vscode: add support for inline completions

The commit adds support for the `inline completions` VS Code API.

Signed-off-by: vince-fugnitto <vincent.fugnitto@ericsson.com>

packages/plugin-ext/src/common/plugin-api-rpc-model.ts

@@ -764,3 +764,98 @@ export interface InlayHintsProvider {
     resolveInlayHint?(hint: InlayHint, token: monaco.CancellationToken): InlayHint[] | undefined | Thenable<InlayHint[] | undefined>;
 }
 
+/**
+ * How an {@link InlineCompletionsProvider inline completion provider} was triggered.
+ */
+export enum InlineCompletionTriggerKind {
+    /**
+     * Completion was triggered automatically while editing.
+     * It is sufficient to return a single completion item in this case.
+     */
+    Automatic = 0,
+
+    /**
+     * Completion was triggered explicitly by a user gesture.
+     * Return multiple completion items to enable cycling through them.
+     */
+    Explicit = 1,
+}
+
+export interface InlineCompletionContext {
+    /**
+     * How the completion was triggered.
+     */
+    readonly triggerKind: InlineCompletionTriggerKind;
+
+    readonly selectedSuggestionInfo: SelectedSuggestionInfo | undefined;
+}
+
+export interface SelectedSuggestionInfo {
+    range: Range;
+    text: string;
+    isSnippetText: boolean;
+    completionKind: CompletionItemKind;
+}
+
+export interface InlineCompletion {
+    /**
+     * The text to insert.
+     * If the text contains a line break, the range must end at the end of a line.
+     * If existing text should be replaced, the existing text must be a prefix of the text to insert.
+     *
+     * The text can also be a snippet. In that case, a preview with default parameters is shown.
+     * When accepting the suggestion, the full snippet is inserted.
+     */
+    readonly insertText: string | { snippet: string };
+
+    /**
+     * A text that is used to decide if this inline completion should be shown.
+     * An inline completion is shown if the text to replace is a subword of the filter text.
+     */
+    readonly filterText?: string;
+
+    /**
+     * An optional array of additional text edits that are applied when
+     * selecting this completion. Edits must not overlap with the main edit
+     * nor with themselves.
+     */
+    readonly additionalTextEdits?: SingleEditOperation[];
+
+    /**
+     * The range to replace.
+     * Must begin and end on the same line.
+     */
+    readonly range?: Range;
+
+    readonly command?: Command;
+
+    /**
+     * If set to `true`, unopened closing brackets are removed and unclosed opening brackets are closed.
+     * Defaults to `false`.
+     */
+    readonly completeBracketPairs?: boolean;
+}
+
+export interface InlineCompletions<TItem extends InlineCompletion = InlineCompletion> {
+    readonly items: readonly TItem[];
+}
+
+export interface InlineCompletionsProvider<T extends InlineCompletions = InlineCompletions> {
+    provideInlineCompletions(
+        model: monaco.editor.ITextModel,
+        position: monaco.Position,
+        context: InlineCompletionContext,
+        token: monaco.CancellationToken
+    ): T[] | undefined | Thenable<T[] | undefined>;
+
+    /**
+     * Will be called when an item is shown.
+     */
+    handleItemDidShow?(completions: T, item: T['items'][number]): void;
+
+    /**
+     * Will be called when a completions list is no longer in use and can be garbage-collected.
+     */
+    freeInlineCompletions(completions: T): void;
+}
+

packages/plugin-ext/src/common/plugin-api-rpc.ts

@@ -81,7 +81,10 @@ import {
     InlayHint,
     CachedSession,
     CachedSessionItem,
-    TypeHierarchyItem
+    TypeHierarchyItem,
+    InlineCompletion,
+    InlineCompletions,
+    InlineCompletionContext
 } from './plugin-api-rpc-model';
 import { ExtPluginApi } from './plugin-ext-api-contribution';
 import { KeysToAnyValues, KeysToKeysToAnyValue } from './types';
@@ -1576,6 +1579,8 @@ export interface LanguagesExt {
     $provideSuperTypes(handle: number, sessionId: string, itemId: string, token: theia.CancellationToken): Promise<TypeHierarchyItem[] | undefined>
     $provideSubTypes(handle: number, sessionId: string, itemId: string, token: theia.CancellationToken): Promise<TypeHierarchyItem[] | undefined>;
     $releaseTypeHierarchy(handle: number, session?: string): Promise<boolean>;
+    $provideInlineCompletions(handle: number, resource: UriComponents, position: Position, context: InlineCompletionContext, token: CancellationToken): Promise<IdentifiableInlineCompletions | undefined>;
+    $freeInlineCompletionsList(handle: number, pid: number): void;
 }
 
 export const LanguagesMainFactory = Symbol('LanguagesMainFactory');
@@ -1633,6 +1638,7 @@ export interface LanguagesMain {
     $registerTypeHierarchyProvider(handle: number, selector: SerializedDocumentFilter[]): void;
     $setLanguageStatus(handle: number, status: LanguageStatus): void;
     $removeLanguageStatus(handle: number): void;
+    $registerInlineCompletionsSupport(handle: number, selector: SerializedDocumentFilter[]): void;
 }
 
 export interface WebviewInitData {
@@ -2040,3 +2046,11 @@ export interface SecretsMain {
 
 export type InlayHintDto = CachedSessionItem<InlayHint>;
 export type InlayHintsDto = CachedSession<{ hints: InlayHint[] }>;
+
+export interface IdentifiableInlineCompletions extends InlineCompletions<IdentifiableInlineCompletion> {
+    pid: number;
+}
+
+export interface IdentifiableInlineCompletion extends InlineCompletion {
+    idx: number;
+}

