octave: liboctave/util/unwind-prot.h annotate

annotate liboctave/util/unwind-prot.h @ 27372:2f8428b61bd6

new single-action unwind-protect classes * unwind-prot.h (unwind_action, unwind_protect_var): New classes.

author	John W. Eaton <jwe@octave.org>
date	Wed, 04 Sep 2019 12:17:46 -0400
parents	8498dccc15c7
children	b442ec6dda5c

rev	line source
1 78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	1 /*
78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	2
26376 00f796120a6d maint: Update copyright dates in all source files. John W. Eaton <jwe@octave.org> parents: 25653 diff changeset	3 Copyright (C) 1993-2019 John W. Eaton
11523 fd0a3ac60b0e update copyright notices John W. Eaton <jwe@octave.org> parents: 10781 diff changeset	4 Copyright (C) 2009-2010 VZLU Prague
1 78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	5
78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	6 This file is part of Octave.
78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	7
24534 194eb4bd202b maint: Update punctuation for GPL v3 license text. Rik <rik@octave.org> parents: 23615 diff changeset	8 Octave is free software: you can redistribute it and/or modify it
22755 3a2b891d0b33 maint: Standardize Copyright formatting. Rik <rik@octave.org> parents: 22402 diff changeset	9 under the terms of the GNU General Public License as published by
24534 194eb4bd202b maint: Update punctuation for GPL v3 license text. Rik <rik@octave.org> parents: 23615 diff changeset	10 the Free Software Foundation, either version 3 of the License, or
22755 3a2b891d0b33 maint: Standardize Copyright formatting. Rik <rik@octave.org> parents: 22402 diff changeset	11 (at your option) any later version.
1 78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	12
22755 3a2b891d0b33 maint: Standardize Copyright formatting. Rik <rik@octave.org> parents: 22402 diff changeset	13 Octave is distributed in the hope that it will be useful, but
3a2b891d0b33 maint: Standardize Copyright formatting. Rik <rik@octave.org> parents: 22402 diff changeset	14 WITHOUT ANY WARRANTY; without even the implied warranty of
3a2b891d0b33 maint: Standardize Copyright formatting. Rik <rik@octave.org> parents: 22402 diff changeset	15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
3a2b891d0b33 maint: Standardize Copyright formatting. Rik <rik@octave.org> parents: 22402 diff changeset	16 GNU General Public License for more details.
1 78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	17
78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	18 You should have received a copy of the GNU General Public License
7016 93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6109 diff changeset	19 along with Octave; see the file COPYING. If not, see
24534 194eb4bd202b maint: Update punctuation for GPL v3 license text. Rik <rik@octave.org> parents: 23615 diff changeset	20 <https://www.gnu.org/licenses/>.
1 78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	21
78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	22 */
78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	23
20791 f7084eae3318 maint: Use Octave coding conventions for #if statements. Rik <rik@octave.org> parents: 20545 diff changeset	24 #if ! defined (octave_unwind_prot_h)
383 0b52c68ec81f [project @ 1994-03-09 21:19:44 by jwe] jwe parents: 240 diff changeset	25 #define octave_unwind_prot_h 1
1 78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	26
21244 1473547f50f5 include octave-config.h in public header files John W. Eaton <jwe@octave.org> parents: 21141 diff changeset	27 #include "octave-config.h"
1473547f50f5 include octave-config.h in public header files John W. Eaton <jwe@octave.org> parents: 21141 diff changeset	28
17552 d07d59cc8775 move unwind-protect to liboctave John W. Eaton <jwe@octave.org> parents: 16892 diff changeset	29 #include <cstddef>
d07d59cc8775 move unwind-protect to liboctave John W. Eaton <jwe@octave.org> parents: 16892 diff changeset	30
15396 1054ab58cd58 abstract unwind_protect John W. Eaton <jwe@octave.org> parents: 15195 diff changeset	31 #include <stack>
9394 b3ab22ee8544 further improve unwind_protect Jaroslav Hajek <highegg@gmail.com> parents: 9384 diff changeset	32 #include <memory>
240 a99f28f5e351 [project @ 1993-11-30 20:24:36 by jwe] jwe parents: 164 diff changeset	33
15396 1054ab58cd58 abstract unwind_protect John W. Eaton <jwe@octave.org> parents: 15195 diff changeset	34 #include "action-container.h"
1054ab58cd58 abstract unwind_protect John W. Eaton <jwe@octave.org> parents: 15195 diff changeset	35
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	36 namespace octave
2985 aa9d0c0e0458 [project @ 1997-05-16 06:54:18 by jwe] jwe parents: 2847 diff changeset	37 {
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	38 class
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	39 OCTAVE_API
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	40 unwind_protect : public action_container
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	41 {
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	42 public:
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	43
27177 8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	44 unwind_protect (void) : m_lifo () { }
2985 aa9d0c0e0458 [project @ 1997-05-16 06:54:18 by jwe] jwe parents: 2847 diff changeset	45
22869 f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	46 // No copying!
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	47
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	48 unwind_protect (const unwind_protect&) = delete;
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	49
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	50 unwind_protect& operator = (const unwind_protect&) = delete;
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	51
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	52 // Destructor should not raise an exception, so all actions
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	53 // registered should be exception-safe. If you're not sure, see
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	54 // unwind_protect_safe.
9394 b3ab22ee8544 further improve unwind_protect Jaroslav Hajek <highegg@gmail.com> parents: 9384 diff changeset	55
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	56 ~unwind_protect (void) { run (); }
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	57
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	58 operator bool (void) const { return ! empty (); }
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	59
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	60 void run_first (void)
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	61 {
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	62 if (! empty ())
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	63 {
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	64 // No leak on exception!
27177 8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	65 std::unique_ptr<elem> ptr (m_lifo.top ());
8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	66 m_lifo.pop ();
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	67 ptr->run ();
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	68 }
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	69 }
12122 f4689107dd8c Explicitly disallow copying in some classes. Pascal Dupuis <Pascal.Dupuis@uclouvain.be> parents: 11586 diff changeset	70
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	71 void discard_first (void)
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	72 {
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	73 if (! empty ())
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	74 {
27177 8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	75 elem *ptr = m_lifo.top ();
