[Oracle] Parse sets lazily to slash importer peak memory

- Add a raw JSON scanner that splits the document into per-set byte ranges
  without materializing the JSON tree
- Keep only the raw document bytes and parse one set at a time in startImport
- Take readSetsFromByteArray by value so the wizard's buffer is moved, not copied
- Clear the retained raw data in releaseSetData()/clear()
- Cover the scanner and lazy parsing with tests

Took 2 minutes

cockatrice/src/interface/widgets/dialogs/dlg_convert_deck_to_cod_format.cpp

@@ -1,17 +1,9 @@
 #include "dlg_convert_deck_to_cod_format.h"
 
-#include "../../../client/settings/cache_settings.h"
-#include "../../deck_loader/deck_loader.h"
-
 #include <QCheckBox>
 #include <QDialogButtonBox>
-#include <QDir>
-#include <QFile>
-#include <QFileInfo>
 #include <QLabel>
-#include <QMessageBox>
 #include <QVBoxLayout>
-#include <libcockatrice/settings/visual_deck_storage_settings.h>
 
 DialogConvertDeckToCodFormat::DialogConvertDeckToCodFormat(QWidget *parent) : QDialog(parent)
 {
@@ -46,71 +38,3 @@ bool DialogConvertDeckToCodFormat::dontAskAgain() const
 {
     return dontAskAgainCheckbox->isChecked();
 }
-
-namespace
-{
-
-bool confirmOverwriteIfExists(QWidget *parent, const QString &filePath)
-{
-    QFileInfo fileInfo(filePath);
-    QString newFileName = QDir::toNativeSeparators(fileInfo.path() + "/" + fileInfo.completeBaseName() + ".cod");
-
-    if (QFile::exists(newFileName)) {
-        QMessageBox::StandardButton reply =
-            QMessageBox::question(parent, QObject::tr("Overwrite Existing File?"),
-                                  QObject::tr("A .cod version of this deck already exists. Overwrite it?"),
-                                  QMessageBox::Yes | QMessageBox::No);
-        return reply == QMessageBox::Yes;
-    }
-    return true; // Safe to proceed
-}
-
-} // namespace
-
-bool DialogConvertDeckToCodFormat::promptIfRequired(QWidget *parent,
-                                                    const QString &filePath,
-                                                    const std::function<bool()> &convert)
-{
-    if (DeckFileFormat::getFormatFromName(filePath) == DeckFileFormat::Cockatrice) {
-        return true;
-    }
-
-    // Retrieve saved preference if the prompt is disabled
-    if (!SettingsCache::instance().visualDeckStorage().getVisualDeckStoragePromptForConversion()) {
-        if (!SettingsCache::instance().visualDeckStorage().getVisualDeckStorageAlwaysConvert()) {
-            return false;
-        }
-
-        if (!confirmOverwriteIfExists(parent, filePath)) {
-            return false;
-        }
-
-        return convert();
-    }
-
-    // Show the dialog to the user
-    DialogConvertDeckToCodFormat conversionDialog(parent);
-    if (conversionDialog.exec() != QDialog::Accepted) {
-        SettingsCache::instance().visualDeckStorage().setVisualDeckStoragePromptForConversion(
-            !conversionDialog.dontAskAgain());
-        SettingsCache::instance().visualDeckStorage().setVisualDeckStorageAlwaysConvert(false);
-
-        return false;
-    }
-
-    // Try to convert file
-    if (!confirmOverwriteIfExists(parent, filePath)) {
-        return false;
-    }
-
-    if (!convert()) {
-        return false;
-    }
-
-    if (conversionDialog.dontAskAgain()) {
-        SettingsCache::instance().visualDeckStorage().setVisualDeckStoragePromptForConversion(false);
-        SettingsCache::instance().visualDeckStorage().setVisualDeckStorageAlwaysConvert(true);
-    }
-
-    return true;
-}

cockatrice/src/interface/widgets/dialogs/dlg_convert_deck_to_cod_format.h

@@ -13,9 +13,6 @@
 #include <QDialogButtonBox>
 #include <QLabel>
 #include <QVBoxLayout>
-#include <functional>
-
-class QWidget;
 
 class DialogConvertDeckToCodFormat : public QDialog
 {
@@ -27,21 +24,6 @@ public:
 