packages/plugin-ext/src/common/reference-map.ts

@@ -0,0 +1,38 @@
+// *****************************************************************************
+// Copyright (C) 2022 Ericsson 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
+// *****************************************************************************
+
+// copied from hhttps://github.com/microsoft/vscode/blob/6261075646f055b99068d3688932416f2346dd3b/src/vs/workbench/api/common/extHostLanguageFeatures.ts#L1291-L1310.
+
+export class ReferenceMap<T> {
+    private readonly _references = new Map<number, T>();
+    private _idPool = 1;
+
+    createReferenceId(value: T): number {
+        const id = this._idPool++;
+        this._references.set(id, value);
+        return id;
+    }
+
+    disposeReferenceId(referenceId: number): T | undefined {
+        const value = this._references.get(referenceId);
+        this._references.delete(referenceId);
+        return value;
+    }
+
+    get(referenceId: number): T | undefined {
+        return this._references.get(referenceId);
+    }
+}

packages/plugin-ext/src/main/browser/languages-main.ts

@@ -34,7 +34,8 @@ import {
     WorkspaceTextEditDto,
     PluginInfo,
     LanguageStatus as LanguageStatusDTO,
-    InlayHintDto
+    InlayHintDto,
+    IdentifiableInlineCompletions
 } from '../../common/plugin-api-rpc';
 import { injectable, inject } from '@theia/core/shared/inversify';
 import {
@@ -868,6 +869,22 @@ export class LanguagesMainImpl implements LanguagesMain, Disposable {
         }
     }
 
+    $registerInlineCompletionsSupport(handle: number, selector: SerializedDocumentFilter[]): void {
+        const languageSelector = this.toLanguageSelector(selector);
+        const provider: monaco.languages.InlineCompletionsProvider<IdentifiableInlineCompletions> = {
+            provideInlineCompletions: async (
+                model: monaco.editor.ITextModel,
+                position: monaco.Position,
+                context: monaco.languages.InlineCompletionContext,
+                token: CancellationToken
+            ): Promise<IdentifiableInlineCompletions | undefined> => this.proxy.$provideInlineCompletions(handle, model.uri, position, context, token),
+            freeInlineCompletions: (completions: IdentifiableInlineCompletions): void => {
+                this.proxy.$freeInlineCompletionsList(handle, completions.pid);
+            }
+        };
+        this.register(handle, (monaco.languages.registerInlineCompletionsProvider as RegistrationFunction<monaco.languages.InlineCompletionsProvider>)(languageSelector, provider));
+    }
+
     $registerQuickFixProvider(
         handle: number,
         pluginInfo: PluginInfo,

packages/plugin-ext/src/plugin/languages.ts

@@ -27,6 +27,7 @@ import {
     Plugin,
     InlayHintsDto,
     InlayHintDto,
+    IdentifiableInlineCompletions,
 } from '../common/plugin-api-rpc';
 import { RPCProtocol } from '../common/rpc-protocol';
 import * as theia from '@theia/plugin';
@@ -67,7 +68,8 @@ import {
     EvaluatableExpression,
     InlineValue,
     InlineValueContext,
-    TypeHierarchyItem
+    TypeHierarchyItem,
+    InlineCompletionContext
 } from '../common/plugin-api-rpc-model';
 import { CompletionAdapter } from './languages/completion';
 import { Diagnostics } from './languages/diagnostics';
@@ -106,6 +108,7 @@ import { Severity } from '@theia/core/lib/common/severity';
 import { LinkedEditingRangeAdapter } from './languages/linked-editing-range';
 import { serializeEnterRules, serializeIndentation, serializeRegExp } from './languages-utils';
 import { InlayHintsAdapter } from './languages/inlay-hints';
+import { InlineCompletionAdapter, InlineCompletionAdapterBase } from './languages/inline-completion';
 
 type Adapter = CompletionAdapter |
     SignatureHelpAdapter |
@@ -135,7 +138,8 @@ type Adapter = CompletionAdapter |
     DocumentRangeSemanticTokensAdapter |
     DocumentSemanticTokensAdapter |
     LinkedEditingRangeAdapter |
-    TypeHierarchyAdapter;
+    TypeHierarchyAdapter |
+    InlineCompletionAdapter;
 
 export class LanguagesExtImpl implements LanguagesExt {
 
@@ -275,6 +279,28 @@ export class LanguagesExtImpl implements LanguagesExt {
     }
     // ### Completion end
 
+    // ### Inline completion provider begin
+    registerInlineCompletionsProvider(selector: theia.DocumentSelector, provider: theia.InlineCompletionItemProvider): theia.Disposable {
+        const callId = this.addNewAdapter(new InlineCompletionAdapter(this.documents, provider, this.commands));
+        this.proxy.$registerInlineCompletionsSupport(callId, this.transformDocumentSelector(selector));
+        return this.createDisposable(callId);
+    }
+
+    $provideInlineCompletions(
+        handle: number,
+        resource: UriComponents,
+        position: Position,
+        context: InlineCompletionContext,
+        token: theia.CancellationToken
+    ): Promise<IdentifiableInlineCompletions | undefined> {
+        return this.withAdapter(handle, InlineCompletionAdapterBase, adapter => adapter.provideInlineCompletions(URI.revive(resource), position, context, token), undefined);
+    }
+
+    $freeInlineCompletionsList(handle: number, pid: number): void {
+        this.withAdapter(handle, InlineCompletionAdapterBase, async adapter => { adapter.disposeCompletions(pid); }, undefined);
+    }
+    // ### Inline completion provider end
+
     // ### Definition provider begin
     $provideDefinition(handle: number, resource: UriComponents, position: Position, token: theia.CancellationToken): Promise<Definition | undefined> {
         return this.withAdapter(handle, DefinitionAdapter, adapter => adapter.provideDefinition(URI.revive(resource), position, token), undefined);