Objectivec: Refactor to use io::Printer::Sub.

This allows us to use `io::Printer::Sub`'s more advanced features, like automatically adding references to symbols in output metadata. We need a new utility class because a lot of code in this generator depends on overwriting placeholders, as well as looking up existing ones.

PiperOrigin-RevId: 719268162

src/google/protobuf/compiler/objectivec/enum_field.cc

@@ -10,11 +10,11 @@
 #include <string>
 
 #include "absl/container/btree_set.h"
-#include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "google/protobuf/compiler/objectivec/field.h"
+#include "google/protobuf/compiler/objectivec/helpers.h"
 #include "google/protobuf/compiler/objectivec/names.h"
 #include "google/protobuf/compiler/objectivec/options.h"
 #include "google/protobuf/descriptor.h"
@@ -27,38 +27,37 @@ namespace objectivec {
 
 namespace {
 
-void SetEnumVariables(
-    const FieldDescriptor* descriptor,
-    const GenerationOptions& generation_options,
-    absl::flat_hash_map<absl::string_view, std::string>* variables) {
+void SetEnumVariables(const FieldDescriptor* descriptor,
+                      const GenerationOptions& generation_options,
+                      SubstitutionMap& variables) {
   const std::string type = EnumName(descriptor->enum_type());
   const std::string enum_desc_func = absl::StrCat(type, "_EnumDescriptor");
-  (*variables)["enum_name"] = type;
+  variables.Set("enum_name", type);
   // When using fwd decls, for non repeated fields, if it was defined in a
   // different file, the property decls need to use "enum NAME" rather than just
   // "NAME" to support the forward declaration of the enums.
   if (generation_options.headers_use_forward_declarations &&
       !descriptor->is_repeated() &&
       !IsProtobufLibraryBundledProtoFile(descriptor->enum_type()->file()) &&
       (descriptor->file() != descriptor->enum_type()->file())) {
-    (*variables)["property_type"] = absl::StrCat("enum ", type, " ");
+    variables.Set("property_type", absl::StrCat("enum ", type, " "));
   }
-  (*variables)["enum_verifier"] = absl::StrCat(type, "_IsValidValue");
-  (*variables)["enum_desc_func"] = enum_desc_func;
+  variables.Set("enum_verifier", absl::StrCat(type, "_IsValidValue"));
+  variables.Set("enum_desc_func", enum_desc_func);
 
-  (*variables)["dataTypeSpecific_name"] = "enumDescFunc";
-  (*variables)["dataTypeSpecific_value"] = enum_desc_func;
+  variables.Set("dataTypeSpecific_name", "enumDescFunc");
+  variables.Set("dataTypeSpecific_value", enum_desc_func);
 
   const Descriptor* msg_descriptor = descriptor->containing_type();
-  (*variables)["owning_message_class"] = ClassName(msg_descriptor);
+  variables.Set("owning_message_class", ClassName(msg_descriptor));
 }
 }  // namespace
 
 EnumFieldGenerator::EnumFieldGenerator(
     const FieldDescriptor* descriptor,
     const GenerationOptions& generation_options)
     : SingleFieldGenerator(descriptor, generation_options) {
-  SetEnumVariables(descriptor, generation_options, &variables_);
+  SetEnumVariables(descriptor, generation_options, variables_);
 }
 
 void EnumFieldGenerator::GenerateCFunctionDeclarations(
@@ -67,7 +66,7 @@ void EnumFieldGenerator::GenerateCFunctionDeclarations(
     return;
   }
 
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit(R"objc(
     /**
      * Fetches the raw value of a @c $owning_message_class$'s @c $name$ property, even
@@ -90,7 +89,7 @@ void EnumFieldGenerator::GenerateCFunctionImplementations(
     return;
   }
 
