/*
 * Protocol Buffers - Google's data interchange format
 * Copyright 2008 Google Inc.  All rights reserved.
 * https://developers.google.com/protocol-buffers/
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * 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.
 *
 * The messages in this file describe the definitions found in .proto files.
 * A valid .proto file can be translated directly to a FileDescriptorProto
 * without any other information (e.g. without reading its imports).
 */

syntax = "proto2";

package google.protobuf;

option cc_enable_arenas = true;

option csharp_namespace = "Google.Protobuf.Reflection";

option go_package = "github.com/golang/protobuf/protoc-gen-go/descriptor;descriptor";

option java_outer_classname = "DescriptorProtos";

option java_package = "com.google.protobuf";

option objc_class_prefix = "GPB";

/*
 * descriptor.proto must be optimized for speed because reflection-based
 * algorithms don't work during bootstrapping.
 */
option optimize_for = SPEED;

/* Describes a message type. */
message DescriptorProto {
  optional string name = 1;

  repeated FieldDescriptorProto field = 2;

  repeated DescriptorProto nested_type = 3;

  repeated EnumDescriptorProto enum_type = 4;

  repeated ExtensionRange extension_range = 5;

  repeated FieldDescriptorProto extension = 6;

  optional MessageOptions options = 7;

  repeated OneofDescriptorProto oneof_decl = 8;

  repeated ReservedRange reserved_range = 9;

  /*
   * Reserved field names, which may not be used by fields in the same message.
   * A given name may only be reserved once.
   */
  repeated string reserved_name = 10;

  message ExtensionRange {
    optional int32 start = 1; /* Inclusive. */

    optional int32 end = 2; /* Exclusive. */

    optional ExtensionRangeOptions options = 3;
  }

  /*
   * Range of reserved tag numbers. Reserved tag numbers may not be used by
   * fields or extension ranges in the same message. Reserved ranges may
   * not overlap.
   */
  message ReservedRange {
    optional int32 start = 1; /* Inclusive. */

    optional int32 end = 2; /* Exclusive. */
  }
}

/* Describes an enum type. */
message EnumDescriptorProto {
  optional string name = 1;

  repeated EnumValueDescriptorProto value = 2;

  optional EnumOptions options = 3;

  /*
   * Range of reserved numeric values. Reserved numeric values may not be used
   * by enum values in the same enum declaration. Reserved ranges may not
   * overlap.
   */
  repeated EnumReservedRange reserved_range = 4;

  /*
   * Reserved enum value names, which may not be reused. A given name may only
   * be reserved once.
   */
  repeated string reserved_name = 5;

  /*
   * Range of reserved numeric values. Reserved values may not be used by
   * entries in the same enum. Reserved ranges may not overlap.
   *
   * Note that this is distinct from DescriptorProto.ReservedRange in that it
   * is inclusive such that it can appropriately represent the entire int32
   * domain.
   */
  message EnumReservedRange {
    optional int32 start = 1; /* Inclusive. */

    optional int32 end = 2; /* Inclusive. */
  }
}

message EnumOptions {
  /*
   * Set this option to true to allow mapping different tag names to the same
   * value.
   */
  optional bool allow_alias = 2;

  /*
   * Is this enum deprecated?
   * Depending on the target platform, this can emit Deprecated annotations
   * for the enum, or it will be completely ignored; in the very least, this
   * is a formalization for deprecating enums.
   */
  optional bool deprecated = 3 [default = false];

  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  extensions 1000 to max;

  reserved 5;
}

/* Describes a value within an enum. */
message EnumValueDescriptorProto {
  optional string name = 1;

  optional int32 number = 2;

  optional EnumValueOptions options = 3;
}

message EnumValueOptions {
  /*
   * Is this enum value deprecated?
   * Depending on the target platform, this can emit Deprecated annotations
   * for the enum value, or it will be completely ignored; in the very least,
   * this is a formalization for deprecating enum values.
   */
  optional bool deprecated = 1 [default = false];

  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  extensions 1000 to max;
}

message ExtensionRangeOptions {
  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  extensions 1000 to max;
}

/* Describes a field within a message. */
message FieldDescriptorProto {
  optional string name = 1;

  /*
   * For extensions, this is the name of the type being extended.  It is
   * resolved in the same manner as type_name.
   */
  optional string extendee = 2;

  optional int32 number = 3;

  optional Label label = 4;

  /*
   * If type_name is set, this need not be set.  If both this and type_name
   * are set, this must be one of TYPE_ENUM, TYPE_MESSAGE or TYPE_GROUP.
   */
  optional Type type = 5;