8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	76 m_lifo.pop ();
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	77 delete ptr;
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	78 }
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	79 }
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	80
27177 8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	81 size_t size (void) const { return m_lifo.size (); }
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	82
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	83 protected:
9376 d58086453171 refactor unwind_protect Jaroslav Hajek <highegg@gmail.com> parents: 8920 diff changeset	84
25653 b3d357990b52 better use of templates for action_container and derived classes John W. Eaton <jwe@octave.org> parents: 25147 diff changeset	85 virtual void add_action (elem *new_elem)
b3d357990b52 better use of templates for action_container and derived classes John W. Eaton <jwe@octave.org> parents: 25147 diff changeset	86 {
27177 8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	87 m_lifo.push (new_elem);
25653 b3d357990b52 better use of templates for action_container and derived classes John W. Eaton <jwe@octave.org> parents: 25147 diff changeset	88 }
b3d357990b52 better use of templates for action_container and derived classes John W. Eaton <jwe@octave.org> parents: 25147 diff changeset	89
27177 8498dccc15c7 minor style fixes John W. Eaton <jwe@octave.org> parents: 26376 diff changeset	90 std::stack<elem *> m_lifo;
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	91 };
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	92
21751 b571fc85953f maint: Use two spaces after period to indicate sentence break. Rik <rik@octave.org> parents: 21743 diff changeset	93 // Like unwind_protect, but this one will guard against the possibility
b571fc85953f maint: Use two spaces after period to indicate sentence break. Rik <rik@octave.org> parents: 21743 diff changeset	94 // of seeing an exception (or interrupt) in the cleanup actions.
b571fc85953f maint: Use two spaces after period to indicate sentence break. Rik <rik@octave.org> parents: 21743 diff changeset	95 // Not that we can do much about it, but at least we won't crash.
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	96
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	97 class
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	98 OCTAVE_API
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	99 unwind_protect_safe : public unwind_protect
15396 1054ab58cd58 abstract unwind_protect John W. Eaton <jwe@octave.org> parents: 15195 diff changeset	100 {
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	101 private:
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	102
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	103 void warn_unhandled_exception (void) const;
9396 17af7cce7d1b yet more unwind_protect improvements Jaroslav Hajek <highegg@gmail.com> parents: 9394 diff changeset	104
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	105 public:
9396 17af7cce7d1b yet more unwind_protect improvements Jaroslav Hajek <highegg@gmail.com> parents: 9394 diff changeset	106
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	107 unwind_protect_safe (void) : unwind_protect () { }
9394 b3ab22ee8544 further improve unwind_protect Jaroslav Hajek <highegg@gmail.com> parents: 9384 diff changeset	108
22869 f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	109 // No copying!
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	110
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	111 unwind_protect_safe (const unwind_protect_safe&) = delete;
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	112
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	113 unwind_protect_safe& operator = (const unwind_protect_safe&) = delete;
f75d289645ec make deleted functions public John W. Eaton <jwe@octave.org> parents: 22865 diff changeset	114
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	115 ~unwind_protect_safe (void)
22402 4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	116 {
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	117 while (! empty ())
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	118 {
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	119 try
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	120 {
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	121 run_first ();
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	122 }
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	123 catch (...) // Yes, the black hole. Remember we're in a destructor.
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	124 {
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	125 warn_unhandled_exception ();
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	126 }
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	127 }
4caa7b28d183 maint: Style check C++ code in liboctave/ Rik <rik@octave.org> parents: 22323 diff changeset	128 }
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	129 };
27372 2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	130
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	131 // In most cases, the following are preferred for efficiency. Some
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	132 // cases may require the flexibility of the general unwind_protect
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	133 // mechanism defined above.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	134
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	135 // Perform action at end of the current scope when unwind_action
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	136 // object destructor is called.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	137 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	138 // For example:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	139 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	140 // void fcn (int val) { ... }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	141 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	142 // ...
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	143 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	144 // {
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	145 // int val = 42;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	146 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	147 // // template parameters, std::bind and std::function provide
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	148 // // flexibility in calling forms:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	149 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	150 // unwind_action act1 (fcn, val);
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	151 // unwind_action act2 ([val] (void) { fcn (val); });
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	152 // }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	153 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	154 // NOTE: Don't forget to provide a name for the unwind_action
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	155 // variable. If you write
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	156 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	157 // unwind_action /* NO NAME! */ (...);
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	158 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	159 // then the destructor for the temporary anonymous object will be
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	160 // called immediately after the object is constructed instead of at
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	161 // the end of teh current scope.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	162
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	163 class unwind_action