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit(R"objc(
     int32_t $owning_message_class$_$capitalized_name$_RawValue($owning_message_class$ *message) {
       GPBDescriptor *descriptor = [$owning_message_class$ descriptor];
@@ -134,11 +133,11 @@ RepeatedEnumFieldGenerator::RepeatedEnumFieldGenerator(
     const FieldDescriptor* descriptor,
     const GenerationOptions& generation_options)
     : RepeatedFieldGenerator(descriptor, generation_options) {
-  SetEnumVariables(descriptor, generation_options, &variables_);
+  SetEnumVariables(descriptor, generation_options, variables_);
 }
 
 void RepeatedEnumFieldGenerator::EmitArrayComment(io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit(R"objc(
     // |$name$| contains |$enum_name$|
   )objc");

src/google/protobuf/compiler/objectivec/field.cc

@@ -12,7 +12,6 @@
 #include <vector>
 
 #include "absl/container/btree_set.h"
-#include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/log/absl_check.h"
 #include "absl/log/absl_log.h"
@@ -35,9 +34,8 @@ namespace objectivec {
 
 namespace {
 
-void SetCommonFieldVariables(
-    const FieldDescriptor* descriptor,
-    absl::flat_hash_map<absl::string_view, std::string>* variables) {
+void SetCommonFieldVariables(const FieldDescriptor* descriptor,
+                             SubstitutionMap& variables) {
   std::string camel_case_name = FieldName(descriptor);
   std::string raw_field_name;
   if (internal::cpp::IsGroupLike(*descriptor)) {
@@ -51,26 +49,31 @@ void SetCommonFieldVariables(
   const bool needs_custom_name = (raw_field_name != un_camel_case_name);
 
   const std::string& classname = ClassName(descriptor->containing_type());
-  (*variables)["classname"] = classname;
-  (*variables)["name"] = camel_case_name;
+  variables.Set("classname", classname);
+  variables.Set("name", camel_case_name);
+
   const std::string& capitalized_name = FieldNameCapitalized(descriptor);
-  (*variables)["capitalized_name"] = capitalized_name;
-  (*variables)["raw_field_name"] = raw_field_name;
-  (*variables)["field_number_name"] =
-      absl::StrCat(classname, "_FieldNumber_", capitalized_name);
-  (*variables)["field_number"] = absl::StrCat(descriptor->number());
-  (*variables)["property_type"] = FieldObjCType(
-      descriptor, static_cast<FieldObjCTypeOptions>(
-                      kFieldObjCTypeOptions_IncludeSpaceAfterBasicTypes |
-                      kFieldObjCTypeOptions_IncludeSpaceBeforeStar));
-  (*variables)["storage_type"] = FieldObjCType(
-      descriptor, static_cast<FieldObjCTypeOptions>(
-                      kFieldObjCTypeOptions_IncludeSpaceAfterBasicTypes |
-                      kFieldObjCTypeOptions_OmitLightweightGenerics |
-                      kFieldObjCTypeOptions_IncludeSpaceBeforeStar));
-  (*variables)["field_type"] = GetCapitalizedType(descriptor);
-  (*variables)["deprecated_attribute"] =
-      GetOptionalDeprecatedAttribute(descriptor);
+  variables.Set("capitalized_name", capitalized_name);
+  variables.Set("raw_field_name", raw_field_name);
+  variables.Set("field_number_name",
+                absl::StrCat(classname, "_FieldNumber_", capitalized_name));
+  variables.Set("field_number", absl::StrCat(descriptor->number()));
+  variables.Set(
+      "property_type",
+      FieldObjCType(descriptor,
+                    static_cast<FieldObjCTypeOptions>(
+                        kFieldObjCTypeOptions_IncludeSpaceAfterBasicTypes |
+                        kFieldObjCTypeOptions_IncludeSpaceBeforeStar)));
+  variables.Set(
+      "storage_type",
+      FieldObjCType(descriptor,
+                    static_cast<FieldObjCTypeOptions>(
+                        kFieldObjCTypeOptions_IncludeSpaceAfterBasicTypes |
+                        kFieldObjCTypeOptions_OmitLightweightGenerics |
+                        kFieldObjCTypeOptions_IncludeSpaceBeforeStar)));
+  variables.Set("field_type", GetCapitalizedType(descriptor));
+  variables.Set("deprecated_attribute",
+                GetOptionalDeprecatedAttribute(descriptor));
   std::vector<std::string> field_flags;
   if (descriptor->is_repeated()) field_flags.push_back("GPBFieldRepeated");
   if (descriptor->is_required()) field_flags.push_back("GPBFieldRequired");
@@ -96,20 +99,21 @@ void SetCommonFieldVariables(
     field_flags.push_back("GPBFieldClearHasIvarOnZero");
   }
 
