From patchwork Mon Nov 7 05:47:23 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Tromey X-Patchwork-Id: 17244 Received: (qmail 75788 invoked by alias); 7 Nov 2016 05:47:59 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 75676 invoked by uid 89); 7 Nov 2016 05:47:55 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=0.4 required=5.0 tests=AWL, BAYES_20, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_SPAM, SPF_PASS autolearn=no version=3.3.2 spammy=transfers, H*r:4.86_1, resource, subsequent X-HELO: gproxy9-pub.mail.unifiedlayer.com Received: from gproxy9-pub.mail.unifiedlayer.com (HELO gproxy9-pub.mail.unifiedlayer.com) (69.89.20.122) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with SMTP; Mon, 07 Nov 2016 05:47:44 +0000 Received: (qmail 1763 invoked by uid 0); 7 Nov 2016 05:47:42 -0000 Received: from unknown (HELO CMOut01) (10.0.90.82) by gproxy9.mail.unifiedlayer.com with SMTP; 7 Nov 2016 05:47:42 -0000 Received: from box522.bluehost.com ([74.220.219.122]) by CMOut01 with id 4tne1u0022f2jeq01tnhgd; Sun, 06 Nov 2016 22:47:41 -0700 X-Authority-Analysis: v=2.1 cv=beT4Do/B c=1 sm=1 tr=0 a=GsOEXm/OWkKvwdLVJsfwcA==:117 a=GsOEXm/OWkKvwdLVJsfwcA==:17 a=L9H7d07YOLsA:10 a=9cW_t1CCXrUA:10 a=s5jvgZ67dGcA:10 a=L24OOQBejmoA:10 a=zstS-IiYAAAA:8 a=BzObnAOqAAAA:8 a=mDV3o1hIAAAA:8 a=6wURTTF73w2fTzsHGeEA:9 a=4G6NA9xxw8l3yy4pmD5M:22 a=PuSIgb6VMkSJ0_1bSHE4:22 a=_FVE-zBwftR9WsbkzFJk:22 Received: from 174-16-143-211.hlrn.qwest.net ([174.16.143.211]:47918 helo=bapiya.Home) by box522.bluehost.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.86_1) (envelope-from ) id 1c3cmR-0008A3-GB; Sun, 06 Nov 2016 22:47:39 -0700 From: Tom Tromey To: gdb-patches@sourceware.org Cc: Tom Tromey Subject: [RFA 01/14] Introduce py-ref.h Date: Sun, 6 Nov 2016 22:47:23 -0700 Message-Id: <1478497656-11832-2-git-send-email-tom@tromey.com> In-Reply-To: <1478497656-11832-1-git-send-email-tom@tromey.com> References: <1478497656-11832-1-git-send-email-tom@tromey.com> X-BWhitelist: no X-Exim-ID: 1c3cmR-0008A3-GB X-Source-Sender: 174-16-143-211.hlrn.qwest.net (bapiya.Home) [174.16.143.211]:47918 X-Source-Auth: tom+tromey.com X-Email-Count: 2 X-Source-Cap: ZWx5bnJvYmk7ZWx5bnJvYmk7Ym94NTIyLmJsdWVob3N0LmNvbQ== 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 * 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 + + * python/py-ref.h: New file. + 2016-10-29 Manish Goregaokar * 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 . */ + +#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 */