Implement basic multithreading support

A few CPU heavy operations, which are opening an archive and displaying
a selected Activity, have been moved to another thread to avoid having
long-running operations on the main thread.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/archive_parser.cpp b/src/archive_parser.cpp
index 77d3ec0..96df1ec 100644
--- a/src/archive_parser.cpp
+++ b/src/archive_parser.cpp
@@ -19,7 +19,7 @@
 Archive::Archive(QString outbox_filename, ArchiveType archive_type) :
     outbox_filename(outbox_filename), archive_type(archive_type) {}
 
-Archive::InitError Archive::init() {
+std::variant<QString, Archive::InitError> Archive::init() {
     QFile outbox_file(outbox_filename);
 
     if (!outbox_file.open(QIODevice::ReadOnly | QIODevice::Text))
@@ -233,7 +233,7 @@ std::vector<APAttachmentFields> Archive::get_status_attachments_list(QJsonValueR
 }
 
 // status_index is assumed to be a valid index
-QString Archive::get_html_status_info(int status_index, int text_zone_width, StatusType status_type, QLocale* locale) {
+const QString Archive::get_html_status_info(int status_index, int text_zone_width, StatusType status_type, QLocale* locale) {
     // the JSON AP Activity (TODO: fix misleading name)
     QJsonObject obj = outbox_items->at(status_index).toObject();
 
@@ -303,7 +303,7 @@ QString Archive::get_html_status_info(int status_index, int text_zone_width, Sta
 }
 
 // TODO: make this use an APActivity object that will be present as an StatusListItem member.
-QString Archive::get_html_status_text(int status_index) {
+const QString Archive::get_html_status_text(int status_index) {
     QString text("");
     QJsonObject obj = outbox_items->at(status_index).toObject();