Use weak layer pointers in labeling engine #4095
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
m-kuhn
reviewed
Feb 3, 2017
| @@ -760,7 +760,7 @@ QgsExpressionContextScope* QgsExpressionContextUtils::layerScope( const QgsMapLa | |||
|
|
|||
| scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "layer_name" ), layer->name(), true ) ); | |||
| scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "layer_id" ), layer->id(), true ) ); | |||
| scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "layer" ), QVariant::fromValue<QPointer<QgsMapLayer> >( QPointer<QgsMapLayer>( const_cast<QgsMapLayer*>( layer ) ) ), true ) ); | |||
| scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "layer" ), QVariant::fromValue<QgsWeakMapLayerPointer >( QgsWeakMapLayerPointer( const_cast<QgsMapLayer*>( layer ) ) ), true ) ); | |||
There was a problem hiding this comment.
Maybe we should remove the const from this method instead?
There was a problem hiding this comment.
Hmm... no strong opinions either way. Ideally we'd store a const pointer here I guess, but that doesn't seem possible
|
The concept looks good to me |
wonder-sk
approved these changes
Feb 3, 2017
There was a problem hiding this comment.
Hi Nyall - the changes look good to me.
By the way, for classes that may be written to / read from XML (e.g. QgsAnnotation) we may need to use the helper QgsMapLayerRef structure, to allow delayed resolution from layer ID to pointer - but that's again for some future de-qgsproject::instance-ization work :-)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This flips the labeling engine/providers to use weak map layer pointers instead of layer ids. It removes an existing use of the project instance (and avoids another one I was about to add!)
I've also added some typedefs for QPointer QgsMapLayer* - I got sick of writing these out in full!