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jnthntatum
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Draft: add support for cloning cel::Expr.
PiperOrigin-RevId: 723626957
1 parent 148c393 commit 77aad9d

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‎common/BUILD‎

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@@ -33,6 +33,7 @@ cc_library(
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"@com_google_absl//absl/algorithm:container",
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"@com_google_absl//absl/base:core_headers",
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"@com_google_absl//absl/base:no_destructor",
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"@com_google_absl//absl/functional:overload",
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"@com_google_absl//absl/strings:string_view",
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"@com_google_absl//absl/types:optional",
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"@com_google_absl//absl/types:span",

‎common/expr.cc‎

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@@ -14,10 +14,124 @@
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#include "common/expr.h"
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#include <vector>
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#include "absl/base/no_destructor.h"
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#include "absl/functional/overload.h"
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#include "absl/types/variant.h"
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#include "common/constant.h"
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namespace cel {
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namespace {
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struct CopyStackRecord {
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const Expr* src;
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Expr* dst;
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};
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void CopyNode(CopyStackRecord element, std::vector<CopyStackRecord>& stack) {
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const Expr* src = element.src;
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Expr* dst = element.dst;
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dst->set_id(src->id());
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absl::visit(
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absl::Overload(
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[](const UnspecifiedExpr&) {},
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[=](const IdentExpr& i) {
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dst->mutable_ident_expr().set_name(i.name());
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},
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[=](const Constant& c) { dst->mutable_const_expr() = c; },
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[&](const SelectExpr& s) {
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dst->mutable_select_expr().set_field(s.field());
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dst->mutable_select_expr().set_test_only(s.test_only());
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if (s.has_operand()) {
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stack.push_back({&s.operand(),
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&dst->mutable_select_expr().mutable_operand()});
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}
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},
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[&](const CallExpr& c) {
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dst->mutable_call_expr().set_function(c.function());
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if (c.has_target()) {
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stack.push_back(
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{&c.target(), &dst->mutable_call_expr().mutable_target()});
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}
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dst->mutable_call_expr().mutable_args().resize(c.args().size());
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for (int i = 0; i < dst->mutable_call_expr().mutable_args().size();
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++i) {
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stack.push_back(
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{&c.args()[i], &dst->mutable_call_expr().mutable_args()[i]});
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}
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},
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[&](const ListExpr& c) {
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auto& dst_list = dst->mutable_list_expr();
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dst_list.mutable_elements().resize(c.elements().size());
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for (int i = 0; i < src->list_expr().elements().size(); ++i) {
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dst_list.mutable_elements()[i].set_optional(
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c.elements()[i].optional());
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stack.push_back({&c.elements()[i].expr(),
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&dst_list.mutable_elements()[i].mutable_expr()});
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}
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},
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[&](const StructExpr& s) {
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auto& dst_struct = dst->mutable_struct_expr();
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dst_struct.mutable_fields().resize(s.fields().size());
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dst_struct.set_name(s.name());
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for (int i = 0; i < s.fields().size(); ++i) {
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dst_struct.mutable_fields()[i].set_optional(
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s.fields()[i].optional());
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dst_struct.mutable_fields()[i].set_name(s.fields()[i].name());
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dst_struct.mutable_fields()[i].set_id(s.fields()[i].id());
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stack.push_back(
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{&s.fields()[i].value(),
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&dst_struct.mutable_fields()[i].mutable_value()});
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}
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},
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[&](const MapExpr& c) {
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auto& dst_map = dst->mutable_map_expr();
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dst_map.mutable_entries().resize(c.entries().size());
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for (int i = 0; i < c.entries().size(); ++i) {
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dst_map.mutable_entries()[i].set_optional(
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c.entries()[i].optional());
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dst_map.mutable_entries()[i].set_id(c.entries()[i].id());
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stack.push_back({&c.entries()[i].key(),
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&dst_map.mutable_entries()[i].mutable_key()});
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stack.push_back({&c.entries()[i].value(),
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&dst_map.mutable_entries()[i].mutable_value()});
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}
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},
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[&](const ComprehensionExpr& c) {
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auto& dst_comprehension = dst->mutable_comprehension_expr();
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dst_comprehension.set_iter_var(c.iter_var());
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dst_comprehension.set_iter_var2(c.iter_var2());
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dst_comprehension.set_accu_var(c.accu_var());
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if (c.has_accu_init()) {
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stack.push_back(
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{&c.accu_init(), &dst_comprehension.mutable_accu_init()});
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}
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if (c.has_iter_range()) {
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stack.push_back(
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{&c.iter_range(), &dst_comprehension.mutable_iter_range()});
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}
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if (c.has_loop_condition()) {
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stack.push_back({&c.loop_condition(),
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&dst_comprehension.mutable_loop_condition()});
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}
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if (c.has_loop_step()) {
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stack.push_back(
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{&c.loop_step(), &dst_comprehension.mutable_loop_step()});
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}
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if (c.has_result()) {
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stack.push_back(
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{&c.result(), &dst_comprehension.mutable_result()});
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}
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}
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),
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src->kind());
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}
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} // namespace
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const UnspecifiedExpr& UnspecifiedExpr::default_instance() {
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static const absl::NoDestructor<UnspecifiedExpr> instance;
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return *instance;
@@ -63,4 +177,16 @@ const Expr& Expr::default_instance() {
63177
return *instance;
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}
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Expr CloneExpr(const Expr& expr) {
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Expr result;
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std::vector<CopyStackRecord> stack;
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stack.push_back({&expr, &result});
184+
while (!stack.empty()) {
185+
CopyStackRecord element = stack.back();
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stack.pop_back();
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CopyNode(element, stack);
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}
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return result;
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}
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} // namespace cel