-  (*variables)["fieldflags"] = BuildFlagsString(FLAGTYPE_FIELD, field_flags);
+  variables.Set("fieldflags", BuildFlagsString(FLAGTYPE_FIELD, field_flags));
 
-  (*variables)["default"] = DefaultValue(descriptor);
-  (*variables)["default_name"] = GPBGenericValueFieldName(descriptor);
+  variables.Set("default", DefaultValue(descriptor));
+  variables.Set("default_name", GPBGenericValueFieldName(descriptor));
 
-  (*variables)["dataTypeSpecific_name"] = "clazz";
-  (*variables)["dataTypeSpecific_value"] = "Nil";
+  variables.Set("dataTypeSpecific_name", "clazz");
+  variables.Set("dataTypeSpecific_value", "Nil");
 
-  (*variables)["storage_offset_value"] = absl::StrCat(
-      "(uint32_t)offsetof(", classname, "__storage_, ", camel_case_name, ")");
-  (*variables)["storage_offset_comment"] = "";
+  variables.Set("storage_offset_value",
+                absl::StrCat("(uint32_t)offsetof(", classname, "__storage_, ",
+                             camel_case_name, ")"));
+  variables.Set("storage_offset_comment", "");
 
   // Clear some common things so they can be set just when needed.
-  (*variables)["storage_attribute"] = "";
+  variables.Set("storage_attribute", "");
 }
 
 bool HasNonZeroDefaultValue(const FieldDescriptor* field) {
@@ -192,11 +196,11 @@ FieldGenerator* FieldGenerator::Make(
 FieldGenerator::FieldGenerator(const FieldDescriptor* descriptor,
                                const GenerationOptions& generation_options)
     : descriptor_(descriptor), generation_options_(generation_options) {
-  SetCommonFieldVariables(descriptor, &variables_);
+  SetCommonFieldVariables(descriptor, variables_);
 }
 
 void FieldGenerator::GenerateFieldNumberConstant(io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit("$field_number_name$ = $field_number$,\n");
 }
 
@@ -228,7 +232,7 @@ void FieldGenerator::DetermineNeededFiles(
 void FieldGenerator::GenerateFieldDescription(io::Printer* printer,
                                               bool include_default) const {
   // Printed in the same order as the structure decl.
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit(
       {{"prefix", include_default ? ".core" : ""},
        {"maybe_default",
@@ -252,10 +256,12 @@ void FieldGenerator::GenerateFieldDescription(io::Printer* printer,
 }
 
 void FieldGenerator::SetRuntimeHasBit(int has_index) {
-  variables_["has_index"] = absl::StrCat(has_index);
+  variables_.Set("has_index", has_index);
 }
 
-void FieldGenerator::SetNoHasBit() { variables_["has_index"] = "GPBNoHasBit"; }
+void FieldGenerator::SetNoHasBit() {
+  variables_.Set("has_index", "GPBNoHasBit");
+}
 
 int FieldGenerator::ExtraRuntimeHasBitsNeeded() const { return 0; }
 
@@ -269,7 +275,7 @@ void FieldGenerator::SetOneofIndexBase(int index_base) {
   if (oneof != nullptr) {
     int index = oneof->index() + index_base;
     // Flip the sign to mark it as a oneof.
-    variables_["has_index"] = absl::StrCat(-index);
+    variables_.Set("has_index", -index);
   }
 }
 
@@ -286,13 +292,13 @@ SingleFieldGenerator::SingleFieldGenerator(
 
 void SingleFieldGenerator::GenerateFieldStorageDeclaration(
     io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit("$storage_type$$name$;\n");
 }
 
 void SingleFieldGenerator::GeneratePropertyDeclaration(
     io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit({{"comments",
                   [&] {
                     EmitCommentsString(printer, generation_options_,
@@ -312,7 +318,7 @@ void SingleFieldGenerator::GeneratePropertyDeclaration(
 
