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Rework layer dependencies to work also with layer definition files

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mhugo committed Jan 7, 2016
1 parent ba2e9df commit 1a1af3788ce889ddb78f4b7e2cbca6a5bfb61143
@@ -19,5 +19,26 @@ class QgsLayerDefinition
static bool exportLayerDefinition( QString path, const QList<QgsLayerTreeNode*>& selectedTreeNodes, QString &errorMessage /Out/ );
/** Export the selected layer tree nodes to a QLR-XML document */
static bool exportLayerDefinition( QDomDocument doc, const QList<QgsLayerTreeNode*>& selectedTreeNodes, QString &errorMessage, const QString& relativeBasePath = QString::null );

/**
* Class used to work with layer dependencies stored in a XML project or layer definition file
*/
class DependencySorter
{
public:
/** Constructor
* @param doc The XML document containing maplayer elements
*/
DependencySorter( QDomDocument doc );

/** Get the layer nodes in an order where they can be loaded incrementally without dependency break */
QVector<QDomNode> sortedLayerNodes() const;

/** Whether some cyclic dependency has been detected */
bool hasCycle() const;

/** Whether some dependency is missing */
bool hasMissingDependency() const;
};
};

@@ -317,7 +317,7 @@ class QgsMapLayer : QObject

/** Creates a new layer from a layer defininition document
*/
static QList<QgsMapLayer*> fromLayerDefinition( QDomDocument& document );
static QList<QgsMapLayer*> fromLayerDefinition( QDomDocument& document, bool addToRegistry = false, bool addToLegend = false );
static QList<QgsMapLayer*> fromLayerDefinitionFile( const QString &qlrfile );

/** Set a custom property for layer. Properties are stored in a map and saved in project file. */
@@ -40,6 +40,33 @@ bool QgsLayerDefinition::loadLayerDefinition( QDomDocument doc, QgsLayerTreeGrou

QgsLayerTreeGroup *root = new QgsLayerTreeGroup();

// reorder maplayer nodes based on dependencies
// dependencies have to be resolved before IDs get changed
DependencySorter depSorter( doc );
if ( !depSorter.hasMissingDependency() )
{
QVector<QDomNode> sortedLayerNodes = depSorter.sortedLayerNodes();
QVector<QDomNode> clonedSorted;
foreach ( QDomNode node, sortedLayerNodes )
{
clonedSorted << node.cloneNode();
}
QDomNode layersNode = doc.elementsByTagName( "maplayers" ).at( 0 );
// remove old children
QDomNodeList childNodes = layersNode.childNodes();
for ( int i = 0; i < childNodes.size(); i++ )
{
layersNode.removeChild( childNodes.at( i ) );
}
// replace with new ones
foreach ( QDomNode node, clonedSorted )
{
layersNode.appendChild( node );
}
}
// if a dependency is missing, we still try to load layers, since dependencies may already be loaded

// IDs of layers should be changed otherwise we may have more then one layer with the same id
// We have to replace the IDs before we load them because it's too late once they are loaded
QDomNodeList ids = doc.elementsByTagName( "id" );
for ( int i = 0; i < ids.size(); ++i )
@@ -85,8 +112,7 @@ bool QgsLayerDefinition::loadLayerDefinition( QDomDocument doc, QgsLayerTreeGrou
loadInLegend = false;
}

QList<QgsMapLayer*> layers = QgsMapLayer::fromLayerDefinition( doc );
QgsMapLayerRegistry::instance()->addMapLayers( layers, loadInLegend );
QList<QgsMapLayer*> layers = QgsMapLayer::fromLayerDefinition( doc, /*addToRegistry*/ true, loadInLegend );

// Now that all layers are loaded, refresh the vectorjoins to get the joined fields
Q_FOREACH ( QgsMapLayer* layer, layers )
@@ -159,3 +185,93 @@ bool QgsLayerDefinition::exportLayerDefinition( QDomDocument doc, const QList<Qg
qgiselm.appendChild( layerselm );
return true;
}

QgsLayerDefinition::DependencySorter::DependencySorter( QDomDocument doc ) :
mHasCycle( false ), mHasMissingDependency( false )
{
// Determine a loading order of layers based on a graph of dependencies
QMap< QString, QVector< QString > > dependencies;
QVector<QString> sortedLayers;
QList< QPair<QString, QDomNode> > layersToSort;

QDomNodeList nl = doc.elementsByTagName( "maplayer" );
for ( int i = 0; i < nl.count(); i++ )
{
QVector<QString> deps;
QDomNode node = nl.item( i );
QDomElement element = node.toElement();

