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fl_task_runner.cc
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "flutter/shell/platform/linux/fl_task_runner.h"
6 #include "flutter/shell/platform/linux/fl_engine_private.h"
7
8 static constexpr int kMicrosecondsPerNanosecond = 1000;
9 static constexpr int kMillisecondsPerMicrosecond = 1000;
10
11 struct _FlTaskRunner {
12 GObject parent_instance;
13
14 GWeakRef engine;
15
16 GMutex mutex;
17 GCond cond;
18
19 guint timeout_source_id;
20 GList /*<FlTaskRunnerTask>*/* pending_tasks;
21 gboolean blocking_main_thread;
22 };
23
24 typedef struct _FlTaskRunnerTask {
25 // absolute time of task (based on g_get_monotonic_time)
26 gint64 task_time_micros;
27 FlutterTask task;
28 } FlTaskRunnerTask;
29
30 G_DEFINE_TYPE(FlTaskRunner, fl_task_runner, G_TYPE_OBJECT)
31
32 // Removes expired tasks from the task queue and executes them.
33 // The execution is performed with mutex unlocked.
34 static void fl_task_runner_process_expired_tasks_locked(FlTaskRunner* self) {
35 GList* expired_tasks = nullptr;
36
37 gint64 current_time = g_get_monotonic_time();
38
39 GList* l = self->pending_tasks;
40 while (l != nullptr) {
41 FlTaskRunnerTask* task = static_cast<FlTaskRunnerTask*>(l->data);
42 if (task->task_time_micros <= current_time) {
43 GList* link = l;
44 l = l->next;
45 self->pending_tasks = g_list_remove_link(self->pending_tasks, link);
46 expired_tasks = g_list_concat(expired_tasks, link);
47 } else {
48 l = l->next;
49 }
50 }
51
52 g_mutex_unlock(&self->mutex);
53
54 g_autoptr(FlEngine) engine = FL_ENGINE(g_weak_ref_get(&self->engine));
55 if (engine != nullptr) {
56 l = expired_tasks;
57 while (l != nullptr) {
58 FlTaskRunnerTask* task = static_cast<FlTaskRunnerTask*>(l->data);
59 fl_engine_execute_task(engine, &task->task);
60 l = l->next;
61 }
62 }
63
64 g_list_free_full(expired_tasks, g_free);
65
66 g_mutex_lock(&self->mutex);
67 }
68
69 static void fl_task_runner_tasks_did_change_locked(FlTaskRunner* self);
70
71 // Invoked from a timeout source. Removes and executes expired tasks
72 // and reschedules timeout if needed.
73 static gboolean fl_task_runner_on_expired_timeout(gpointer data) {
74 FlTaskRunner* self = FL_TASK_RUNNER(data);
75
76 g_autoptr(GMutexLocker) locker = g_mutex_locker_new(&self->mutex);
77 (void)locker; // unused variable
78
79 g_object_ref(self);
80
81 self->timeout_source_id = 0;
82 fl_task_runner_process_expired_tasks_locked(self);
83
84 // reschedule timeout
85 fl_task_runner_tasks_did_change_locked(self);
86
87 g_object_unref(self);
88
89 return FALSE;
90 }
91
92 // Returns the absolute time of next expired task (in microseconds, based on
93 // g_get_monotonic_time). If no task is scheduled returns G_MAXINT64.
