#86678 Implement syncing snippets

src/vs/platform/userDataSync/common/snippetsMerge.ts

@@ -0,0 +1,169 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { values } from 'vs/base/common/map';
+import { IStringDictionary } from 'vs/base/common/collections';
+import { deepClone } from 'vs/base/common/objects';
+
+export interface IMergeResult {
+	added: IStringDictionary<string>;
+	updated: IStringDictionary<string>;
+	removed: string[];
+	conflicts: string[];
+	remote: IStringDictionary<string> | null;
+}
+
+export function merge(local: IStringDictionary<string>, remote: IStringDictionary<string> | null, base: IStringDictionary<string> | null): IMergeResult {
+	const added: IStringDictionary<string> = {};
+	const updated: IStringDictionary<string> = {};
+	const removed: string[] = [];
+
+	if (!remote) {
+		return {
+			added,
+			removed,
+			updated,
+			conflicts: [],
+			remote: local
+		};
+	}
+
+	const localToRemote = compare(local, remote);
+	if (localToRemote.added.size === 0 && localToRemote.removed.size === 0 && localToRemote.updated.size === 0) {
+		// No changes found between local and remote.
+		return {
+			added,
+			removed,
+			updated,
+			conflicts: [],
+			remote: null
+		};
+	}
+
+	const baseToLocal = compare(base, local);
+	const baseToRemote = compare(base, remote);
+	const conflicts: Set<string> = new Set<string>();
+	let remoteContent: IStringDictionary<string> = deepClone(remote);
+
+	// Removed snippets in Local
+	for (const key of values(baseToLocal.removed)) {
+		// Conflict - Got updated in remote.
+		if (baseToRemote.updated.has(key)) {
+			// Add to local
+			added[key] = remote[key];
+		}
+		// Remove it in remote
+		else {
+			delete remoteContent[key];
+		}
+	}
+
+	// Removed snippets in Remote
+	for (const key of values(baseToRemote.removed)) {
+		if (conflicts.has(key)) {
+			continue;
+		}
+		// Conflict - Got updated in local
+		if (baseToLocal.updated.has(key)) {
+			conflicts.add(key);
+		}
+		// Also remove in Local
+		else {
+			removed.push(key);
+		}
+	}
+
+	// Updated snippets in Local
+	for (const key of values(baseToLocal.updated)) {
+		if (conflicts.has(key)) {
+			continue;
+		}
+		// Got updated in remote
+		if (baseToRemote.updated.has(key)) {
+			// Has different value
+			if (localToRemote.updated.has(key)) {
+				conflicts.add(key);
+			}
+		} else {
+			remoteContent[key] = local[key];
+		}
+	}
+
+	// Updated snippets in Remote
+	for (const key of values(baseToRemote.updated)) {
+		if (conflicts.has(key)) {
+			continue;
+		}
+		// Got updated in local
+		if (baseToLocal.updated.has(key)) {
+			// Has different value
+			if (localToRemote.updated.has(key)) {
+				conflicts.add(key);
+			}
+		} else if (local[key] !== undefined) {
+			updated[key] = remote[key];
+		}
+	}
+
+	// Added snippets in Local
+	for (const key of values(baseToLocal.added)) {
+		if (conflicts.has(key)) {
+			continue;
+		}
+		// Got added in remote
+		if (baseToRemote.added.has(key)) {
+			// Has different value
+			if (localToRemote.updated.has(key)) {
+				conflicts.add(key);
+			}
+		} else {
+			remoteContent[key] = local[key];
+		}
+	}
+
+	// Added snippets in remote
+	for (const key of values(baseToRemote.added)) {
+		if (conflicts.has(key)) {
+			continue;
+		}
+		// Got added in local
+		if (baseToLocal.added.has(key)) {
+			// Has different value
+			if (localToRemote.updated.has(key)) {
+				conflicts.add(key);
+			}
+		} else {
+			added[key] = remote[key];
+		}
+	}
+
+	return { added, removed, updated, conflicts: values(conflicts), remote: areSame(remote, remoteContent) ? null : remoteContent };
+}
+
+function compare(from: IStringDictionary<string> | null, to: IStringDictionary<string> | null): { added: Set<string>, removed: Set<string>, updated: Set<string> } {
+	const fromKeys = from ? Object.keys(from) : [];
+	const toKeys = to ? Object.keys(to) : [];
+	const added = toKeys.filter(key => fromKeys.indexOf(key) === -1).reduce((r, key) => { r.add(key); return r; }, new Set<string>());
+	const removed = fromKeys.filter(key => toKeys.indexOf(key) === -1).reduce((r, key) => { r.add(key); return r; }, new Set<string>());
+	const updated: Set<string> = new Set<string>();
+
+	for (const key of fromKeys) {
+		if (removed.has(key)) {
+			continue;
+		}
+		const fromSnippet = from![key]!;
+		const toSnippet = to![key]!;
+		if (fromSnippet !== toSnippet) {
+			updated.add(key);
+		}
+	}
+
+	return { added, removed, updated };
+}
+
+function areSame(a: IStringDictionary<string>, b: IStringDictionary<string>): boolean {
+	const { added, removed, updated } = compare(a, b);
+	return added.size === 0 && removed.size === 0 && updated.size === 0;
+}