compiler/java/java_enum.cc

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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//
//     * Redistributions of source code must retain the above copyright
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// in the documentation and/or other materials provided with the
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// contributors may be used to endorse or promote products derived from
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// Author: kenton@google.com (Kenton Varda)
//  Based on original Protocol Buffers design by
//  Sanjay Ghemawat, Jeff Dean, and others.

#include <map>
#include <string>

#include <google/protobuf/compiler/java/java_context.h>
#include <google/protobuf/compiler/java/java_enum.h>
#include <google/protobuf/compiler/java/java_doc_comment.h>
#include <google/protobuf/compiler/java/java_helpers.h>
#include <google/protobuf/compiler/java/java_name_resolver.h>
#include <google/protobuf/io/printer.h>
#include <google/protobuf/descriptor.pb.h>
#include <google/protobuf/stubs/strutil.h>

namespace google {
namespace protobuf {
namespace compiler {
namespace java {

namespace {
bool EnumHasCustomOptions(const EnumDescriptor* descriptor) {
  if (descriptor->options().unknown_fields().field_count() > 0) return true;
  for (int i = 0; i < descriptor->value_count(); ++i) {
    const EnumValueDescriptor* value = descriptor->value(i);
    if (value->options().unknown_fields().field_count() > 0) return true;
  }
  return false;
}
}  // namespace

EnumGenerator::EnumGenerator(const EnumDescriptor* descriptor,
                             bool immutable_api,
                             Context* context)
  : descriptor_(descriptor), immutable_api_(immutable_api),
    name_resolver_(context->GetNameResolver())  {
  for (int i = 0; i < descriptor_->value_count(); i++) {
    const EnumValueDescriptor* value = descriptor_->value(i);
    const EnumValueDescriptor* canonical_value =
      descriptor_->FindValueByNumber(value->number());

    if (value == canonical_value) {
      canonical_values_.push_back(value);
    } else {
      Alias alias;
      alias.value = value;
      alias.canonical_value = canonical_value;
      aliases_.push_back(alias);
    }
  }
}

EnumGenerator::~EnumGenerator() {}

void EnumGenerator::Generate(io::Printer* printer) {
  WriteEnumDocComment(printer, descriptor_);
  if (HasDescriptorMethods(descriptor_)) {
    printer->Print(
      "public enum $classname$\n"
      "    implements com.google.protobuf.ProtocolMessageEnum {\n",
      "classname", descriptor_->name());
  } else {
    printer->Print(
      "public enum $classname$\n"
      "    implements com.google.protobuf.Internal.EnumLite {\n",
      "classname", descriptor_->name());
  }
  printer->Indent();

  for (int i = 0; i < canonical_values_.size(); i++) {
    map<string, string> vars;
    vars["name"] = canonical_values_[i]->name();
    vars["index"] = SimpleItoa(canonical_values_[i]->index());
    vars["number"] = SimpleItoa(canonical_values_[i]->number());
    WriteEnumValueDocComment(printer, canonical_values_[i]);
    if (canonical_values_[i]->options().deprecated()) {
      printer->Print("@java.lang.Deprecated\n");
    }
    printer->Print(vars,
      "$name$($index$, $number$),\n");
  }

  printer->Print(
    ";\n"
    "\n");

  // -----------------------------------------------------------------

  for (int i = 0; i < aliases_.size(); i++) {
    map<string, string> vars;
    vars["classname"] = descriptor_->name();
    vars["name"] = aliases_[i].value->name();
    vars["canonical_name"] = aliases_[i].canonical_value->name();
    WriteEnumValueDocComment(printer, aliases_[i].value);
    printer->Print(vars,
      "public static final $classname$ $name$ = $canonical_name$;\n");
  }

  for (int i = 0; i < descriptor_->value_count(); i++) {
    map<string, string> vars;
    vars["name"] = descriptor_->value(i)->name();
    vars["number"] = SimpleItoa(descriptor_->value(i)->number());
    WriteEnumValueDocComment(printer, descriptor_->value(i));
    printer->Print(vars,
      "public static final int $name$_VALUE = $number$;\n");
  }
  printer->Print("\n");

  // -----------------------------------------------------------------

  printer->Print(
    "\n"
    "public final int getNumber() { return value; }\n"
    "\n"
    "public static $classname$ valueOf(int value) {\n"
    "  switch (value) {\n",
    "classname", descriptor_->name());
  printer->Indent();
  printer->Indent();

  for (int i = 0; i < canonical_values_.size(); i++) {
    printer->Print(
      "case $number$: return $name$;\n",
      "name", canonical_values_[i]->name(),
      "number", SimpleItoa(canonical_values_[i]->number()));
  }

  printer->Outdent();
  printer->Outdent();
  printer->Print(
    "    default: return null;\n"
    "  }\n"
    "}\n"
    "\n"
    "public static com.google.protobuf.Internal.EnumLiteMap<$classname$>\n"
    "    internalGetValueMap() {\n"
    "  return internalValueMap;\n"
    "}\n"
    "private static com.google.protobuf.Internal.EnumLiteMap<$classname$>\n"
    "    internalValueMap =\n"
    "      new com.google.protobuf.Internal.EnumLiteMap<$classname$>() {\n"
    "        public $classname$ findValueByNumber(int number) {\n"
    "          return $classname$.valueOf(number);\n"
    "        }\n"
    "      };\n"
    "\n",
    "classname", descriptor_->name());

