1 files changed, 149 insertions, 0 deletions
diff --git a/python/openvino/runtime/common/demo_utils/include/utils/input_wrappers.hpp b/python/openvino/runtime/common/demo_utils/include/utils/input_wrappers.hpp
new file mode 100644
index 0000000..eff38a7
--- /dev/null
+++ b/python/openvino/runtime/common/demo_utils/include/utils/input_wrappers.hpp
@@ -0,0 +1,149 @@
+// Copyright (C) 2018-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+//
+
+#pragma once
+
+#include <list>
+#include <memory>
+#include <set>
+#include <thread>
+#include <vector>
+#include <queue>
+
+#include <opencv2/opencv.hpp>
+
+class InputChannel;
+
+class IInputSource {
+public:
+    virtual bool read(cv::Mat& mat, const std::shared_ptr<InputChannel>& caller) = 0;
+    virtual void addSubscriber(const std::weak_ptr<InputChannel>& inputChannel) = 0;
+    virtual cv::Size getSize() = 0;
+    virtual void lock() {
+        sourceLock.lock();
+    }
+    virtual void unlock() {
+        sourceLock.unlock();
+    }
+    virtual ~IInputSource() = default;
+private:
+    std::mutex sourceLock;
+};
+
+class InputChannel: public std::enable_shared_from_this<InputChannel> { // note: public inheritance
+public:
+    InputChannel(const InputChannel&) = delete;
+    InputChannel& operator=(const InputChannel&) = delete;
+    static std::shared_ptr<InputChannel> create(const std::shared_ptr<IInputSource>& source) {
+        auto tmp = std::shared_ptr<InputChannel>(new InputChannel(source));
+        source->addSubscriber(tmp);
+        return tmp;
+    }
+    bool read(cv::Mat& mat) {
+        readQueueMutex.lock();
+        if (readQueue.empty()) {
+            readQueueMutex.unlock();
+            source->lock();
+            readQueueMutex.lock();
+            if (readQueue.empty()) {
+                bool res = source->read(mat, shared_from_this());
+                readQueueMutex.unlock();
+                source->unlock();
+                return res;
+            } else {
+                source->unlock();
+            }
+        }
+        mat = readQueue.front().clone();
+        readQueue.pop();
+        readQueueMutex.unlock();
+        return true;
+    }
+    void push(const cv::Mat& mat) {
+        readQueueMutex.lock();
+        readQueue.push(mat);
+        readQueueMutex.unlock();
+    }
+    cv::Size getSize() {
+        return source->getSize();
+    }
+
+private:
+    explicit InputChannel(const std::shared_ptr<IInputSource>& source): source{source} {}
+    std::shared_ptr<IInputSource> source;
+    std::queue<cv::Mat, std::list<cv::Mat>> readQueue;
+    std::mutex readQueueMutex;
+};
+
+class VideoCaptureSource: public IInputSource {
+public:
+    VideoCaptureSource(const cv::VideoCapture& videoCapture, bool loop): videoCapture{videoCapture}, loop{loop},
+        imSize{static_cast<int>(videoCapture.get(cv::CAP_PROP_FRAME_WIDTH)), static_cast<int>(videoCapture.get(cv::CAP_PROP_FRAME_HEIGHT))} {}
+    bool read(cv::Mat& mat, const std::shared_ptr<InputChannel>& caller) override {
+        if (!videoCapture.read(mat)) {
+            if (loop) {
+                videoCapture.set(cv::CAP_PROP_POS_FRAMES, 0);
+                videoCapture.read(mat);
+            } else {
+                return false;
+            }
+        }
+        if (1 != subscribedInputChannels.size()) {
+            cv::Mat shared = mat.clone();
+            for (const std::weak_ptr<InputChannel>& weakInputChannel : subscribedInputChannels) {
+                try {
+                    std::shared_ptr<InputChannel> sharedInputChannel = std::shared_ptr<InputChannel>(weakInputChannel);
+                    if (caller != sharedInputChannel) {
+                        sharedInputChannel->push(shared);
+                    }
+                } catch (const std::bad_weak_ptr&) {}
+            }
+        }
+        return true;
+    }
+    void addSubscriber(const std::weak_ptr<InputChannel>& inputChannel) override {
+        subscribedInputChannels.push_back(inputChannel);
+    }
+    cv::Size getSize() override {
+        return imSize;
+    }
+
+private:
+    std::vector<std::weak_ptr<InputChannel>> subscribedInputChannels;
+    cv::VideoCapture videoCapture;
+    bool loop;
+    cv::Size imSize;
+};
+
+class ImageSource: public IInputSource {
+public:
+    ImageSource(const cv::Mat& im, bool loop): im{im.clone()}, loop{loop} {}  // clone to avoid image changing
+    bool read(cv::Mat& mat, const std::shared_ptr<InputChannel>& caller) override {
+        if (!loop) {
+            auto subscribedInputChannelsIt = subscribedInputChannels.find(caller);
+            if (subscribedInputChannels.end() == subscribedInputChannelsIt) {
+                return false;
+            } else {
+                subscribedInputChannels.erase(subscribedInputChannelsIt);
+                mat = im;
+                return true;
+            }
+        } else {
+            mat = im;
+            return true;
+        }
+    }
+    void addSubscriber(const std::weak_ptr<InputChannel>& inputChannel) override {
+        if (false == subscribedInputChannels.insert(inputChannel).second)
+            throw std::invalid_argument("The insertion did not take place");
+    }
+    cv::Size getSize() override {
+        return im.size();
+    }
+
+private:
+    std::set<std::weak_ptr<InputChannel>, std::owner_less<std::weak_ptr<InputChannel>>> subscribedInputChannels;
+    cv::Mat im;
+    bool loop;
+};