opencv/modules/gapi/src/executor/gstreamingexecutor.cpp
Alexander Alekhin fe4f27b99b gapi: fix build
- gcc 4.8.4 (ARMv7)
2019-10-22 16:31:40 +03:00

772 lines
29 KiB
C++

// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.
//
// Copyright (C) 2019 Intel Corporation
#include "precomp.hpp"
#include <iostream>
#include <ade/util/zip_range.hpp>
#include <opencv2/gapi/opencv_includes.hpp>
#include "executor/gstreamingexecutor.hpp"
#include "compiler/passes/passes.hpp"
#include "backends/common/gbackend.hpp" // createMat
namespace
{
using namespace cv::gimpl::stream;
#if !defined(GAPI_STANDALONE)
class VideoEmitter final: public cv::gimpl::GIslandEmitter {
cv::gapi::wip::IStreamSource::Ptr src;
virtual bool pull(cv::GRunArg &arg) override {
// FIXME: probably we can maintain a pool of (then) pre-allocated
// buffers to avoid runtime allocations.
// Pool size can be determined given the internal queue size.
cv::gapi::wip::Data newData;
if (!src->pull(newData)) {
return false;
}
arg = std::move(static_cast<cv::GRunArg&>(newData));
return true;
}
public:
explicit VideoEmitter(const cv::GRunArg &arg) {
src = cv::util::get<cv::gapi::wip::IStreamSource::Ptr>(arg);
}
};
#endif // GAPI_STANDALONE
class ConstEmitter final: public cv::gimpl::GIslandEmitter {
cv::GRunArg m_arg;
virtual bool pull(cv::GRunArg &arg) override {
arg = const_cast<const cv::GRunArg&>(m_arg); // FIXME: variant workaround
return true;
}
public:
explicit ConstEmitter(const cv::GRunArg &arg) : m_arg(arg) {
}
};
struct DataQueue {
static const char *name() { return "StreamingDataQueue"; }
explicit DataQueue(std::size_t capacity) {
if (capacity) {
q.set_capacity(capacity);
}
}
cv::gimpl::stream::Q q;
};
std::vector<cv::gimpl::stream::Q*> reader_queues( ade::Graph &g,
const ade::NodeHandle &obj)
{
ade::TypedGraph<DataQueue> qgr(g);
std::vector<cv::gimpl::stream::Q*> result;
for (auto &&out_eh : obj->outEdges())
{
result.push_back(&qgr.metadata(out_eh).get<DataQueue>().q);
}
return result;
}
std::vector<cv::gimpl::stream::Q*> input_queues( ade::Graph &g,
const ade::NodeHandle &obj)
{
ade::TypedGraph<DataQueue> qgr(g);
std::vector<cv::gimpl::stream::Q*> result;
for (auto &&in_eh : obj->inEdges())
{
result.push_back(qgr.metadata(in_eh).contains<DataQueue>()
? &qgr.metadata(in_eh).get<DataQueue>().q
: nullptr);
}
return result;
}
void sync_data(cv::GRunArgs &results, cv::GRunArgsP &outputs)
{
namespace own = cv::gapi::own;
for (auto && it : ade::util::zip(ade::util::toRange(outputs),
ade::util::toRange(results)))
{
auto &out_obj = std::get<0>(it);
auto &res_obj = std::get<1>(it);
// FIXME: this conversion should be unified
using T = cv::GRunArgP;
switch (out_obj.index())
{
#if !defined(GAPI_STANDALONE)
case T::index_of<cv::Mat*>():
*cv::util::get<cv::Mat*>(out_obj) = std::move(cv::util::get<cv::Mat>(res_obj));
break;
case T::index_of<cv::Scalar*>():
*cv::util::get<cv::Scalar*>(out_obj) = std::move(cv::util::get<cv::Scalar>(res_obj));
break;
#endif // !GAPI_STANDALONE
case T::index_of<own::Mat*>():
*cv::util::get<own::Mat*>(out_obj) = std::move(cv::util::get<own::Mat>(res_obj));
break;
case T::index_of<own::Scalar*>():
*cv::util::get<own::Scalar*>(out_obj) = std::move(cv::util::get<own::Scalar>(res_obj));
break;
case T::index_of<cv::detail::VectorRef>():
cv::util::get<cv::detail::VectorRef>(out_obj).mov(cv::util::get<cv::detail::VectorRef>(res_obj));
break;
default:
GAPI_Assert(false && "This value type is not supported!"); // ...maybe because of STANDALONE mode.