QString id = node.namedItem( "id" ).toElement().text();

// dependencies for this layer
QDomElement layerDependenciesElem = node.firstChildElement( "layerDependencies" );
if ( !layerDependenciesElem.isNull() )
{
QDomNodeList dependencyList = layerDependenciesElem.elementsByTagName( "layer" );
for ( int j = 0; j < dependencyList.size(); ++j )
{
QDomElement depElem = dependencyList.at( j ).toElement();
deps << depElem.attribute( "id" );
}
}
dependencies[id] = deps;

if ( deps.empty() )
{
sortedLayers << id;
mSortedLayerNodes << node;
}
else
layersToSort << qMakePair( id, node );
}

// check that all dependencies are present
foreach ( QString id, dependencies.keys() )
{
foreach ( QString depId, dependencies[id] )
{
if ( !dependencies.contains( depId ) )
{
// some dependencies are not satisfied
mHasMissingDependency = true;
return;
}
}
}

// cycles should be very rare, since layers with cyclic dependencies may only be created by
// manually modifying the project file
mHasCycle = false;

while ( !layersToSort.empty() && !mHasCycle )
{
QList< QPair<QString, QDomNode> >::iterator it = layersToSort.begin();
while ( it != layersToSort.end() )
{
QString idToSort = it->first;
QDomNode node = it->second;
mHasCycle = true;
bool resolved = true;
foreach ( QString dep, dependencies[idToSort] )
{
if ( !sortedLayers.contains( dep ) )
{
resolved = false;
break;
}
}
if ( resolved ) // dependencies for this layer are resolved
{
sortedLayers << idToSort;
mSortedLayerNodes << node;
it = layersToSort.erase( it ); // erase and go to the next
mHasCycle = false;
}
else
{
it++;
}
}
}
}

@@ -21,6 +21,32 @@ class CORE_EXPORT QgsLayerDefinition
static bool exportLayerDefinition( QString path, const QList<QgsLayerTreeNode*>& selectedTreeNodes, QString &errorMessage );
/** Export the selected layer tree nodes to a QLR-XML document */
static bool exportLayerDefinition( QDomDocument doc, const QList<QgsLayerTreeNode*>& selectedTreeNodes, QString &errorMessage, const QString& relativeBasePath = QString::null );

/**
* Class used to work with layer dependencies stored in a XML project or layer definition file
*/
class CORE_EXPORT DependencySorter
{
public:
/** Constructor
* @param doc The XML document containing maplayer elements
*/
DependencySorter( QDomDocument doc );

/** Get the layer nodes in an order where they can be loaded incrementally without dependency break */
QVector<QDomNode> sortedLayerNodes() const { return mSortedLayerNodes; }

/** Whether some cyclic dependency has been detected */
bool hasCycle() const { return mHasCycle; }

/** Whether some dependency is missing */
bool hasMissingDependency() const { return mHasMissingDependency; }

private:
QVector<QDomNode> mSortedLayerNodes;
bool mHasCycle;
bool mHasMissingDependency;
};
};

#endif // QGSLAYERDEFINITION_H
@@ -47,6 +47,7 @@
#include "qgsrectangle.h"
#include "qgsvectorlayer.h"
#include "qgsvectordataprovider.h"
#include "qgsmaplayerregistry.h"


QgsMapLayer::QgsMapLayer( QgsMapLayer::LayerType type,
@@ -788,7 +789,7 @@ QDomDocument QgsMapLayer::asLayerDefinition( const QList<QgsMapLayer *>& layers,
return doc;
}

QList<QgsMapLayer*> QgsMapLayer::fromLayerDefinition( QDomDocument& document )
QList<QgsMapLayer*> QgsMapLayer::fromLayerDefinition( QDomDocument& document, bool addToRegistry, bool addToLegend )
{
QList<QgsMapLayer*> layers;
QDomNodeList layernodes = document.elementsByTagName( "maplayer" );
@@ -820,7 +821,11 @@ QList<QgsMapLayer*> QgsMapLayer::fromLayerDefinition( QDomDocument& document )

bool ok = layer->readLayerXML( layerElem );
if ( ok )
{
layers << layer;
if ( addToRegistry )
QgsMapLayerRegistry::instance()->addMapLayer( layer, addToLegend );
}
}
return layers;
}
@@ -333,7 +333,7 @@ class CORE_EXPORT QgsMapLayer : public QObject