 void SingleFieldGenerator::GeneratePropertyImplementation(
     io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   if (WantsHasProperty()) {
     printer->Emit("@dynamic has$capitalized_name$, $name$;\n");
   } else {
@@ -332,15 +338,15 @@ ObjCObjFieldGenerator::ObjCObjFieldGenerator(
     const FieldDescriptor* descriptor,
     const GenerationOptions& generation_options)
     : SingleFieldGenerator(descriptor, generation_options) {
-  variables_["property_storage_attribute"] = "strong";
-  if (IsRetainedName(variables_["name"])) {
-    variables_["storage_attribute"] = " NS_RETURNS_NOT_RETAINED";
+  variables_.Set("property_storage_attribute", "strong");
+  if (IsRetainedName(variable("name"))) {
+    variables_.Set("storage_attribute", " NS_RETURNS_NOT_RETAINED");
   }
 }
 
 void ObjCObjFieldGenerator::GenerateFieldStorageDeclaration(
     io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit("$storage_type$$name$;\n");
 }
 
@@ -350,7 +356,7 @@ void ObjCObjFieldGenerator::GeneratePropertyDeclaration(
   // it uses pointers and deals with Objective-C's rules around storage name
   // conventions (init*, new*, etc.)
 
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit({{"comments",
                   [&] {
                     EmitCommentsString(printer, generation_options_,
@@ -366,7 +372,7 @@ void ObjCObjFieldGenerator::GeneratePropertyDeclaration(
         @property(nonatomic, readwrite) BOOL has$capitalized_name$$ deprecated_attribute$;
     )objc");
   }
-  if (IsInitName(variables_.find("name")->second)) {
+  if (IsInitName(variable("name"))) {
     // If property name starts with init we need to annotate it to get past ARC.
     // http://stackoverflow.com/questions/18723226/how-do-i-annotate-an-objective-c-property-with-an-objc-method-family/18723227#18723227
     printer->Emit(R"objc(
@@ -383,13 +389,13 @@ RepeatedFieldGenerator::RepeatedFieldGenerator(
 
 void RepeatedFieldGenerator::GenerateFieldStorageDeclaration(
     io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit("$storage_type$$name$;\n");
 }
 
 void RepeatedFieldGenerator::GeneratePropertyImplementation(
     io::Printer* printer) const {
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit("@dynamic $name$, $name$_Count;\n");
 }
 
@@ -401,7 +407,7 @@ void RepeatedFieldGenerator::GeneratePropertyDeclaration(
   // dealing with needing Objective-C's rules around storage name conventions
   // (init*, new*, etc.)
 
-  auto vars = printer->WithVars(variables_);
+  auto vars = variables_.Install(printer);
   printer->Emit(
       {{"comments",
         [&] { EmitCommentsString(printer, generation_options_, descriptor_); }},
@@ -413,7 +419,7 @@ void RepeatedFieldGenerator::GeneratePropertyDeclaration(
         /** The number of items in @c $name$ without causing the container to be created. */
         @property(nonatomic, readonly) NSUInteger $name$_Count$ deprecated_attribute$;
       )objc");
-  if (IsInitName(variables_.find("name")->second)) {
+  if (IsInitName(variable("name"))) {
     // If property name starts with init we need to annotate it to get past ARC.
     // http://stackoverflow.com/questions/18723226/how-do-i-annotate-an-objective-c-property-with-an-objc-method-family/18723227#18723227
     printer->Emit(R"objc(

src/google/protobuf/compiler/objectivec/field.h

@@ -13,10 +13,10 @@
 #include <vector>
 
 #include "absl/container/btree_set.h"
-#include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/strings/match.h"
 #include "absl/strings/string_view.h"
+#include "google/protobuf/compiler/objectivec/helpers.h"
 #include "google/protobuf/compiler/objectivec/options.h"
 #include "google/protobuf/descriptor.h"
 #include "google/protobuf/io/printer.h"
@@ -70,8 +70,8 @@ class FieldGenerator {
   virtual void SetExtraRuntimeHasBitsBase(int index_base);
   void SetOneofIndexBase(int index_base);
 
-  std::string variable(const char* key) const {
-    return variables_.find(key)->second;
+  std::string variable(absl::string_view key) const {
+    return variables_.Value(key);
   }
 
   bool needs_textformat_name_support() const {
@@ -89,7 +89,7 @@ class FieldGenerator {
 
   const FieldDescriptor* descriptor_;
   const GenerationOptions& generation_options_;
-  absl::flat_hash_map<absl::string_view, std::string> variables_;
+  SubstitutionMap variables_;
 };
 
 class SingleFieldGenerator : public FieldGenerator {