break;
}
}
}
// This thread is a plain dump source actor. What it do is just:
// - Check input queue (the only one) for a control command
// - Depending on the state, obtains next data object and pushes it to the
// pipeline.
void emitterActorThread(std::shared_ptr<cv::gimpl::GIslandEmitter> emitter,
Q& in_queue,
std::vector<Q*> out_queues,
std::function<void()> cb_completion)
{
// Wait for the explicit Start command.
// ...or Stop command, this also happens.
Cmd cmd;
in_queue.pop(cmd);
GAPI_Assert( cv::util::holds_alternative<Start>(cmd)
|| cv::util::holds_alternative<Stop>(cmd));
if (cv::util::holds_alternative<Stop>(cmd))
{
for (auto &&oq : out_queues) oq->push(cmd);
return;
}
// Now start emitting the data from the source to the pipeline.
while (true)
{
Cmd cancel;
if (in_queue.try_pop(cancel))
{
// if we just popped a cancellation command...
GAPI_Assert(cv::util::holds_alternative<Stop>(cancel));
// Broadcast it to the readers and quit.
for (auto &&oq : out_queues) oq->push(cancel);
return;
}
// Try to obrain next data chunk from the source
cv::GRunArg data;
if (emitter->pull(data))
{
// // On success, broadcast it to our readers
for (auto &&oq : out_queues)
{
// FIXME: FOR SOME REASON, oq->push(Cmd{data}) doesn't work!!
// empty mats are arrived to the receivers!
// There may be a fatal bug in our variant!
const auto tmp = data;
oq->push(Cmd{tmp});
}
}
else
{
// Otherwise, broadcast STOP message to our readers and quit.
// This usually means end-of-stream, so trigger a callback
for (auto &&oq : out_queues) oq->push(Cmd{Stop{}});
if (cb_completion) cb_completion();
return;
}
}
}
// This thread is a plain dumb processing actor. What it do is just:
// - Reads input from the input queue(s), sleeps if there's nothing to read
// - Once a full input vector is obtained, passes it to the underlying island
// executable for processing.
// - Pushes processing results down to consumers - to the subsequent queues.
// Note: Every data object consumer has its own queue.
void islandActorThread(std::vector<cv::gimpl::RcDesc> in_rcs, // FIXME: this is...
std::vector<cv::gimpl::RcDesc> out_rcs, // FIXME: ...basically just...
cv::GMetaArgs out_metas, // ...
std::shared_ptr<cv::gimpl::GIslandExecutable> island, // FIXME: ...a copy of OpDesc{}.
std::vector<Q*> in_queues,
std::vector<cv::GRunArg> in_constants,
std::vector< std::vector<Q*> > out_queues)
{
GAPI_Assert(in_queues.size() == in_rcs.size());
GAPI_Assert(out_queues.size() == out_rcs.size());
GAPI_Assert(out_queues.size() == out_metas.size());
while (true)
{
std::vector<cv::gimpl::GIslandExecutable::InObj> isl_inputs;
isl_inputs.resize(in_rcs.size());
// Try to obtain the full input vector.
// Note this may block us. We also may get Stop signal here
// and then exit the thread.
