Flutter Linux Embedder
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 
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 
20  GList /*<FlTaskRunnerTask>*/* pending_tasks;
22 };
23 
24 typedef struct _FlTaskRunnerTask {
25  // absolute time of task (based on g_get_monotonic_time)
27  FlutterTask task;
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;
83 
84  // reschedule timeout
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.
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,
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);
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,
189  }
190 
191  // Tasks might have changed in the meanwhile, reschedule timeout
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