1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
// SPDX-License-Identifier: MIT OR LGPL-2.0-or-later
// SPDX-FileCopyrightText: 2017 Endless Mobile, Inc.
// SPDX-FileCopyrightText: 2021 Canonical Ltd.
// SPDX-FileContributor: Authored by: Philip Chimento <philip@endlessm.com>
// SPDX-FileContributor: Philip Chimento <philip.chimento@gmail.com>
// SPDX-FileContributor: Marco Trevisan <marco.trevisan@canonical.com>
#include <config.h>
#include <algorithm> // for find_if
#include <atomic>
#include <deque>
#include <utility> // for pair
#include "gi/object.h"
#include "gi/toggle.h"
#include "util/log.h"
/* No-op unless GJS_VERBOSE_ENABLE_LIFECYCLE is defined to 1. */
inline void debug(const char* did GJS_USED_VERBOSE_LIFECYCLE,
const ObjectInstance* object GJS_USED_VERBOSE_LIFECYCLE) {
gjs_debug_lifecycle(GJS_DEBUG_GOBJECT, "ToggleQueue %s %p (%s @ %p)", did,
object, object ? g_type_name(object->gtype()) : "",
object ? object->ptr() : nullptr);
}
void ToggleQueue::lock() {
auto holding_thread = std::thread::id();
auto current_thread = std::this_thread::get_id();
while (!m_holder.compare_exchange_weak(holding_thread, current_thread,
std::memory_order_acquire)) {
// In case the current thread is holding the lock, we can just try
// again, checking if this is still true and in case continue
if (holding_thread != current_thread)
holding_thread = std::thread::id();
}
m_holder_ref_count++;
}
void ToggleQueue::maybe_unlock() {
g_assert(owns_lock() && "Nothing to unlock here");
if (!(--m_holder_ref_count))
m_holder.store(std::thread::id(), std::memory_order_release);
}
std::deque<ToggleQueue::Item>::iterator ToggleQueue::find_operation_locked(
const ObjectInstance* obj, ToggleQueue::Direction direction) {
return std::find_if(
q.begin(), q.end(), [obj, direction](const Item& item) -> bool {
return item.object == obj && item.direction == direction;
});
}
std::deque<ToggleQueue::Item>::const_iterator
ToggleQueue::find_operation_locked(const ObjectInstance* obj,
ToggleQueue::Direction direction) const {
return std::find_if(
q.begin(), q.end(), [obj, direction](const Item& item) -> bool {
return item.object == obj && item.direction == direction;
});
}
void ToggleQueue::handle_all_toggles(Handler handler) {
g_assert(owns_lock() && "Unsafe access to queue");
while (handle_toggle(handler))
;
}
gboolean
ToggleQueue::idle_handle_toggle(void *data)
{
auto self = Locked(static_cast<ToggleQueue*>(data));
self->handle_all_toggles(self->m_toggle_handler);
return G_SOURCE_REMOVE;
}
void
ToggleQueue::idle_destroy_notify(void *data)
{
auto self = Locked(static_cast<ToggleQueue*>(data));
self->m_idle_id = 0;
self->m_toggle_handler = nullptr;
}
std::pair<bool, bool> ToggleQueue::is_queued(ObjectInstance* obj) const {
g_assert(owns_lock() && "Unsafe access to queue");
bool has_toggle_down = find_operation_locked(obj, DOWN) != q.end();
bool has_toggle_up = find_operation_locked(obj, UP) != q.end();
return {has_toggle_down, has_toggle_up};
}
std::pair<bool, bool> ToggleQueue::cancel(ObjectInstance* obj) {
debug("cancel", obj);
g_assert(owns_lock() && "Unsafe access to queue");
bool had_toggle_down = false;
bool had_toggle_up = false;
for (auto it = q.begin(); it != q.end();) {
if (it->object == obj) {
had_toggle_down |= (it->direction == Direction::DOWN);
had_toggle_up |= (it->direction == Direction::UP);
it = q.erase(it);
continue;
}
it++;
}
gjs_debug_lifecycle(GJS_DEBUG_GOBJECT, "ToggleQueue: %p (%p) was %s", obj,
obj ? obj->ptr() : nullptr,
had_toggle_down && had_toggle_up
? "queued to toggle BOTH"
: had_toggle_down ? "queued to toggle DOWN"
: had_toggle_up ? "queued to toggle UP"
: "not queued");
return {had_toggle_down, had_toggle_up};
}
bool ToggleQueue::handle_toggle(Handler handler) {
g_assert(owns_lock() && "Unsafe access to queue");
if (q.empty())
return false;
auto const& item = q.front();
if (item.direction == UP)
debug("handle UP", item.object);
else
debug("handle DOWN", item.object);
handler(item.object, item.direction);
q.pop_front();
return true;
}
void
ToggleQueue::shutdown(void)
{
debug("shutdown", nullptr);
g_assert(((void)"Queue should have been emptied before shutting down",
q.empty()));
m_shutdown = true;
}
void ToggleQueue::enqueue(ObjectInstance* obj, ToggleQueue::Direction direction,
// https://trac.cppcheck.net/ticket/10733
// cppcheck-suppress passedByValue
ToggleQueue::Handler handler) {
g_assert(owns_lock() && "Unsafe access to queue");
if (G_UNLIKELY (m_shutdown)) {
gjs_debug(GJS_DEBUG_GOBJECT,
"Enqueuing GObject %p to toggle %s after "
"shutdown, probably from another thread (%p).",
obj->ptr(), direction == UP ? "UP" : "DOWN", g_thread_self());
return;
}
auto other_item = find_operation_locked(obj, direction == UP ? DOWN : UP);
if (other_item != q.end()) {
if (direction == UP) {
debug("enqueue UP, dequeuing already DOWN object", obj);
} else {
debug("enqueue DOWN, dequeuing already UP object", obj);
}
q.erase(other_item);
return;
}
/* Only keep an unowned reference on the object here, as if we're here, the
* JSObject wrapper has already a reference and we don't want to cause
* any weak notify in case it has lost one already in the main thread.
* So let's just save the pointer to keep track of the object till we
* don't handle this toggle.
* We rely on object's cancelling the queue in case an object gets
* finalized earlier than we've processed it.
*/
q.emplace_back(obj, direction);
if (direction == UP) {
debug("enqueue UP", obj);
} else {
debug("enqueue DOWN", obj);
}
if (m_idle_id) {
g_assert(((void) "Should always enqueue with the same handler",
m_toggle_handler == handler));
return;
}
m_toggle_handler = handler;
m_idle_id = g_idle_add_full(G_PRIORITY_HIGH, idle_handle_toggle, this,
idle_destroy_notify);
}
|