  // -----------------------------------------------------------------
  // Reflection

  if (HasDescriptorMethods(descriptor_)) {
    printer->Print(
      "public final com.google.protobuf.Descriptors.EnumValueDescriptor\n"
      "    getValueDescriptor() {\n"
      "  return getDescriptor().getValues().get(index);\n"
      "}\n"
      "public final com.google.protobuf.Descriptors.EnumDescriptor\n"
      "    getDescriptorForType() {\n"
      "  return getDescriptor();\n"
      "}\n"
      "public static final com.google.protobuf.Descriptors.EnumDescriptor\n"
      "    getDescriptor() {\n");

    // TODO(kenton):  Cache statically?  Note that we can't access descriptors
    //   at module init time because it wouldn't work with descriptor.proto, but
    //   we can cache the value the first time getDescriptor() is called.
    if (descriptor_->containing_type() == NULL) {
      if (!MultipleJavaFiles(descriptor_->file(), immutable_api_)) {
        printer->Print(
          "  return $file$.getDescriptor().getEnumTypes().get($index$);\n",
          "file", name_resolver_->GetClassName(descriptor_->file(),
                                               immutable_api_),
          "index", SimpleItoa(descriptor_->index()));
      } else {
        printer->Indent();
        if (EnumHasCustomOptions(descriptor_)) {
          // We need to load the immutable classes in order to parse custom
          // options. However, since file level enums (no outer class) are
          // shared by immutable code and mutable code, the immutable classes
          // may not exist. So we try to use Java reflection to retrieve the
          // descriptor from immutable classes.
          printer->Print(
            "try {\n"
            "  java.lang.Class immutableFileClass =\n"
            "      java.lang.Class.forName(\"$immutable_file_class_name$\");\n"
            "  @java.lang.SuppressWarnings(\"unchecked\")\n"
            "  java.lang.reflect.Method m =\n"
            "      immutableFileClass.getMethod(\"getDescriptor\");\n"
            "  com.google.protobuf.Descriptors.FileDescriptor file =\n"
            "      (com.google.protobuf.Descriptors.FileDescriptor)\n"
            "          m.invoke(immutableFileClass);\n"
            "  return file.getEnumTypes().get($index$);\n"
            "} catch (Exception e) {\n"
            // Immutable classes cannot be found. Proceed as if custom options
            // don't exist.
            "}\n",
            "immutable_file_class_name",
            name_resolver_->GetImmutableClassName(descriptor_->file()),
            "index", SimpleItoa(descriptor_->index()));
        }
        printer->Print(
          "return $immutable_package$.$descriptor_class$.getDescriptor()\n"
          "    .getEnumTypes().get($index$);\n",
          "immutable_package", FileJavaPackage(descriptor_->file(), true),
          "descriptor_class",
          name_resolver_->GetDescriptorClassName(descriptor_->file()),
          "index", SimpleItoa(descriptor_->index()));
        printer->Outdent();
      }
    } else {
      printer->Print(
          "  return $parent$.$descriptor$.getEnumTypes().get($index$);\n",
          "parent", name_resolver_->GetClassName(descriptor_->containing_type(),
                                                 immutable_api_),
          "descriptor", descriptor_->containing_type()->options()
                        .no_standard_descriptor_accessor()
                        ? "getDefaultInstance().getDescriptorForType()"
                        : "getDescriptor()",
          "index", SimpleItoa(descriptor_->index()));
    }

    printer->Print(
      "}\n"
      "\n"
      "private static final $classname$[] VALUES = ",
      "classname", descriptor_->name());

    if (CanUseEnumValues()) {
      // If the constants we are going to output are exactly the ones we
      // have declared in the Java enum in the same order, then we can use
      // the values() method that the Java compiler automatically generates
      // for every enum.
      printer->Print("values();\n");
    } else {
      printer->Print(
        "{\n"
        "  ");
      for (int i = 0; i < descriptor_->value_count(); i++) {
        printer->Print("$name$, ",
          "name", descriptor_->value(i)->name());
      }
      printer->Print(
          "\n"
          "};\n");
    }

    printer->Print(
      "\n"
      "public static $classname$ valueOf(\n"
      "    com.google.protobuf.Descriptors.EnumValueDescriptor desc) {\n"
      "  if (desc.getType() != getDescriptor()) {\n"
      "    throw new java.lang.IllegalArgumentException(\n"
      "      \"EnumValueDescriptor is not for this type.\");\n"
      "  }\n"
      "  return VALUES[desc.getIndex()];\n"
      "}\n"
      "\n",
      "classname", descriptor_->name());

    // index is only used for reflection; lite implementation does not need it
    printer->Print("private final int index;\n");
  }

  // -----------------------------------------------------------------

  printer->Print(
    "private final int value;\n\n"
    "private $classname$(int index, int value) {\n",
    "classname", descriptor_->name());
  if (HasDescriptorMethods(descriptor_)) {
    printer->Print("  this.index = index;\n");
  }
  printer->Print(
    "  this.value = value;\n"
    "}\n");

  printer->Print(
    "\n"
    "// @@protoc_insertion_point(enum_scope:$full_name$)\n",
    "full_name", descriptor_->full_name());

  printer->Outdent();
  printer->Print("}\n\n");
}

bool EnumGenerator::CanUseEnumValues() {
  if (canonical_values_.size() != descriptor_->value_count()) {
    return false;
  }
  for (int i = 0; i < descriptor_->value_count(); i++) {
    if (descriptor_->value(i)->name() != canonical_values_[i]->name()) {
      return false;
    }
  }
  return true;
}

}  // namespace java
}  // namespace compiler
}  // namespace protobuf
}  // namespace google