diff options
Diffstat (limited to 'examples/corelib/serialization/savegame')
| -rw-r--r-- | examples/corelib/serialization/savegame/CMakeLists.txt | 30 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/character.cpp | 53 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/character.h | 19 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/doc/src/savegame.qdoc | 154 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/game.cpp | 130 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/game.h | 15 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/level.cpp | 55 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/level.h | 13 | ||||
| -rw-r--r-- | examples/corelib/serialization/savegame/main.cpp | 27 |
9 files changed, 275 insertions, 221 deletions
diff --git a/examples/corelib/serialization/savegame/CMakeLists.txt b/examples/corelib/serialization/savegame/CMakeLists.txt index f757d1359b..14621ccc23 100644 --- a/examples/corelib/serialization/savegame/CMakeLists.txt +++ b/examples/corelib/serialization/savegame/CMakeLists.txt @@ -1,16 +1,17 @@ +# Copyright (C) 2022 The Qt Company Ltd. +# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause + cmake_minimum_required(VERSION 3.16) project(savegame LANGUAGES CXX) -set(CMAKE_AUTOMOC ON) - -if(NOT DEFINED INSTALL_EXAMPLESDIR) - set(INSTALL_EXAMPLESDIR "examples") +if (ANDROID) + message(FATAL_ERROR "This project cannot be built on Android.") endif() -set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/corelib/serialization/savegame") - find_package(Qt6 REQUIRED COMPONENTS Core) +qt_standard_project_setup() + qt_add_executable(savegame character.cpp character.h game.cpp game.h @@ -18,12 +19,19 @@ qt_add_executable(savegame main.cpp ) -target_link_libraries(savegame PUBLIC - Qt::Core +target_link_libraries(savegame PRIVATE + Qt6::Core ) install(TARGETS savegame - RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}" - BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}" - LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}" + BUNDLE DESTINATION . + RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} + LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} +) + +qt_generate_deploy_app_script( + TARGET savegame + OUTPUT_SCRIPT deploy_script + NO_UNSUPPORTED_PLATFORM_ERROR ) +install(SCRIPT ${deploy_script}) diff --git a/examples/corelib/serialization/savegame/character.cpp b/examples/corelib/serialization/savegame/character.cpp index 43be084d3e..863fcb9153 100644 --- a/examples/corelib/serialization/savegame/character.cpp +++ b/examples/corelib/serialization/savegame/character.cpp @@ -6,17 +6,10 @@ #include <QMetaEnum> #include <QTextStream> -Character::Character() : - mLevel(0), - mClassType(Warrior) { -} +Character::Character() = default; -Character::Character(const QString &name, - int level, - Character::ClassType classType) : - mName(name), - mLevel(level), - mClassType(classType) +Character::Character(const QString &name, int level, Character::ClassType classType) + : mName(name), mLevel(level), mClassType(classType) { } @@ -50,35 +43,41 @@ void Character::setClassType(Character::ClassType classType) mClassType = classType; } -//! [0] -void Character::read(const QJsonObject &json) +//! [fromJson] +Character Character::fromJson(const QJsonObject &json) { - if (json.contains("name") && json["name"].isString()) - mName = json["name"].toString(); + Character result; + + if (const QJsonValue v = json["name"]; v.isString()) + result.mName = v.toString(); + + if (const QJsonValue v = json["level"]; v.isDouble()) + result.mLevel = v.toInt(); - if (json.contains("level") && json["level"].isDouble()) - mLevel = json["level"].toInt(); + if (const QJsonValue v = json["classType"]; v.isDouble()) + result.mClassType = ClassType(v.toInt()); - if (json.contains("classType") && json["classType"].isDouble()) - mClassType = ClassType(json["classType"].toInt()); + return result; } -//! [0] +//! [fromJson] -//! [1] -void Character::write(QJsonObject &json) const +//! [toJson] +QJsonObject Character::toJson() const { + QJsonObject json; json["name"] = mName; json["level"] = mLevel; json["classType"] = mClassType; + return