From f47c1454fcff4d29b62d79a2045e7ebbccf57ccb Mon Sep 17 00:00:00 2001
From: Lorn Potter <lorn.potter@gmail.com>
Date: Fri, 15 Mar 2024 14:23:11 +1000
Subject: wasm: fix camera showing in declarative
MIME-Version: 1.0
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Wait for camera to become found before trying to make it active

Fixes: QTBUG-112316
Change-Id: Ic68c48be03909dbac11cf92d75387e25c74d573e
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
(cherry picked from commit 841fe1e93b38cbfc4af78e6135501cda143161e5)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 .../multimedia/wasm/common/qwasmvideooutput.cpp    |  2 +-
 .../multimedia/wasm/mediacapture/qwasmcamera.cpp   | 43 +++++++++++++++++++---
 .../multimedia/wasm/mediacapture/qwasmcamera_p.h   |  5 ++-
 3 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/src/plugins/multimedia/wasm/common/qwasmvideooutput.cpp b/src/plugins/multimedia/wasm/common/qwasmvideooutput.cpp
index 452ea28f8..41b4208d3 100644
--- a/src/plugins/multimedia/wasm/common/qwasmvideooutput.cpp
+++ b/src/plugins/multimedia/wasm/common/qwasmvideooutput.cpp
@@ -232,7 +232,7 @@ void QWasmVideoOutput::setSource(const QUrl &url)
     if (url.isLocalFile()) {
         QFile localFile(url.toLocalFile());
         if (localFile.open(QIODevice::ReadOnly)) {
-            QDataStream buffer(&localFile);   // we will serialize the data into the file
+            QDataStream buffer(&localFile); // we will serialize the data into the file
             setSource(buffer.device());
         } else {
             qWarning() << "Failed to open file";
diff --git a/src/plugins/multimedia/wasm/mediacapture/qwasmcamera.cpp b/src/plugins/multimedia/wasm/mediacapture/qwasmcamera.cpp
index 031cc8dd3..976d94d96 100644
--- a/src/plugins/multimedia/wasm/mediacapture/qwasmcamera.cpp
+++ b/src/plugins/multimedia/wasm/mediacapture/qwasmcamera.cpp
@@ -8,6 +8,7 @@
 #include "private/qplatformvideosink_p.h"
 #include <private/qmemoryvideobuffer_p.h>
 #include <private/qvideotexturehelper_p.h>
+#include <private/qwasmmediadevices_p.h>
 
 #include "qwasmmediacapturesession_p.h"
 #include <common/qwasmvideooutput_p.h>
@@ -23,8 +24,33 @@
 Q_LOGGING_CATEGORY(qWasmCamera, "qt.multimedia.wasm.camera")
 
 QWasmCamera::QWasmCamera(QCamera *camera)
-    : QPlatformCamera(camera), m_cameraOutput(new QWasmVideoOutput)
+    : QPlatformCamera(camera),
+      m_cameraOutput(new QWasmVideoOutput),
+      m_cameraIsReady(false)
 {
+    QWasmMediaDevices *wasmMediaDevices =
+            static_cast<QWasmMediaDevices *>(QPlatformMediaIntegration::instance()->mediaDevices());
+
+    connect(wasmMediaDevices, &QWasmMediaDevices::videoInputsChanged,this, [this]() {
+        const QList<QCameraDevice> cameras = QMediaDevices::videoInputs();
+
+        if (!cameras.isEmpty()) {
+            if (m_cameraDev.id().isEmpty())
+                setCamera(cameras.at(0)); // default camera
+            else
+                setCamera(m_cameraDev);
+            return;
+        }
+    });
+
+    connect(this, &QWasmCamera::cameraIsReady, this, [this]() {
+        m_cameraIsReady = true;
+        if (m_cameraShouldStartActive) {
+            QTimer::singleShot(50, this, [this]() {
+                setActive(true);
+            });
+        }
+    });
 }
 
 QWasmCamera::~QWasmCamera() = default;
@@ -41,6 +67,11 @@ void QWasmCamera::setActive(bool active)
         return;
     }
 
+    if (!m_cameraIsReady) {
+        m_cameraShouldStartActive = true;
+        return;
+    }
+
     m_cameraOutput->setSurface(m_CaptureSession->videoSink());
 
     m_cameraActive = active;
@@ -56,6 +87,9 @@ void QWasmCamera::setActive(bool active)
 
 void QWasmCamera::setCamera(const QCameraDevice &camera)
 {
+    if (!m_cameraDev.id().isEmpty())
+        return;
+
     m_cameraOutput->setVideoMode(QWasmVideoOutput::Camera);
 
     constexpr QSize initialSize(0, 0);
@@ -65,15 +99,18 @@ void QWasmCamera::setCamera(const QCameraDevice &camera)
     m_cameraOutput->updateVideoElementGeometry(initialRect);
 
     const auto cameras = QMediaDevices::videoInputs();
+
     if (std::find(cameras.begin(), cameras.end(), camera) != cameras.end()) {
         m_cameraDev = camera;
         createCamera(m_cameraDev);
+        emit cameraIsReady();
         return;
     }
 
     if (cameras.count() > 0) {
         m_cameraDev = camera;
         createCamera(m_cameraDev);
+        emit cameraIsReady();
     } else {
         emit error(QCamera::CameraError, QStringLiteral("Failed to find a camera"));
     }
@@ -399,10 +436,6 @@ void QWasmCamera::setColorTemperature(int temperature)
 void QWasmCamera::createCamera(const QCameraDevice &camera)
 {
     m_cameraOutput->addCameraSourceElement(camera.id().toStdString());
-    // getUserMedia is async
-    QTimer::singleShot(100, [this] () {
-        m_cameraIsReady = m_cameraOutput->isCameraReady();
-    });
 }
 
 void QWasmCamera::updateCameraFeatures()
diff --git a/src/plugins/multimedia/wasm/mediacapture/qwasmcamera_p.h b/src/plugins/multimedia/wasm/mediacapture/qwasmcamera_p.h
index ccf5f99ce..b9399c6de 100644
--- a/src/plugins/multimedia/wasm/mediacapture/qwasmcamera_p.h
+++ b/src/plugins/multimedia/wasm/mediacapture/qwasmcamera_p.h
@@ -67,7 +67,8 @@ public:
     void setColorTemperature(int temperature) override;
 
     QWasmVideoOutput *cameraOutput() { return m_cameraOutput.data(); }
-
+Q_SIGNALS:
+    void cameraIsReady();
 private:
     void createCamera(const QCameraDevice &camera);
     void updateCameraFeatures();
@@ -89,6 +90,8 @@ private:
     QCamera::WhiteBalanceMode m_wasmWhiteBalanceMode;
     int m_wasmColorTemperature;
     bool m_cameraIsReady = false;
+    bool m_cameraShouldStartActive = false;
+    bool m_shouldBeActive = false;
 };
 
 QT_END_NAMESPACE
-- 
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