[Win32] Reduce usage of long paths in assets which can cause long path issues (#11839)

* Add saveAssetPlugin to fix long path assets

* Change files

* comment

* add back compat

* fix

* turn off win32 assetPlugin for now

* fix

* fix

* fix

* Change files

* fix

Author: acoates-ms

change/@office-iss-react-native-win32-43b80e6f-96e4-479c-b4d7-46c1fb056647.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "Add saveAssetPlugin to fix long path assets",
+  "packageName": "@office-iss/react-native-win32",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}

change/react-native-windows-c92794d1-18fd-49dc-a15e-a50992c2413c.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "Fix CoreApp build failure with latest VS version",
+  "packageName": "react-native-windows",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}

packages/@office-iss/react-native-win32/metro.config.js

@@ -14,3 +14,5 @@ if (
 
 const {makeMetroConfig} = require('@rnw-scripts/metro-dev-config');
 module.exports = makeMetroConfig();
+// Enable this when RN CLI gets support for saveAssetPlugins: https://github.com/react-native-community/cli/pull/2002
+// module.exports.transformer.assetPlugins = [require.resolve('./metroShortPathAssetDataPlugin.js')];

packages/@office-iss/react-native-win32/metroShortPathAssetDataPlugin.js

@@ -0,0 +1,15 @@
+// @ts-check
+/**
+ * @typedef {import("metro").AssetData} AssetData;
+ **/
+
+/**
+ * @param {AssetData & {__useShortPath: boolean}} asset
+ * @returns {Promise<AssetData>}
+ */
+async function metroShortPathAssetDataPlugin(asset) {
+  asset.__useShortPath = true;
+  return Promise.resolve(asset);
+  }
+
+module.exports = metroShortPathAssetDataPlugin;

packages/@office-iss/react-native-win32/overrides.json

@@ -233,6 +233,10 @@
       "baseFile": "packages/react-native/Libraries/DevToolsSettings/DevToolsSettingsManager.android.js",
       "baseHash": "1c9eb481e8ed077fa650e3ea34837e2a31310366"
     },
+    {
+      "type": "platform",
+      "file": "src/Libraries/Image/assetPaths.js"
+    },
     {
       "type": "derived",
       "file": "src/Libraries/Image/Image.win32.js",

packages/@office-iss/react-native-win32/react-native.config.js

@@ -7,6 +7,8 @@ module.exports = {
         projectConfig: (projectRoot, projectParams) => null,
         dependencyConfig: (projectRoot, dependencyParams) => null,
         npmPackageName: '@office-iss/react-native-win32',
+        // Enable once CLI config supports it - https://github.com/react-native-community/cli/pull/2002
+        // saveAssetsPlugin: '@office-iss/react-native-win32/saveAssetPlugin'
       },
     },
   };

packages/@office-iss/react-native-win32/saveAssetPlugin.js

@@ -0,0 +1,45 @@
+// @ts-check
+const path = require('path');
+const ensureShortPath = require('./Libraries/Image/assetPaths');
+
+/**
+ * @typedef {import("metro").AssetData} AssetData;
+ **/
+
+/**
+ * @param {AssetData} asset
+ * @param {number} scale 
+ * @returns {string}
+ */
+function getAssetDestPath(asset, scale) {
+  const suffix = scale === 1 ? '' : `@${scale}x`;
+  const fileName = `${asset.name + suffix}.${asset.type}`;
+  return path.join(
+    // Assets can have relative paths outside of the project root.
+    // Replace `../` with `_` to make sure they don't end up outside of
+    // the expected assets directory.
+    ensureShortPath(asset.httpServerLocation.substr(1).replace(/\.\.\//g, '_')),
+    fileName,
+  );
+}
+
+/**
+ * @param {ReadonlyArray<AssetData>} assets 
+ * @param {string} _platform 
+ * @param {string | undefined} _assetsDest 
+ * @param {string | undefined} _assetCatalogDest 
+ * @param {(asset: AssetData, allowedScales: number[] | undefined, getAssetDestPath: (asset: AssetData, scale: number) => string) => void} addAssetToCopy 
+ */
+function saveAssetsWin32(
+  assets,
+  _platform,
+  _assetsDest,
+  _assetCatalogDest,
+  addAssetToCopy,
+) {
+  assets.forEach((asset) =>
+    addAssetToCopy(asset, undefined, getAssetDestPath),
+  );
+}
+
+module.exports = saveAssetsWin32;

packages/@office-iss/react-native-win32/src/Libraries/Image/assetPaths.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+'use strict';
+
+// Some windows machines may not have long paths enabled
+// https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation
+// Assets in nested node_modules (common when using pnpm) - end up creating very long paths
+// Using this function we shorten longer paths to prevent paths from hitting the path limit
+function ensureShortPath(str: string): string {
+  if (str.length < 40) return str;
+
+  const assetsPrefix = 'assets/';
+
+  if (!str.startsWith(assetsPrefix)) {
+    console.warn(`Unexpected asset uri - ${str} may not load correctly.`);
+  }
+
+  const postStr = str.slice(assetsPrefix.length);
+  var hash = 0,
+    i,
+    chr;
+  for (i = 0; i < postStr.length; i++) {
+    chr = postStr.charCodeAt(i);
+    hash = (hash << 5) - hash + chr;
+    hash |= 0; // Convert to 32bit integer
+  }
+  return assetsPrefix + hash.toString();
+}
+
+module.exports = ensureShortPath;

packages/@office-iss/react-native-win32/src/Libraries/Image/resolveAssetSource.win32.js

@@ -10,6 +10,7 @@
 
 const resolveAssetSource = require('./resolveAssetSource.js'); // Get base impl
 const Platform = require('../Utilities/Platform');
+const ensureShortPath = require('./assetPaths.js');
 
 type IPackagerAsset = {
   __packager_asset: boolean,
@@ -56,7 +57,7 @@ class AssetResolverLateScaleResolution {
    */
   _scaledAssetURLInBundle() {
     const path = this._resolver.bundleUrl || 'file://';
-    return this._fromSource(path + this._getAssetPath());
+    return this._fromSource(path + this._getAssetPath(true));
   }
 
   /**
@@ -66,7 +67,7 @@ class AssetResolverLateScaleResolution {
   _assetServerURL() {
     return this._fromSource(
       this._resolver.serverUrl +
-        this._getAssetPath() +
+        this._getAssetPath(false) +
         '?platform=' +
         Platform.OS +
         '&hash=' +
@@ -77,8 +78,8 @@ class AssetResolverLateScaleResolution {
   /**
    * Returns a path like 'assets/AwesomeModule/icon.png'
    */
-  _getAssetPath(): string {
-    const assetDir = this._getBasePath();
+  _getAssetPath(local: boolean): string {
+    const assetDir = this._getBasePath(local);
     return (
       assetDir +
       '/' +
@@ -88,7 +89,19 @@ class AssetResolverLateScaleResolution {
     );
   }
 
-  _getBasePath() {
+  _getBasePath(local: boolean) {
+    if (local) {
+      const safePath = this._resolver.asset.httpServerLocation
+        .substr(1)
+        .replace(/\.\.\//g, '_');
+      // If this asset was created with the newer saveAssetPlugin, then we should shorten the path
+      // This conditional is added to allow back compat of older bundles which might have been created without the saveAssetPlugin
+      if (this._resolver.asset.__useShortPath) {
+        return ensureShortPath(safePath);
+      }
+      return safePath;
+    }
+
     let basePath = this._resolver.asset.httpServerLocation;
     if (basePath[0] === '/') {
       basePath = basePath.substr(1);