video: add support for camera modules

Issue: #910

2 files changed, 161 insertions, 0 deletions

diff --git a/video/camera.cpp b/video/camera.cpp
new file mode 100644
index 00000000..c33ab13a
--- /dev/null
+++ b/video/camera.cpp
@@ -0,0 +1,66 @@
+#include "camera.hpp"
+
+#include <algorithm>
+#include <utility>
+#include <QMutex>
+
+static std::vector<std::unique_ptr<video::impl::camera_>> metadata;
+static QMutex mtx;
+
+namespace video::impl {
+
+camera_::camera_() = default;
+camera_::~camera_() = default;
+
+camera::camera() = default;
+camera::~camera() = default;
+
+void register_camera(std::unique_ptr<impl::camera_> camera)
+{
+    QMutexLocker l(&mtx);
+    metadata.push_back(std::move(camera));
+}
+
+} // ns video::impl
+
+namespace video {
+
+bool show_dialog(const QString& camera_name)
+{
+    QMutexLocker l(&mtx);
+
+    for (auto& camera : metadata)
+        for (const QString& name : camera->camera_names())
+            if (name == camera_name)
+                return camera->show_dialog(camera_name);
+
+    return false;
+}
+
+std::unique_ptr<camera_impl> make_camera(const QString& name)
+{
+    QMutexLocker l(&mtx);
+
+    for (auto& camera : metadata)
+        for (const QString& name_ : camera->camera_names())
+            if (name_ == name)
+                return camera->make_camera(name);
+
+    return nullptr;
+}
+
+std::vector<QString> camera_names()
+{
+    QMutexLocker l(&mtx);
+    std::vector<QString> names; names.reserve(32);
+
+    for (auto& camera : metadata)
+        for (const QString& name : camera->camera_names())
+            if (std::find(names.cbegin(), names.cend(), name) == names.cend())
+                names.push_back(name);
+
+    std::sort(names.begin(), names.end());
+    return names;
+}
+
+} // ns video
diff --git a/video/camera.hpp b/video/camera.hpp
new file mode 100644
index 00000000..c9577933
--- /dev/null
+++ b/video/camera.hpp
@@ -0,0 +1,95 @@
+/* Copyright (c) 2019 Stanislaw Halik <sthalik@misaki.pl>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ */
+
+#pragma once
+
+#include "export.hpp"
+
+#include <memory>
+#include <vector>
+
+#include <QString>
+
+namespace video
+{
+
+struct frame final
+{
+    unsigned char* data = nullptr;
+    int width = 0, height = 0, stride = 0, channels = 0;
+};
+
+} // ns video
+
+namespace video::impl {
+
+using namespace video;
+
+struct camera;
+
+struct OTR_VIDEO_EXPORT camera_
+{
+    camera_();
+    virtual ~camera_();
+
+    virtual std::vector<QString> camera_names() const = 0;
+    virtual std::unique_ptr<camera> make_camera(const QString& name) = 0;
+    [[nodiscard]] virtual bool show_dialog(const QString& camera_name) = 0;
+    virtual bool can_show_dialog(const QString& camera_name) = 0;
+};
+
+struct OTR_VIDEO_EXPORT camera
+{
+    struct info final
+    {
+        int width = 0, height = 0, fps = 0;
+    };
+
+    camera();
+    virtual ~camera();
+
+    [[nodiscard]] virtual bool start(const info& args) = 0;
+    virtual void stop() = 0;
+    virtual bool is_open() = 0;
+
+    virtual std::tuple<const frame&, bool> get_frame() = 0;
+    [[nodiscard]] virtual bool show_dialog() = 0;
+};
+
+OTR_VIDEO_EXPORT
+void register_camera(std::unique_ptr<impl::camera_> metadata);
+
+} // ns video::impl
+
+#define OTR_REGISTER_CAMERA2(type, ctr)                                     \
+    namespace {                                                             \
+        struct init_##ctr                                                   \
+        {                                                                   \
+            static char fuzz;                                               \
+        };                                                                  \
+        char init_##ctr :: fuzz =                                           \
+            (::video::impl::register_camera(std::make_unique<type>()), 0);  \
+    } // anon ns
+
+#define OTR_REGISTER_CAMERA(type)                                           \
+    OTR_REGISTER_CAMERA2(type, __COUNTER__)
+
+namespace video
+{
+using camera_impl = typename impl::camera;
+
+OTR_VIDEO_EXPORT
+std::unique_ptr<camera_impl> make_camera(const QString& name);
+
+OTR_VIDEO_EXPORT
+std::vector<QString> camera_names();
+
+[[nodiscard]]
+OTR_VIDEO_EXPORT
+bool show_dialog(const QString& camera_name);
+
+} // ns video