Feature/feature drafts

app/CMakeLists.txt

@@ -50,6 +50,8 @@ set(MM_SRCS
     androidutils.cpp
     mapsketchingcontroller.cpp
     appsettings.cpp
+    drafts/featuredraftstorage.cpp
+    drafts/featuredraftcontroller.cpp
     autosynccontroller.cpp
     bluetoothdiscoverymodel.cpp
     qrcodedecoder.cpp
@@ -147,6 +149,8 @@ set(MM_HDRS
     androidutils.h
     mapsketchingcontroller.h
     appsettings.h
+    drafts/featuredraftstorage.h
+    drafts/featuredraftcontroller.h
     autosynccontroller.h
     bluetoothdiscoverymodel.h
     qrcodedecoder.h
@@ -335,6 +339,7 @@ target_include_directories(
   MerginMaps
   PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/
          ${CMAKE_CURRENT_SOURCE_DIR}/attributes
+         ${CMAKE_CURRENT_SOURCE_DIR}/drafts
          ${CMAKE_CURRENT_SOURCE_DIR}/filter
          ${CMAKE_CURRENT_SOURCE_DIR}/map
          ${CMAKE_CURRENT_SOURCE_DIR}/layer

app/activeproject.cpp

@@ -78,6 +78,9 @@ ActiveProject::ActiveProject( AppSettings &appSettings
 
   mFilterController = std::make_unique<FilterController>();
   connect( this, &ActiveProject::projectReloaded, mFilterController.get(), &FilterController::loadFilterConfig );
+
+  mFeatureDraftController = std::make_unique<FeatureDraftController>();
+  connect( this, &ActiveProject::loadingFinished, mFeatureDraftController.get(), &FeatureDraftController::checkForDraft );
 }
 
 ActiveProject::~ActiveProject() = default;
@@ -683,3 +686,8 @@ FilterController *ActiveProject::filterController() const
 {
   return mFilterController.get();
 }
+
+FeatureDraftController *ActiveProject::featureDraftController() const
+{
+  return mFeatureDraftController.get();
+}

app/activeproject.h

@@ -25,6 +25,7 @@
 #include "merginprojectmetadata.h"
 #include "synchronizationoptions.h"
 #include "filter/filtercontroller.h"
+#include "drafts/featuredraftcontroller.h"
 
 /**
  * \brief The ActiveProject class can load a QGIS project and holds its data.
@@ -36,6 +37,7 @@ class ActiveProject: public QObject
     Q_PROPERTY( QgsProject *qgsProject READ qgsProject NOTIFY qgsProjectChanged ) // QgsProject instance of active project, never changes
     Q_PROPERTY( AutosyncController *autosyncController READ autosyncController NOTIFY autosyncControllerChanged )
     Q_PROPERTY( FilterController *filterController READ filterController NOTIFY filterControllerChanged )
+    Q_PROPERTY( FeatureDraftController *featureDraftController READ featureDraftController NOTIFY featureDraftControllerChanged )
     Q_PROPERTY( InputMapSettings *mapSettings READ mapSettings WRITE setMapSettings NOTIFY mapSettingsChanged )
     Q_PROPERTY( QString projectRole READ projectRole WRITE setProjectRole NOTIFY projectRoleChanged )
 
@@ -156,6 +158,11 @@ class ActiveProject: public QObject
      */
     FilterController *filterController() const;
 
+    /**
+     * Returns featureDraftController, which detects unsaved feature drafts left behind for this project
+     */
+    FeatureDraftController *featureDraftController() const;
+
   signals:
     void qgsProjectChanged();
     void localProjectChanged( LocalProject project );
@@ -193,6 +200,8 @@ class ActiveProject: public QObject
 
     void filterControllerChanged( FilterController *controller );
 