     [[nodiscard]] bool dontAskAgain() const;
 
-    /**
-     * @brief Checks whether the deck file at \a filePath can store tags.
-     *
-     * If the file is not a .cod deck, prompts the user for conversion to the
-     * Cockatrice format, honoring the saved "always convert / don't ask again"
-     * preference. On acceptance \a convert is called to perform the conversion.
-     *
-     * @param parent The widget to parent the prompt to.
-     * @param filePath The path of the deck file to check.
-     * @param convert Called to convert the deck once the user agrees.
-     * @return true if tags can be stored (no conversion needed, or the conversion
-     *         was performed), false if the user declined to convert.
-     */
-    static bool promptIfRequired(QWidget *parent, const QString &filePath, const std::function<bool()> &convert);
-
 private:
     QVBoxLayout *layout;
     QLabel *label;

cockatrice/src/interface/widgets/server/user/user_info_popup.cpp

@@ -525,13 +525,6 @@ void UserInfoPopup::rebuildActionButtons(const ServerInfo_User &userInfo, bool o
     connect(games, &QPushButton::clicked, this, [this, name] { emit showGamesRequested(name); });
     add(games);
 
-    // ── Invite (only while the inviter has a joinable game for this user) ────
-    if (!isSelf && online && gameInviteAvailable && gameInviteAvailable(name)) {
-        auto *invite = makeBtn(tr("Invite"), tr("Invite to your game"), actionArea, theme);
-        connect(invite, &QPushButton::clicked, this, [this, name] { emit inviteRequested(name); });
-        add(invite);
-    }
-
     // ── Buddy / ignore (registered users only) ────────────────────────────────
     if (!isSelf && isReg) {
         if (isBuddy) {

cockatrice/src/interface/widgets/server/user/user_info_popup.h

@@ -9,7 +9,6 @@
 #include <QMap>
 #include <QPixmap>
 #include <QStandardItemModel>
-#include <functional>
 #include <libcockatrice/network/server/remote/user_level.h>
 #include <libcockatrice/protocol/pb/response.pb.h>
 #include <libcockatrice/protocol/pb/serverinfo_game.pb.h>
@@ -150,17 +149,6 @@ public:
     /** Re-pulls the avatar/card art for the currently shown user (e.g. after it loads). */
     void refreshHeader();
 
-    /**
-     * Sets a predicate evaluated on every action-button rebuild. It receives
-     * the name of the user the popup currently shows; when it returns true an
-     * "Invite" button is shown. The popup itself never resolves the invite
-     * link, it just forwards the request.
-     */
-    void setGameInviteAvailable(std::function<bool(const QString &userName)> available)
-    {
-        gameInviteAvailable = std::move(available);
-    }
-
 signals:
     void mouseEnteredPopup();
     void mouseLeftPopup();
@@ -171,7 +159,6 @@ signals:
 
     // ── Action signals — connect to UserContextMenu::exec*() ──────────────────
     void chatRequested(const QString &userName);
-    void inviteRequested(const QString &userName);
     void detailsRequested(const QString &userName);
     void showGamesRequested(const QString &userName);
     void addBuddyRequested(const QString &userName);
@@ -213,7 +200,6 @@ private:
     QString currentUser;
     ServerInfo_User currentUserInfo;
     bool currentOnline = false;
-    std::function<bool(const QString &userName)> gameInviteAvailable;
 
     UserInfoHeaderWidget *header;
     QWidget *actionArea; ///< rebuilt per user

cockatrice/src/interface/widgets/server/user/user_list_widget.cpp

@@ -345,11 +345,6 @@ UserListWidget::UserListWidget(TabSupervisor *_tabSupervisor,
                                           &cardArtProvider->cache(), &cardArtParamsMap,
                                           window()); // parented to main window so it floats above siblings
 
