Move enum value name calculation

PiperOrigin-RevId: 596767666

src/google/protobuf/compiler/rust/BUILD.bazel

@@ -152,6 +152,7 @@ cc_library(
         "//src/google/protobuf",
         "//src/google/protobuf/compiler:code_generator",
         "//src/google/protobuf/compiler/cpp:names_internal",
+        "@com_google_absl//absl/log:absl_check",
         "@com_google_absl//absl/log:absl_log",
         "@com_google_absl//absl/strings",
     ],

src/google/protobuf/compiler/rust/enum.cc

@@ -17,12 +17,9 @@
 #include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/log/absl_check.h"
-#include "absl/strings/ascii.h"
-#include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_join.h"
 #include "absl/strings/string_view.h"
-#include "absl/strings/strip.h"
 #include "absl/types/span.h"
 #include "google/protobuf/compiler/rust/context.h"
 #include "google/protobuf/compiler/rust/naming.h"
@@ -52,17 +49,7 @@ std::vector<std::pair<absl::string_view, int32_t>> EnumValuesInput(
 std::vector<RustEnumValue> EnumValues(
     absl::string_view enum_name,
     absl::Span<const std::pair<absl::string_view, int32_t>> values) {
-  // Enum values may have a prefix of the name of the enum stripped from the
-  // value names in the gencode. This prefix is flexible:
-  // - It can be the original enum name, the name as UpperCamel, or snake_case.
-  // - The stripped prefix may also end in an underscore.
-
-  // The set of prefixes that will be stripped.
-  std::initializer_list<std::string> prefixes = {
-      std::string(enum_name),
-      ScreamingSnakeToUpperCamelCase(enum_name),
-      CamelToSnakeCase(enum_name),
-  };
+  MultiCasePrefixStripper stripper(enum_name);
 
   absl::flat_hash_set<std::string> seen_by_name;
   absl::flat_hash_map<int32_t, RustEnumValue*> seen_by_number;
@@ -74,32 +61,9 @@ std::vector<RustEnumValue> EnumValues(
   seen_by_number.reserve(values.size());
 
   for (const auto& name_and_number : values) {
-    absl::string_view base_value_name = name_and_number.first;
-    for (absl::string_view prefix : prefixes) {
-      if (absl::StartsWithIgnoreCase(base_value_name, prefix)) {
-        base_value_name.remove_prefix(prefix.size());
-
-        // Also strip a joining underscore, if present.
-        absl::ConsumePrefix(&base_value_name, "_");
-
-        // Only strip one prefix.
-        break;
-      }
-    }
-
-    if (base_value_name.empty()) {
-      // The enum value name has a similar name to the enum - don't strip.
-      base_value_name = name_and_number.first;
-    }
-
     int32_t number = name_and_number.second;
     std::string rust_value_name =
-        ScreamingSnakeToUpperCamelCase(base_value_name);
-
-    // Invalid identifiers are prefixed with `_`.
-    if (absl::ascii_isdigit(rust_value_name[0])) {
-      rust_value_name = absl::StrCat("_", rust_value_name);
-    }
+        EnumValueRsName(stripper, name_and_number.first);
 
     if (seen_by_name.contains(rust_value_name)) {
       // Don't add an alias with the same normalized name.

src/google/protobuf/compiler/rust/naming.cc

@@ -10,13 +10,16 @@
 #include <string>
 #include <vector>
 
+#include "absl/log/absl_check.h"
 #include "absl/log/absl_log.h"
 #include "absl/strings/ascii.h"
+#include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_join.h"
 #include "absl/strings/str_replace.h"
 #include "absl/strings/str_split.h"
 #include "absl/strings/string_view.h"
+#include "absl/strings/strip.h"
 #include "absl/strings/substitute.h"
 #include "google/protobuf/compiler/code_generator.h"
 #include "google/protobuf/compiler/cpp/helpers.h"
@@ -257,6 +260,29 @@ std::string EnumRsName(const EnumDescriptor& desc) {
   return SnakeToUpperCamelCase(desc.name());
 }
 
