From 67f48ebf845a40e73b4933f8b28b55a0a6019be6 Mon Sep 17 00:00:00 2001
From: Kristóf Marussy <kristof@marussy.com>
Date: Sun, 26 Dec 2021 21:28:32 +0100
Subject: refactor: Improve error handling in preload

---
 .../src/contextBridge/SophieRendererImpl.ts        | 58 ++++++++++++++++------
 1 file changed, 43 insertions(+), 15 deletions(-)

(limited to 'packages')

diff --git a/packages/preload/src/contextBridge/SophieRendererImpl.ts b/packages/preload/src/contextBridge/SophieRendererImpl.ts
index 5d29071..153fdd1 100644
--- a/packages/preload/src/contextBridge/SophieRendererImpl.ts
+++ b/packages/preload/src/contextBridge/SophieRendererImpl.ts
@@ -32,35 +32,63 @@ import { RendererToMainIpcService } from '../services/RendererToMainIpcService';
 class SophieRendererImpl implements SophieRenderer {
   readonly #ipcService: RendererToMainIpcService;
 
+  #onSharedStoreChangeCalled = false;
+
   #listener: SharedStoreListener | null = null;
 
   constructor(ipcService: RendererToMainIpcService) {
     this.#ipcService = ipcService;
     ipcService.onSharedStorePatch((patch) => {
-      // `mobx-state-tree` will validate the patch, so we can safely cast here.
-      this.#listener?.onPatch(patch as IJsonPatch);
+      try {
+        // `mobx-state-tree` will validate the patch, so we can safely cast here.
+        this.#listener?.onPatch(patch as IJsonPatch);
+      } catch (err) {
+        console.log('Shared store listener onPatch failed', err);
+      }
     });
   }
 
-  onSharedStoreChange(listener: SharedStoreListener): void {
-    this.#ipcService.getSharedStoreSnapshot().then((snapshot) => {
-      if (sharedStore.is(snapshot)) {
+  async #setSharedStoreChangeListener(listener: SharedStoreListener): Promise<void> {
+    let snapshot: unknown;
+    try {
+      snapshot = await this.#ipcService.getSharedStoreSnapshot();
+    } catch (err) {
+      console.error('Failed to get initial shared store snapshot', err);
+      return;
+    }
+    if (sharedStore.is(snapshot)) {
+      try {
         listener.onSnapshot(snapshot);
-        this.#listener = listener;
-      } else {
-        console.error('Got invalid initial shared store snapshot', snapshot);
+      } catch (err) {
+        console.error('Shared store listener onSnapshot failed', err);
+        return;
       }
-    }).catch((err) => {
-      console.error('Failed set initial shared store snapshot', err);
+      this.#listener = listener;
+      return;
+    }
+    console.error('Got invalid initial shared store snapshot', snapshot);
+  }
+
+  onSharedStoreChange(listener: SharedStoreListener): void {
+    if (this.#onSharedStoreChangeCalled) {
+      throw new Error('Shared store change listener was already set');
+    }
+    this.#setSharedStoreChangeListener(listener).catch((err) => {
+      console.log('Failed to set shared store change listener', err);
     });
   }
 
   dispatchAction(actionToDispatch: Action): void {
-    const parsedAction = action.safeParse(actionToDispatch);
-    if (parsedAction.success) {
-      this.#ipcService.dispatchAction(parsedAction.data);
-    } else {
-      console.error('Trying to dispatch invalid action', actionToDispatch, parsedAction.error);
+    // Let the full zod parse error bubble up to the main world,
+    // since all data it may contain was provided from the main world.
+    const parsedAction = action.parse(actionToDispatch);
+    try {
+      this.#ipcService.dispatchAction(parsedAction);
+    } catch (err) {
+      // Do not leak IPC failure details into the main world.
+      const message = 'Failed to dispatch action';
+      console.error(message, actionToDispatch, err);
+      throw new Error(message);
     }
   }
 }
-- 
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