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Thread Class Reference

A thread; that is, a lightweight process. More...

#include "thread.h"

Inheritance diagram for Thread:
TypedReferenceCount Namable TypedObject ReferenceCount MemoryBase MemoryBase MemoryBase AsyncTaskChain::AsyncTaskChainThread ExternalThread GenericThread MainThread

List of all members.

Classes

class  PStatsCallback

Public Member Functions

virtual TypeHandle force_init_type ()
AsyncTaskBaseget_current_task () const
 Returns the task currently executing on this thread (via the AsyncTaskManager), if any, or NULL if the thread is not currently servicing a task.
int get_pipeline_stage () const
 Returns the Pipeline stage number associated with this thread.
PStatsCallbackget_pstats_callback () const
 Returns the PStats callback associated with this thread, or NULL if no callback has yet been associated with this thread.
int get_pstats_index () const
 Returns the PStats index associated with this thread, or -1 if no index has yet been associated with this thread.
const string & get_sync_name () const
 Returns the sync name of the thread.
virtual TypeHandle get_type () const
string get_unique_id () const
 Returns a string that is guaranteed to be unique to this thread, across all processes on the machine, during at least the lifetime of this process.
bool is_joinable () const
 Returns the value of joinable that was passed to the start() call.
bool is_started () const
 Returns true if the thread has been started, false if it has not, or if join() has already been called.
void join ()
 Blocks the calling process until the thread terminates.
virtual void output (ostream &out) const
 Outputs the Namable.
void output_blocker (ostream &out) const
 Writes a description of the mutex or condition variable that this thread is blocked on.
void preempt ()
 Indicates that this thread should run as soon as possible, preemptying any other threads that may be scheduled to run.
void set_min_pipeline_stage (int min_pipeline_stage)
 Sets this thread's pipeline stage number to at least the indicated value, unless it is already larger.
void set_pipeline_stage (int pipeline_stage)
 Specifies the Pipeline stage number associated with this thread.
void set_pstats_callback (PStatsCallback *pstats_callback)
 Stores a PStats callback to be associated with this thread.
void set_pstats_index (int pstats_index)
 Stores a PStats index to be associated with this thread.
bool start (ThreadPriority priority, bool joinable)
 Starts the thread executing.

Static Public Member Functions

static void consider_yield ()
 Possibly suspends the current thread for the rest of the current epoch, if it has run for enough this epoch.
static void force_yield ()
 Suspends the current thread for the rest of the current epoch.
static TypeHandle get_class_type ()
static int get_current_pipeline_stage ()
 Returns the integer pipeline stage associated with the current thread.
static Threadget_current_thread ()
 Returns a pointer to the currently-executing Thread object.
static Threadget_external_thread ()
 Returns a pointer to the "external" Thread object--this is a special Thread object that corresponds to any thread spawned outside of Panda's threading interface.
static Threadget_main_thread ()
 Returns a pointer to the "main" Thread object--this is the Thread that started the whole process.
static void init_type ()
static bool is_simple_threads ()
 Returns true if Panda is currently compiled for "simple threads", which is to say, cooperative context switching only, reducing the need for quite so many critical section protections.
static bool is_threading_supported ()
 Returns true if threading support has been compiled in and enabled, or false if no threading is available (and Thread::start() will always fail).
static bool is_true_threads ()
 Returns true if a real threading library is available that supports actual OS-implemented threads, or false if the only threading we can provide is simulated user-space threading.
static void prepare_for_exit ()
 Should be called by the main thread just before exiting the program, this blocks until any remaining thread cleanup has finished.
static PT (Thread) bind_thread(const string &name
static void sleep (double seconds)
 Suspends the current thread for at least the indicated amount of time.
static void write_status (ostream &out)

Public Attributes

static const string & sync_name

Protected Member Functions

 Thread (const string &name, const string &sync_name)
 Creates a new Thread object, but does not immediately start executing it.
virtual void thread_main ()=0

Protected Attributes

bool _started

Friends

class AsyncTaskBase
class ConditionVarDebug
class ConditionVarFullDebug
class MainThread
class MutexDebug
class ThreadDummyImpl
class ThreadPosixImpl
class ThreadSimpleImpl
class ThreadWin32Impl

Detailed Description

A thread; that is, a lightweight process.

This is an abstract base class; to use it, you must subclass from it and redefine thread_main().

The thread itself will keep a reference count on the Thread object while it is running; when the thread returns from its root function, the Thread object will automatically be destructed if no other pointers are referencing it.

