Hash images upon loading divelog file rather than when loading image

Up to now, we only computed hashes of images upon actually displaying the images.

With this patch we start to compute hashes once we load the xml or from git. This
happens in the background, so the user should note an increased CPU load only once
per divelog.

Signed-off-by: Robert C. Helling <helling@atdotde.de>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

dive.c

@@ -9,6 +9,7 @@
 #include "libdivecomputer.h"
 #include "device.h"
 #include "divelist.h"
+#include "qthelperfromc.h"
 
 /* one could argue about the best place to have this variable -
  * it's used in the UI, but it seems to make the most sense to have it
@@ -3014,6 +3015,7 @@ void dive_add_picture(struct dive *dive, struct picture *newpic)
 		pic_ptr = &(*pic_ptr)->next;
 	newpic->next = *pic_ptr;
 	*pic_ptr = newpic;
+	cache_picture(newpic);
 	return;
 }
 

qthelper.cpp

@@ -1057,6 +1057,7 @@ void read_hashes()
 	if (hashfile.open(QIODevice::ReadOnly)) {
 		QDataStream stream(&hashfile);
 		stream >> localFilenameOf;
+		stream >> hashOf;
 		hashfile.close();
 	}
 }
@@ -1067,6 +1068,7 @@ void write_hashes()
 	if (hashfile.open(QIODevice::WriteOnly)) {
 		QDataStream stream(&hashfile);
 		stream << localFilenameOf;
+		stream << hashOf;
 		hashfile.commit();
 	} else {
 		qDebug() << "cannot open" << hashfile.fileName();
@@ -1124,6 +1126,20 @@ void updateHash(struct picture *picture) {
 	free(old);
 }
 
+void hashPicture(struct picture *picture)
+{
+	learnHash(picture, hashFile(QString(picture->filename)));
+	mark_divelist_changed((true));
+
+}
+
+extern "C" void cache_picture(struct picture *picture)
+{
+	QString filename = picture->filename;
+	if (!hashOf.contains(filename))
+		QtConcurrent::run(hashPicture, picture);
+}
+
 void learnImages(const QDir dir, int max_recursions, bool recursed)
 {
 	QDir current(dir);

qthelper.h

@@ -118,6 +118,7 @@ void add_hash(const QString filename, QByteArray hash);
 QString localFilePath(const QString originalFilename);
 QString fileFromHash(char *hash);
 void learnHash(struct picture *picture, QByteArray hash);
+extern "C" void cache_picture(struct picture *picture);
 weight_t string_to_weight(const char *str);
 depth_t string_to_depth(const char *str);
 pressure_t string_to_pressure(const char *str);

qthelperfromc.h

@@ -12,5 +12,6 @@ char *hashstring(char *filename);
 bool picture_exists(struct picture *picture);
 const char *local_file_path(struct picture *picture);
 void savePictureLocal(struct picture *picture, const char *data, int len);
+void cache_picture(struct picture *picture);
 
 #endif // QTHELPERFROMC_H