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#include "eval/compiler/qualified_reference_resolver.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/str_cat.h"
#include "absl/types/optional.h"
#include "eval/eval/const_value_step.h"
#include "eval/eval/expression_build_warning.h"
#include "eval/public/cel_builtins.h"
#include "eval/public/cel_function_registry.h"
#include "base/status_macros.h"
namespace google {
namespace api {
namespace expr {
namespace runtime {
namespace {
using google::api::expr::v1alpha1::Expr;
using google::api::expr::v1alpha1::Reference;
class ReferenceResolver {
public:
ReferenceResolver(const google::protobuf::Map<int64_t, Reference>& reference_map,
BuilderWarnings* warnings)
: reference_map_(reference_map), warnings_(warnings) {}
// Attempt to resolve references in expr. Return true if part of the
// expression was rewritten.
absl::StatusOr<bool> Rewrite(Expr* out) {
absl::StatusOr<bool> maybe_rewrite_result = MaybeRewriteReferences(out);
RETURN_IF_ERROR(maybe_rewrite_result.status());
if (maybe_rewrite_result.value()) {
return true;
}
// If we don't have a rewrite rule, continue traversing the AST.
switch (out->expr_kind_case()) {
case Expr::kConstExpr: {
return false;
}
case Expr::kIdentExpr:
return false;
case Expr::kSelectExpr: {
return Rewrite(out->mutable_select_expr()->mutable_operand());
}
case Expr::kCallExpr: {
auto* call_expr = out->mutable_call_expr();
const bool receiver_style = call_expr->has_target();
const int arg_num = call_expr->args_size();
bool args_updated = false;
if (receiver_style) {
absl::StatusOr<bool> rewrite_result =
Rewrite(call_expr->mutable_target());
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
}
for (int i = 0; i < arg_num; i++) {
absl::StatusOr<bool> rewrite_result =
Rewrite(call_expr->mutable_args(i));
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
}
return args_updated;
}
case Expr::kListExpr: {
auto* list_expr = out->mutable_list_expr();
int list_size = list_expr->elements_size();
bool args_updated = false;
for (int i = 0; i < list_size; i++) {
absl::StatusOr<bool> rewrite_result =
Rewrite(list_expr->mutable_elements(i));
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
}
return args_updated;
}
case Expr::kStructExpr: {
auto* struct_expr = out->mutable_struct_expr();
int entries_size = struct_expr->entries_size();
bool args_updated = false;
for (int i = 0; i < entries_size; i++) {
auto* new_entry = struct_expr->mutable_entries(i);
switch (new_entry->key_kind_case()) {
case Expr::CreateStruct::Entry::kFieldKey:
// Nothing to do.
break;
case Expr::CreateStruct::Entry::kMapKey:
args_updated =
Rewrite(new_entry->mutable_map_key()).ok() || args_updated;
break;
default:
GOOGLE_LOG(ERROR) << "Unsupported Entry kind: "
<< new_entry->key_kind_case();
break;
}
args_updated =
Rewrite(new_entry->mutable_value()).ok() || args_updated;
}
return args_updated;
}
case Expr::kComprehensionExpr: {
auto* out_expr = out->mutable_comprehension_expr();
bool args_updated = false;
absl::StatusOr<bool> rewrite_result;
rewrite_result = Rewrite(out_expr->mutable_accu_init());
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
rewrite_result = Rewrite(out_expr->mutable_iter_range());
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
rewrite_result = Rewrite(out_expr->mutable_loop_condition());
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
rewrite_result = Rewrite(out_expr->mutable_loop_step());
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
rewrite_result = Rewrite(out_expr->mutable_result());
RETURN_IF_ERROR(rewrite_result.status());
args_updated = args_updated || rewrite_result.value();
return args_updated;
}
default:
GOOGLE_LOG(ERROR) << "Unsupported Expr kind: " << out->expr_kind_case();
return false;
}
}
private:
// Attempts to apply rewrites for reference map. Returns true if rewrites
// occur.
absl::StatusOr<bool> MaybeRewriteReferences(Expr* expr) {
const auto iter = reference_map_.find(expr->id());
if (iter == reference_map_.end()) {
return false;
}
const Reference& reference = iter->second;
if (reference.has_value() || !reference.overload_id().empty()) {
// TODO(issues/71): Add support for functions and compile time
// constants.
return false;
}
switch (expr->expr_kind_case()) {
case Expr::ExprKindCase::kIdentExpr:
if (reference.name() != expr->ident_expr().name()) {
// Possibly shorthand for a namespaced name.
expr->clear_ident_expr();
expr->mutable_ident_expr()->set_name(reference.name());
return true;
} else {
return false;
}
case Expr::ExprKindCase::kStructExpr:
// reference to a create struct message type. nothing to do.
// TODO(issues/72): annotating the execution plan with this may help
// identify problems with the environment setup. This will probably
// also require the type map information from a checked expression.
return false;
case Expr::ExprKindCase::kSelectExpr:
if (expr->select_expr().test_only()) {
RETURN_IF_ERROR(warnings_->AddWarning(
absl::InvalidArgumentError("Reference map points to a presence "
"test -- has(container.attr)")));
return false;
}
expr->clear_select_expr();
expr->mutable_ident_expr()->set_name(reference.name());
return true;
default:
RETURN_IF_ERROR(
warnings_->AddWarning(absl::InvalidArgumentError(absl::StrCat(
"Unsupported reference kind: ", expr->expr_kind_case()))));
return false;
}
}
const google::protobuf::Map<int64_t, Reference>& reference_map_;
BuilderWarnings* warnings_;
};
} // namespace
absl::StatusOr<absl::optional<Expr>> ResolveReferences(
const Expr& expr, const google::protobuf::Map<int64_t, Reference>& reference_map,
BuilderWarnings* warnings) {
Expr out(expr);
ReferenceResolver resolver(reference_map, warnings);
absl::StatusOr<bool> rewrite_result = resolver.Rewrite(&out);
if (!rewrite_result.ok()) {
return rewrite_result.status();
} else if (rewrite_result.value()) {
return absl::optional<Expr>(out);
} else {
return absl::optional<Expr>();
}
}
} // namespace runtime
} // namespace expr
} // namespace api
} // namespace google