Definition at line 51 of file thread.h.


Constructor & Destructor Documentation

Thread::Thread ( const string &  name,
const string &  sync_name 
) [protected]

Creates a new Thread object, but does not immediately start executing it.

This gives the caller a chance to store it in a PT(Thread) object, if desired, before the thread gets a chance to terminate and destruct itself.

Call start() to begin thread execution.

The name should be unique for each thread (though this is not enforced, and not strictly required). The sync_name can be shared between multiple different threads; threads that run synchronously with each other should be given the same sync_name, for the benefit of PStats.

Definition at line 46 of file thread.cxx.


Member Function Documentation

void Thread::consider_yield ( ) [inline, static]
void Thread::force_yield ( ) [inline, static]
int Thread::get_current_pipeline_stage ( ) [inline, static]
AsyncTaskBase * Thread::get_current_task ( ) const [inline]

Returns the task currently executing on this thread (via the AsyncTaskManager), if any, or NULL if the thread is not currently servicing a task.

Definition at line 329 of file thread.I.

Thread * Thread::get_current_thread ( ) [inline, static]

Returns a pointer to the currently-executing Thread object.

If this is called from the main thread, this will return the same value as get_main_thread().

This will always return some valid Thread pointer. It will never return NULL, even if the current thread was spawned outside of Panda's threading system, although all non-Panda threads will return the exact same Thread pointer.

Definition at line 145 of file thread.I.

References get_external_thread(), and get_main_thread().

Referenced by GeomNode::add_geom(), GeomNode::add_geoms_from(), SpeedTreeNode::add_instances(), CharacterJoint::add_local_transform(), CharacterJoint::add_net_transform(), Geom::add_primitive(), TransformBlend::add_transform(), PandaNode::adjust_draw_mask(), PandaNode::apply_attribs_to_vertices(), GeomNode::apply_attribs_to_vertices(), PartBundleNode::apply_attribs_to_vertices(), GeomPrimitive::check_valid(), Geom::check_valid(), PandaNode::clear_attrib(), PandaNode::clear_effect(), Geom::clear_primitives(), DXGraphicsStateGuardian9::close_gsg(), DXGraphicsStateGuardian8::close_gsg(), GraphicsStateGuardian::close_gsg(), GeomVertexArrayData::compare_to(), PandaNode::copy_all_properties(), PandaNode::copy_tags(), RigidBodyCombiner::cull_callback(), GeomNode::decompose(), Geom::decompose_in_place(), PandaNode::disable_cull_callback(), GeomNode::do_premunge(), AsyncTaskChain::do_stop_threads(), AnimateVerticesRequest::do_task(), MayaPview::doIt(), Geom::doubleside_in_place(), JointVertexTransform::fillin(), GeomNode::finalize(), PartBundle::finalize(), GraphicsEngine::flip_frame(), DriveInterface::force_dgraph(), PartBundle::force_update(), get_current_pipeline_stage(), CycleDataWriter< CycleDataType >::get_current_thread(), CycleDataStageWriter< CycleDataType >::get_current_thread(), CycleDataStageReader< CycleDataType >::get_current_thread(), CycleDataReader< CycleDataType >::get_current_thread(), CycleDataLockedStageReader< CycleDataType >::get_current_thread(), CycleDataLockedReader< CycleDataType >::get_current_thread(), GeomPrimitive::get_first_vertex(), GeomPrimitive::get_index_stride(), GeomPrimitive::get_max_vertex(), GeomPrimitive::get_min_vertex(), PandaNode::get_net_draw_control_mask(), PandaNode::get_net_draw_show_mask(), GeomVertexData::get_num_bytes(), WorkingNodePath::get_num_nodes(), GeomPrimitive::get_num_primitives(), GeomVertexData::get_num_rows(), GeomPrimitive::get_num_vertices(), PStatThread::get_thread(), GeomPrimitive::get_vertex(), RenderAttrib::init_attribs(), TransformState::init_states(), RenderState::init_states(), RenderEffects::init_states(), GeomPrimitive::is_indexed(), JointVertexTransform::JointVertexTransform(), PandaFramework::main_loop(), GeomPrimitive::make_nonindexed(), Geom::make_nonindexed(), Geom::make_points_in_place(), TransformBlend::normalize_weights(), Geom::offset_vertices(), GraphicsEngine::open_windows(), NodePathComponent::output(), GeomPrimitive::pack_vertices(), PandaNode::prepare_scene(), BamReader::read_cdata(), VertexDataSaveFile::read_data(), GraphicsEngine::ready_flip(), GeomTransformer::register_vertices(), GraphicsEngine::remove_all_windows(), Geom::remove_primitive(), TransformBlend::remove_transform(), GraphicsEngine::remove_window(), GraphicsEngine::render_frame(), PandaNode::replace_node(), GeomVertexData::reserve_num_rows(), SheetNode::reset_bound(), RopeNode::reset_bound(), DXGraphicsStateGuardian9::reset_d3d_device(), DXGraphicsStateGuardian8::reset_d3d_device(), Geom::reverse_in_place(), Geom::rotate_in_place(), AsyncTaskChain::service_one_task(), GeomVertexData::set_array(), PandaNode::set_attrib(), PandaNode::set_bounds(), PandaNode::set_bounds_type(), PandaNode::set_cull_callback(), ClockObject::set_dt(), PandaNode::set_effect(), ClockObject::set_frame_rate(), PandaNode::set_internal_bounds(), PandaNode::set_into_collide_mask(), UserVertexTransform::set_matrix(), ClockObject::set_mode(), GeomVertexData::set_num_rows(), Geom::set_primitive(), UserVertexSlider::set_slider(), FrameRateMeter::set_text_pattern(), Geom::set_usage_hint(), Geom::set_vertex_data(), BamCache::store(), GraphicsEngine::sync_frame(), GeomTransformer::transform_vertices(), GeomVertexData::unclean_set_num_rows(), GeomNode::unify(), Geom::unify_in_place(), AsyncTask::unlock_and_do_task(), VideoTexture::unlocked_ensure_ram_image(), Texture::unlocked_ensure_ram_image(), GeomDrawCallbackData::upcall(), DisplayRegionDrawCallbackData::upcall(), DisplayRegionCullCallbackData::upcall(), CallbackGraphicsWindow::RenderCallbackData::upcall(), SceneGraphAnalyzerMeter::update(), FrameRateMeter::update(), PartBundle::update(), AnimControl::wait_pending(), and BamWriter::write_cdata().

