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LibJS: Use the EnumerateObjectProperties AO to print objects

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Instead of just iterating indexed properties and direct properties on
the object's shape, let's walk the prototype chain and grab every
non-symbol property by re-using the AO for for-in statements.

We'll probably want to move this to a custom algorithm just for pretty
printing that doesn't skip some property types, but this already gives
a major improvement when printing LegacyPlatformObjects from LibWeb to
the console.
This commit is contained in:
Andrew Kaster 2023-01-08 11:09:24 -07:00 • committed by Linus Groh
parent f40094d014
commit 2bec236ea6
1 changed files with 34 additions and 18 deletions
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52
Userland/Libraries/LibJS/Print.cpp
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@ -188,29 +188,45 @@ ErrorOr<void> print_array(JS::PrintContext& print_context, JS::Array const& arra
ErrorOr<void> print_object(JS::PrintContext& print_context, JS::Object const& object, HashTable<JS::Object*>& seen_objects)
{
TRY(js_out(print_context, "{{"));
TRY(js_out(print_context, "{}{{", object.class_name()));
bool first = true;
for (auto& entry : object.indexed_properties()) {
TRY(print_separator(print_context, first));
TRY(js_out(print_context, "\"\033[33;1m{}\033[0m\": ", entry.index()));
auto value_or_error = object.get(entry.index());
// The V8 repl doesn't throw an exception here, and instead just
static constexpr size_t max_number_of_new_objects = 20; // Arbitrary limit
size_t original_num_seen_objects = seen_objects.size();
auto maybe_completion = object.enumerate_object_properties([&](JS::Value property_key) -> Optional<JS::Completion> {
// The V8 repl doesn't throw an exception on accessing properties, and instead just
// prints 'undefined'. We may choose to replicate that behavior in
// the future, but for now lets just catch the error
auto error = print_separator(print_context, first);
if (error.is_error())
return JS::js_undefined();
error = js_out(print_context, "\033[33;1m");
if (error.is_error())
return JS::js_undefined();
error = print_value(print_context, property_key, seen_objects);
// NOTE: Ignore this error to always print out "reset" ANSI sequence
error = js_out(print_context, "\033[0m: ");
if (error.is_error())
return JS::js_undefined();
auto maybe_property_key = JS::PropertyKey::from_value(print_context.vm, property_key);
if (maybe_property_key.is_error())
return JS::js_undefined();
auto value_or_error = object.get(maybe_property_key.value());
if (value_or_error.is_error())
return {};
return JS::js_undefined();
auto value = value_or_error.release_value();
TRY(print_value(print_context, value, seen_objects));
}
for (auto& it : object.shape().property_table_ordered()) {
TRY(print_separator(print_context, first));
if (it.key.is_string()) {
TRY(js_out(print_context, "\"\033[33;1m{}\033[0m\": ", it.key.to_display_string()));
} else {
TRY(js_out(print_context, "[\033[33;1m{}\033[0m]: ", it.key.to_display_string()));
}
TRY(print_value(print_context, object.get_direct(it.value.offset), seen_objects));
}
error = print_value(print_context, value, seen_objects);
// FIXME: Come up with a better way to structure the data so that we don't care about this limit
if (seen_objects.size() > original_num_seen_objects + max_number_of_new_objects)
return JS::js_undefined(); // Stop once we've seen a ton of objects, to prevent spamming the console.
if (error.is_error())
return JS::js_undefined();
return {};
});
// Swallow Error/undefined from printing properties
if (maybe_completion.has_value())
return {};
if (!first)
TRY(js_out(print_context, " "));
TRY(js_out(print_context, "}}"));