// NOTE: in order to maintain the GRunArg's underlying object
// lifetime, keep the whole cmd vector (of size == # of inputs)
// in memory.
std::vector<Cmd> cmd(in_queues.size());
for (auto &&it : ade::util::indexed(in_queues))
{
auto id = ade::util::index(it);
auto &q = ade::util::value(it);
isl_inputs[id].first = in_rcs[id];
if (q == nullptr)
{
// NULL queue means a graph-constant value
// (like a value-initialized scalar)
// FIXME: Variant move problem
isl_inputs[id].second = const_cast<const cv::GRunArg&>(in_constants[id]);
}
else
{
q->pop(cmd[id]);
if (cv::util::holds_alternative<Stop>(cmd[id]))
{
// FIXME: This logic must be unified with what collectorThread is doing!
// Just got a stop sign. Reiterate through all queues
// and rewind data to every Stop sign per queue
for (auto &&qit : ade::util::indexed(in_queues))
{
auto id2 = ade::util::index(qit);
auto &q2 = ade::util::value(qit);
if (id == id2) continue;
Cmd cmd2;
while (q2 && !cv::util::holds_alternative<Stop>(cmd2))
q2->pop(cmd2);
}
// Broadcast Stop down to the pipeline and quit
for (auto &&out_qq : out_queues)
{
for (auto &&out_q : out_qq) out_q->push(Cmd{Stop{}});
}
return;
}
// FIXME: MOVE PROBLEM
const cv::GRunArg &in_arg = cv::util::get<cv::GRunArg>(cmd[id]);
#if defined(GAPI_STANDALONE)
// Standalone mode - simply store input argument in the vector as-is
isl_inputs[id].second = in_arg;
#else
// Make Islands operate on own:: data types (i.e. in the same
// environment as GExecutor provides)
// This way several backends (e.g. Fluid) remain OpenCV-independent.
switch (in_arg.index()) {
case cv::GRunArg::index_of<cv::Mat>():
isl_inputs[id].second = cv::GRunArg{cv::to_own(cv::util::get<cv::Mat>(in_arg))};
break;
case cv::GRunArg::index_of<cv::Scalar>():
isl_inputs[id].second = cv::GRunArg{cv::to_own(cv::util::get<cv::Scalar>(in_arg))};
break;
default:
isl_inputs[id].second = in_arg;
break;
}
#endif // GAPI_STANDALONE
}
}
// Once the vector is obtained, prepare data for island execution
// Note - we first allocate output vector via GRunArg!
// Then it is converted to a GRunArgP.
std::vector<cv::gimpl::GIslandExecutable::OutObj> isl_outputs;
std::vector<cv::GRunArg> out_data;
isl_outputs.resize(out_rcs.size());
out_data.resize(out_rcs.size());
for (auto &&it : ade::util::indexed(out_rcs))
{
auto id = ade::util::index(it);
auto &r = ade::util::value(it);
#if !defined(GAPI_STANDALONE)
using MatType = cv::Mat;
using SclType = cv::Scalar;
#else
using MatType = cv::gapi::own::Mat;
using SclType = cv::gapi::own::Scalar;
#endif // GAPI_STANDALONE
switch (r.shape) {
// Allocate a data object based on its shape & meta, and put it into our vectors.
// Yes, first we put a cv::Mat GRunArg, and then specify _THAT_
// pointer as an output parameter - to make sure that after island completes,
// our GRunArg still has the right (up-to-date) value.
// Same applies to other types.
// FIXME: This is absolutely ugly but seem to work perfectly for its purpose.