94 static gint64 fl_task_runner_next_task_expiration_time_locked(
95 FlTaskRunner* self) {
96 gint64 min_time = G_MAXINT64;
97 GList* l = self->pending_tasks;
98 while (l != nullptr) {
99 FlTaskRunnerTask* task = static_cast<FlTaskRunnerTask*>(l->data);
100 min_time = MIN(min_time, task->task_time_micros);
101 l = l->next;
102 }
103 return min_time;
104 }
105
106 static void fl_task_runner_tasks_did_change_locked(FlTaskRunner* self) {
107 if (self->blocking_main_thread) {
108 // Wake up blocked thread
109 g_cond_signal(&self->cond);
110 } else {
111 // Reschedule timeout
112 if (self->timeout_source_id != 0) {
113 g_source_remove(self->timeout_source_id);
114 self->timeout_source_id = 0;
115 }
116 gint64 min_time = fl_task_runner_next_task_expiration_time_locked(self);
117 if (min_time != G_MAXINT64) {
118 gint64 remaining = MAX(min_time - g_get_monotonic_time(), 0);
119 self->timeout_source_id =
120 g_timeout_add(remaining / kMillisecondsPerMicrosecond + 1,
121 fl_task_runner_on_expired_timeout, self);
122 }
123 }
124 }
125
126 void fl_task_runner_dispose(GObject* object) {
127 FlTaskRunner* self = FL_TASK_RUNNER(object);
128
129 // this should never happen because the task runner is retained while blocking
130 // main thread
131 g_assert(!self->blocking_main_thread);
132
133 g_weak_ref_clear(&self->engine);
134 g_mutex_clear(&self->mutex);
135 g_cond_clear(&self->cond);
136
137 g_list_free_full(self->pending_tasks, g_free);
138 if (self->timeout_source_id != 0) {
139 g_source_remove(self->timeout_source_id);
140 }
141
142 G_OBJECT_CLASS(fl_task_runner_parent_class)->dispose(object);
143 }
144
145 static void fl_task_runner_class_init(FlTaskRunnerClass* klass) {
146 G_OBJECT_CLASS(klass)->dispose = fl_task_runner_dispose;
147 }
148
149 static void fl_task_runner_init(FlTaskRunner* self) {
150 g_mutex_init(&self->mutex);
151 g_cond_init(&self->cond);
152 }
153
154 FlTaskRunner* fl_task_runner_new(FlEngine* engine) {
155 FlTaskRunner* self =
156 FL_TASK_RUNNER(g_object_new(fl_task_runner_get_type(), nullptr));
157 g_weak_ref_init(&self->engine, G_OBJECT(engine));
158 return self;
159 }
160
161 void fl_task_runner_post_task(FlTaskRunner* self,
162 FlutterTask task,
163 uint64_t target_time_nanos) {
164 g_autoptr(GMutexLocker) locker = g_mutex_locker_new(&self->mutex);
165 (void)locker; // unused variable
166
167 FlTaskRunnerTask* runner_task = g_new0(FlTaskRunnerTask, 1);
168 runner_task->task = task;
169 runner_task->task_time_micros =
170 target_time_nanos / kMicrosecondsPerNanosecond;
171
172 self->pending_tasks = g_list_append(self->pending_tasks, runner_task);
173 fl_task_runner_tasks_did_change_locked(self);
174 }
175
176 void fl_task_runner_block_main_thread(FlTaskRunner* self) {
177 g_autoptr(GMutexLocker) locker = g_mutex_locker_new(&self->mutex);
178 (void)locker; // unused variable
179
180 g_return_if_fail(self->blocking_main_thread == FALSE);
181
182 g_object_ref(self);
183
184 self->blocking_main_thread = true;
185 while (self->blocking_main_thread) {
186 g_cond_wait_until(&self->cond, &self->mutex,
187 fl_task_runner_next_task_expiration_time_locked(self));
188 fl_task_runner_process_expired_tasks_locked(self);
189 }
190
191 // Tasks might have changed in the meanwhile, reschedule timeout
192 fl_task_runner_tasks_did_change_locked(self);
193
194 g_object_unref(self);