json; } -//! [1] +//! [toJson] -void Character::print(int indentation) const +void Character::print(QTextStream &s, int indentation) const { const QString indent(indentation * 2, ' '); - QTextStream(stdout) << indent << "Name:\t" << mName << "\n"; - QTextStream(stdout) << indent << "Level:\t" << mLevel << "\n"; + const QString className = QMetaEnum::fromType<ClassType>().valueToKey(mClassType); - QString className = QMetaEnum::fromType<ClassType>().valueToKey(mClassType); - QTextStream(stdout) << indent << "Class:\t" << className << "\n"; + s << indent << "Name:\t" << mName << "\n" + << indent << "Level:\t" << mLevel << "\n" + << indent << "Class:\t" << className << "\n"; } diff --git a/examples/corelib/serialization/savegame/character.h b/examples/corelib/serialization/savegame/character.h index dfb3837331..0504750320 100644 --- a/examples/corelib/serialization/savegame/character.h +++ b/examples/corelib/serialization/savegame/character.h @@ -8,15 +8,15 @@ #include <QObject> #include <QString> +QT_FORWARD_DECLARE_CLASS(QTextStream) + //! [0] class Character { - Q_GADGET; + Q_GADGET public: - enum ClassType { - Warrior, Mage, Archer - }; + enum ClassType { Warrior, Mage, Archer }; Q_ENUM(ClassType) Character(); @@ -31,14 +31,15 @@ public: ClassType classType() const; void setClassType(ClassType classType); - void read(const QJsonObject &json); - void write(QJsonObject &json) const; + static Character fromJson(const QJsonObject &json); + QJsonObject toJson() const; + + void print(QTextStream &s, int indentation = 0) const; - void print(int indentation = 0) const; private: QString mName; - int mLevel; - ClassType mClassType; + int mLevel = 0; + ClassType mClassType = Warrior; }; //! [0] diff --git a/examples/corelib/serialization/savegame/doc/src/savegame.qdoc b/examples/corelib/serialization/savegame/doc/src/savegame.qdoc index 0246ae48bb..46fca15b62 100644 --- a/examples/corelib/serialization/savegame/doc/src/savegame.qdoc +++ b/examples/corelib/serialization/savegame/doc/src/savegame.qdoc @@ -3,18 +3,19 @@ /*! \example serialization/savegame - \title JSON Save Game Example + \examplecategory {Data Processing & I/O} + \title Saving and Loading a Game - \brief The JSON Save Game example demonstrates how to save and load a - small game using QJsonDocument, QJsonObject and QJsonArray. + \brief How to save and load a game using Qt's JSON or CBOR classes. Many games provide save functionality, so that the player's progress through the game can be saved and loaded at a later time. The process of saving a - game generally involves serializing each game object's member variables - to a file. Many formats can be used for this purpose, one of which is JSON. - With QJsonDocument, you also have the ability to serialize a document in a - \l {RFC 7049} {CBOR} format, which is great if you - don't want the save file to be readable, or if you need to keep the file size down. + game generally involves serializing each game object's member variables to a + file. Many formats can be used for this purpose, one of which is JSON. With + QJsonDocument, you also have the ability to serialize a document in a \l + {RFC 7049} {CBOR} format, which is great if you don't want the save file to + be easy to read (but see \l {Parsing and displaying CBOR data} for how it \e + can be read), or if you need to keep the file size down. In this example, we'll demonstrate how to save and load a simple game to and from JSON and binary formats. @@ -24,45 +25,83 @@ The Character class represents a non-player character (NPC) in our game, and stores the player's name, level, and class type. - It provides read() and write() functions to serialise its member variables. + It provides static fromJson() and non-static toJson() functions to + serialise itself. + + \note This pattern (fromJson()/toJson()) works because QJsonObjects can be + constructed independent of an owning QJsonDocument, and because the data + types being (de)serialized here are value types, so can be copied. When + serializing to another format — for example XML or QDataStream, which require passing + a document-like object — or when the object identity is important (QObject + subclasses, for example), other patterns may be more suitable. See the + \l{dombookmarks} example for XML, and the implementation of + \l QListWidgetItem::read() and \l QListWidgetItem::write() + for idiomatic QDataStream serialization. The \c{print()} functions in this example + are good examples of QTextStream serialization, even though they, of course, lack + the deserialization side. \snippet serialization/savegame/character.h 0 - Of particular interest to us are the read and write function + Of particular interest to us are the fromJson() and toJson() function implementations: - \snippet serialization/savegame/character.cpp 0 + \snippet serialization/savegame/character.cpp fromJson - In the read() function, we assign Character's members values from the - QJsonObject argument. You can use either \l QJsonObject::operator[]() or - QJsonObject::value() to access values within the JSON object; both are - const functions and return QJsonValue::Undefined if the key is invalid. We - check if the keys are valid before attempting to read them with - QJsonObject::contains(). + In the fromJson() function, we construct a local \c result Character object + and assign \c{result}'s members values from the QJsonObject argument. You + can use either \l QJsonObject::operator[]() or QJsonObject::value() to + access values within the JSON object; both are const functions and return + QJsonValue::Undefined if the key is invalid. In particular, the \c{is...} + functions (for example \l QJsonValue::isString(), \l + QJsonValue::isDouble()) return \c false for QJsonValue::Undefined, so we + can check for existence as well as the correct type in a single lookup. - \snippet serialization/savegame/character.cpp 1 + If a value does not exist in the JSON object, or has the wrong type, we + don't write to the corresponding \c result member, either, thereby + preserving any values the default constructor may have set. This means + default values are centrally defined in one location (the default + constructor) and need not be repeated in serialisation code + (\l{https://en.wikipedia.org/wiki/Don%27t_repeat_yourself}{DRY}). - In the write() function, we do the reverse of the read() function; assign - values from the Character object to the JSON object. As with accessing - values, there are two ways to set values on a QJsonObject: - \l QJsonObject::operator[]() and QJsonObject::insert(). Both will override - any existing value at the given key. + Observe the use of + \l{https://en.cppreference.com/w/cpp/language/if#If_statements_with_initializer} + {C++17 if-with-initializer} to separate scoping and checking of the variable \c v. + This means we can keep the variable name short, because its scope is limited. - Next up is the Level class: + Compare that to the naïve approach using \c QJsonObject::contains(): + + \badcode + if (json.contains("name") && json["name"].isString()) + result.mName = json["name"].toString(); + \endcode + + which, beside being less readable, requires a total of three lookups (no, + the compiler will \e not optimize these into one), so is three times + slower and repeats \c{"name"} three times (violating the DRY principle). + + \snippet serialization/savegame/character.cpp toJson + + In the toJson() function, we do the reverse of the fromJson() function; + assign values from the Character object to a new JSON object we then + return. As with accessing values, there are two ways to set values on a + QJsonObject: \l QJsonObject::operator[]() and \l QJsonObject::insert(). + Both will override any existing value at the given key. + + \section1 The Level Class \snippet serialization/savegame/level.h 0 - We want to have several levels in our game, each with several NPCs, so we - keep a QList of Character objects. We also provide the familiar read() and - write() functions. + We want the levels in our game to each each have several NPCs, so we keep a QList + of Character objects. We also provide the familiar fromJson() and toJson() + functions. - \snippet serialization/savegame/level.cpp 0 + \snippet serialization/savegame/level.cpp fromJson - Containers can be written and read to and from JSON