Thread * Thread::get_external_thread ( ) [inline, static]

Returns a pointer to the "external" Thread object--this is a special Thread object that corresponds to any thread spawned outside of Panda's threading interface.

Note that multiple different threads may share this same pointer.

Definition at line 124 of file thread.I.

Referenced by get_current_thread().

Thread * Thread::get_main_thread ( ) [inline, static]

Returns a pointer to the "main" Thread object--this is the Thread that started the whole process.

Definition at line 107 of file thread.I.

Referenced by get_current_thread(), RenderAttrib::init_attribs(), TransformState::init_states(), RenderState::init_states(), and RenderEffects::init_states().

int Thread::get_pipeline_stage ( ) const [inline]
Thread::PStatsCallback * Thread::get_pstats_callback ( ) const [inline]

Returns the PStats callback associated with this thread, or NULL if no callback has yet been associated with this thread.

This is used internally by the PStatClient; you should not need to call this directly.

Definition at line 379 of file thread.I.

int Thread::get_pstats_index ( ) const [inline]

Returns the PStats index associated with this thread, or -1 if no index has yet been associated with this thread.

This is used internally by the PStatClient; you should not need to call this directly.

Definition at line 60 of file thread.I.

Referenced by PStatThread::PStatThread().

const string & Thread::get_sync_name ( ) const [inline]

Returns the sync name of the thread.

This name collects threads into "sync groups", which are expected to run synchronously. This is mainly used for the benefit of PStats; threads with the same sync name can be ticked all at once via the thread_tick() call.

Definition at line 47 of file thread.I.

string Thread::get_unique_id ( ) const [inline]

Returns a string that is guaranteed to be unique to this thread, across all processes on the machine, during at least the lifetime of this process.

Definition at line 72 of file thread.I.

Referenced by BamCache::store().

bool Thread::is_joinable ( ) const [inline]

Returns the value of joinable that was passed to the start() call.

Definition at line 286 of file thread.I.

bool Thread::is_simple_threads ( ) [inline, static]

Returns true if Panda is currently compiled for "simple threads", which is to say, cooperative context switching only, reducing the need for quite so many critical section protections.

This is not necessarily the opposite of "true threads", since one possible implementation of simple threads is via true threads with mutex protection to ensure only one runs at a time.

