Add raw QgsProviderMetadata/QgsProviderRegistry API to save

QGIS layer metadata to a URI for the provider
qgis · May 2, 2021 · 5d703a4 · 5d703a4
1 parent fb1ac59
commit 5d703a4
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diff --git a/python/core/auto_generated/qgsprovidermetadata.sip.in b/python/core/auto_generated/qgsprovidermetadata.sip.in
@@ -423,6 +423,20 @@ Saves a layer style to provider
 Loads a layer style defined by ``uri``
 
 .. versionadded:: 3.10
+%End
+
+    virtual bool saveLayerMetadata( const QString &uri, const QgsLayerMetadata &metadata, QString &errorMessage /Out/ );
+%Docstring
+Saves ``metadata`` to the layer corresponding to the specified ``uri``.
+
+:param uri: uri of layer to store metadata for
+:param metadata: layer metadata
+
+:return: - ``True`` if the metadata was successfully saved.
+         - errorMessage: descriptive string of error if encountered
+
+
+.. versionadded:: 3.20
 %End
 
     virtual bool createDb( const QString &dbPath, QString &errCause );

diff --git a/python/core/auto_generated/qgsproviderregistry.sip.in b/python/core/auto_generated/qgsproviderregistry.sip.in
@@ -231,6 +231,21 @@ Saves a layer style to provider
 Loads a layer style defined by ``uri``
 
 .. versionadded:: 3.10
+%End
+
+    bool saveLayerMetadata( const QString &providerKey, const QString &uri, const QgsLayerMetadata &metadata, QString &errorMessage /Out/ );
+%Docstring
+Saves ``metadata`` to the layer corresponding to the specified ``uri``.
+
+:param providerKey: identifier of the provider
+:param uri: uri of layer to store metadata for
+:param metadata: layer metadata
+
+:return: - ``True`` if the metadata was successfully saved.
+         - errorMessage: descriptive string of error if encountered
+
+
+.. versionadded:: 3.20
 %End
 
     bool createDb( const QString &providerKey, const QString &dbPath, QString &errCause );

diff --git a/src/core/qgsprovidermetadata.cpp b/src/core/qgsprovidermetadata.cpp
@@ -232,6 +232,12 @@ QString QgsProviderMetadata::loadStyle( const QString &, QString &errCause )
   return QString();
 }
 
+bool QgsProviderMetadata::saveLayerMetadata( const QString &, const QgsLayerMetadata &, QString &errorMessage )
+{
+  errorMessage = QObject::tr( "Provider %1 does not support writing layer metadata" ).arg( key() );
+  return false;
+}
+
 bool QgsProviderMetadata::createDb( const QString &, QString &errCause )
 {
   errCause = QObject::tr( "Provider %1 has no %2 method" ).arg( key(), QStringLiteral( "createDb" ) );

diff --git a/src/core/qgsprovidermetadata.h b/src/core/qgsprovidermetadata.h
@@ -43,6 +43,7 @@ class QgsTransaction;
 class QgsRasterDataProvider;
 class QgsMeshDataProvider;
 class QgsAbstractDatabaseProviderConnection;
+class QgsLayerMetadata;
 
 struct QgsMesh;
 
@@ -472,6 +473,19 @@ class CORE_EXPORT QgsProviderMetadata : public QObject
      */
     virtual QString loadStyle( const QString &uri, QString &errCause );
 
+    /**
+     * Saves \a metadata to the layer corresponding to the specified \a uri.
+     *
+     * \param uri uri of layer to store metadata for
+     * \param metadata layer metadata
+     * \param errorMessage descriptive string of error if encountered
+     *
+     * \returns TRUE if the metadata was successfully saved.
+     *
+     * \since QGIS 3.20
+     */
+    virtual bool saveLayerMetadata( const QString &uri, const QgsLayerMetadata &metadata, QString &errorMessage SIP_OUT );
+
     /**
      * Creates database by the provider on the path
      * \since QGIS 3.10

diff --git a/src/core/qgsproviderregistry.cpp b/src/core/qgsproviderregistry.cpp
@@ -661,6 +661,18 @@ QString QgsProviderRegistry::loadStyle( const QString &providerKey, const QStrin
   return ret;
 }
 
+bool QgsProviderRegistry::saveLayerMetadata( const QString &providerKey, const QString &uri, const QgsLayerMetadata &metadata, QString &errorMessage )
+{
+  errorMessage.clear();
+  if ( QgsProviderMetadata *meta = findMetadata_( mProviders, providerKey ) )
+    return meta->saveLayerMetadata( uri, metadata, errorMessage );
+  else
+  {
+    errorMessage = QObject::tr( "Unable to load %1 provider" ).arg( providerKey );
+    return false;
+  }
+}
+
 bool QgsProviderRegistry::createDb( const QString &providerKey, const QString &dbPath, QString &errCause )
 {
   QgsProviderMetadata *meta = findMetadata_( mProviders, providerKey );

diff --git a/src/core/qgsproviderregistry.h b/src/core/qgsproviderregistry.h
@@ -261,6 +261,20 @@ class CORE_EXPORT QgsProviderRegistry
      */
     QString loadStyle( const QString &providerKey,  const QString &uri, QString &errCause );
 
+    /**
+     * Saves \a metadata to the layer corresponding to the specified \a uri.
+     *
+     * \param providerKey identifier of the provider
+     * \param uri uri of layer to store metadata for
+     * \param metadata layer metadata
+     * \param errorMessage descriptive string of error if encountered
+     *
+     * \returns TRUE if the metadata was successfully saved.
+     *
+     * \since QGIS 3.20
+     */
+    bool saveLayerMetadata( const QString &providerKey, const QString &uri, const QgsLayerMetadata &metadata, QString &errorMessage SIP_OUT );
+
     /**
      * Creates database by the provider on the path
      * \since QGIS 3.10