refactor(screenshots): make ScreenshotsWatcher async

launcher/minecraft/ScreenshotsWatcher.cpp

@@ -17,49 +17,78 @@
  */
 
 #include <QClipboard>
-#include <QFileSystemWatcher>
 #include <QImage>
-#include <QThread>
 
 #include "Application.h"
+#include "FileSystem.h"
 #include "MinecraftInstance.h"
 
 #include "ScreenshotsWatcher.h"
 
-ScreenshotsWatcher::ScreenshotsWatcher(const QString& path) : QObject(), m_path(path)
+ScreenshotsWatcher::ScreenshotsWatcher(const QString& path) : m_watcher(QStringList{ path })
 {
-    auto watcher = new QFileSystemWatcher({ path });
-
-    connect(watcher, &QFileSystemWatcher::directoryChanged, this, &ScreenshotsWatcher::dirUpdated);
-
-    m_watcher = std::make_unique<QFileSystemWatcher>(watcher);
+    m_retryTimer.setSingleShot(true);
+    m_retryTimer.setInterval(200);
+    connect(&m_retryTimer, &QTimer::timeout, this, &ScreenshotsWatcher::tryCopy);
+    connect(&m_watcher, &QFileSystemWatcher::directoryChanged, this, &ScreenshotsWatcher::dirUpdated);
 }
 
-void ScreenshotsWatcher::dirUpdated()
+void ScreenshotsWatcher::dirUpdated(const QString& path)
 {
-    QDir d(m_path, "*.png", QDir::Time, QDir::Files);
+    QDir d(path, "*.png", QDir::Time, QDir::Files);
     if (!d.exists() || !d.count()) {
         qDebug() << "Invalid screenshots dir";
         return;
     }
-    QString path = m_path + '/' + d[0];
 
-    auto clipboard = Application::clipboard();
-    if (clipboard == nullptr) {
-        qDebug() << "Clipboard ptr is null, aborting copying";
+    QString file = FS::PathCombine(path, d[0]);
+    if (file == m_pendingPath)
+        return;
+
+    m_pendingPath = file;
+    m_attempt = 0;
+    m_lastSize = QFileInfo(m_pendingPath).size();
+
+    scheduleRetry();
+}
+
+void ScreenshotsWatcher::tryCopy()
+{
+    const QFileInfo fileInfo(m_pendingPath);
+    if (!fileInfo.exists())
+        return;
+
+    if (m_lastSize == 0 || m_lastSize != fileInfo.size()) {
+        m_lastSize = fileInfo.size();
+        scheduleRetry();
         return;
     }
+    m_lastSize = fileInfo.size();
 
     QImage img;
-    bool loaded = img.load(path);
-    for (int i = 0; i < 5 && !loaded; i++) {
-        QThread::msleep(200);
-        loaded = img.load(path);
-    }
+    bool loaded = img.load(m_pendingPath);
+
     if (!loaded) {
-        qDebug() << "Image wasn't loaded in 1 sec, aborting copying";
+        scheduleRetry();
+        return;
+    }
+
+    const auto clipboard = QApplication::clipboard();
+    if (clipboard == nullptr) {
+        qDebug() << "Clipboard is null";
         return;
     }
 
     clipboard->setImage(img);
 }
+
+void ScreenshotsWatcher::scheduleRetry()
+{
+    ++m_attempt;
+    if (m_attempt > 5) {
+        qDebug() << "Image wasn't loaded after 5 retries";
+        return;
+    }
+
+    m_retryTimer.start();
+}

launcher/minecraft/ScreenshotsWatcher.h

@@ -18,23 +18,27 @@
 
 #pragma once
 
+#include <QFileSystemWatcher>
 #include <QObject>
-#include <memory>
-
-class QFileSystemWatcher;
-class QString;
-class QObject;
-class MinecraftInstance;
+#include <QString>
+#include <QTimer>
+#include <cstddef>
 
 class ScreenshotsWatcher : public QObject {
     Q_OBJECT
    public:
     explicit ScreenshotsWatcher(const QString& path);
 
    private slots:
-    void dirUpdated();
+    void dirUpdated(const QString& path);
+    void tryCopy();
 
    private:
-    std::unique_ptr<QFileSystemWatcher> m_watcher;
-    const QString m_path;
+    void scheduleRetry();
+
+    QFileSystemWatcher m_watcher;
+    QString m_pendingPath;
+    std::size_t m_attempt{};
+    std::size_t m_lastSize{};
+    QTimer m_retryTimer;
 };