case cv::GShape::GMAT:
{
MatType newMat;
cv::gimpl::createMat(cv::util::get<cv::GMatDesc>(out_metas[id]), newMat);
out_data[id] = cv::GRunArg(std::move(newMat));
isl_outputs[id] = { r, cv::GRunArgP(&cv::util::get<MatType>(out_data[id])) };
}
break;
case cv::GShape::GSCALAR:
{
SclType newScl;
out_data[id] = cv::GRunArg(std::move(newScl));
isl_outputs[id] = { r, cv::GRunArgP(&cv::util::get<SclType>(out_data[id])) };
}
break;
case cv::GShape::GARRAY:
{
cv::detail::VectorRef newVec;
cv::util::get<cv::detail::ConstructVec>(r.ctor)(newVec);
out_data[id] = cv::GRunArg(std::move(newVec));
// VectorRef is implicitly shared so no pointer is taken here
const auto &rr = cv::util::get<cv::detail::VectorRef>(out_data[id]); // FIXME: that variant MOVE problem again
isl_outputs[id] = { r, cv::GRunArgP(rr) };
}
break;
default:
cv::util::throw_error(std::logic_error("Unsupported GShape"));
break;
}
}
// Now ask Island to execute on this data
island->run(std::move(isl_inputs), std::move(isl_outputs));
// Once executed, dispatch our results down to the pipeline.
for (auto &&it : ade::util::zip(ade::util::toRange(out_queues),
ade::util::toRange(out_data)))
{
for (auto &&q : std::get<0>(it))
{
// FIXME: FATAL VARIANT ISSUE!!
const auto tmp = std::get<1>(it);
q->push(Cmd{tmp});
}
}
}
}
// The idea of collectorThread is easy. If there're multiple outputs
// in the graph, we need to pull an object from every associated queue
// and then put the resulting vector into one single queue. While it
// looks redundant, it simplifies dramatically the way how try_pull()
// is implemented - we need to check one queue instead of many.
void collectorThread(std::vector<Q*> in_queues,
Q& out_queue)
{
while (true)
{
cv::GRunArgs this_result(in_queues.size());
for (auto &&it : ade::util::indexed(in_queues))
{
Cmd cmd;
ade::util::value(it)->pop(cmd);
if (cv::util::holds_alternative<Stop>(cmd))
{
// FIXME: Unify this code with island thread
for (auto &&qit : ade::util::indexed(in_queues))
{
if (ade::util::index(qit) == ade::util::index(it)) continue;
Cmd cmd2;
while (!cv::util::holds_alternative<Stop>(cmd2))
ade::util::value(qit)->pop(cmd2);
}
out_queue.push(Cmd{Stop{}});
return;
}
else
{
// FIXME: MOVE_PROBLEM
const cv::GRunArg &in_arg = cv::util::get<cv::GRunArg>(cmd);
this_result[ade::util::index(it)] = in_arg;
// FIXME: Check for other message types.
}
}
out_queue.push(Cmd{this_result});
}
}
} // anonymous namespace
cv::gimpl::GStreamingExecutor::GStreamingExecutor(std::unique_ptr<ade::Graph> &&g_model)
: m_orig_graph(std::move(g_model))
, m_island_graph(GModel::Graph(*m_orig_graph).metadata()
.get<IslandModel>().model)
, m_gim(*m_island_graph)
{
GModel::Graph gm(*m_orig_graph);
// NB: Right now GIslandModel is acyclic, and all the below code assumes that.
// NB: This naive execution code is taken from GExecutor nearly "as-is"
const auto proto = gm.metadata().get<Protocol>();
m_emitters .resize(proto.in_nhs.size());
m_emitter_queues.resize(proto.in_nhs.size());
m_sinks .resize(proto.out_nhs.size());
m_sink_queues .resize(proto.out_nhs.size());
// Very rough estimation to limit internal queue sizes.
// Pipeline depth is equal to number of its (pipeline) steps.
const auto queue_capacity = std::count_if
(m_gim.nodes().begin(),
m_gim.nodes().end(),
[&](ade::NodeHandle nh) {
return m_gim.metadata(nh).get<NodeKind>().k == NodeKind::ISLAND;
});
auto sorted = m_gim.metadata().get<ade::passes::TopologicalSortData>();
for (auto nh : sorted.nodes())
{
switch (m_gim.metadata(nh).get<NodeKind>().k)
{
case NodeKind::ISLAND:
{
std::vector<RcDesc> input_rcs;
std::vector<RcDesc> output_rcs;
std::vector<GRunArg> in_constants;
cv::GMetaArgs output_metas;
input_rcs.reserve(nh->inNodes().size());
in_constants.reserve(nh->inNodes().size()); // FIXME: Ugly
output_rcs.reserve(nh->outNodes().size());
output_metas.reserve(nh->outNodes().size());
std::unordered_set<ade::NodeHandle, ade::HandleHasher<ade::Node> > const_ins;
// FIXME: THIS ORDER IS IRRELEVANT TO PROTOCOL OR ANY OTHER ORDER!
