prefetch images

include/datadragon.h

@@ -3,6 +3,7 @@
 #include <condition_variable>
 #include <functional>
 #include <mutex>
+#include <set>
 #include <string>
 #include <thread>
 #include <vector>
@@ -45,7 +46,7 @@ public:
 	// might block until champ data is available
 	const std::vector<ChampData>& getChamps();
 	// might block until image is downloaded
-	QPixmap getImage(const std::string& champid, ImageType imgtype = ImageType::SQUARE);
+	QPixmap getImage(const std::string& champid, ImageType imgtype = ImageType::SQUARE, bool writeMemcache = true);
 	void getImageAsnyc(const std::string& champid, notifyImgfunc_t func, ImageType imgtype = ImageType::SQUARE);
 	// might block until champ data is available
 	const ChampData& getBestMatchingChamp(const std::string& name, int* count = nullptr);
@@ -58,6 +59,7 @@ protected:
 	std::string getImageUrl(const std::string& champid, ImageType type);
 	std::string getCDNString() const;
 
+	void prefetchChampImage(const std::string& champid, ImageType imgtype = ImageType::SQUARE);
 	void getVersionInternal();
 	void getChampsInternal();
 	void startThread();
@@ -70,6 +72,7 @@ protected:
 	std::vector<ChampData> champs;
 	std::mutex cachedatamutex;
 	std::condition_variable cachedatacv;
+	std::set<std::string> notDownloadedImages; // the champions of which the square image is not downloaded yet. Is used to download them on idle
 
 private:
 	struct Task {

include/datadragonimagecache.h

@@ -9,6 +9,7 @@ public:
 	DataDragonImageCache(const std::string& folderextra, const std::string& imageext = ".jpg");
 	~DataDragonImageCache();
 
+	bool hasImage(const std::string& name);
 	QPixmap getImage(const std::string& name);
 	void addImageRaw(const QByteArray& arr, const std::string& name);
 private:

src/datadragon.cpp

@@ -50,7 +50,7 @@ const std::vector<DataDragon::ChampData>& DataDragon::getChamps() {
 	return champs;
 }
 
-QPixmap DataDragon::getImage(const std::string& champid, ImageType imgtype) {
+QPixmap DataDragon::getImage(const std::string& champid, ImageType imgtype, bool writeMemcache) {
 	if(champid.empty()) return {};
 
 	// query mem cache
@@ -84,11 +84,16 @@ QPixmap DataDragon::getImage(const std::string& champid, ImageType imgtype) {
 	// store HDD cache
 	cache[(int) imgtype].addImageRaw(arr, champid);
 
+	// remove from notDownloadedList
+	notDownloadedImages.erase(champid);
+
 	QPixmap decodedImage;
 	decodedImage.loadFromData(arr);
 
 	// store mem cache
-	memcache.addImage(decodedImage, champid, (int) imgtype);
+	if(writeMemcache) {
+		memcache.addImage(decodedImage, champid, (int) imgtype);
+	}
 
 	return decodedImage;
 }
@@ -228,6 +233,13 @@ std::string DataDragon::getCDNString() const {
 	return "cdn/" + version + "/";
 }
 
+void DataDragon::prefetchChampImage(const std::string& champid, ImageType imgtype) {
+	if(!cache[(int) imgtype].hasImage(champid)) {
+		Log::debug << "prefetch " << champid << " type: " << (int) imgtype;
+		getImage(champid, imgtype, false);
+	}
+}
+
 void DataDragon::getVersionInternal() {
 	std::unique_lock lock(cachedatamutex);
 
@@ -268,6 +280,7 @@ void DataDragon::getChampsInternal() {
 			for(auto champit = jchampsdata.constBegin(); champit != jchampsdata.constEnd(); champit++) {
 				if(champit.value().isObject()) {
 					champs.emplace_back(champit.value().toObject());
+					notDownloadedImages.insert(champs.back().id);
 				}
 			}
 		}
@@ -305,7 +318,28 @@ void DataDragon::threadLoop() {
 		{
 			std::unique_lock lock(tasksmutex);
 			if(tasks.empty()) {
-				tasksnotemptycv.wait(lock);
+				if(notDownloadedImages.empty()) {
+					tasksnotemptycv.wait(lock);
+				} else {
+					Log::note << "DataDragon background thread is idleing - prefetching champion images TODO: " << notDownloadedImages.size();
+
+					while(!notDownloadedImages.empty() && tasks.empty()) {
+						lock.unlock();
+
+						auto it = notDownloadedImages.begin();
+						std::string champid = *it;
+						notDownloadedImages.erase(it);
+
+						prefetchChampImage(champid, ImageType::SQUARE);
+
+						lock.lock();
+					}
+
+					if(notDownloadedImages.empty() && tasks.empty()) {
+						// everything prefetched, but nothing more to do
+						tasksnotemptycv.wait(lock);
+					}
+				}
 			}
 			if(tasks.empty()) continue;
 

src/datadragonimagecache.cpp

@@ -15,6 +15,11 @@ DataDragonImageCache::DataDragonImageCache(const std::string& folderextra, const
 }
 DataDragonImageCache::~DataDragonImageCache() {}
 
+bool DataDragonImageCache::hasImage(const std::string& name) {
+	QFile file(QString::fromStdString(getFilepath(name)));
+	return file.size() > 1024; // a image with less than 1KiB? assume it would be readable (r-Permissions)
+}
+
 QPixmap DataDragonImageCache::getImage(const std::string& name) {
 	return QPixmap(QString::fromStdString(getFilepath(name)));
 }