using QJsonArray. In our + Containers can be written to and read from JSON using QJsonArray. In our case, we construct a QJsonArray from the value associated with the key \c "npcs". Then, for each QJsonValue element in the array, we call - toObject() to get the Character's JSON object. The Character object can then - read their JSON and be appended to our NPC array. + toObject() to get the Character's JSON object. Character::fromJson() can + then turn that QJSonObject into a Character object to append to our NPC array. \note \l{Container Classes}{Associate containers} can be written by storing the key in each value object (if it's not already). With this approach, the @@ -70,11 +109,13 @@ element is used as the key to construct the container when reading it back in. - \snippet serialization/savegame/level.cpp 1 + \snippet serialization/savegame/level.cpp toJson - Again, the write() function is similar to the read() function, except + Again, the toJson() function is similar to the fromJson() function, except reversed. + \section1 The Game Class + Having established the Character and Level classes, we can move on to the Game class: @@ -86,26 +127,43 @@ Next, we provide accessors for the player and levels. We then expose three functions: newGame(), saveGame() and loadGame(). - The read() and write() functions are used by saveGame() and loadGame(). + The read() and toJson() functions are used by saveGame() and loadGame(). + + \div{class="admonition note"}\b{Note:} + Despite \c Game being a value class, we assume that the author wants a game to have + identity, much like your main window would have. We therefore don't use a + static fromJson() function, which would create a new object, but a read() + function we can call on existing objects. There's a 1:1 correspondence + between read() and fromJson(), in that one can be implemented in terms of + the other: + + \code + void read(const QJsonObject &json) { *this = fromJson(json); } + static Game fromObject(const QJsonObject &json) { Game g; g.read(json); return g; } + \endcode - \snippet serialization/savegame/game.cpp 0 + We just use what's more convenient for callers of the functions. + \enddiv + + \snippet serialization/savegame/game.cpp newGame To setup a new game, we create the player and populate the levels and their NPCs. - \snippet serialization/savegame/game.cpp 1 + \snippet serialization/savegame/game.cpp read - The first thing we do in the read() function is tell the player to read - itself. We then clear the level array so that calling loadGame() on the - same Game object twice doesn't result in old levels hanging around. + The read() function starts by replacing the player with the + one read from JSON. We then clear() the level array so that calling + loadGame() on the same Game object twice doesn't result in old levels + hanging around. We then populate the level array by reading each Level from a QJsonArray. - \snippet serialization/savegame/game.cpp 2 + \snippet serialization/savegame/game.cpp toJson - We write the game to JSON similarly to how we write Level. + Writing the game to JSON is similar to writing a level. - \snippet serialization/savegame/game.cpp 3 + \snippet serialization/savegame/game.cpp loadGame When loading a saved game in loadGame(), the first thing we do is open the save file based on which format it was saved to; \c "save.json" for JSON, @@ -119,14 +177,16 @@ After constructing the QJsonDocument, we instruct the Game object to read itself and then return \c true to indicate success. - \snippet serialization/savegame/game.cpp 4 + \snippet serialization/savegame/game.cpp saveGame Not surprisingly, saveGame() looks very much like loadGame(). We determine the file extension based on the format, print a warning and return \c false if the opening of the file fails. We then write the Game object to a - QJsonDocument, and call either QJsonDocument::toJson() or to - QJsonDocument::toBinaryData() to save the game, depending on which format - was specified. + QJsonObject. To save the game in the format that was specified, we + convert the JSON object into either a QJsonDocument for a subsequent + QJsonDocument::toJson() call, or