// FIXME: SAME APPLIES TO THE REGULAR GEEXECUTOR!!
auto xtract_in = [&](ade::NodeHandle slot_nh, std::vector<RcDesc> &vec) {
const auto orig_data_nh
= m_gim.metadata(slot_nh).get<DataSlot>().original_data_node;
const auto &orig_data_info
= gm.metadata(orig_data_nh).get<Data>();
if (orig_data_info.storage == Data::Storage::CONST_VAL) {
const_ins.insert(slot_nh);
// FIXME: Variant move issue
in_constants.push_back(const_cast<const cv::GRunArg&>(gm.metadata(orig_data_nh).get<ConstValue>().arg));
} else in_constants.push_back(cv::GRunArg{}); // FIXME: Make it in some smarter way pls
if (orig_data_info.shape == GShape::GARRAY) {
// FIXME: GArray lost host constructor problem
GAPI_Assert(!cv::util::holds_alternative<cv::util::monostate>(orig_data_info.ctor));
}
vec.emplace_back(RcDesc{ orig_data_info.rc
, orig_data_info.shape
, orig_data_info.ctor});
};
auto xtract_out = [&](ade::NodeHandle slot_nh, std::vector<RcDesc> &vec, cv::GMetaArgs &metas) {
const auto orig_data_nh
= m_gim.metadata(slot_nh).get<DataSlot>().original_data_node;
const auto &orig_data_info
= gm.metadata(orig_data_nh).get<Data>();
if (orig_data_info.shape == GShape::GARRAY) {
// FIXME: GArray lost host constructor problem
GAPI_Assert(!cv::util::holds_alternative<cv::util::monostate>(orig_data_info.ctor));
}
vec.emplace_back(RcDesc{ orig_data_info.rc
, orig_data_info.shape
, orig_data_info.ctor});
metas.emplace_back(orig_data_info.meta);
};
// FIXME: JEZ IT WAS SO AWFUL!!!!
for (auto in_slot_nh : nh->inNodes()) xtract_in(in_slot_nh, input_rcs);
for (auto out_slot_nh : nh->outNodes()) xtract_out(out_slot_nh, output_rcs, output_metas);
m_ops.emplace_back(OpDesc{ std::move(input_rcs)
, std::move(output_rcs)
, std::move(output_metas)
, nh
, in_constants
, m_gim.metadata(nh).get<IslandExec>().object});
// Initialize queues for every operation's input
ade::TypedGraph<DataQueue> qgr(*m_island_graph);
for (auto eh : nh->inEdges())
{
// ...only if the data is not compile-const
if (const_ins.count(eh->srcNode()) == 0) {
qgr.metadata(eh).set(DataQueue(queue_capacity));
m_internal_queues.insert(&qgr.metadata(eh).get<DataQueue>().q);
}
}
}
break;
case NodeKind::SLOT:
{
const auto orig_data_nh
= m_gim.metadata(nh).get<DataSlot>().original_data_node;
m_slots.emplace_back(DataDesc{nh, orig_data_nh});
}
break;
case NodeKind::EMIT:
{
const auto emitter_idx
= m_gim.metadata(nh).get<Emitter>().proto_index;
GAPI_Assert(emitter_idx < m_emitters.size());
m_emitters[emitter_idx] = nh;
}
break;
case NodeKind::SINK:
{
const auto sink_idx
= m_gim.metadata(nh).get<Sink>().proto_index;
GAPI_Assert(sink_idx < m_sinks.size());
m_sinks[sink_idx] = nh;
// Also initialize Sink's input queue
ade::TypedGraph<DataQueue> qgr(*m_island_graph);
GAPI_Assert(nh->inEdges().size() == 1u);
qgr.metadata(nh->inEdges().front()).set(DataQueue(queue_capacity));
m_sink_queues[sink_idx] = &qgr.metadata(nh->inEdges().front()).get<DataQueue>().q;
}
break;
default:
GAPI_Assert(false);
break;
} // switch(kind)
} // for(gim nodes)
m_out_queue.set_capacity(queue_capacity);
}
cv::gimpl::GStreamingExecutor::~GStreamingExecutor()
{
