Merge pull request #15536 from glassez/expected

Don't use output parameters for error handling

src/base/bittorrent/session.cpp

@@ -69,7 +69,6 @@
 #include <QUuid>
 
 #include "base/algorithm.h"
-#include "base/exceptions.h"
 #include "base/global.h"
 #include "base/logger.h"
 #include "base/net/downloadmanager.h"
@@ -1698,7 +1697,7 @@ void Session::handleDownloadFinished(const Net::DownloadResult &result)
     {
     case Net::DownloadStatus::Success:
         emit downloadFromUrlFinished(result.url);
-        addTorrent(TorrentInfo::load(result.data), m_downloadedTorrents.take(result.url));
+        addTorrent(TorrentInfo::load(result.data).value_or(TorrentInfo()), m_downloadedTorrents.take(result.url));
         break;
     case Net::DownloadStatus::RedirectedToMagnet:
         emit downloadFromUrlFinished(result.url);
@@ -2028,7 +2027,7 @@ bool Session::addTorrent(const QString &source, const AddTorrentParams &params)
         return addTorrent(magnetUri, params);
 
     TorrentFileGuard guard {source};
-    if (addTorrent(TorrentInfo::loadFromFile(source), params))
+    if (addTorrent(TorrentInfo::loadFromFile(source).value_or(TorrentInfo()), params))
     {
         guard.markAsAddedToSession();
         return true;
@@ -2317,14 +2316,11 @@ void Session::exportTorrentFile(const TorrentInfo &torrentInfo, const QString &f
             newTorrentPath = exportDir.absoluteFilePath(torrentExportFilename);
         }
 
-        try
-        {
-            torrentInfo.saveToFile(newTorrentPath);
-        }
-        catch (const RuntimeError &err)
+        const nonstd::expected<void, QString> result = torrentInfo.saveToFile(newTorrentPath);
+        if (!result)
         {
             LogMsg(tr("Couldn't export torrent metadata file '%1'. Reason: %2.")
-                   .arg(newTorrentPath, err.message()), Log::WARNING);
+                   .arg(newTorrentPath, result.error()), Log::WARNING);
         }
     }
 }
@@ -3938,8 +3934,7 @@ void Session::handleTorrentFinished(TorrentImpl *const torrent)
             qDebug("Found possible recursive torrent download.");
             const QString torrentFullpath = torrent->savePath(true) + '/' + torrentRelpath;
             qDebug("Full subtorrent path is %s", qUtf8Printable(torrentFullpath));
-            TorrentInfo torrentInfo = TorrentInfo::loadFromFile(torrentFullpath);
-            if (torrentInfo.isValid())
+            if (TorrentInfo::loadFromFile(torrentFullpath))
             {
                 qDebug("emitting recursiveTorrentDownloadPossible()");
                 emit recursiveTorrentDownloadPossible(torrent);
@@ -4167,7 +4162,7 @@ void Session::recursiveTorrentDownload(const TorrentID &id)
             AddTorrentParams params;
             // Passing the save path along to the sub torrent file
             params.savePath = torrent->savePath();
-            addTorrent(TorrentInfo::loadFromFile(torrentFullpath), params);
+            addTorrent(TorrentInfo::loadFromFile(torrentFullpath).value_or(TorrentInfo()), params);
         }
     }
 }

src/base/bittorrent/torrentinfo.cpp

@@ -40,7 +40,6 @@
 #include <QUrl>
 #include <QVector>
 
-#include "base/exceptions.h"
 #include "base/global.h"
 #include "base/utils/fs.h"
 #include "base/utils/io.h"
@@ -106,7 +105,7 @@ TorrentInfo &TorrentInfo::operator=(const TorrentInfo &other)
     return *this;
 }
 
-TorrentInfo TorrentInfo::load(const QByteArray &data, QString *error) noexcept
+nonstd::expected<TorrentInfo, QString> TorrentInfo::load(const QByteArray &data) noexcept
 {
     // 2-step construction to overcome default limits of `depth_limit` & `token_limit` which are
     // used in `torrent_info()` constructor
@@ -117,42 +116,23 @@ TorrentInfo TorrentInfo::load(const QByteArray &data, QString *error) noexcept
     const lt::bdecode_node node = lt::bdecode(data, ec
         , nullptr, depthLimit, tokenLimit);
     if (ec)
-    {
-        if (error)
-            *error = QString::fromStdString(ec.message());
-        return TorrentInfo();
-    }
+        return nonstd::make_unexpected(QString::fromStdString(ec.message()));
 
