macOS: optional lift of WKWebView's 60fps requestAnimationFrame cap

src/bridge/root.zig

@@ -2,12 +2,33 @@ const std = @import("std");
 const json = @import("json");
 const security = @import("../security/root.zig");
 
-pub const max_message_bytes: usize = 1024 * 1024;
-pub const max_response_bytes: usize = 1024 * 1024;
-pub const max_result_bytes: usize = 1024 * 1024;
+// Requests may carry base64-encoded image/video bytes (annex.media.write), so
+// the request cap matches the response caps. At 1 MB, any write of a file whose
+// base64 exceeded ~750 KB was rejected as "too large" — and that rejection
+// carries an empty id, so the JS promise never resolves and the call hangs.
+pub const max_message_bytes: usize = 48 * 1024 * 1024;
+// Responses/results may carry base64-encoded HTTP bodies (e.g. images) from the
+// native net.fetch bridge, so these are sized generously (48 MB). Buffers of this
+// size must never live on the stack — see the shared static buffers below.
+pub const max_response_bytes: usize = 48 * 1024 * 1024;
+pub const max_result_bytes: usize = 48 * 1024 * 1024;
 pub const max_id_bytes: usize = 64;
 pub const max_command_bytes: usize = 128;
 
+// Bridge dispatch runs on the single main event-loop thread, so these large
+// buffers are shared statics rather than per-call stack arrays (a 48 MB stack
+// allocation would overflow the thread stack).
+var shared_response_buffer: [max_response_bytes]u8 = undefined;
+var shared_result_buffer: [max_result_bytes]u8 = undefined;
+
+pub fn sharedResponseBuffer() []u8 {
+    return &shared_response_buffer;
+}
+
+pub fn sharedResultBuffer() []u8 {
+    return &shared_result_buffer;
+}
+
 const null_json = "null";
 
 pub const ErrorCode = enum {
@@ -95,13 +116,11 @@ pub const AsyncResponder = struct {
     }
 
     pub fn success(self: AsyncResponder, id: []const u8, result: []const u8) anyerror!void {
-        var buffer: [max_response_bytes]u8 = undefined;
-        try self.respond(writeSuccessResponse(&buffer, id, result));
+        try self.respond(writeSuccessResponse(sharedResponseBuffer(), id, result));
     }
 
     pub fn fail(self: AsyncResponder, id: []const u8, code: ErrorCode, message: []const u8) anyerror!void {
-        var buffer: [max_response_bytes]u8 = undefined;
-        try self.respond(writeErrorResponse(&buffer, id, code, message));
+        try self.respond(writeErrorResponse(sharedResponseBuffer(), id, code, message));
     }
 };
 
@@ -155,8 +174,7 @@ pub const Dispatcher = struct {
             return writeErrorResponse(output, request.id, .unknown_command, "Bridge command is not registered");
         };
 
-        var result_buffer: [max_result_bytes]u8 = undefined;
-        const result = handler.invoke_fn(handler.context, .{ .request = request, .source = source }, &result_buffer) catch |err| {
+        const result = handler.invoke_fn(handler.context, .{ .request = request, .source = source }, sharedResultBuffer()) catch |err| {
             return writeErrorResponse(output, request.id, .handler_failed, @errorName(err));
         };
         return writeSuccessResponse(output, request.id, if (result.len == 0) null_json else result);

src/platform/macos/appkit_host.h

@@ -95,6 +95,10 @@ typedef struct {
     size_t tertiary_button_len;
 } zero_native_appkit_message_dialog_opts_t;
 
+typedef void (*zero_native_appkit_http_fetch_callback_t)(void *ctx, int status, const char *json_utf8, size_t json_len);
+
+void zero_native_appkit_http_fetch_async(zero_native_appkit_host_t *host, const char *url, size_t url_len, zero_native_appkit_http_fetch_callback_t callback, void *ctx);
+
 typedef void (*zero_native_appkit_tray_callback_t)(void *context, uint32_t item_id);
 
 zero_native_appkit_open_dialog_result_t zero_native_appkit_show_open_dialog(zero_native_appkit_host_t *host, const zero_native_appkit_open_dialog_opts_t *opts, char *buffer, size_t buffer_len);