Provide API to filter unwanted contributions

Adds the ContributionFilterRegistry which can be used to filter
contributions of Theia extensions before they are bound.

This mechanism can be used by application developers to specifically
filter individual contributions from Theia extensions they have no
control over, i.e. core or 3rd party extensions.

Resolves #9069

Contributed on behalf of STMicroelectronics

Signed-off-by: Tobias Ortmayr <tortmayr@eclipsesource.com>
Co-Authored-By: Paul Maréchal <paul.marechal@ericsson.com>

squash me?

Signed-off-by: Paul Maréchal <paul.marechal@ericsson.com>

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 [1.14.0 Milestone](https://github.com/eclipse-theia/theia/milestone/20)
 
+- [core] add API to filter contributions at runtime [#9317](https://github.com/eclipse-theia/theia/pull/9317) Contributed on behalf of STMicroelectronics
 - [debug] Fix behavior of `Add Configurations` command when empty `launch.json` present. [#9467](https://github.com/eclipse-theia/theia/pull/9467)
 
 <a name="breaking_changes_1.14.0">[Breaking Changes:](#breaking_changes_1.14.0)</a>

examples/api-samples/src/browser/api-samples-frontend-module.ts

@@ -16,6 +16,7 @@
 
 import { ContainerModule } from '@theia/core/shared/inversify';
 import { bindDynamicLabelProvider } from './label/sample-dynamic-label-provider-command-contribution';
+import { bindSampleFilteredCommandContribution } from './contribution-filter/sample-filtered-command-contribution';
 import { bindSampleUnclosableView } from './view/sample-unclosable-view-contribution';
 import { bindSampleOutputChannelWithSeverity } from './output/sample-output-channel-with-severity';
 import { bindSampleMenu } from './menu/sample-menu-contribution';
@@ -31,4 +32,5 @@ export default new ContainerModule(bind => {
     bindSampleMenu(bind);
     bindSampleFileWatching(bind);
     bindVSXCommand(bind);
+    bindSampleFilteredCommandContribution(bind);
 });

examples/api-samples/src/browser/contribution-filter/sample-filtered-command-contribution.ts

@@ -0,0 +1,80 @@
+/********************************************************************************
+ * Copyright (C) 2021 STMicroelectronics and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { Command, CommandContribution, CommandRegistry, FilterContribution, ContributionFilterRegistry, bindContribution, Filter } from '@theia/core/lib/common';
+import { injectable, interfaces } from '@theia/core/shared/inversify';
+
+export namespace SampleFilteredCommand {
+
+    const EXAMPLE_CATEGORY = 'Examples';
+
+    export const FILTERED: Command = {
+        id: 'example_command.filtered',
+        category: EXAMPLE_CATEGORY,
+        label: 'This command should be filtered out'
+    };
+
+    export const FILTERED2: Command = {
+        id: 'example_command.filtered2',
+        category: EXAMPLE_CATEGORY,
+        label: 'This command should be filtered out (2)'
+    };
+}
+
+/**
+ * This sample command is used to test the runtime filtering of already bound contributions.
+ */
+@injectable()
+export class SampleFilteredCommandContribution implements CommandContribution {
+
+    registerCommands(commands: CommandRegistry): void {
+        commands.registerCommand(SampleFilteredCommand.FILTERED, { execute: () => { } });
+    }
+}
+
+@injectable()
+export class SampleFilterAndCommandContribution implements FilterContribution, CommandContribution {
+
+    registerCommands(commands: CommandRegistry): void {
+        commands.registerCommand(SampleFilteredCommand.FILTERED2, { execute: () => { } });
+    }
+
+    registerContributionFilters(registry: ContributionFilterRegistry): void {
+        registry.addFilters([CommandContribution], [
+            // filter ourselves out
+            contrib => contrib.constructor === this.constructor
+        ]);
+        registry.addFilters('*', [
+            // filter a contribution based on its class name
+            filterClassName(name => name === 'SampleFilteredCommandContribution')
+        ]);
+    }
+}
+
+export function bindSampleFilteredCommandContribution(bind: interfaces.Bind): void {
+    bind(CommandContribution).to(SampleFilteredCommandContribution).inSingletonScope();
+    bind(SampleFilterAndCommandContribution).toSelf().inSingletonScope();
+    bindContribution(bind, SampleFilterAndCommandContribution, [CommandContribution, FilterContribution]);
+}
+
+function filterClassName(filter: Filter<string>): Filter<Object> {
+    return object => {
+        const className = object?.constructor?.name;
+        return className
+            ? filter(className)
+            : false;
+    };
+}

examples/api-tests/src/contribution-filter.spec.js

@@ -0,0 +1,36 @@
+/********************************************************************************
+ * Copyright (C) 2021 STMicroelectronics and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+// @ts-check
+describe('Contribution filter', function () {
+    this.timeout(5000);
+    const { assert } = chai;
+
+    const { CommandRegistry, CommandContribution } = require('@theia/core/lib/common/command');
+    const { SampleFilteredCommandContribution, SampleFilteredCommand } = require('@theia/api-samples/lib/browser/contribution-filter/sample-filtered-command-contribution');
+
+    const container = window.theia.container;
+    const commands = container.get(CommandRegistry);
+
+    it('filtered command in container but not in registry', async function () {
+        const allCommands = container.getAll(CommandContribution);
+        assert.isDefined(allCommands.find(contribution => contribution instanceof SampleFilteredCommandContribution),
+            'SampleFilteredCommandContribution is not bound in container');
+        const filteredCommand = commands.getCommand(SampleFilteredCommand.FILTERED.id);
+        assert.isUndefined(filteredCommand, 'SampleFilteredCommandContribution should be filtered out but is present in "CommandRegistry"');
+    });
+
+});

packages/core/src/browser/frontend-application-module.ts

@@ -98,6 +98,7 @@ import { EncodingRegistry } from './encoding-registry';
 import { EncodingService } from '../common/encoding-service';
 import { AuthenticationService, AuthenticationServiceImpl } from '../browser/authentication-service';
 import { DecorationsService, DecorationsServiceImpl } from './decorations-service';
+import { ContributionFilterRegistryImpl } from '../common/contribution-filter';
 
 export { bindResourceProvider, bindMessageService, bindPreferenceService };
 