if (state == State::READY || state == State::RUNNING)
stop();
}
void cv::gimpl::GStreamingExecutor::setSource(GRunArgs &&ins)
{
GAPI_Assert(state == State::READY || state == State::STOPPED);
const auto is_video = [](const GRunArg &arg) {
return util::holds_alternative<cv::gapi::wip::IStreamSource::Ptr>(arg);
};
const auto num_videos = std::count_if(ins.begin(), ins.end(), is_video);
if (num_videos > 1)
{
// See below why (another reason - no documented behavior
// on handling videos streams of different length)
util::throw_error(std::logic_error("Only one video source is"
" currently supported!"));
}
// Walk through the protocol, set-up emitters appropriately
// There's a 1:1 mapping between emitters and corresponding data inputs.
for (auto it : ade::util::zip(ade::util::toRange(m_emitters),
ade::util::toRange(ins),
ade::util::iota(m_emitters.size())))
{
auto emit_nh = std::get<0>(it);
auto& emit_arg = std::get<1>(it);
auto emit_idx = std::get<2>(it);
auto& emitter = m_gim.metadata(emit_nh).get<Emitter>().object;
using T = GRunArg;
switch (emit_arg.index())
{
// Create a streaming emitter.
// Produces the next video frame when pulled.
case T::index_of<cv::gapi::wip::IStreamSource::Ptr>():
#if !defined(GAPI_STANDALONE)
emitter.reset(new VideoEmitter{emit_arg});
#else
util::throw_error(std::logic_error("Video is not supported in the "
"standalone mode"));
#endif
break;
default:
// Create a constant emitter.
// Produces always the same ("constant") value when pulled.
emitter.reset(new ConstEmitter{emit_arg});
m_const_emitter_queues.push_back(&m_emitter_queues[emit_idx]);
break;
}
}
// FIXME: The below code assumes our graph may have only one
// real video source (and so, only one stream which may really end)
// all other inputs are "constant" generators.
// Craft here a completion callback to notify Const emitters that
// a video source is over
auto real_video_completion_cb = [this]() {
for (auto q : m_const_emitter_queues) q->push(Cmd{Stop{}});
};
// FIXME: ONLY now, after all executable objects are created,
// we can set up our execution threads. Let's do it.
// First create threads for all the emitters.
// FIXME: One way to avoid this may be including an Emitter object as a part of
// START message. Why not?
if (state == State::READY)
{
stop();
}
for (auto it : ade::util::indexed(m_emitters))
{
const auto id = ade::util::index(it); // = index in GComputation's protocol
const auto eh = ade::util::value(it);
// Prepare emitter thread parameters
auto emitter = m_gim.metadata(eh).get<Emitter>().object;
// Collect all reader queues from the emitter's the only output object
auto out_queues = reader_queues(*m_island_graph, eh->outNodes().front());
m_threads.emplace_back(emitterActorThread,
emitter,
std::ref(m_emitter_queues[id]),
out_queues,
real_video_completion_cb);
}
// Now do this for every island (in a topological order)
for (auto &&op : m_ops)
{
// Prepare island thread parameters
auto island = m_gim.metadata(op.nh).get<IslandExec>().object;
// Collect actor's input queues
auto in_queues = input_queues(*m_island_graph, op.nh);
// Collect actor's output queues.
