feat(Storybook): Track pages dir in PagesModel

storybook/pagesmodel.cpp

@@ -1,43 +1,148 @@
 #include "pagesmodel.h"
 
-#include <QRegularExpression>
 #include <QDir>
+#include <QFileSystemWatcher>
+#include <QRegularExpression>
 
 namespace {
 const auto categoryUncategorized QStringLiteral("Uncategorized");
 }
 
 PagesModel::PagesModel(const QString &path, QObject *parent)
-    : QAbstractListModel{parent}
+    : QAbstractListModel{parent}, m_path{path},
+      fsWatcher(new QFileSystemWatcher(this))
 {
-    QDir dir(path);
-    dir.setFilter(QDir::Files);
+    m_items = load();
+    readMetadata(m_items);
 
+    fsWatcher->addPath(path);
+
+    connect(fsWatcher, &QFileSystemWatcher::directoryChanged,
+            this, &PagesModel::reload);
+}
+
+QList<PagesModelItem> PagesModel::load() {
     static QRegularExpression fileNameRegex(
                 QRegularExpression::anchoredPattern("(.*)Page\\.qml"));
-    static QRegularExpression categoryRegex(
-                "^//(\\s)*category:(.+)$", QRegularExpression::MultilineOption);
+
+    QDir dir(m_path);
+    dir.setFilter(QDir::Files);
 
     const QFileInfoList files = dir.entryInfoList();
+    QList<PagesModelItem> items;
 
-    std::for_each(files.begin(), files.end(), [this] (auto &fileInfo) {
+    std::for_each(files.begin(), files.end(), [this, &items] (auto &fileInfo) {
         QString fileName = fileInfo.fileName();
         QRegularExpressionMatch fileNameMatch = fileNameRegex.match(fileName);
 
         if (!fileNameMatch.hasMatch())
             return;
 
-        QFile file(fileInfo.filePath());
-        file.open(QIODevice::ReadOnly);
-        QByteArray content = file.readAll();
+        PagesModelItem item;
+        item.path = fileInfo.filePath();
+        item.title = fileNameMatch.captured(1);
+        item.lastModified = fileInfo.lastModified();
 
-        QRegularExpressionMatch categoryMatch = categoryRegex.match(content);
-        QString category = categoryMatch.hasMatch()
-                ? categoryMatch.captured(2).trimmed() : categoryUncategorized;
-
-        QString title = fileNameMatch.captured(1);
-        m_items << PagesModelItem { title, category };
+        items << item;
     });
+
+    return items;
+}
+
+void PagesModel::readMetadata(PagesModelItem& item) {
+    static QRegularExpression categoryRegex(
+                "^//(\\s)*category:(.+)$", QRegularExpression::MultilineOption);
+
+    QFile file(item.path);
+    file.open(QIODevice::ReadOnly);
+    QByteArray content = file.readAll();
+
+    QRegularExpressionMatch categoryMatch = categoryRegex.match(content);
+    QString category = categoryMatch.hasMatch()
+            ? categoryMatch.captured(2).trimmed() : categoryUncategorized;
+
+    item.category = category;
+}
+
+void PagesModel::readMetadata(QList<PagesModelItem> &items) {
+    std::for_each(items.begin(), items.end(), [](auto&item) {
+        readMetadata(item);
+    });
+}
+
+void PagesModel::reload() {
+    QList<PagesModelItem> currentItems = load();
+    std::map<QString, PagesModelItem> mapping;
+
+    for (const PagesModelItem &item : qAsConst(m_items))
+        mapping[item.title] = item;
+
+    std::vector<PagesModelItem> newItems;
+    std::vector<PagesModelItem> changedItems;
+    std::vector<PagesModelItem> removedItems;
+
+    for (const PagesModelItem &item : qAsConst(currentItems)) {
+        auto it = mapping.find(item.title);
+
+        if (it == mapping.end()) {
+            newItems.push_back(item);
+        } else {
+            if (item.lastModified != it->second.lastModified)
+                changedItems.push_back(item);
+
+            mapping.erase(it);
+        }
+    }
+
+    for (auto& [key, value] : mapping)
+        removedItems.push_back(value);
+
+    for (auto& item : removedItems) {
+
+        auto it = std::find_if(m_items.begin(), m_items.end(), [&item](auto& it){
+            return it.title == item.title;
+        });
+
+        auto index = std::distance(m_items.begin(), it);
+
+        beginRemoveRows(QModelIndex{}, index, index);
+        m_items.removeAt(index);
+        endRemoveRows();
+    }
+
+    if (newItems.size()) {
+        beginInsertRows(QModelIndex{}, rowCount(), rowCount() + newItems.size() - 1);
+
+        for (auto& item : newItems) {
+            readMetadata(item);
+            m_items << item;
+        }
+
+        endInsertRows();
+    }
+
+    for (auto& item : changedItems) {
+        auto it = std::find_if(m_items.begin(), m_items.end(), [&item](auto& it){
+            return it.title == item.title;
+        });
+
+        auto index = std::distance(m_items.begin(), it);
+        const auto& previous = *it;
+        readMetadata(item);
+
+        if (previous.category != item.category) {
+            // For simplicity category change is handled by removing and
+            // adding item. In the future it can be changed to regular dataChanged
+            // event and handled properly in upstream models like SectionSDecoratorModel.
+            beginRemoveRows(QModelIndex{}, index, index);
+            m_items.removeAt(index);
+            endRemoveRows();
+
+            beginInsertRows(QModelIndex{}, rowCount(), rowCount());
+            m_items << item;
+            endInsertRows();
+        }
+    }
 }
 
 QHash<int, QByteArray> PagesModel::roleNames() const

storybook/pagesmodel.h

@@ -1,8 +1,13 @@
 #pragma once
 
 #include <QAbstractListModel>
+#include <QDateTime>
+
+class QFileSystemWatcher;
 
 struct PagesModelItem {
+    QString path;
+    QDateTime lastModified;
     QString title;
     QString category;
 };
@@ -22,6 +27,14 @@ public:
     int rowCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role) const override;
 
+    void reload();
 private:
+    QList<PagesModelItem> load();
+
+    static void readMetadata(PagesModelItem &item);
+    static void readMetadata(QList<PagesModelItem> &items);
+
+    QString m_path;
     QList<PagesModelItem> m_items;
+    QFileSystemWatcher* fsWatcher;
 };