@@ -340,4 +341,6 @@ export const frontendApplicationModule = new ContainerModule((bind, unbind, isBo
 
     bind(AuthenticationService).to(AuthenticationServiceImpl).inSingletonScope();
     bind(DecorationsService).to(DecorationsServiceImpl).inSingletonScope();
+
+    bind(ContributionFilterRegistryImpl).toSelf().inSingletonScope();
 });

packages/core/src/common/contribution-filter/contribution-filter-registry.ts

@@ -0,0 +1,78 @@
+/********************************************************************************
+ * Copyright (C) 2021 STMicroelectronics and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { injectable, multiInject, optional } from 'inversify';
+import { ContributionFilterRegistry, ContributionType, FilterContribution } from './contribution-filter';
+import { applyFilters, Filter } from './filter';
+
+/**
+ * Registry of contribution filters.
+ *
+ * Implement/bind to the `FilterContribution` interface/symbol to register your contribution filters.
+ */
+@injectable()
+export class ContributionFilterRegistryImpl implements ContributionFilterRegistry {
+
+    protected initialized = false;
+    protected genericFilters: Filter<Object>[] = [];
+    protected typeToFilters = new Map<ContributionType, Filter<Object>[]>();
+
+    constructor(
+        @multiInject(FilterContribution) @optional() contributions: FilterContribution[] = []
+    ) {
+        for (const contribution of contributions) {
+            contribution.registerContributionFilters(this);
+        }
+        this.initialized = true;
+    }
+
+    addFilters(types: '*' | ContributionType[], filters: Filter<Object>[]): void {
+        if (this.initialized) {
+            throw new Error('cannot add filters after initialization is done.');
+        } else if (types === '*') {
+            this.genericFilters.push(...filters);
+        } else {
+            for (const type of types) {
+                this.getOrCreate(type).push(...filters);
+            }
+        }
+    }
+
+    /**
+     * Applies the filters for the given contribution type. Generic filters will be applied on any given type.
+     * @param toFilter the elements to filter
+     * @param type the contribution type for which potentially filters were registered
+     * @returns the filtered elements
+     */
+    applyFilters<T extends Object>(toFilter: T[], type: ContributionType): T[] {
+        return applyFilters<T>(toFilter, this.getFilters(type));
+    }
+
+    protected getOrCreate(type: ContributionType): Filter<Object>[] {
+        let value = this.typeToFilters.get(type);
+        if (value === undefined) {
+            this.typeToFilters.set(type, value = []);
+        }
+        return value;
+    }
+
+    protected getFilters(type: ContributionType): Filter<Object>[] {
+        return [
+            ...this.typeToFilters.get(type) || [],
+            ...this.genericFilters
+        ];
+    }
+}

packages/core/src/common/contribution-filter/contribution-filter.ts

@@ -0,0 +1,46 @@
+/********************************************************************************
+ * Copyright (C) 2021 STMicroelectronics and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+import { interfaces } from 'inversify';
+import { Filter } from './filter';
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type ContributionType = interfaces.ServiceIdentifier<any>;
+
+export interface ContributionFilterRegistry {
+
+    /**
+     * Add filters to be applied for every type of contribution.
+     */
+    addFilters(types: '*', filters: Filter<Object>[]): void;
+
+    /**
+     * Given a list of contribution types, register filters to apply.
+     * @param types types for which to register the filters.
+     */
+    addFilters(types: ContributionType[], filters: Filter<Object>[]): void;
+}
+
+export const FilterContribution = Symbol('FilterContribution');
+/**
+ * Register filters to remove contributions.
+ */
+export interface FilterContribution {
+    /**
+     * Use the registry to register your contribution filters.
+     */
+    registerContributionFilters(registry: ContributionFilterRegistry): void;
+}

packages/core/src/common/contribution-filter/filter.ts

@@ -0,0 +1,43 @@
+/********************************************************************************
+ * Copyright (C) 2021 STMicroelectronics and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+export const Filter = Symbol('Filter');
+
+/**
+ * @param toTest Object that should be tested
+ * @returns `true` if the object should be filtered out, `false` otherwise
+ */
+export type Filter<T extends Object> = (toTest: T) => boolean;
+
+/**
+ * Applies a set of filters to a set of given objects and returns the set of filtered objects.
+ * @param toFilter Set of objects which should be filtered
+ * @param filters Set of filters that should be applied
+ * @param negate Negation flag. If set to true the result of all filters is negated
+ * @returns The set of filtered arguments
+ */
+export function applyFilters<T extends Object>(toFilter: T[], filters: Filter<T>[], negate: boolean = false): T[] {
+    if (filters.length === 0) {
+        return toFilter;
+    }
+    return toFilter.filter(
+        object => filters.every(
+            // By default we want to *keep* objects when false === filter.test(object)
+            // because filter.test(object) returns true to exclude items.
+            filter => negate === filter(object)
+        )
+    );
+}

packages/core/src/common/contribution-filter/index.ts

@@ -0,0 +1,20 @@
+/********************************************************************************
+ * Copyright (C) 2021 STMicroelectronics and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+export * from './contribution-filter';
+export * from './contribution-filter-registry';
+export * from './filter';
+export * from './string-utils';