a QCborValue for QCborValue::toCbor(). + + \section1 Tying It All Together We are now ready to enter main(): @@ -158,5 +218,5 @@ human-readable JSON files, but you also have the option to use a binary format if it's required, \e without rewriting any code. - \sa {JSON Support in Qt}, {Data Storage} + \sa {JSON Support in Qt}, {CBOR Support in Qt}, {Data Input Output} */ diff --git a/examples/corelib/serialization/savegame/game.cpp b/examples/corelib/serialization/savegame/game.cpp index 111fbfc6ea..f99ecb8b51 100644 --- a/examples/corelib/serialization/savegame/game.cpp +++ b/examples/corelib/serialization/savegame/game.cpp @@ -11,6 +11,8 @@ #include <QRandomGenerator> #include <QTextStream> +using namespace Qt::StringLiterals; + Character Game::player() const { return mPlayer; @@ -21,52 +23,45 @@ QList<Level> Game::levels() const return mLevels; } -//! [0] +//! [newGame] void Game::newGame() { mPlayer = Character(); - mPlayer.setName(QStringLiteral("Hero")); + mPlayer.setName("Hero"_L1); mPlayer.setClassType(Character::Archer); mPlayer.setLevel(QRandomGenerator::global()->bounded(15, 21)); mLevels.clear(); mLevels.reserve(2); - Level village(QStringLiteral("Village")); + Level village("Village"_L1); QList<Character> villageNpcs; villageNpcs.reserve(2); - villageNpcs.append(Character(QStringLiteral("Barry the Blacksmith"), - QRandomGenerator::global()->bounded(8, 11), - Character::Warrior)); - villageNpcs.append(Character(QStringLiteral("Terry the Trader"), - QRandomGenerator::global()->bounded(6, 8), - Character::Warrior)); + villageNpcs.append(Character("Barry the Blacksmith"_L1, + QRandomGenerator::global()->bounded(8, 11), Character::Warrior)); + villageNpcs.append(Character("Terry the Trader"_L1, + QRandomGenerator::global()->bounded(6, 8), Character::Warrior)); village.setNpcs(villageNpcs); mLevels.append(village); - Level dungeon(QStringLiteral("Dungeon")); + Level dungeon("Dungeon"_L1); QList<Character> dungeonNpcs; dungeonNpcs.reserve(3); - dungeonNpcs.append(Character(QStringLiteral("Eric the Evil"), - QRandomGenerator::global()->bounded(18, 26), - Character::Mage)); - dungeonNpcs.append(Character(QStringLiteral("Eric's Left Minion"), - QRandomGenerator::global()->bounded(5, 7), - Character::Warrior)); - dungeonNpcs.append(Character(QStringLiteral("Eric's Right Minion"), - QRandomGenerator::global()->bounded(4, 9), - Character::Warrior)); + dungeonNpcs.append(Character("Eric the Evil"_L1, + QRandomGenerator::global()->bounded(18, 26), Character::Mage)); + dungeonNpcs.append(Character("Eric's Left Minion"_L1, + QRandomGenerator::global()->bounded(5, 7), Character::Warrior)); + dungeonNpcs.append(Character("Eric's Right Minion"_L1, + QRandomGenerator::global()->bounded(4, 9), Character::Warrior)); dungeon.setNpcs(dungeonNpcs); mLevels.append(dungeon); } -//! [0] +//! [newGame] -//! [3] +//! [loadGame] bool Game::loadGame(Game::SaveFormat saveFormat) { - QFile loadFile(saveFormat == Json - ? QStringLiteral("save.json") - : QStringLiteral("save.dat")); + QFile loadFile(saveFormat == Json ? "save.json"_L1 : "save.dat"_L1); if (!loadFile.open(QIODevice::ReadOnly)) { qWarning("Couldn't open save file."); @@ -76,85 +71,72 @@ bool Game::loadGame(Game::SaveFormat saveFormat) QByteArray saveData = loadFile.readAll(); QJsonDocument loadDoc(saveFormat == Json - ? QJsonDocument::fromJson(saveData) - : QJsonDocument(QCborValue::fromCbor(saveData).toMap().toJsonObject())); + ? QJsonDocument::fromJson(saveData) + : QJsonDocument(QCborValue::fromCbor(saveData).toMap().toJsonObject())); read(loadDoc.object()); - QTextStream(stdout) << "Loaded save for " - << loadDoc["player"]["name"].toString() - << " using " - << (saveFormat != Json ? "CBOR" : "JSON") << "...\n"; + QTextStream(stdout) << "Loaded save for " << loadDoc["player"]["name"].toString() + << " using " << (saveFormat != Json ? "CBOR" : "JSON") << "...