// This may be tricky...
std::vector< std::vector<stream::Q*> > out_queues;
for (auto &&out_eh : op.nh->outNodes()) {
out_queues.push_back(reader_queues(*m_island_graph, out_eh));
}
m_threads.emplace_back(islandActorThread,
op.in_objects,
op.out_objects,
op.out_metas,
island,
in_queues,
op.in_constants,
out_queues);
}
// Finally, start a collector thread.
m_threads.emplace_back(collectorThread,
m_sink_queues,
std::ref(m_out_queue));
state = State::READY;
}
void cv::gimpl::GStreamingExecutor::start()
{
if (state == State::STOPPED)
{
util::throw_error(std::logic_error("Please call setSource() before start() "
"if the pipeline has been already stopped"));
}
GAPI_Assert(state == State::READY);
// Currently just trigger our emitters to work
state = State::RUNNING;
for (auto &q : m_emitter_queues)
{
q.push(stream::Cmd{stream::Start{}});
}
}
void cv::gimpl::GStreamingExecutor::wait_shutdown()
{
// This utility is used by pull/try_pull/stop() to uniformly
// shutdown the worker threads.
// FIXME: Of course it can be designed much better
for (auto &t : m_threads) t.join();
m_threads.clear();
// Clear all queues
// If there are constant emitters, internal queues
// may be polluted with constant values and have extra
// data at the point of shutdown.
// It usually happens when there's multiple inputs,
// one constant and one is not, and the latter ends (e.g.
// with end-of-stream).
for (auto &q : m_emitter_queues) q.clear();
for (auto &q : m_sink_queues) q->clear();
for (auto &q : m_internal_queues) q->clear();
m_out_queue.clear();
state = State::STOPPED;
}
bool cv::gimpl::GStreamingExecutor::pull(cv::GRunArgsP &&outs)
{
if (state == State::STOPPED)
return false;
GAPI_Assert(state == State::RUNNING);
GAPI_Assert(m_sink_queues.size() == outs.size());
Cmd cmd;
m_out_queue.pop(cmd);
if (cv::util::holds_alternative<Stop>(cmd))
{
wait_shutdown();
return false;
}
GAPI_Assert(cv::util::holds_alternative<cv::GRunArgs>(cmd));
cv::GRunArgs &this_result = cv::util::get<cv::GRunArgs>(cmd);
sync_data(this_result, outs);
return true;
}
bool cv::gimpl::GStreamingExecutor::try_pull(cv::GRunArgsP &&outs)
{
if (state == State::STOPPED)
return false;
GAPI_Assert(m_sink_queues.size() == outs.size());
Cmd cmd;
if (!m_out_queue.try_pop(cmd)) {
return false;
}
if (cv::util::holds_alternative<Stop>(cmd))
{
wait_shutdown();
return false;
}
GAPI_Assert(cv::util::holds_alternative<cv::GRunArgs>(cmd));
cv::GRunArgs &this_result = cv::util::get<cv::GRunArgs>(cmd);
sync_data(this_result, outs);
return true;
}
void cv::gimpl::GStreamingExecutor::stop()
{
if (state == State::STOPPED)
return;
// FIXME: ...and how to deal with still-unread data then?
// Push a Stop message to the every emitter,
// wait until it broadcasts within the pipeline,
// FIXME: worker threads could stuck on push()!
// need to read the output queues until Stop!
for (auto &q : m_emitter_queues) {
q.push(stream::Cmd{stream::Stop{}});
}
// Pull messages from the final queue to ensure completion
Cmd cmd;
while (!cv::util::holds_alternative<Stop>(cmd))
{
m_out_queue.pop(cmd);
}
GAPI_Assert(cv::util::holds_alternative<Stop>(cmd));
wait_shutdown();
}
bool cv::gimpl::GStreamingExecutor::running() const
{
return (state == State::RUNNING);
}