From cafe1f96ef91c9bf5822c8274bd5b3e6eaec2723 Mon Sep 17 00:00:00 2001
From: Michael Naumov <mnaoumov@gmail.com>
Date: Thu, 12 Sep 2024 22:41:38 -0600
Subject: [PATCH] Ensure RenameDeleteHandler is executed only once

---
 src/obsidian/App.ts                 | 25 ++++++++++++++++++++++
 src/obsidian/RenameDeleteHandler.ts | 33 +++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/src/obsidian/App.ts b/src/obsidian/App.ts
index 86faa6a..ae9a80b 100644
--- a/src/obsidian/App.ts
+++ b/src/obsidian/App.ts
@@ -43,3 +43,28 @@ export function getApp(): App {
 
   throw new Error('Obsidian app not found');
 }
+
+interface ObsidianDevUtilsStateWrapper {
+  obsidianDevUtilsState: Record<string, unknown>;
+}
+
+/**
+ * Wrapper type for storing shared state in the Obsidian app.
+ */
+export class ValueWrapper<T> {
+  public constructor(public value: T) { }
+}
+
+/**
+ * Retrieves or creates a shared state wrapper object for a given key in the Obsidian app.
+ *
+ * @param app - The Obsidian app instance.
+ * @param key - The key to store or retrieve the shared state.
+ * @param defaultValue - The default value to use if the shared state does not exist.
+ * @returns The ValueWrapper object that stores the shared state.
+ */
+export function getObsidianDevUtilsState<T>(app: App, key: string, defaultValue: T): ValueWrapper<T> {
+  const sharedStateWrapper = app as Partial<ObsidianDevUtilsStateWrapper>;
+  const sharedState = sharedStateWrapper.obsidianDevUtilsState ??= {};
+  return (sharedState[key] ??= new ValueWrapper<T>(defaultValue)) as ValueWrapper<T>;
+}
diff --git a/src/obsidian/RenameDeleteHandler.ts b/src/obsidian/RenameDeleteHandler.ts
index 820cc5f..d3d494b 100644
--- a/src/obsidian/RenameDeleteHandler.ts
+++ b/src/obsidian/RenameDeleteHandler.ts
@@ -18,6 +18,7 @@ import {
   join,
   relative
 } from '../Path.ts';
+import { getObsidianDevUtilsState } from './App.ts';
 import { getAttachmentFolderPath } from './AttachmentPath.ts';
 import {
   extractLinkFile,
@@ -70,21 +71,49 @@ export interface RenameDeleteHandlerSettings {
  * @returns void
  */
 export function registerRenameDeleteHandlers(plugin: Plugin, settingsBuilder: () => RenameDeleteHandlerSettings): void {
+  const renameDeleteHandlerPluginIds = getRenameDeleteHandlerPluginIds(plugin.app);
+  const pluginId = plugin.manifest.id;
+
+  if (renameDeleteHandlerPluginIds.length > 0) {
+    console.warn(`Plugin ${pluginId} is registering a rename/delete handler, but it is already registered by plugins: ${renameDeleteHandlerPluginIds.join(', ')}. The handler for ${pluginId} will be skipped until all previous plugins are disabled.`);
+  }
+
+  renameDeleteHandlerPluginIds.push(pluginId);
+  plugin.register(() => {
+    renameDeleteHandlerPluginIds.remove(pluginId);
+  });
+
   const app = plugin.app;
   const renameDeleteHandler = new RenameDeleteHandler(app, settingsBuilder);
   plugin.registerEvent(
     app.vault.on('delete', (file) => {
+      if (!shouldInvokeHandler(app, pluginId, 'Delete')) {
+        return;
+      }
       invokeAsyncSafely(renameDeleteHandler.handleDelete(file));
     })
   );
 
   plugin.registerEvent(
     app.vault.on('rename', (file, oldPath) => {
+      if (!shouldInvokeHandler(app, pluginId, 'Rename')) {
+        return;
+      }
       invokeAsyncSafely(renameDeleteHandler.handleRename(file, oldPath));
     })
   );
 }
 
+function shouldInvokeHandler(app: App, pluginId: string, handlerType: string): boolean {
+  const renameDeleteHandlerPluginIds = getRenameDeleteHandlerPluginIds(app);
+  const mainPluginId = renameDeleteHandlerPluginIds[0];
+  if (mainPluginId !== pluginId) {
+    console.warn(`${handlerType} handler for plugin ${pluginId} is skipped, because it is handled by plugin ${mainPluginId ?? '(none)'}`);
+    return false;
+  }
+  return true;
+}
+
 class RenameDeleteHandler {
   public constructor(private app: App, private settingsBuilder: () => RenameDeleteHandlerSettings) { }
 
@@ -361,3 +390,7 @@ class RenameDeleteHandler {
     return backlinks;
   }
 }
+
+function getRenameDeleteHandlerPluginIds(app: App): string[] {
+  return getObsidianDevUtilsState<string[]>(app, 'renameDeleteHandlerPluginIds', []).value;
+}