Skip IO errors in web frontend on non-relative URIs

lib/cmd_line.dart

@@ -418,12 +418,12 @@ ResourcesLoader getFileResourceValidator(
       // GLB-stored buffer
       return readerResult.buffer;
     }
-    if (isNonRelativeUri(uri)) {
+    if (uri.isNonRelative) {
       return null;
     }
     return fileGuarded(uri).readAsBytes();
   }, externalStreamFetch: (uri) {
-    if (isNonRelativeUri(uri)) {
+    if (uri.isNonRelative) {
       return null;
     }
     return fileGuarded(uri).openRead();

lib/src/utils.dart

@@ -166,7 +166,7 @@ String getString(Map<String, Object> map, String name, Context context,
 Uri getUri(String uriString, Context context) {
   try {
     final uri = Uri.parse(uriString);
-    if (isNonRelativeUri(uri)) {
+    if (uri.isNonRelative) {
       context
           .addIssue(SemanticError.nonRelativeUri, name: URI, args: [uriString]);
     }
@@ -727,13 +727,6 @@ bool isTrsDecomposable(Matrix4 matrix) {
 
 bool isPot(int value) => (value != 0) && (value & (value - 1) == 0);
 
-bool isNonRelativeUri(Uri uri) =>
-    uri.hasScheme ||
-    uri.hasAuthority ||
-    uri.hasAbsolutePath ||
-    uri.hasQuery ||
-    uri.hasFragment;
-
 int padLength(int length) => length + (-length & 3);
 
 List<int> createTypedIntList(int type, int length) {
@@ -766,6 +759,11 @@ extension Vector3IsOneOrZero on Vector3 {
   bool get isZero => x == 0 && y == 0 && z == 0;
 }
 
+extension IsNonRelativeUri on Uri {
+  bool get isNonRelative =>
+      hasScheme || hasAuthority || hasAbsolutePath || hasQuery || hasFragment;
+}
+
 abstract class ElementChecker<T extends num> {
   const ElementChecker();
   String get path => '';

test/utils.dart

@@ -20,7 +20,7 @@ import 'dart:io';
 
 import 'package:gltf/gltf.dart';
 import 'package:gltf/src/errors.dart';
-import 'package:gltf/src/utils.dart' show isNonRelativeUri;
+import 'package:gltf/src/utils.dart' show IsNonRelativeUri;
 import 'package:test/test.dart';
 
 Future compareReports(String basePath) async {
@@ -73,7 +73,7 @@ ResourcesLoader _getFileResourceValidator(
         // GLB-stored buffer
         return readerResult.buffer;
       }
-      if (isNonRelativeUri(uri)) {
+      if (uri.isNonRelative) {
         return null;
       }
 
@@ -83,7 +83,7 @@ ResourcesLoader _getFileResourceValidator(
         throw GltfExternalResourceNotFoundException(uri.toString());
       });
     }, externalStreamFetch: (uri) {
-      if (isNonRelativeUri(uri)) {
+      if (uri.isNonRelative) {
         return null;
       }
       // TODO: refactor resource loader to remove this

web/scripts/validator.dart

@@ -27,6 +27,7 @@ import 'dart:math';
 
 import 'dart:typed_data';
 import 'package:gltf/gltf.dart';
+import 'package:gltf/src/utils.dart';
 
 const _kChunkSize = 1024 * 1024;
 const _kMaxReportLength = 512 * 1024;
@@ -143,6 +144,9 @@ Future<ValidationResult> _doValidate(List<File> files) async {
     final resourcesLoader = ResourcesLoader(context, readerResult.gltf,
         externalBytesFetch: ([uri]) {
       if (uri != null) {
+        if (uri.isNonRelative) {
+          return null;
+        }
         final file = _getFileByUri(files, uri);
         if (file != null) {
           return _getFile(file);
@@ -154,6 +158,9 @@ Future<ValidationResult> _doValidate(List<File> files) async {
       }
     }, externalStreamFetch: (uri) {
       if (uri != null) {
+        if (uri.isNonRelative) {
+          return null;
+        }
         final file = _getFileByUri(files, uri);
         if (file != null) {
           return _getFileStream(file);