Plasma/conditionalQMLImports: Difference between revisions
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= Conditional imports = | = Conditional imports = | ||
In order to restrict applications or components in general, a security mechanism is needed in Qt. The basic design should be the following: | == General Design == | ||
In order to restrict applications or components in general, a security mechanism is needed in Qt. This should be implemented in collaboration with upstream Qt The basic design should be the following: | |||
* In the import code path, the import is either done right away (current case), or it uses an optional import policy agent, which checks if the application or component has sufficient privileges, and either allows or denies the import | * In the import code path, the import is either done right away (current case), or it uses an optional import policy agent, which checks if the application or component has sufficient privileges, and either allows or denies the import | ||
* The policy agent is | * The policy agent is replaceable, much like QNetworkAccessManager: QQmlImportManager (?) | ||
* import manager is kept minimal in Qt API, but flexible in reimplementation | |||
* different policies for subsets of the scenegraph are possible, for example per plasmoid import restrictions | |||
* detailed failure information import failures can be handled gracefully by the application | |||
* import performance in current case should not suffer | * import performance in current case should not suffer | ||
On the Plasma side, this needs | |||
* signing of Plasmoids and other components (clients) | |||
* permission validation extensions in imports metadata | |||
* client UI for validation feedback in Plasma/Shell package | |||
* an implementation of QQmlImportManager using the above parts | |||
== Performance Measuring == | |||
Ideas for evaluating performance with or without import manager: | |||
* instrument a minimal binary that loads a QML file, measure load performance, measure performance with and without overridden QQmlImportManager | |||
* Generate 10000 files that each import a bunch of modules, put them in a ListView, model: 10000 | |||
* Dynamically create those components with a bit of javascript, measure loading performance | |||
Revision as of 02:29, 2 May 2013
Conditional imports
General Design
In order to restrict applications or components in general, a security mechanism is needed in Qt. This should be implemented in collaboration with upstream Qt The basic design should be the following:
- In the import code path, the import is either done right away (current case), or it uses an optional import policy agent, which checks if the application or component has sufficient privileges, and either allows or denies the import
- The policy agent is replaceable, much like QNetworkAccessManager: QQmlImportManager (?)
- import manager is kept minimal in Qt API, but flexible in reimplementation
- different policies for subsets of the scenegraph are possible, for example per plasmoid import restrictions
- detailed failure information import failures can be handled gracefully by the application
- import performance in current case should not suffer
On the Plasma side, this needs
- signing of Plasmoids and other components (clients)
- permission validation extensions in imports metadata
- client UI for validation feedback in Plasma/Shell package
- an implementation of QQmlImportManager using the above parts
Performance Measuring
Ideas for evaluating performance with or without import manager:
- instrument a minimal binary that loads a QML file, measure load performance, measure performance with and without overridden QQmlImportManager
- Generate 10000 files that each import a bunch of modules, put them in a ListView, model: 10000
- Dynamically create those components with a bit of javascript, measure loading performance