+    void featureDraftControllerChanged( FeatureDraftController *controller );
+
   public slots:
     // Reloads project if current project path matches given path (it's the same project)
     bool reloadProject( QString projectDir );
@@ -235,6 +244,7 @@ class ActiveProject: public QObject
     InputMapSettings *mMapSettings = nullptr;
     std::unique_ptr<AutosyncController> mAutosyncController;
     std::unique_ptr<FilterController> mFilterController;
+    std::unique_ptr<FeatureDraftController> mFeatureDraftController;
 
     QString mProjectLoadingLog;
     QString mProjectRole;

app/attributes/attributecontroller.cpp

@@ -20,6 +20,12 @@
 
 #include <QDebug>
 #include <QSet>
+#include <QTimer>
+#include <QDateTime>
+#include <QJsonObject>
+#include <QJsonArray>
+
+#include "featuredraftstorage.h"
 
 #include "qgis.h"
 #include "qgsproject.h"
@@ -41,7 +47,11 @@
 AttributeController::AttributeController( QObject *parent )
   : QObject( parent )
   , mAttributeTabProxyModel( new AttributeTabProxyModel() )
+  , mDraftSaveTimer( new QTimer( this ) )
 {
+  mDraftSaveTimer->setSingleShot( true );
+  mDraftSaveTimer->setInterval( 1000 );
+  connect( mDraftSaveTimer, &QTimer::timeout, this, &AttributeController::saveDraft );
 }
 
 void AttributeController::reset()
@@ -67,8 +77,17 @@ void AttributeController::setFeatureLayerPair( const FeatureLayerPair &pair )
     blockSignals( true );
 
     bool hasLayerChanged = mFeatureLayerPair.layer() != pair.layer();
+    // geometry edits round-trip back into this same setter (via the live QML
+    // binding once the geometry-editing map tool hands the feature back) - that
+    // must not wipe attribute changes already tracked for this same feature
+    bool isSameFeature = !hasLayerChanged && mFeatureLayerPair.feature().id() == pair.feature().id();
+
     // Set new active pair
     mFeatureLayerPair = pair;
+    if ( !isSameFeature )
+    {
+      mTouchedFieldIndices.clear();
+    }
     if ( hasLayerChanged )
     {
       // layer changed!
@@ -646,6 +665,72 @@ bool AttributeController::isNewFeature() const
   return FID_IS_NEW( id ) || FID_IS_NULL( id );
 }
 
+QJsonObject AttributeController::attributeToJson( const QgsFields &fields, const QgsFeature &feature, int fieldIndex ) const
+{
+  QJsonObject attribute;
+  attribute[ QStringLiteral( "name" ) ] = fields.at( fieldIndex ).name();
+  attribute[ QStringLiteral( "type" ) ] = fields.at( fieldIndex ).typeName();
+  attribute[ QStringLiteral( "value" ) ] = QJsonValue::fromVariant( feature.attribute( fieldIndex ) );
+  return attribute;
+}
+
+void AttributeController::saveDraft()
+{
+  if ( !mFeatureLayerPair.layer() )
+    return;
+
+  const QgsFeature feature = mFeatureLayerPair.feature();
+  const QgsFields fields = feature.fields();
+  const bool featureIsNew = isNewFeature();
+
+  QJsonArray attributes;
+
+  if ( featureIsNew )
+  {
+    for ( int i = 0; i < feature.attributeCount(); ++i )
+    {
+      attributes.append( attributeToJson( fields, feature, i ) );
+    }
+  }
+  else
+  {
+    for ( int fieldIndex : mTouchedFieldIndices )
+    {
+      if ( fieldIndex >= 0 && fieldIndex < feature.attributeCount() )
+      {
+        attributes.append( attributeToJson( fields, feature, fieldIndex ) );
+      }
+    }
+  }
+
+  QJsonObject draft;
+  draft[ QStringLiteral( "layerId" ) ] = mFeatureLayerPair.layer()->id();
+  draft[ QStringLiteral( "stage" ) ] = QStringLiteral( "attributeForm" );
+  draft[ QStringLiteral( "timestamp" ) ] = QDateTime::currentDateTimeUtc().toString( Qt::ISODate );
+  draft[ QStringLiteral( "attributes" ) ] = attributes;
+
+  if ( featureIsNew )
+  {
+    // existing-feature geometry edits are drafted separately, by RecordingMapTool
+    draft[ QStringLiteral( "geometry" ) ] = feature.geometry().asWkt();
+  }
+  else
+  {
+    draft[ QStringLiteral( "featureId" ) ] = QJsonValue( static_cast<qint64>( feature.id() ) );
+  }
+
+  FeatureDraftStorage::saveDraft( QgsProject::instance()->homePath(), draft );
+}
+
+void AttributeController::clearDraft()
+{
+  // a pending debounced write must not be allowed to resurrect the draft
+  // after we've just told the storage (and possibly the user) it's gone
+  mDraftSaveTimer->stop();
+
+  FeatureDraftStorage::clearDraft( QgsProject::instance()->homePath() );
+}
+
 void AttributeController::acquireId()
 {
   if ( !mFeatureLayerPair.layer() )
@@ -1203,6 +1288,7 @@ bool AttributeController::deleteFeature()
   {
     mFeatureLayerPair = FeatureLayerPair();
     emit featureLayerPairChanged();
+    clearDraft();
     emit changesCommited();
   }
 
