#include <embedder_task_runner.h>

Inheritance diagram for flutter::EmbedderTaskRunner:

Classes
struct	DispatchTable
	A. More...

Public Member Functions
	EmbedderTaskRunner (DispatchTable table, size_t embedder_identifier)
	Create a task runner with a dispatch table for delegation of task runner responsibility to the embedder. When embedders specify task runner dispatch tables that service tasks on the same thread, they also must ensure that their `embedder_idetifier`s match. This allows the engine to determine task runner equality without actually posting tasks to the task runner.

	~EmbedderTaskRunner () override

size_t	GetEmbedderIdentifier () const
	The unique identifier provided by the embedder for the task runner. Embedders whose dispatch tables service tasks on the same underlying OS thread must ensure that their identifiers match. This allows the engine to determine task runner equality without posting tasks on the thread.

bool	PostTask (uint64_t baton)

Public Member Functions inherited from fml::TaskRunner
virtual	~TaskRunner ()

Public Member Functions inherited from fml::RefCountedThreadSafe< TaskRunner >
void	Release () const

Public Member Functions inherited from fml::internal::RefCountedThreadSafeBase
void	AddRef () const

bool	HasOneRef () const

void	AssertHasOneRef () const

Private Member Functions
void	PostTask (const fml::closure &task) override

void	PostTaskForTime (const fml::closure &task, fml::TimePoint target_time) override

void	PostDelayedTask (const fml::closure &task, fml::TimeDelta delay) override

bool	RunsTasksOnCurrentThread () override

fml::TaskQueueId	GetTaskQueueId () override

Additional Inherited Members
Static Public Member Functions inherited from fml::TaskRunner
static void	RunNowOrPostTask (const fml::RefPtr< fml::TaskRunner > &runner, const fml::closure &task)

Protected Member Functions inherited from fml::TaskRunner
	TaskRunner (fml::RefPtr< MessageLoopImpl > loop)

Protected Member Functions inherited from fml::RefCountedThreadSafe< TaskRunner >
	RefCountedThreadSafe ()

	~RefCountedThreadSafe ()

Protected Member Functions inherited from fml::internal::RefCountedThreadSafeBase
	RefCountedThreadSafeBase ()

	~RefCountedThreadSafeBase ()

bool	Release () const

void	Adopt ()

Detailed Description

A task runner which delegates responsibility of task execution to an embedder. This is done by managing a dispatch table to the embedder.

Definition at line 20 of file embedder_task_runner.h.

Constructor & Destructor Documentation

◆ EmbedderTaskRunner()

flutter::EmbedderTaskRunner::EmbedderTaskRunner	(	DispatchTable	table,
		size_t	embedder_identifier
	)

Create a task runner with a dispatch table for delegation of task runner responsibility to the embedder. When embedders specify task runner dispatch tables that service tasks on the same thread, they also must ensure that their embedder_idetifiers match. This allows the engine to determine task runner equality without actually posting tasks to the task runner.

Parameters

[in]	table	The task runner dispatch table.
[in]	embedder_identifier	The embedder identifier

Definition at line 12 of file embedder_task_runner.cc.

    : TaskRunner(nullptr /* loop implemenation*/),
      embedder_identifier_(embedder_identifier),
      dispatch_table_(std::move(table)),
      placeholder_id_(
          fml::MessageLoopTaskQueues::GetInstance()->CreateTaskQueue()) {
  FML_DCHECK(dispatch_table_.post_task_callback);
  FML_DCHECK(dispatch_table_.runs_task_on_current_thread_callback);
}

◆ ~EmbedderTaskRunner()

flutter::EmbedderTaskRunner::~EmbedderTaskRunner ( )

overridedefault

Member Function Documentation

◆ GetEmbedderIdentifier()

size_t flutter::EmbedderTaskRunner::GetEmbedderIdentifier ( ) const

The unique identifier provided by the embedder for the task runner. Embedders whose dispatch tables service tasks on the same underlying OS thread must ensure that their identifiers match. This allows the engine to determine task runner equality without posting tasks on the thread.