195 }
196
197 void fl_task_runner_release_main_thread(FlTaskRunner* self) {
198 g_autoptr(GMutexLocker) locker = g_mutex_locker_new(&self->mutex);
199 (void)locker; // unused variable
200
201 g_return_if_fail(self->blocking_main_thread == TRUE);
202
203 self->blocking_main_thread = FALSE;
204 g_cond_signal(&self->cond);
205 }
kMicrosecondsPerNanosecond
static constexpr int kMicrosecondsPerNanosecond
Definition: fl_task_runner.cc:8
_FlTaskRunner::engine
GWeakRef engine
Definition: fl_task_runner.cc:14
fl_task_runner.h
_FlTaskRunnerTask::task_time_micros
gint64 task_time_micros
Definition: fl_task_runner.cc:26
FlTaskRunnerTask
struct _FlTaskRunnerTask FlTaskRunnerTask
fl_task_runner_process_expired_tasks_locked
static void fl_task_runner_process_expired_tasks_locked(FlTaskRunner *self)
Definition: fl_task_runner.cc:34
fl_task_runner_dispose
void fl_task_runner_dispose(GObject *object)
Definition: fl_task_runner.cc:126
fl_task_runner_next_task_expiration_time_locked
static gint64 fl_task_runner_next_task_expiration_time_locked(FlTaskRunner *self)
Definition: fl_task_runner.cc:94
fl_task_runner_init
static void fl_task_runner_init(FlTaskRunner *self)
Definition: fl_task_runner.cc:149
fl_task_runner_class_init
static void fl_task_runner_class_init(FlTaskRunnerClass *klass)
Definition: fl_task_runner.cc:145
fl_task_runner_on_expired_timeout
static gboolean fl_task_runner_on_expired_timeout(gpointer data)
Definition: fl_task_runner.cc:73
_FlTaskRunner::cond
GCond cond
Definition: fl_task_runner.cc:17
_FlTaskRunner::pending_tasks
GList * pending_tasks
Definition: fl_task_runner.cc:20
fl_task_runner_post_task
void fl_task_runner_post_task(FlTaskRunner *self, FlutterTask task, uint64_t target_time_nanos)
Definition: fl_task_runner.cc:161
fl_engine_private.h
G_DEFINE_TYPE
G_DEFINE_TYPE(FlBasicMessageChannelResponseHandle, fl_basic_message_channel_response_handle, G_TYPE_OBJECT) static void fl_basic_message_channel_response_handle_dispose(GObject *object)
Definition: fl_basic_message_channel.cc:37
TRUE
return TRUE
Definition: fl_pixel_buffer_texture_test.cc:53
_FlTaskRunner::parent_instance
GObject parent_instance
Definition: fl_task_runner.cc:12
_FlTaskRunner::blocking_main_thread
gboolean blocking_main_thread
Definition: fl_task_runner.cc:21
fl_task_runner_release_main_thread
void fl_task_runner_release_main_thread(FlTaskRunner *self)
Definition: fl_task_runner.cc:197
_FlTaskRunner
Definition: fl_task_runner.cc:11
kMillisecondsPerMicrosecond
static constexpr int kMillisecondsPerMicrosecond
Definition: fl_task_runner.cc:9
fl_task_runner_tasks_did_change_locked
static void fl_task_runner_tasks_did_change_locked(FlTaskRunner *self)
Definition: fl_task_runner.cc:106
_FlTaskRunner::timeout_source_id
guint timeout_source_id
Definition: fl_task_runner.cc:19
fl_engine_execute_task
void fl_engine_execute_task(FlEngine *self, FlutterTask *task)
Definition: fl_engine.cc:929
_FlTaskRunnerTask::task
FlutterTask task
Definition: fl_task_runner.cc:27
fl_task_runner_block_main_thread
void fl_task_runner_block_main_thread(FlTaskRunner *self)
Definition: fl_task_runner.cc:176
fl_task_runner_new
FlTaskRunner * fl_task_runner_new(FlEngine *engine)
Definition: fl_task_runner.cc:154
_FlTaskRunnerTask
Definition: fl_task_runner.cc:24
_FlTaskRunner::mutex
GMutex mutex
Definition: fl_task_runner.cc:16