‎common/expr.h‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -48,6 +48,9 @@ class ComprehensionExpr;
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inline constexpr absl::string_view kAccumulatorVariableName = "__result__";
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// Returns a deep copy of the given expression node.
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Expr CloneExpr(const Expr& expr);
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bool operator==(const Expr& lhs, const Expr& rhs);
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inline bool operator!=(const Expr& lhs, const Expr& rhs) {

‎extensions/protobuf/BUILD‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -76,6 +76,7 @@ cc_test(
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":ast_converters",
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"//base/ast_internal:ast_impl",
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"//base/ast_internal:expr",
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"//common:expr",
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"//internal:proto_matchers",
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"//internal:testing",
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"//parser",

‎extensions/protobuf/ast_converters_test.cc‎

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@@ -31,6 +31,7 @@
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#include "absl/types/variant.h"
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#include "base/ast_internal/ast_impl.h"
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#include "base/ast_internal/expr.h"
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#include "common/expr.h"
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#include "internal/proto_matchers.h"
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#include "internal/testing.h"
3637
#include "parser/options.h"
@@ -801,6 +802,23 @@ TEST_P(ConversionRoundTripTest, ParsedExprCopyable) {
801802
IsOkAndHolds(EqualsProto(parsed_expr)));
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}
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805+
TEST_P(ConversionRoundTripTest, ExprClonable) {
806+
ASSERT_OK_AND_ASSIGN(ParsedExprPb parsed_expr,
807+
Parse(GetParam().expr, "<input>", options_));
808+
809+
ASSERT_OK_AND_ASSIGN(std::unique_ptr<Ast> ast,
810+
CreateAstFromParsedExpr(parsed_expr));
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812+
auto& impl = ast_internal::AstImpl::CastFromPublicAst(*ast);
813+
impl.root_expr() = CloneExpr(impl.root_expr());
814+
815+
EXPECT_THAT(CreateCheckedExprFromAst(impl),
816+
StatusIs(absl::StatusCode::kInvalidArgument,
817+
HasSubstr("AST is not type-checked")));
818+
EXPECT_THAT(CreateParsedExprFromAst(impl),
819+
IsOkAndHolds(EqualsProto(parsed_expr)));
820+
}
821+
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TEST_P(ConversionRoundTripTest, CheckedExprCopyable) {
805823
ASSERT_OK_AND_ASSIGN(ParsedExprPb parsed_expr,
806824
Parse(GetParam().expr, "<input>", options_));

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