     TorrentInfo info {std::shared_ptr<lt::torrent_info>(new lt::torrent_info(node, ec))};
     if (ec)
-    {
-        if (error)
-            *error = QString::fromStdString(ec.message());
-        return TorrentInfo();
-    }
+        return nonstd::make_unexpected(QString::fromStdString(ec.message()));
 
     return info;
 }
 
-TorrentInfo TorrentInfo::loadFromFile(const QString &path, QString *error) noexcept
+nonstd::expected<TorrentInfo, QString> TorrentInfo::loadFromFile(const QString &path) noexcept
 {
-    if (error)
-        error->clear();
-
     QFile file {path};
     if (!file.open(QIODevice::ReadOnly))
-    {
-        if (error)
-            *error = file.errorString();
-        return TorrentInfo();
-    }
+        return nonstd::make_unexpected(file.errorString());
 
     if (file.size() > MAX_TORRENT_SIZE)
-    {
-        if (error)
-            *error = tr("File size exceeds max limit %1").arg(Utils::Misc::friendlyUnit(MAX_TORRENT_SIZE));
-        return TorrentInfo();
-    }
+        return nonstd::make_unexpected(tr("File size exceeds max limit %1").arg(Utils::Misc::friendlyUnit(MAX_TORRENT_SIZE)));
 
     QByteArray data;
     try
@@ -161,26 +141,21 @@ TorrentInfo TorrentInfo::loadFromFile(const QString &path, QString *error) noexc
     }
     catch (const std::bad_alloc &e)
     {
-        if (error)
-            *error = tr("Torrent file read error: %1").arg(e.what());
-        return TorrentInfo();
+        return nonstd::make_unexpected(tr("Torrent file read error: %1").arg(e.what()));
     }
+
     if (data.size() != file.size())
-    {
-        if (error)
-            *error = tr("Torrent file read error: size mismatch");
-        return TorrentInfo();
-    }
+        return nonstd::make_unexpected(tr("Torrent file read error: size mismatch"));
 
     file.close();
 
-    return load(data, error);
+    return load(data);
 }
 
-void TorrentInfo::saveToFile(const QString &path) const
+nonstd::expected<void, QString> TorrentInfo::saveToFile(const QString &path) const
 {
     if (!isValid())
-        throw RuntimeError {tr("Invalid metadata")};
+        return nonstd::make_unexpected(tr("Invalid metadata"));
 
     try
     {
@@ -188,12 +163,14 @@ void TorrentInfo::saveToFile(const QString &path) const
         const lt::entry torrentEntry = torrentCreator.generate();
         const nonstd::expected<void, QString> result = Utils::IO::saveToFile(path, torrentEntry);
         if (!result)
-            throw RuntimeError(result.error());
+            return result.get_unexpected();
     }
     catch (const lt::system_error &err)
     {
-        throw RuntimeError(QString::fromLocal8Bit(err.what()));
+        return nonstd::make_unexpected(QString::fromLocal8Bit(err.what()));
     }
+
+    return {};
 }
 
 bool TorrentInfo::isValid() const

src/base/bittorrent/torrentinfo.h

@@ -33,6 +33,7 @@
 #include <QCoreApplication>
 #include <QtContainerFwd>
 
+#include "base/3rdparty/expected.hpp"
 #include "base/indexrange.h"
 #include "abstractfilestorage.h"
 #include "torrentcontentlayout.h"
@@ -55,9 +56,9 @@ namespace BitTorrent
         explicit TorrentInfo(std::shared_ptr<const lt::torrent_info> nativeInfo = {});
         TorrentInfo(const TorrentInfo &other);
 
-        static TorrentInfo load(const QByteArray &data, QString *error = nullptr) noexcept;
-        static TorrentInfo loadFromFile(const QString &path, QString *error = nullptr) noexcept;
-        void saveToFile(const QString &path) const;
+        static nonstd::expected<TorrentInfo, QString> load(const QByteArray &data) noexcept;
+        static nonstd::expected<TorrentInfo, QString> loadFromFile(const QString &path) noexcept;
+        nonstd::expected<void, QString> saveToFile(const QString &path) const;
 
         TorrentInfo &operator=(const TorrentInfo &other);