From 033af47aa634d727d0e2102c1f5dea5c513916a9 Mon Sep 17 00:00:00 2001
From: Hsin-Yi Chen <hsinyichen@google.com>
Date: Mon, 13 Feb 2023 16:46:00 +0800
Subject: [PATCH] Replace TypeQueueCheckAndPushBack with TypeStackGuard

A followup commit will rename type_queue to type_stack.

Test: ./test.py
Bug: 255702405
Change-Id: Ie5c21b0883f08386d30b80ca955708aa7f4bdb16
---
 .../src/diff/abi_diff_wrappers.cpp            |  5 +++--
 .../src/repr/abi_diff_helpers.cpp             | 20 ++-----------------
 .../src/repr/abi_diff_helpers.h               | 20 +++++++++++++++++++
 3 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/vndk/tools/header-checker/src/diff/abi_diff_wrappers.cpp b/vndk/tools/header-checker/src/diff/abi_diff_wrappers.cpp
index eeaa8819f..4e51ef697 100644
--- a/vndk/tools/header-checker/src/diff/abi_diff_wrappers.cpp
+++ b/vndk/tools/header-checker/src/diff/abi_diff_wrappers.cpp
@@ -25,6 +25,7 @@ namespace diff {
 
 using repr::AbiElementMap;
 using repr::DiffStatus;
+using repr::TypeStackGuard;
 using repr::Unwind;
 
 
@@ -56,7 +57,7 @@ template <>
 bool DiffWrapper<repr::GlobalVarIR>::DumpDiff(
     repr::DiffMessageIR::DiffKind diff_kind) {
   std::deque<std::string> type_queue;
-  type_queue.push_back(oldp_->GetName());
+  TypeStackGuard guard(&type_queue, oldp_->GetName());
   DiffStatus type_diff = CompareAndDumpTypeDiff(oldp_->GetReferencedType(),
                                                 newp_->GetReferencedType(),
                                                 &type_queue, diff_kind);
@@ -78,7 +79,7 @@ template <>
 bool DiffWrapper<repr::FunctionIR>::DumpDiff(
     repr::DiffMessageIR::DiffKind diff_kind) {
   std::deque<std::string> type_queue;
-  type_queue.push_back(oldp_->GetName());
+  TypeStackGuard guard(&type_queue, oldp_->GetName());
 
   DiffStatus function_type_diff =
       CompareFunctionTypes(oldp_, newp_, &type_queue, diff_kind);
diff --git a/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp b/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp
index 03cff4313..1184b770b 100644
--- a/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp
+++ b/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp
@@ -38,19 +38,6 @@ std::string Unwind(const std::deque<std::string> *type_queue) {
   return stack_str;
 }
 
-static void TypeQueueCheckAndPushBack(std::deque<std::string> *type_queue,
-                                      const std::string &str) {
-  if (type_queue) {
-    type_queue->push_back(str);
-  }
-}
-
-static void TypeQueueCheckAndPop(std::deque<std::string> *type_queue) {
-  if (type_queue && !type_queue->empty()) {
-    type_queue->pop_back();
-  }
-}
-
 static std::string ConvertTypeIdToString(
     const AbiElementMap<const TypeIR *> &type_graph,
     const std::string &type_id) {
@@ -1067,8 +1054,8 @@ DiffStatus AbiDiffHelper::CompareAndDumpTypeDiff(
     return DiffStatus::kNoDiff;
   }
 
-  TypeQueueCheckAndPushBack(
-      type_queue, ConvertTypeIdToString(old_types_,old_type_id));
+  TypeStackGuard guard(type_queue,
+                       ConvertTypeIdToString(old_types_, old_type_id));
 
   AbiElementMap<const TypeIR *>::const_iterator old_it =
       old_types_.find(old_type_id);
@@ -1076,7 +1063,6 @@ DiffStatus AbiDiffHelper::CompareAndDumpTypeDiff(
       new_types_.find(new_type_id);
 
   if (old_it == old_types_.end() || new_it == new_types_.end()) {
-    TypeQueueCheckAndPop(type_queue);
     // One of the types were hidden, we cannot compare further.
     return AreOpaqueTypesEqual(old_type_id, new_type_id)
                ? DiffStatus::kNoDiff
@@ -1092,8 +1078,6 @@ DiffStatus AbiDiffHelper::CompareAndDumpTypeDiff(
     diff_status = CompareAndDumpTypeDiff(old_it->second , new_it->second ,
                                          old_kind, type_queue, diff_kind);
   }
-
-  TypeQueueCheckAndPop(type_queue);
   return diff_status;
 }
 
diff --git a/vndk/tools/header-checker/src/repr/abi_diff_helpers.h b/vndk/tools/header-checker/src/repr/abi_diff_helpers.h
index 6a63fbc38..8f1fdbd67 100644
--- a/vndk/tools/header-checker/src/repr/abi_diff_helpers.h
+++ b/vndk/tools/header-checker/src/repr/abi_diff_helpers.h
@@ -70,6 +70,26 @@ struct RecordFieldDiffResult {
   std::vector<const RecordFieldIR *> added_fields;
 };
 
+class TypeStackGuard {
+ public:
+  TypeStackGuard(std::deque<std::string> *type_stack,
+                 const std::string &type_name) {
+    type_stack_ = type_stack;
+    if (type_stack_) {
+      type_stack_->push_back(type_name);
+    }
+  }
+
+  ~TypeStackGuard() {
+    if (type_stack_ && !type_stack_->empty()) {
+      type_stack_->pop_back();
+    }
+  }
+
+ private:
+  std::deque<std::string> *type_stack_;
+};
+
 std::string Unwind(const std::deque<std::string> *type_queue);
 
 struct DiffPolicyOptions {