-        // The invite availability is scoped to the room this list belongs to,
-        // and gated on the room's buddy-only setting for the hovered user.
-        userInfoPopup->setGameInviteAvailable(
-            [this](const QString &userName) { return userContextMenu->hasGameInviteLink(userName); });
-
         userInfoPopup->hide();
         userInfoPopup->setWindowOpacity(0.0);
         userInfoPopup->installEventFilter(this);
@@ -667,8 +662,6 @@ void UserListWidget::connectPopupSignals()
 
     // Wire all action signals to UserContextMenu::exec*()
     connect(userInfoPopup, &UserInfoPopup::chatRequested, userContextMenu, &UserContextMenu::execChat);
-    connect(userInfoPopup, &UserInfoPopup::inviteRequested, this,
-            [this](const QString &userName) { userContextMenu->execInvite(userName); });
     connect(userInfoPopup, &UserInfoPopup::detailsRequested, userContextMenu, &UserContextMenu::execDetails);
     connect(userInfoPopup, &UserInfoPopup::showGamesRequested, userContextMenu, &UserContextMenu::execShowGames);
     connect(userInfoPopup, &UserInfoPopup::addBuddyRequested, userContextMenu, &UserContextMenu::execAddToBuddy);

cockatrice/src/interface/widgets/server/user/user_list_widget.h

@@ -22,7 +22,6 @@
 #include <QTextEdit>
 #include <QTreeWidgetItem>
 #include <functional>
-#include <libcockatrice/network/server/remote/user_level.h>
 #include <libcockatrice/protocol/pb/moderator_commands.pb.h>
 
 class QTreeWidget;

cockatrice/src/interface/widgets/tabs/tab_supervisor.cpp

@@ -1091,8 +1091,7 @@ QList<GameInviteOption> TabSupervisor::getGameInviteLinksForRoom(int roomId) con
     // The inviter may be in several games of the same room (hosting one and
     // spectating another, for example). Return every game so the caller can
     // let the user choose which one to invite to.
-    for (auto it = gameTabs.cbegin(); it != gameTabs.cend(); ++it) {
-        TabGame *tab = it.value();
+    for (TabGame *tab : gameTabs) {
         GameMetaInfo *metaInfo = tab->getGame()->getGameMetaInfo();
         if (metaInfo->proto().room_id() != roomId) {
             continue;

cockatrice/src/interface/widgets/visual_deck_storage/deck_preview/deck_preview_widget.cpp

@@ -10,6 +10,8 @@
 #include "../visual_deck_storage_widget.h"
 #include "deck_preview_deck_tags_display_widget.h"
 
+#include <QDir>
+#include <QFile>
 #include <QFileInfo>
 #include <QInputDialog>
 #include <QLabel>
@@ -497,6 +499,21 @@ void DeckPreviewWidget::actDeleteFile()
     // The folder widget removes this preview once the row is gone.
 }
 
+static bool confirmOverwriteIfExists(QWidget *parent, const QString &filePath)
+{
+    QFileInfo fileInfo(filePath);
+    QString newFileName = QDir::toNativeSeparators(fileInfo.path() + "/" + fileInfo.completeBaseName() + ".cod");
+
+    if (QFile::exists(newFileName)) {
+        QMessageBox::StandardButton reply =
+            QMessageBox::question(parent, QObject::tr("Overwrite Existing File?"),
+                                  QObject::tr("A .cod version of this deck already exists. Overwrite it?"),
+                                  QMessageBox::Yes | QMessageBox::No);
+        return reply == QMessageBox::Yes;
+    }
+    return true; // Safe to proceed
+}
+
 /**
  * Checks if the deck's file format supports tags.
  * If not, then prompt the user for file conversion.
@@ -504,8 +521,45 @@ void DeckPreviewWidget::actDeleteFile()
  */
 bool DeckPreviewWidget::promptFileConversionIfRequired()
 {
-    return DialogConvertDeckToCodFormat::promptIfRequired(this, filePath, [this] {
+    if (DeckFileFormat::getFormatFromName(filePath) == DeckFileFormat::Cockatrice) {
+        return true;
+    }
+
+    // Retrieve saved preference if the prompt is disabled
+    if (!SettingsCache::instance().visualDeckStorage().getVisualDeckStoragePromptForConversion()) {
+        if (!SettingsCache::instance().visualDeckStorage().getVisualDeckStorageAlwaysConvert()) {
+            return false;
+        }
+
+        if (!confirmOverwriteIfExists(this, filePath)) {
+            return false;
+        }
+
         model->convertToCockatriceFormat(row());
         return true;
-    });
+    }
+
+    // Show the dialog to the user
+    DialogConvertDeckToCodFormat conversionDialog(this);
+    if (conversionDialog.exec() != QDialog::Accepted) {
+        SettingsCache::instance().visualDeckStorage().setVisualDeckStoragePromptForConversion(
+            !conversionDialog.dontAskAgain());
+        SettingsCache::instance().visualDeckStorage().setVisualDeckStorageAlwaysConvert(false);
+
+        return false;
+    }
+
+    // Try to convert file
+    if (!confirmOverwriteIfExists(this, filePath)) {
+        return false;
+    }
+
+    model->convertToCockatriceFormat(row());
+
+    if (conversionDialog.dontAskAgain()) {
+        SettingsCache::instance().visualDeckStorage().setVisualDeckStoragePromptForConversion(false);
+        SettingsCache::instance().visualDeckStorage().setVisualDeckStorageAlwaysConvert(true);
+    }
+
+    return true;
 }

