[ios, macos] Accept absolute file paths as style URLs (#6026)

It turns out that mbgl::AssetFileSource supports absolute file URLs in addition to relative file URLs. So replace the file: scheme with asset: while percent-escaping as necessary.

Also added amsterdam.geojson to macos.xcodeproj for consistency with ios.xcodeproj.

1 files changed, 21 insertions, 0 deletions

diff --git a/platform/darwin/src/NSURL+MGLAdditions.m b/platform/darwin/src/NSURL+MGLAdditions.m
new file mode 100644
index 0000000000..11b84ed8fa
--- /dev/null
+++ b/platform/darwin/src/NSURL+MGLAdditions.m
@@ -0,0 +1,21 @@
+#import "NSURL+MGLAdditions.h"
+
+@implementation NSURL (MGLAdditions)
+
+- (nullable NSURL *)mgl_URLByStandardizingScheme {
+    if (!self.scheme) {
+        // Relative file URL, already escaped (in order to create the NSURL).
+        // Assume a relative path into the application’s resource folder.
+        return [NSURL URLWithString:[@"asset://" stringByAppendingString:self.absoluteString]];
+    } else if (self.fileURL) {
+        // Absolute file URL, so construct a new URL using the unescaped path.
+        NSURLComponents *components = [[NSURLComponents alloc] init];
+        components.scheme = @"asset";
+        components.host = @"";
+        components.path = self.path;
+        return components.URL;
+    }
+    return self;
+}
+
+@end