@@ -1214,6 +1300,8 @@ bool AttributeController::rollback()
   if ( !mFeatureLayerPair.layer() )
     return false;
 
+  clearDraft();
+
   if ( !mFeatureLayerPair.layer()->isEditable() )
   {
     return false;
@@ -1281,6 +1369,7 @@ bool AttributeController::save()
 
   if ( rv )
   {
+    clearDraft();
     emit changesCommited();
   }
   else
@@ -1509,6 +1598,8 @@ bool AttributeController::setFormValue( const QUuid &id, QVariant value )
     {
       mFeatureLayerPair.featureRef().setAttribute( item->fieldIndex(), val );
       emit formDataChanged( item->id(), { AttributeFormModel::AttributeValue, AttributeFormModel::RawValueIsNull, AttributeFormModel::HasMixedValues } );
+      mTouchedFieldIndices.insert( item->fieldIndex() );
+      mDraftSaveTimer->start();
     }
     recalculateDerivedItems( true, false );
     return true;

app/attributes/attributecontroller.h

@@ -21,8 +21,10 @@
 #include <QVariant>
 #include <memory>
 #include <QMap>
+#include <QSet>
 #include <QVector>
 #include <QUuid>
+#include <QJsonObject>
 
 #include "featurelayerpair.h"
 #include "attributedata.h"
@@ -40,6 +42,7 @@
 class AttributeFormModel;
 class AttributeTabModel;
 class QgsVectorLayer;
+class QTimer;
 
 /**
  * This is implementation of the controller between Attribute*Model
@@ -185,6 +188,17 @@ class  AttributeController : public QObject
 
     bool isNewFeature() const;
 
+    // Persists attribute changes as a draft, debounced. New feature: all attributes.
+    // Existing feature: only touched fields, so an untouched one is never clobbered
+    // by a concurrent change made elsewhere via sync.
+    void saveDraft();
+
+    //! Removes any persisted draft for the current project
+    void clearDraft();
+
+    //! Builds the {name, type, value} JSON object for one attribute, used by saveDraft()
+    QJsonObject attributeToJson( const QgsFields &fields, const QgsFeature &feature, int fieldIndex ) const;
+
     /**
      * Recalculates visibility & constrains & default values
      * Note that reevaluate default values is needed only when an attribnute has changed.
@@ -246,5 +260,10 @@ class  AttributeController : public QObject
 
     AttributeController *mParentController = nullptr; // not owned
     QgsRelation mLinkedRelation;
+
+    QTimer *mDraftSaveTimer = nullptr; // owned by this, debounces saveDraft()
+
+    //! Indices of fields the user has actually changed this session - only valid for existing (edit-mode) features
+    QSet<int> mTouchedFieldIndices;
 };
 #endif // ATTRIBUTECONTROLLER_H