format.sh

@@ -22,6 +22,7 @@ libcockatrice_* \
 exclude=("libcockatrice_rng/libcockatrice/rng/sfmt/" \
 "libcockatrice_utility/libcockatrice/utility/peglib.h" \
 "oracle/src/lzma/" \
+"oracle/src/qt-json/" \
 "oracle/src/zip/" \
 "servatrice/src/smtp/")
 exts=("cpp" "h" "proto")

oracle/src/oracleimporter.cpp

@@ -46,10 +46,10 @@ static CardSet::Priority getSetPriority(const QString &setType, const QString &s
 
 bool OracleImporter::readSetsFromByteArray(QByteArray data)
 {
-    RawJson::ScanError error;
-    const QList<RawJson::SetRange> ranges = RawJson::scanSetRanges(data, &error);
-    if (error.isError()) {
-        qDebug() << "error: RawJson::scanSetRanges():" << error.message;
+    QList<RawJson::SetRange> ranges;
+    const RawJson::ScanError scanError = RawJson::scanSetRanges(data, ranges);
+    if (scanError.isError()) {
+        qDebug() << "error: RawJson::scanSetRanges():" << scanError.message;
         return false;
     }
 
@@ -81,7 +81,7 @@ bool OracleImporter::readSetsFromByteArray(QByteArray data)
             setType = setType.trimmed();
         }
         SetToDownload set(shortName, longName, priority, setType, releaseDate);
-        set.setRawRange(range);
+        set.setRawRange(range.start, range.length, range.cardCount);
         newSetList.append(set);
     }
 
@@ -91,7 +91,7 @@ bool OracleImporter::readSetsFromByteArray(QByteArray data)
         return false;
     }
     allSets = newSetList;
-    rawSetsData = data;
+    rawSetsData = std::move(data);
     return true;
 }
 
@@ -221,7 +221,7 @@ CardInfoPtr OracleImporter::addCard(QString name,
     return newCard;
 }
 
-static QString getJsonString(const QJsonObject &obj, const QString &key)
+static inline QString getJsonString(const QJsonObject &obj, const QString &key)
 {
     return obj.value(key).toString();
 }
@@ -465,8 +465,13 @@ int OracleImporter::importCardsFromSet(const CardSetPtr &currentSet, const QJson
     return numCards;
 }
 
-static FormatRulesNameMap buildDefaultMagicFormats()
+FormatRulesNameMap OracleImporter::createDefaultMagicFormats()
 {
+    static FormatRulesNameMap cached;
+    if (!cached.isEmpty()) {
+        return cached;
+    }
+
     // Predefined common exceptions
     CardCondition superTypeIsBasic;
     superTypeIsBasic.field = "type";
@@ -484,7 +489,8 @@ static FormatRulesNameMap buildDefaultMagicFormats()
     ExceptionRule mayContainAnyNumber;
     mayContainAnyNumber.conditions.append(anyNumberAllowed);
 