Returns: The embedder identifier.

Definition at line 25 of file embedder_task_runner.cc.

                                                       {
  return embedder_identifier_;
}

◆ GetTaskQueueId()

fml::TaskQueueId flutter::EmbedderTaskRunner::GetTaskQueueId ( )

overrideprivatevirtual

Returns the unique identifier associated with the TaskRunner.

See also: fml::MessageLoopTaskQueues

Reimplemented from fml::TaskRunner.

Definition at line 82 of file embedder_task_runner.cc.

                                                  {
  return placeholder_id_;
}

◆ PostDelayedTask()

void flutter::EmbedderTaskRunner::PostDelayedTask	(	const fml::closure &	task,
		fml::TimeDelta	delay
	)

overrideprivatevirtual

Schedules a task to be run on the MessageLoop after the time delay has passed.

Note: There is latency between when the task is schedule and actually executed so that the actual execution time is: now + delay + message_loop_latency, where message_loop_latency is undefined and could be tens of milliseconds.

Reimplemented from fml::TaskRunner.

Definition at line 51 of file embedder_task_runner.cc.

                                                             {
  PostTaskForTime(task, fml::TimePoint::Now() + delay);
}

◆ PostTask() [1/2]

void flutter::EmbedderTaskRunner::PostTask ( const fml::closure & task )

overrideprivatevirtual

Schedules task to be executed on the TaskRunner's associated event loop.

Reimplemented from fml::TaskRunner.

Definition at line 29 of file embedder_task_runner.cc.

                                                        {
  PostTaskForTime(task, fml::TimePoint::Now());
}

◆ PostTask() [2/2]

bool flutter::EmbedderTaskRunner::PostTask ( uint64_t baton )

Definition at line 60 of file embedder_task_runner.cc.

                                                {
  fml::closure task;
 
  {
    std::scoped_lock lock(tasks_mutex_);
    auto found = pending_tasks_.find(baton);
    if (found == pending_tasks_.end()) {
      FML_LOG(ERROR) << "Embedder attempted to post an unknown task.";
      return false;
    }
    task = found->second;
    pending_tasks_.erase(found);
 
    // Let go of the tasks mutex befor executing the task.
  }
 
  FML_DCHECK(task);
  task();
  return true;
}

◆ PostTaskForTime()

void flutter::EmbedderTaskRunner::PostTaskForTime	(	const fml::closure &	task,
		fml::TimePoint	target_time
	)

overrideprivatevirtual

Reimplemented from fml::TaskRunner.

Definition at line 33 of file embedder_task_runner.cc.

                                                                   {
  if (!task) {
    return;
  }
 
  uint64_t baton = 0;
 
  {
    // Release the lock before the jump via the dispatch table.
    std::scoped_lock lock(tasks_mutex_);
    baton = ++last_baton_;
    pending_tasks_[baton] = task;
  }
 
  dispatch_table_.post_task_callback(this, baton, target_time);
}

◆ RunsTasksOnCurrentThread()

bool flutter::EmbedderTaskRunner::RunsTasksOnCurrentThread ( )

overrideprivatevirtual

Returns true when the current executing thread's TaskRunner matches this instance.

Reimplemented from fml::TaskRunner.

Definition at line 56 of file embedder_task_runner.cc.

                                                  {
  return dispatch_table_.runs_task_on_current_thread_callback();
}

The documentation for this class was generated from the following files:

shell/platform/embedder/embedder_task_runner.h
shell/platform/embedder/embedder_task_runner.cc

Classes

Public Member Functions

Private Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ EmbedderTaskRunner()

◆ ~EmbedderTaskRunner()

Member Function Documentation

◆ GetEmbedderIdentifier()

◆ GetTaskQueueId()

◆ PostDelayedTask()

◆ PostTask() [1/2]

◆ PostTask() [2/2]

◆ PostTaskForTime()

◆ RunsTasksOnCurrentThread()