refs #885 Regenerate revision file from available JSON files.

src/blackmisc/datacache.cpp

@@ -292,6 +292,12 @@ namespace BlackMisc
         if (lock && m_cache->m_revision.isPendingRead())
         {
             CValueCachePacket newValues;
+            if (! m_cache->m_revision.isFound())
+            {
+                m_cache->loadFromFiles(persistentStore(), {}, {}, newValues, {}, true);
+                m_cache->m_revision.regenerate(newValues);
+                newValues.clear();
+            }
             auto msg = m_cache->loadFromFiles(persistentStore(), m_cache->m_revision.keysWithNewerTimestamps(), baseline.toVariantMap(), newValues, m_cache->m_revision.timestampsAsString());
             newValues.setTimestamps(m_cache->m_revision.newerTimestamps());
 
@@ -364,7 +370,7 @@ namespace BlackMisc
         m_originalTimestamps.clear();
 
         QFile revisionFile(m_basename + "/.rev");
-        if (revisionFile.exists())
+        if ((m_found = revisionFile.exists()))
         {
             if (! revisionFile.open(QFile::ReadOnly | QFile::Text))
             {
@@ -435,6 +441,7 @@ namespace BlackMisc
                 if (m_pendingWrite) { return guard; }
                 return {};
             }
+            else { m_found = false; }
         }
 
         m_pendingRead = true;
@@ -483,6 +490,16 @@ namespace BlackMisc
         }
     }
 
+    void CDataCacheRevision::regenerate(const CValueCachePacket &keys)
+    {
+        QMutexLocker lock(&m_mutex);
+
+        Q_ASSERT(m_updateInProgress);
+        Q_ASSERT(m_lockFile.isLocked());
+
+        writeNewRevision(m_originalTimestamps = keys.toTimestampMap());
+    }
+
     void CDataCacheRevision::finishUpdate(bool keepPromises)
     {
         QMutexLocker lock(&m_mutex);
@@ -497,12 +514,20 @@ namespace BlackMisc
         m_lockFile.unlock();
     }
 
+    bool CDataCacheRevision::isFound() const
+    {
+        QMutexLocker lock(&m_mutex);
+
+        Q_ASSERT(m_updateInProgress);
+        return m_found;
+    }
+
     bool CDataCacheRevision::isPendingRead() const
     {
         QMutexLocker lock(&m_mutex);
 
         Q_ASSERT(m_updateInProgress);
-        return ! m_timestamps.isEmpty();
+        return ! m_timestamps.isEmpty() || ! m_found;
     }
 
     void CDataCacheRevision::notifyPendingWrite()

src/blackmisc/datacache.h

@@ -110,10 +110,16 @@ namespace BlackMisc
         //! During update, writes a new revision file with new timestamps.
         void writeNewRevision(const QMap<QString, qint64> &timestamps, const QSet<QString> &excludeKeys = {});
 
+        //! Write a new revision file with keys deduced from the available JSON files.
+        void regenerate(const CValueCachePacket &keys);
+
         //! Release the revision file lock and mark everything up-to-date (called by LockGuard destructor).
         //! \param keepPromises Don't break pending promises.
         void finishUpdate(bool keepPromises = false);
 
+        //! Existing revision file was found.
+        bool isFound() const;
+
         //! True if beginUpdate found some values with timestamps newer than in memory.
         bool isPendingRead() const;
 
@@ -165,6 +171,7 @@ namespace BlackMisc
     private:
         mutable QMutex m_mutex { QMutex::Recursive };
         bool m_updateInProgress = false;
+        bool m_found = false;
         bool m_pendingRead = false;
         bool m_pendingWrite = false;
         QString m_basename;

src/blackmisc/valuecache.cpp

@@ -402,7 +402,7 @@ namespace BlackMisc
         return status;
     }
 
-    CStatusMessage CValueCache::loadFromFiles(const QString &dir, const QSet<QString> &keys, const CVariantMap &currentValues, CValueCachePacket &o_values, const QString &keysMessage) const
+    CStatusMessage CValueCache::loadFromFiles(const QString &dir, const QSet<QString> &keys, const CVariantMap &currentValues, CValueCachePacket &o_values, const QString &keysMessage, bool keysOnly) const
     {
         if (! QDir(dir).exists())
         {
@@ -442,15 +442,23 @@ namespace BlackMisc
             {
                 return CStatusMessage(this).error("Invalid JSON format in %1") << file.fileName();
             }
+
             CVariantMap temp;
-            const QString messagePrefix = QStringLiteral("Parsing %1.json").arg(it.key());
+            if (keysOnly)
-            auto messages = temp.convertFromMemoizedJsonNoThrow(json.object(), it.value(), this, messagePrefix);
-            if (it.value().isEmpty()) { messages.push_back(temp.convertFromMemoizedJsonNoThrow(json.object(), this, messagePrefix)); }
-            if (! messages.isEmpty())
             {
-                ok = false;
+                for (const auto &key : json.object().keys()) { temp.insert(key, {}); }
-                backupFile(file);
+            }
-                CLogMessage::preformatted(messages);
+            else
+            {
+                const QString messagePrefix = QStringLiteral("Parsing %1.json").arg(it.key());
+                auto messages = temp.convertFromMemoizedJsonNoThrow(json.object(), it.value(), this, messagePrefix);
+                if (it.value().isEmpty()) { messages.push_back(temp.convertFromMemoizedJsonNoThrow(json.object(), this, messagePrefix)); }
+                if (! messages.isEmpty())
+                {
+                    ok = false;
+                    backupFile(file);
+                    CLogMessage::preformatted(messages);
+                }
             }
             temp.removeDuplicates(currentValues);
             o_values.insert(temp, QFileInfo(file).lastModified().toMSecsSinceEpoch());

src/blackmisc/valuecache.h

@@ -284,7 +284,7 @@ namespace BlackMisc
 
         //! Load from Json files in a given directory any values which differ from the current ones, and insert them in o_values.
         //! \threadsafe
-        CStatusMessage loadFromFiles(const QString &directory, const QSet<QString> &keys, const CVariantMap &current, CValueCachePacket &o_values, const QString &keysMessage = {}) const;
+        CStatusMessage loadFromFiles(const QString &directory, const QSet<QString> &keys, const CVariantMap &current, CValueCachePacket &o_values, const QString &keysMessage = {}, bool keysOnly = false) const;
 
         //! Mark all values with keys that start with the given prefix as having been saved.
         //! \threadsafe