Definition at line 221 of file thread.I.

bool Thread::is_started ( ) const [inline]

Returns true if the thread has been started, false if it has not, or if join() has already been called.

Definition at line 275 of file thread.I.

bool Thread::is_threading_supported ( ) [inline, static]

Returns true if threading support has been compiled in and enabled, or false if no threading is available (and Thread::start() will always fail).

Definition at line 185 of file thread.I.

Referenced by ConnectionReader::ConnectionReader(), ConnectionWriter::ConnectionWriter(), AsyncTaskChain::do_start_threads(), AsyncTaskChain::set_num_threads(), and GraphicsEngine::set_threading_model().

bool Thread::is_true_threads ( ) [inline, static]

Returns true if a real threading library is available that supports actual OS-implemented threads, or false if the only threading we can provide is simulated user-space threading.

Definition at line 201 of file thread.I.

Referenced by GraphicsEngine::render_frame(), and NodePath::verify_complete().

void Thread::join ( ) [inline]

Blocks the calling process until the thread terminates.

If the thread has already terminated, this returns immediately.

Definition at line 298 of file thread.I.

Referenced by AsyncTaskChain::do_stop_threads().

void Thread::output ( ostream &  out) const [virtual]

Outputs the Namable.

This function simply writes the name to the output stream; most Namable derivatives will probably redefine this.

Reimplemented from Namable.

Definition at line 172 of file thread.cxx.

void Thread::output_blocker ( ostream &  out) const

Writes a description of the mutex or condition variable that this thread is blocked on.

Writes nothing if there is no blocker, or if we are not in DEBUG_THREADS mode.

Definition at line 185 of file thread.cxx.

void Thread::preempt ( ) [inline]

Indicates that this thread should run as soon as possible, preemptying any other threads that may be scheduled to run.

This may not be implemented on every platform.

Definition at line 315 of file thread.I.

void Thread::prepare_for_exit ( ) [inline, static]

Should be called by the main thread just before exiting the program, this blocks until any remaining thread cleanup has finished.

Definition at line 341 of file thread.I.

Referenced by PandaFramework::close_framework(), and GraphicsEngine::remove_all_windows().

void Thread::set_min_pipeline_stage ( int  min_pipeline_stage) [inline]

Sets this thread's pipeline stage number to at least the indicated value, unless it is already larger.

See set_pipeline_stage().

Definition at line 96 of file thread.I.

References set_pipeline_stage().

void Thread::set_pipeline_stage ( int  pipeline_stage)

Specifies the Pipeline stage number associated with this thread.

The default stage is 0 if no stage is specified otherwise.

This must be a value in the range [0 .. pipeline->get_num_stages() - 1]. It specifies the values that this thread observes for all pipelined data. Typically, an application thread will leave this at 0, but a render thread may set it to 1 or 2 (to operate on the previous frame's data, or the second previous frame's data).

Definition at line 153 of file thread.cxx.

Referenced by set_min_pipeline_stage().

void Thread::set_pstats_callback ( Thread::PStatsCallback pstats_callback) [inline]

Stores a PStats callback to be associated with this thread.

This is used internally by the PStatClient; you should not need to call this directly.

Definition at line 365 of file thread.I.

void Thread::set_pstats_index ( int  pstats_index) [inline]

Stores a PStats index to be associated with this thread.

This is used internally by the PStatClient; you should not need to call this directly.

Definition at line 353 of file thread.I.

void Thread::sleep ( double  seconds) [inline, static]

Suspends the current thread for at least the indicated amount of time.

It might be suspended for longer.

Definition at line 236 of file thread.I.

Referenced by ModelLoadRequest::do_task(), TextureReloadRequest::do_task(), PStatServer::main_loop(), and MayaApi::MayaApi().

bool Thread::start ( ThreadPriority  priority,
bool  joinable 
)

Starts the thread executing.

It is only valid to call this once.

The thread will begin executing its thread_main() function, and will terminate when thread_main() returns.

priority is intended as a hint to the relative importance of this thread. This may be ignored by the thread implementation.

joinable should be set true if you intend to call join() to wait for the thread to terminate, or false if you don't care and you will never call join(). Note that the reference count on the Thread object is incremented while the thread itself is running, so if you just want to fire and forget a thread, you may pass joinable = false, and never store the Thread object. It will automatically destruct itself when it finishes.

The return value is true if the thread is successfully started, false otherwise.

Definition at line 237 of file thread.cxx.


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