\n"; return true; } -//! [3] +//! [loadGame] -//! [4] +//! [saveGame] bool Game::saveGame(Game::SaveFormat saveFormat) const { - QFile saveFile(saveFormat == Json - ? QStringLiteral("save.json") - : QStringLiteral("save.dat")); + QFile saveFile(saveFormat == Json ? "save.json"_L1 : "save.dat"_L1); if (!saveFile.open(QIODevice::WriteOnly)) { qWarning("Couldn't open save file."); return false; } - QJsonObject gameObject; - write(gameObject); - saveFile.write(saveFormat == Json - ? QJsonDocument(gameObject).toJson() - : QCborValue::fromJsonValue(gameObject).toCbor()); + QJsonObject gameObject = toJson(); + saveFile.write(saveFormat == Json ? QJsonDocument(gameObject).toJson() + : QCborValue::fromJsonValue(gameObject).toCbor()); return true; } -//! [4] +//! [saveGame] -//! [1] +//! [read] void Game::read(const QJsonObject &json) { - if (json.contains("player") && json["player"].isObject()) - mPlayer.read(json["player"].toObject()); + if (const QJsonValue v = json["player"]; v.isObject()) + mPlayer = Character::fromJson(v.toObject()); - if (json.contains("levels") && json["levels"].isArray()) { - QJsonArray levelArray = json["levels"].toArray(); + if (const QJsonValue v = json["levels"]; v.isArray()) { + const QJsonArray levels = v.toArray(); mLevels.clear(); - mLevels.reserve(levelArray.size()); - for (int levelIndex = 0; levelIndex < levelArray.size(); ++levelIndex) { - QJsonObject levelObject = levelArray[levelIndex].toObject(); - Level level; - level.read(levelObject); - mLevels.append(level); - } + mLevels.reserve(levels.size()); + for (const QJsonValue &level : levels) + mLevels.append(Level::fromJson(level.toObject())); } } -//! [1] +//! [read] -//! [2] -void Game::write(QJsonObject &json) const +//! [toJson] +QJsonObject Game::toJson() const { - QJsonObject playerObject; - mPlayer.write(playerObject); - json["player"] = playerObject; - - QJsonArray levelArray; - for (const Level &level : mLevels) { - QJsonObject levelObject; - level.write(levelObject); - levelArray.append(levelObject); - } - json["levels"] = levelArray; + QJsonObject json; + json["player"] = mPlayer.toJson(); + + QJsonArray levels; + for (const Level &level : mLevels) + levels.append(level.toJson()); + json["levels"] = levels; + return json; } -//! [2] +//! [toJson] -void Game::print(int indentation) const +void Game::print(QTextStream &s, int indentation) const { const QString indent(indentation * 2, ' '); - QTextStream(stdout) << indent << "Player\n"; - mPlayer.print(indentation + 1); + s << indent << "Player\n"; + mPlayer.print(s, indentation + 1); - QTextStream(stdout) << indent << "Levels\n"; - for (Level level : mLevels) - level.print(indentation + 1); + s << indent << "Levels\n"; + for (const Level &level : mLevels) + level.print(s, indentation + 1); } diff --git a/examples/corelib/serialization/savegame/game.h b/examples/corelib/serialization/savegame/game.h index 266e764a80..5ba5952923 100644 --- a/examples/corelib/serialization/savegame/game.h +++ b/examples/corelib/serialization/savegame/game.h @@ -4,19 +4,19 @@ #ifndef GAME_H #define GAME_H +#include "character.h" +#include "level.h" + #include <QJsonObject> #include <QList> -#include "character.h" -#include "level.h" +QT_FORWARD_DECLARE_CLASS(QTextStream) //! [0] class Game { public: - enum SaveFormat { - Json, Binary - }; + enum SaveFormat { Json, Binary }; Character player() const; QList<Level> levels() const; @@ -26,9 +26,10 @@ public: bool saveGame(SaveFormat saveFormat) const; void read(const QJsonObject &json); - void write(QJsonObject &json) const; + QJsonObject toJson() const; + + void print(QTextStream &s, int indentation = 0) const; - void print(int indentation = 0) const; private: Character mPlayer; QList<Level> mLevels; diff --git a/examples/corelib/serialization/savegame/level.cpp b/examples/corelib/serialization/savegame/level.cpp index 04edadf7f6..f30d35e57f 100644 --- a/examples/corelib/serialization/savegame/level.cpp +++ b/examples/corelib/serialization/savegame/level.cpp @@ -6,9 +6,7 @@ #include <QJsonArray> #include <QTextStream> -Level::Level(const QString &name) : mName(name) -{ -} +Level::Level(const QString &name) : mName(name) { } QString Level::name() const { @@ -25,46 +23,43 @@ void Level::setNpcs(const QList<Character> &npcs) mNpcs = npcs; } -//! [0] -void Level::read(const QJsonObject &json) +//! [fromJson] +Level Level::fromJson(const QJsonObject &json) { - if (json.contains("name") && json["name"].isString()) - mName = json["name"].toString(); + Level result; + + if (const QJsonValue v = json["name"]; v.isString()) + result.mName = v.toString(); - if (json.contains("npcs") && json["npcs"].isArray()) { - QJsonArray npcArray = json["npcs"].toArray(); - mNpcs.clear(); - mNpcs.reserve(npcArray.size()); - for (int npcIndex = 0; npcIndex < npcArray.size(); ++npcIndex) { - QJsonObject npcObject = npcArray[npcIndex].toObject(); - Character npc; - npc.read(npcObject); - mNpcs.append(npc); - } + if (const QJsonValue v = json["npcs"]; v.isArray()) { + const QJsonArray npcs = v.toArray(); + result.mNpcs.reserve(npcs.size()); + for (const QJsonValue &npc : npcs) + result.mNpcs.append(Character::fromJson(npc.toObject())); } + + return result; } -//! [0] +//! [fromJson] -//! [1] -void Level::write(QJsonObject &json) const +//! [toJson] +QJsonObject Level::toJson() const { + QJsonObject json; json["name"] = mName; QJsonArray npcArray; - for (const Character &npc : mNpcs) { - QJsonObject npcObject; - npc.write(npcObject); - npcArray.append(npcObject); - } + for (const Character &npc : mNpcs) + npcArray.append(npc.toJson()); json["npcs"] = npcArray; + return json; } -//! [1] +//! [toJson] -void Level::print(int indentation) const +void Level::print(QTextStream &s, int indentation) const { const QString indent(indentation * 2, ' '); - QTextStream(stdout) << indent << "Name:\t" << mName << "\n"; - QTextStream(stdout) << indent << "NPCs:\n"; + s << indent << "Name:\t" << mName << "\n" << indent << "NPCs:\n"; for (const Character &character : mNpcs) - character.print(2); + character.print(s, indentation + 1); } diff --git a/examples/corelib/serialization/savegame/level.h b/examples/corelib/serialization/savegame/level.h index 4c0a8aed89..e487e55ae3 100644 --- a/examples/corelib/serialization/savegame/level.h +++ b/examples/corelib/serialization/savegame/level.h @@ -4,27 +4,30 @@ #ifndef LEVEL_H #define LEVEL_H +#include "character.h" + #include <QJsonObject> #include <QList> -#include "character.h" +QT_FORWARD_DECLARE_CLASS(QTextStream) //! [0] class Level { public: Level() = default; - Level(const QString &name); + explicit Level(const QString &name); QString name() const; QList<Character> npcs() const; void setNpcs(const QList<Character> &npcs); - void read(const QJsonObject &json); - void write(QJsonObject &json) const; + static Level fromJson(const QJsonObject &json); + QJsonObject toJson() const; + + void print(QTextStream &s, int indentation = 0) const; - void print(int indentation = 0) const; private: QString mName; QList<Character> mNpcs; diff --git a/examples/corelib/serialization/savegame/main.cpp b/examples/corelib/serialization/savegame/main.cpp index c9e713c126..3fc0f3af10 100644 --- a/examples/corelib/serialization/savegame/main.cpp +++ b/examples/corelib/serialization/savegame/main.cpp @@ -1,32 +1,37 @@ // Copyright (C) 2016 The Qt Company Ltd. // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause +#include "game.h" + #include <QCoreApplication> +#include <QStringList> +#include <QString> #include <QTextStream> -#include "game.h" +using namespace Qt::StringLiterals; // for _L1 + //! [0] int main(int argc, char *argv[]) { QCoreApplication app(argc, argv); - QStringList args = QCoreApplication::arguments(); - bool newGame = true; - if (args.length() > 1) - newGame = (args[1].toLower() != QStringLiteral("load")); - bool json = true; - if (args.length() > 2) - json = (args[2].toLower() != QStringLiteral("binary")); + + const QStringList args = QCoreApplication::arguments(); + const bool newGame + = args.size() <= 1 || QString::compare(args[1], "load"_L1, Qt::CaseInsensitive) != 0; + const bool json + = args.size() <= 2 || QString::compare(args[2], "binary"_L1, Qt::CaseInsensitive) != 0; Game game; if (newGame) game.newGame(); else if (!game.loadGame(json ? Game::Json : Game::Binary)) - return 1; + return 1; // Game is played; changes are made... //! [0] //! [1] - QTextStream(stdout) << "Game ended in the following state:\n"; - game.print(); + QTextStream s(stdout); + s << "Game ended in the following state:\n"; + game.print(s); if (!game.saveGame(json ? Game::Json : Game::Binary)) return 1; |