fix hang when importing certain modpacks

Modified findFolderOfFileInZip to use a breadth-first search and support
searching for multiple file names in one pass. This should prevent or at
least make it less likely to hang while importing certain packs.

Signed-off-by: Lenny McLennington <lenny@sneed.church>

launcher/InstanceImportTask.cpp

@@ -164,23 +164,21 @@ void InstanceImportTask::processZipPack()
     }
     else
     {
-        QString mmcRoot = MMCZip::findFolderOfFileInZip(m_packZip.get(), "instance.cfg");
+        auto [rootDirectory, fileName] = MMCZip::findFolderOfFileInZip(m_packZip.get(), {"manifest.json", "instance.cfg"});
-        QString flameRoot = MMCZip::findFolderOfFileInZip(m_packZip.get(), "manifest.json");
+        if(fileName == "manifest.json")
-
-        if (!mmcRoot.isNull())
-        {
-            // process as MultiMC instance/pack
-            qDebug() << "MultiMC:" << mmcRoot;
-            root = mmcRoot;
-            m_modpackType = ModpackType::MultiMC;
-        }
-        else if(!flameRoot.isNull())
         {
             // process as Flame pack
-            qDebug() << "Flame:" << flameRoot;
+            qDebug() << "Flame:" << rootDirectory;
-            root = flameRoot;
+            root = rootDirectory;
             m_modpackType = ModpackType::Flame;
         }
+        else if (fileName == "instance.cfg")
+        {
+            // process as MultiMC instance/pack
+            qDebug() << "MultiMC:" << rootDirectory;
+            root = rootDirectory;
+            m_modpackType = ModpackType::MultiMC;
+        }
     }
     if(m_modpackType == ModpackType::Unknown)
     {

launcher/MMCZip.cpp

@@ -40,6 +40,7 @@
 #include "FileSystem.h"
 
 #include <QDebug>
+#include <deque>
 
 // ours
 bool MMCZip::mergeZipFiles(QuaZip *into, QFileInfo from, QSet<QString> &contained, const FilterFunction filter)
@@ -228,23 +229,27 @@ bool MMCZip::createModdedJar(QString sourceJarPath, QString targetJarPath, const
 }
 
 // ours
-QString MMCZip::findFolderOfFileInZip(QuaZip * zip, const QString & what, const QString &root)
+std::pair<QString, QString> MMCZip::findFolderOfFileInZip(QuaZip * zip, QSet<const QString> what, const QString &root)
 {
-    QuaZipDir rootDir(zip, root);
+    std::deque<QString> pathsToTraverse;
-    for(auto fileName: rootDir.entryList(QDir::Files))
+    pathsToTraverse.push_back(root);
+    while (!pathsToTraverse.empty())
     {
-        if(fileName == what)
+        QString currentPath = pathsToTraverse.front();
-            return root;
+        pathsToTraverse.pop_front();
-    }
+        QuaZipDir rootDir(zip, currentPath);
-    for(auto fileName: rootDir.entryList(QDir::Dirs))
+
-    {
+        for(auto fileName: rootDir.entryList(QDir::Files))
-        QString result = findFolderOfFileInZip(zip, what, root + fileName);
-        if(!result.isEmpty())
         {
-            return result;
+            if (what.contains(fileName))
+                return {currentPath, fileName};
+        }
+        for(auto fileName: rootDir.entryList(QDir::Dirs))
+        {
+            pathsToTraverse.push_back(root);
         }
     }
-    return QString();
+    return {QString(), QString()};
 }
 
 // ours

launcher/MMCZip.h

@@ -78,11 +78,11 @@ namespace MMCZip
     bool createModdedJar(QString sourceJarPath, QString targetJarPath, const QList<Mod*>& mods);
 
     /**
-     * Find a single file in archive by file name (not path)
+     * Breath-first find a single file in archive by a list of file names (not path)
      *
-     * \return the path prefix where the file is
+     * \return pair of {file parent directory, file name}
      */
-    QString findFolderOfFileInZip(QuaZip * zip, const QString & what, const QString &root = QString(""));
+    std::pair<QString, QString> findFolderOfFileInZip(QuaZip * zip, QSet<const QString> what, const QString &root = QString(""));
 
     /**
      * Find a multiple files of the same name in archive by file name

launcher/minecraft/World.cpp

@@ -285,7 +285,7 @@ void World::readFromZip(const QFileInfo &file)
     {
         return;
     }
-    auto location = MMCZip::findFolderOfFileInZip(&zip, "level.dat");
+    auto [location, _] = MMCZip::findFolderOfFileInZip(&zip, {"level.dat"});
     is_valid = !location.isEmpty();
     if (!is_valid)
     {