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Support redef'ing the &log attribute of record fields

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Add new syntax for adding and removing attributes from record fields:

    redef RecordType$field_name += { &log };
    redef RecordType$field_name -= { &log };

For now this only allowed for the &log attribute as the semantics are clear.
For &default and &optional the semantics aren't obvious and no use-cases have
been identified where those would make sense to change.

This enables a mechanism to add potentially interesting fields to the typical
Info records in base scripts, but letting users opt-into actually including
them into their log. At the same time, users that find specific fields in a
standard log uninteresting can opt-out without using `Log::Filter$exclude`
which can be difficult to use correctly. Patching or forking external packages
to remove columns from a log can also be avoided with this mechanism.

Closes #2000.
This commit is contained in:
Arne Welzel 2022-08-05 18:05:22 +02:00
parent 0d0a057d89
commit 985bbe4e57
18 changed files with 237 additions and 0 deletions
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65
src/parse.y
View file

@ -189,6 +189,57 @@ static void parse_redef_enum(ID* id)
}
}
static void parse_redef_record_field(ID* id, const char* field, InitClass ic,
std::unique_ptr<std::vector<AttrPtr>> attrs)
{
if ( ! id->GetType() )
{
reporter->FatalError("unknown record identifier \"%s\"", id->Name());
return;
}
auto t = id->GetType();
if ( ! t || t->Tag() != TYPE_RECORD )
{
reporter->FatalError("identifier \"%s\" has type \"%s\", expected \"record\"",
id->Name(), type_name(t->Tag()));
return;
}
auto rt = t->AsRecordType();
auto idx = rt->FieldOffset(field);
if ( idx < 0 )
{
reporter->FatalError("field \"%s\" not in record \"%s\"", field, id->Name());
return;
}
auto decl = rt->FieldDecl(idx);
if ( ! decl->attrs )
if ( ic == INIT_EXTRA )
decl->attrs = make_intrusive<detail::Attributes>(decl->type,
true /* in_record */,
false /* is_global */);
for ( const auto& attr : *attrs )
{
// At this point, only support &log redef'ing.
if ( attr->Tag() != ATTR_LOG )
{
reporter->FatalError("Can only redef \"&log\" attributes of record fields");
return;
}
if ( ic == INIT_EXTRA )
decl->attrs->AddAttr(attr, true /* is_redef */);
else
// Removing attributes is a noop if they don't exist.
if ( decl->attrs )
decl->attrs->RemoveAttr(attr->Tag());
}
}
static void extend_record(ID* id, std::unique_ptr<type_decl_list> fields,
std::unique_ptr<std::vector<AttrPtr>> attrs)
{
@ -1306,6 +1357,20 @@ decl:
// Zeekygen already grabbed new enum IDs as the type created them.
}
| TOK_REDEF TOK_RECORD global_id '$' TOK_ID
{ cur_decl_type_id = $3; zeekygen_mgr->Redef($3, ::filename, INIT_EXTRA); }
TOK_ADD_TO '{' attr_list '}' ';'
{
cur_decl_type_id = 0;
parse_redef_record_field($3, $5, INIT_EXTRA, std::unique_ptr<std::vector<AttrPtr>>($9));
}
| TOK_REDEF TOK_RECORD global_id '$' TOK_ID
{ cur_decl_type_id = $3; zeekygen_mgr->Redef($3, ::filename, INIT_REMOVE); }
TOK_REMOVE_FROM '{' attr_list '}' ';'
{
cur_decl_type_id = 0;
parse_redef_record_field($3, $5, INIT_REMOVE, std::unique_ptr<std::vector<AttrPtr>>($9));
}
| TOK_REDEF TOK_RECORD global_id
{ cur_decl_type_id = $3; zeekygen_mgr->Redef($3, ::filename); }
TOK_ADD_TO '{'