-    FormatRulesNameMap defaultFormatRulesNameMap;
+    // Map to store default rules
+    FormatRulesNameMap &defaultFormatRulesNameMap = cached;
 
     // ----------------- Helper lambda to create format -----------------
     auto makeFormat = [&](const QString &name, int minDeck = 60, int maxDeck = -1, int maxSideboardSize = 15,
@@ -529,12 +535,6 @@ static FormatRulesNameMap buildDefaultMagicFormats()
     return defaultFormatRulesNameMap;
 }
 
-FormatRulesNameMap OracleImporter::createDefaultMagicFormats()
-{
-    static const FormatRulesNameMap cached = buildDefaultMagicFormats();
-    return cached;
-}
-
 int OracleImporter::startImport()
 {
     static ICardSetPriorityController *noOpController = new NoopCardSetPriorityController();
@@ -542,7 +542,7 @@ int OracleImporter::startImport()
     // Pre-allocate cards hash to avoid rehashing during import
     int estimatedCards = 0;
     for (const SetToDownload &curSetToParse : allSets) {
-        estimatedCards += curSetToParse.getRawRange().cardCount;
+        estimatedCards += curSetToParse.getCardCount();
     }
     cards.reserve(estimatedCards);
 
@@ -563,8 +563,7 @@ int OracleImporter::startImport()
 
         // parse only this set's slice of the raw document so the whole JSON tree is
         // never kept in memory at once
-        const RawJson::SetRange &rawRange = curSetToParse.getRawRange();
-        const QByteArray setBytes(rawSetsData.constData() + rawRange.start, rawRange.length);
+        const QByteArray setBytes(rawSetsData.constData() + curSetToParse.getRawStart(), curSetToParse.getRawLength());
         QJsonParseError parseError;
         const QJsonDocument setDoc = QJsonDocument::fromJson(setBytes, &parseError);
         if (parseError.error != QJsonParseError::NoError) {
@@ -607,4 +606,6 @@ void OracleImporter::clear()
     cards.clear();
     allSets.clear();
     rawSetsData.clear();
+    // Note: createDefaultMagicFormats() uses a function-local static cache that is
+    // intentionally not cleared here since format rules are hardcoded constants.
 }

oracle/src/oracleimporter.h

@@ -54,7 +54,9 @@ private:
     CardSet::Priority priority;
     // Byte range of this set's object within the importer's raw JSON text. Parsing
     // one set at a time keeps peak memory low instead of holding the whole document.
-    RawJson::SetRange rawRange;
+    qsizetype rawStart = -1;
+    qsizetype rawLength = 0;
+    int cardCount = 0;
 
 public:
     const QString &getShortName() const
@@ -77,9 +79,17 @@ public:
     {
         return priority;
     }
-    const RawJson::SetRange &getRawRange() const
+    qsizetype getRawStart() const
     {
-        return rawRange;
+        return rawStart;
+    }
+    qsizetype getRawLength() const
+    {
+        return rawLength;
+    }
+    int getCardCount() const
+    {
+        return cardCount;
     }
     SetToDownload(QString _shortName,
                   QString _longName,
@@ -90,9 +100,11 @@ public:
           setType(std::move(_setType)), priority(_priority)
     {
     }
-    void setRawRange(const RawJson::SetRange &_rawRange)
+    void setRawRange(qsizetype _rawStart, qsizetype _rawLength, int _cardCount)
     {
-        rawRange = _rawRange;
+        rawStart = _rawStart;
+        rawLength = _rawLength;
+        cardCount = _cardCount;
     }
     bool operator<(const SetToDownload &set) const
     {

oracle/src/qt-json/AUTHORS

@@ -0,0 +1,3 @@
+Eeli Reilin <eeli@emicode.fi>
+Luis Gustavo S. Barreto <gustavosbarreto@gmail.com>
+Stephen Kockentiedt <Stephen@Kockentiedt.name>