/** Creates a new layer from a layer defininition document
*/
static QList<QgsMapLayer*> fromLayerDefinition( QDomDocument& document );
static QList<QgsMapLayer*> fromLayerDefinition( QDomDocument& document, bool addToRegistry = false, bool addToLegend = false );
static QList<QgsMapLayer*> fromLayerDefinitionFile( const QString &qlrfile );

/** Set a custom property for layer. Properties are stored in a map and saved in project file. */
@@ -35,6 +35,7 @@
#include "qgsrelationmanager.h"
#include "qgsvectorlayer.h"
#include "qgsvisibilitypresetcollection.h"
#include "qgslayerdefinition.h"

#include <QApplication>
#include <QFileInfo>
@@ -672,83 +673,19 @@ QPair< bool, QList<QDomNode> > QgsProject::_getMapLayers( QDomDocument const &do

emit layerLoaded( 0, nl.count() );

// Determine a loading order of layers based on a graph of dependencies
QMap< QString, QVector< QString > > dependencies;
QVector<QString> sortedLayers;
QMap<QString, int> layerIdIdx;
QList<QString> layersToSort;

for ( int i = 0; i < nl.count(); i++ )
{
QVector<QString> deps;
QDomNode node = nl.item( i );
QDomElement element = node.toElement();

QString id = node.namedItem( "id" ).toElement().text();

// dependencies for this layer
QDomElement layerDependenciesElem = node.firstChildElement( "layerDependencies" );
if ( !layerDependenciesElem.isNull() )
{
QDomNodeList dependencyList = layerDependenciesElem.elementsByTagName( "layer" );
for ( int j = 0; j < dependencyList.size(); ++j )
{
QDomElement depElem = dependencyList.at( j ).toElement();
deps << depElem.attribute( "id" );
}
}
dependencies[id] = deps;

if ( deps.empty() )
sortedLayers << id;
else
layersToSort << id;
layerIdIdx[id] = i;
}

bool hasCycle = false;
while ( !layersToSort.empty() && !hasCycle )
{
QList<QString>::iterator it = layersToSort.begin();
while ( it != layersToSort.end() )
{
hasCycle = true;
bool resolved = true;
foreach ( QString dep, dependencies[*it] )
{
if ( !sortedLayers.contains( dep ) )
{
resolved = false;
break;
}
}
if ( resolved ) // dependencies for this layer are resolved
{
sortedLayers << *it;
it = layersToSort.erase( it ); // erase and go to the next
hasCycle = false;
}
else
{
it++;
}
}
}

if ( hasCycle )
{
// should not happen, since layers with cyclic dependencies may only be created by
// manually modifying the project file
// order layers based on their dependencies
QgsLayerDefinition::DependencySorter depSorter( doc );
if ( depSorter.hasCycle() || depSorter.hasMissingDependency() )
return qMakePair( false, QList<QDomNode>() );
}

QVector<QDomNode> sortedLayerNodes = depSorter.sortedLayerNodes();

// Collect vector layers with joins.
// They need to refresh join caches and symbology infos after all layers are loaded
QList< QPair< QgsVectorLayer*, QDomElement > > vLayerList;
foreach ( QString id, sortedLayers )
int i = 0;
foreach ( QDomNode node, sortedLayerNodes )
{
int i = layerIdIdx[id];
QDomNode node = nl.item( i );
QDomElement element = node.toElement();

QString name = node.namedItem( "layername" ).toElement().text();
@@ -768,6 +705,7 @@ QPair< bool, QList<QDomNode> > QgsProject::_getMapLayers( QDomDocument const &do
}
}
emit layerLoaded( i + 1, nl.count() );
i++;
}

// Update field map of layers with joins and create join caches if necessary
@@ -67,6 +67,7 @@ ADD_PYTHON_TEST(PyQgsZonalStatistics test_qgszonalstatistics.py)
ADD_PYTHON_TEST(PyQgsMapLayerRegistry test_qgsmaplayerregistry.py)
ADD_PYTHON_TEST(PyQgsVirtualLayerProvider test_provider_virtual.py)
ADD_PYTHON_TEST(PyQgsVirtualLayerDefinition test_qgsvirtuallayerdefinition.py)
ADD_PYTHON_TEST(PyQgsLayerDefinition test_qgslayerdefinition.py)

IF (NOT WIN32)
ADD_PYTHON_TEST(PyQgsLogger test_qgslogger.py)
@@ -29,7 +29,7 @@
QgsErrorMessage,
QgsProviderRegistry,
QgsVirtualLayerDefinition,
QgsWKBTypes
QgsWKBTypes,
QgsProject
)

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