15:48 ` Tom Tromey
2016-11-10 23:48 ` Pedro Alves
2016-11-12 17:31 ` Tom Tromey
2016-11-15 14:32 ` Pedro Alves
2016-11-16 23:18 ` Tom Tromey
2016-11-16 23:34 ` Pedro Alves
2016-11-07 5:48 ` [RFA 03/14] Use gdbpy_reference in py-type.c Tom Tromey
2016-11-07 5:48 ` [RFA 05/14] Use gdbpy_reference in py-function.c Tom Tromey
2016-11-07 5:48 ` [RFA 11/14] Use gdbpy_reference in py-prettyprint.c Tom Tromey
2016-11-07 5:48 ` [RFA 08/14] Use gdbpy_reference in py-framefilter.c Tom Tromey
2016-11-07 5:48 ` [RFA 14/14] Use gdbpy_reference in gdbpy_lookup_symbol Tom Tromey
2016-11-07 5:56 ` [RFA 02/14] Change event code to use gdbpy_reference Tom Tromey
2016-11-11 0:09 ` Pedro Alves
2016-11-11 0:51 ` Pedro Alves
2016-11-07 5:57 ` [RFA 09/14] Use gdbpy_reference in py-linetable.c Tom Tromey
2016-11-08 4:07 ` [RFA 00/14] add a smart pointer for PyObject* Tom Tromey
2016-11-11 1:18 ` Pedro Alves
2016-11-11 3:34 ` Tom Tromey
2016-11-11 4:03 ` Pedro Alves
2016-11-11 5:49 ` Tom Tromey
2016-11-12 17:11 ` Tom Tromey
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