oracle/src/qt-json/LICENSE

@@ -0,0 +1,27 @@
+Copyright 2011 Eeli Reilin. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+   1. Redistributions of source code must retain the above copyright notice, 
+      this list of conditions and the following disclaimer.
+
+   2. Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimer in the documentation 
+      and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ''AS IS'' AND ANY EXPRESS OR 
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 
+EVENT SHALL EELI REILIN OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+The views and conclusions contained in the software and documentation 
+are those of the authors and should not be interpreted as representing 
+official policies, either expressed or implied, of Eeli Reilin.
+

oracle/src/qt-json/README

@@ -0,0 +1,96 @@
+########################################################################
+1. INTRODUCTION
+
+The Json class is a simple class for parsing JSON data into a QVariant 
+hierarchies. Now, we can also reverse the process and serialize
+QVariant hierarchies into valid JSON data.
+
+
+########################################################################
+2. HOW TO USE
+
+The parser is really easy to use. Let's say we have the following 
+QString of JSON data:
+
+------------------------------------------------------------------------
+{
+   "encoding" : "UTF-8",
+   "plug-ins" : [
+      "python",
+      "c++",
+      "ruby"
+   ],
+   "indent" : {
+      "length" : 3,
+      "use_space" : true
+   }
+}
+------------------------------------------------------------------------
+
+We would first call the parse-method:
+
+------------------------------------------------------------------------
+//Say that we're using the QtJson namespace
+using namespace QtJson;
+bool ok;
+//json is a QString containing the JSON data
+QVariantMap result = Json::parse(json, ok).toMap();
+
+if(!ok) {
+    qFatal("An error occurred during parsing");
+    exit(1);
+}
+------------------------------------------------------------------------
+
+Assuming the parsing process completed without errors, we would then
+go through the hierarchy:
+
+------------------------------------------------------------------------
+qDebug() << "encoding:" << result["encoding"].toString();
+qDebug() << "plugins:";
+
+foreach(QVariant plugin, result["plug-ins"].toList()) {
+    qDebug() << "\t-" << plugin.toString();
+}
+
+QVariantMap nestedMap = result["indent"].toMap();
+qDebug() << "length:" << nestedMap["length"].toInt();
+qDebug() << "use_space:" << nestedMap["use_space"].toBool();
+------------------------------------------------------------------------
+
+The previous code would print out the following:
+
+------------------------------------------------------------------------
+encoding: "UTF-8"
+plugins:
+  - "python"
+  - "c++"
+  - "ruby"
+length: 3
+use_space: true
+------------------------------------------------------------------------
+
+To write JSON data from Qt object is as simple as parsing:
+
+------------------------------------------------------------------------
+QVariantMap map;
+map["name"] = "Name";
+map["age"] = 22;
+
+QByteArray data = Json::serialize(map);
+------------------------------------------------------------------------
+
+The byte array 'data' contains valid JSON data:
+
+------------------------------------------------------------------------
+{
+        name: "Luis Gustavo",
+        age: 22,
+}
+------------------------------------------------------------------------
+
+
+########################################################################
+4. CONTRIBUTING
+
+The code is available to download at GitHub. Contribute if you dare!

oracle/src/raw_json_scanner.cpp

@@ -468,29 +468,19 @@ int countArrayElements(const char *p, const char *end)
 namespace RawJson
 {
 
-QList<SetRange> scanSetRanges(const QByteArray &json, ScanError *error)
+ScanError scanSetRanges(const QByteArray &json, QList<SetRange> &ranges)
 {
-    QList<SetRange> ranges;
-    if (error) {
-        *error = ScanError{};
-    }
-
-    const auto fail = [&](const QString &message) -> QList<SetRange> {
-        if (error) {
-            error->message = message;
-        }
-        return {};
-    };
+    ranges.clear();
 
     const char *begin = json.constData();
     const char *end = begin + json.size();
     if (begin >= end) {
-        return fail(QStringLiteral("empty JSON document"));
+        return ScanError{"empty JSON document"};
     }
 
     const char *p = skipWhitespace(begin, end);
     if (p >= end || *p != '{') {
-        return fail(QStringLiteral("top-level JSON must be an object"));
+        return ScanError{"top-level JSON must be an object"};
     }
 