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	164 {
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	165 public:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	166
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	167 template <typename F, typename... Args>
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	168 unwind_action (F&& fcn, Args&&... args)
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	169 : m_fcn (std::bind (fcn, args...))
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	170 { }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	171
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	172 // No copying!
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	173
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	174 unwind_action (const unwind_action&) = delete;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	175
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	176 unwind_action& operator = (const unwind_action&) = delete;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	177
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	178 ~unwind_action (void) { m_fcn (); }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	179
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	180 private:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	181
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	182 std::function<void (void)> m_fcn;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	183 };
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	184
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	185 // Reset a variable value at the end of the current scope when
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	186 // unwind_protect_var object destructor is called.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	187 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	188 // For example:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	189 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	190 // {
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	191 // int x = 42;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	192 // unwind_protect_var<int> upv (x); // X will be reset at end of scope
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	193 // x = 13; // Set temporary value.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	194 // }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	195 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	196 // Temporary value may be set at construction:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	197 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	198 // {
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	199 // int x = ...;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	200 // unwind_protect_var<int> upv (x, 13); // X will be reset.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	201 // // temporary value is 13.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	202 // }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	203 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	204 // NOTE: Don't forget to provide a name for the unwind_protect_var
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	205 // variable. If you write
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	206 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	207 // unwind_protect_var<type> /* NO NAME! */ (...);
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	208 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	209 // then the destructor for the temporary anonymous object will be
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	210 // called immediately after the object is constructed instead of at
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	211 // the end of teh current scope.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	212 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	213 // FIXME: Once we are able to use C++17, class template argument
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	214 // deduction will allow us to omit the explicit template type from the
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	215 // constructor expression:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	216 //
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	217 // unwind_protect_var upv (...);
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	218
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	219 template <typename T>
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	220 class unwind_protect_var
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	221 {
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	222 public:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	223
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	224 // Ensure that the value referenced by REF will be reset when this
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	225 // unwind_protect_var object goes out of scope.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	226
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	227 explicit unwind_protect_var (T& ref)
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	228 : m_ref (ref), m_val (ref)
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	229 { }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	230
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	231 // Set the value referenced by REF to NEW_VAL and ensure that it
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	232 // will be reset to its original value when this
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	233 // unwind_protect_var object goes out of scope.
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	234
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	235 unwind_protect_var (T& ref, const T& new_val)
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	236 : m_ref (ref), m_val (ref)
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	237 {
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	238 m_ref = new_val;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	239 }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	240
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	241 // No copying!
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	242
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	243 unwind_protect_var (const unwind_protect_var&) = delete;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	244
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	245 unwind_protect_var& operator = (const unwind_protect_var&) = delete;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	246
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	247 ~unwind_protect_var (void)
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	248 {
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	249 m_ref = m_val;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	250 }
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	251
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	252 private:
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	253
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	254 T& m_ref;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	255 T m_val;
2f8428b61bd6 new single-action unwind-protect classes John W. Eaton <jwe@octave.org> parents: 27177 diff changeset	256 };
21743 f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	257 }
f4d7d0eb5b0c use namespace for unwind_protect class John W. Eaton <jwe@octave.org> parents: 21307 diff changeset	258
1 78fd87e624cb [project @ 1993-08-08 01:13:40 by jwe] jwe parents: diff changeset	259 #endif

Mercurial > octave

annotate liboctave/util/unwind-prot.h @ 27372:2f8428b61bd6