+std::string EnumValueRsName(const EnumValueDescriptor& value) {
+  MultiCasePrefixStripper stripper(value.type()->name());
+  return EnumValueRsName(stripper, value.name());
+}
+
+std::string EnumValueRsName(const MultiCasePrefixStripper& stripper,
+                            absl::string_view value_name) {
+  // Enum values may have a prefix of the name of the enum stripped from the
+  // value names in the gencode. This prefix is flexible:
+  // - It can be the original enum name, the name as UpperCamel, or snake_case.
+  // - The stripped prefix may also end in an underscore.
+  auto stripped = stripper.StripPrefix(value_name);
+
+  auto name = ScreamingSnakeToUpperCamelCase(stripped);
+  ABSL_CHECK(!name.empty());
+
+  // Invalid identifiers are prefixed with `_`.
+  if (absl::ascii_isdigit(name[0])) {
+    name = absl::StrCat("_", name);
+  }
+  return name;
+}
+
 std::string OneofViewEnumRsName(const OneofDescriptor& oneof) {
   return SnakeToUpperCamelCase(oneof.name());
 }
@@ -318,6 +344,34 @@ std::string ScreamingSnakeToUpperCamelCase(absl::string_view input) {
   return result;
 }
 
+MultiCasePrefixStripper::MultiCasePrefixStripper(absl::string_view prefix)
+    : prefixes_{
+          std::string(prefix),
+          ScreamingSnakeToUpperCamelCase(prefix),
+          CamelToSnakeCase(prefix),
+      } {}
+
+absl::string_view MultiCasePrefixStripper::StripPrefix(
+    absl::string_view name) const {
+  absl::string_view start_name = name;
+  for (absl::string_view prefix : prefixes_) {
+    if (absl::StartsWithIgnoreCase(name, prefix)) {
+      name.remove_prefix(prefix.size());
+
+      // Also strip a joining underscore, if present.
+      absl::ConsumePrefix(&name, "_");
+
+      // Only strip one prefix.
+      break;
+    }
+  }
+
+  if (name.empty()) {
+    return start_name;
+  }
+  return name;
+}
+
 }  // namespace rust
 }  // namespace compiler
 }  // namespace protobuf

src/google/protobuf/compiler/rust/naming.h

@@ -8,6 +8,7 @@
 #ifndef GOOGLE_PROTOBUF_COMPILER_RUST_NAMING_H__
 #define GOOGLE_PROTOBUF_COMPILER_RUST_NAMING_H__
 
+#include <array>
 #include <string>
 
 #include "absl/strings/string_view.h"
@@ -39,6 +40,7 @@ std::string ThunkName(Context& ctx, const Descriptor& msg,
 std::string RsTypePath(Context& ctx, const FieldDescriptor& field);
 
 std::string EnumRsName(const EnumDescriptor& desc);
+std::string EnumValueRsName(const EnumValueDescriptor& value);
 
 std::string OneofViewEnumRsName(const OneofDescriptor& oneof);
 std::string OneofMutEnumRsName(const OneofDescriptor& oneof);
@@ -75,6 +77,26 @@ std::string SnakeToUpperCamelCase(absl::string_view input);
 // Converts a SCREAMING_SNAKE_CASE string to an UpperCamelCase string.
 std::string ScreamingSnakeToUpperCamelCase(absl::string_view input);
 
+// Given a fixed prefix, this will repeatedly strip provided
+// string_views if they start with the prefix, the prefix in UpperCamel, or
+// the prefix in snake_case.
+class MultiCasePrefixStripper final {
+ public:
+  explicit MultiCasePrefixStripper(absl::string_view prefix);
+
+  // Strip a prefix from the name in UpperCamel or snake_case, if present.
+  // If there is an underscore after the prefix, that will also be stripped.
+  // The stripping is case-insensitive.
+  absl::string_view StripPrefix(absl::string_view name) const;
+
+ private:
+  std::array<std::string, 3> prefixes_;
+};
+
+// More efficient overload if a stripper is already constructed.
+std::string EnumValueRsName(const MultiCasePrefixStripper& stripper,
+                            absl::string_view value_name);
+
 }  // namespace rust
 }  // namespace compiler
 }  // namespace protobuf