     bool foundData = false;
@@ -555,19 +545,19 @@ QList<SetRange> scanSetRanges(const QByteArray &json, ScanError *error)
     };
 
     if (!forEachObjectMember(p, end, topLevelCallback)) {
-        return fail(malformedSetData ? QStringLiteral("malformed set data") : QStringLiteral("malformed JSON"));
+        return ScanError{malformedSetData ? QStringLiteral("malformed set data") : QStringLiteral("malformed JSON")};
     }
     p = skipWhitespace(p, end);
     if (p != end) {
-        return fail(QStringLiteral("trailing content after top-level JSON object"));
+        return ScanError{"trailing content after top-level JSON object"};
     }
     if (!foundData) {
-        return fail(QStringLiteral("missing \"data\" object"));
+        return ScanError{"missing \"data\" object"};
     }
     if (ranges.isEmpty()) {
-        return fail(QStringLiteral("no sets found in \"data\""));
+        return ScanError{"no sets found in \"data\""};
     }
-    return ranges;
+    return ScanError{};
 }
 
 } // namespace RawJson

oracle/src/raw_json_scanner.h

@@ -42,18 +42,8 @@ struct ScanError
  * The whole document is structurally validated while scanning (strings,
  * escapes, braces, and a trailing-content check), so malformed input is
  * rejected just like QJsonDocument::fromJson would.
- *
- * Following QJsonDocument::fromJson's convention, the parsed ranges are
- * returned by value and any failure is reported through the @p error out
- * parameter.
- *
- * @param json The raw MTGJSON document bytes.
- * @param error Out parameter. Set to an error ScanError when the document
- *              cannot be parsed, otherwise left empty. Passing a null
- *              pointer disables error reporting.
- * @return The detected per-set ranges, or an empty list on failure.
  */
-QList<SetRange> scanSetRanges(const QByteArray &json, ScanError *error = nullptr);
+ScanError scanSetRanges(const QByteArray &json, QList<SetRange> &ranges);
 
 } // namespace RawJson
 

tests/oracle/oracle_importer_test.cpp

@@ -502,8 +502,8 @@ TEST_F(OracleImporterTest, ScanSetRangesMatchFullJsonParse)
 
     const QByteArray bytes = QJsonDocument(root).toJson(QJsonDocument::Compact);
 
-    RawJson::ScanError error;
-    const QList<RawJson::SetRange> ranges = RawJson::scanSetRanges(bytes, &error);
+    QList<RawJson::SetRange> ranges;
+    const RawJson::ScanError error = RawJson::scanSetRanges(bytes, ranges);
     ASSERT_FALSE(error.isError()) << error.message.toStdString();
     ASSERT_EQ(ranges.size(), 2);
 
@@ -524,9 +524,8 @@ TEST_F(OracleImporterTest, ScanSetRangesDecodesEscapesAndCountsCards)
                             "\"type\":\"expansion\",\"releaseDate\":\"2024-01-05\","
                             "\"cards\":[{\"name\":\"a\"},{\"name\":\"b\"},{\"name\":\"c\"}]}}}";
 
-    RawJson::ScanError error;
-    const QList<RawJson::SetRange> ranges = RawJson::scanSetRanges(json, &error);
-    ASSERT_FALSE(error.isError());
+    QList<RawJson::SetRange> ranges;
+    ASSERT_FALSE(RawJson::scanSetRanges(json, ranges).isError());
     ASSERT_EQ(ranges.size(), 1);
 
     const RawJson::SetRange &range = ranges.first();
@@ -559,8 +558,8 @@ TEST_F(OracleImporterTest, ScanSetRangesRejectsInvalidJson)
                                        "{\"data\":{\"A\":{\"cards\":[{\"name\":\"\\ud800\"}]}}}"};
 
     for (const QByteArray &json : invalid) {
-        RawJson::ScanError error;
-        RawJson::scanSetRanges(json, &error);
+        QList<RawJson::SetRange> ranges;
+        const RawJson::ScanError error = RawJson::scanSetRanges(json, ranges);
         EXPECT_TRUE(error.isError()) << "expected failure for: " << json.constData();
     }
 }