  /*
   * For message and enum types, this is the name of the type.  If the name
   * starts with a '.', it is fully-qualified.  Otherwise, C++-like scoping
   * rules are used to find the type (i.e. first the nested types within this
   * message are searched, then within the parent, on up to the root
   * namespace).
   */
  optional string type_name = 6;

  /*
   * For numeric types, contains the original text representation of the value.
   * For booleans, "true" or "false".
   * For strings, contains the default text contents (not escaped in any way).
   * For bytes, contains the C escaped value.  All bytes >= 128 are escaped.
   * TODO(kenton):  Base-64 encode?
   */
  optional string default_value = 7;

  optional FieldOptions options = 8;

  /*
   * If set, gives the index of a oneof in the containing type's oneof_decl
   * list.  This field is a member of that oneof.
   */
  optional int32 oneof_index = 9;

  /*
   * JSON name of this field. The value is set by protocol compiler. If the
   * user has set a "json_name" option on this field, that option's value
   * will be used. Otherwise, it's deduced from the field's name by converting
   * it to camelCase.
   */
  optional string json_name = 10;

  /*
   * If true, this is a proto3 "optional". When a proto3 field is optional, it
   * tracks presence regardless of field type.
   *
   * When proto3_optional is true, this field must be belong to a oneof to
   * signal to old proto3 clients that presence is tracked for this field. This
   * oneof is known as a "synthetic" oneof, and this field must be its sole
   * member (each proto3 optional field gets its own synthetic oneof). Synthetic
   * oneofs exist in the descriptor only, and do not generate any API. Synthetic
   * oneofs must be ordered after all "real" oneofs.
   *
   * For message fields, proto3_optional doesn't create any semantic change,
   * since non-repeated message fields always track presence. However it still
   * indicates the semantic detail of whether the user wrote "optional" or not.
   * This can be useful for round-tripping the .proto file. For consistency we
   * give message fields a synthetic oneof also, even though it is not required
   * to track presence. This is especially important because the parser can't
   * tell if a field is a message or an enum, so it must always create a
   * synthetic oneof.
   *
   * Proto2 optional fields do not set this flag, because they already indicate
   * optional with `LABEL_OPTIONAL`.
   */
  optional bool proto3_optional = 17;

  enum Label {
    /* 0 is reserved for errors */
    LABEL_OPTIONAL = 1;

    LABEL_REQUIRED = 2;

    LABEL_REPEATED = 3;
  }

  enum Type {
    /*
     * 0 is reserved for errors.
     * Order is weird for historical reasons.
     */
    TYPE_DOUBLE = 1;

    TYPE_FLOAT = 2;

    /*
     * Not ZigZag encoded.  Negative numbers take 10 bytes.  Use TYPE_SINT64 if
     * negative values are likely.
     */
    TYPE_INT64 = 3;

    TYPE_UINT64 = 4;

    /*
     * Not ZigZag encoded.  Negative numbers take 10 bytes.  Use TYPE_SINT32 if
     * negative values are likely.
     */
    TYPE_INT32 = 5;

    TYPE_FIXED64 = 6;

    TYPE_FIXED32 = 7;

    TYPE_BOOL = 8;

    TYPE_STRING = 9;

    /*
     * Tag-delimited aggregate.
     * Group type is deprecated and not supported in proto3. However, Proto3
     * implementations should still be able to parse the group wire format and
     * treat group fields as unknown fields.
     */
    TYPE_GROUP = 10;

    TYPE_MESSAGE = 11; /* Length-delimited aggregate. */

    /* New in version 2. */
    TYPE_BYTES = 12;

    TYPE_UINT32 = 13;

    TYPE_ENUM = 14;

    TYPE_SFIXED32 = 15;

    TYPE_SFIXED64 = 16;

    TYPE_SINT32 = 17; /* Uses ZigZag encoding. */

    TYPE_SINT64 = 18; /* Uses ZigZag encoding. */
  }
}

message FieldOptions {
  /*
   * The ctype option instructs the C++ code generator to use a different
   * representation of the field than it normally would.  See the specific
   * options below.  This option is not yet implemented in the open source
   * release -- sorry, we'll try to include it in a future version!
   */
  optional CType ctype = 1 [default = STRING];

  /*
   * The packed option can be enabled for repeated primitive fields to enable
   * a more efficient representation on the wire. Rather than repeatedly
   * writing the tag and type for each element, the entire array is encoded as
   * a single length-delimited blob. In proto3, only explicit setting it to
   * false will avoid using packed encoding.
   */
  optional bool packed = 2;

  /*
   * Is this field deprecated?
   * Depending on the target platform, this can emit Deprecated annotations
   * for accessors, or it will be completely ignored; in the very least, this
   * is a formalization for deprecating fields.
   */
  optional bool deprecated = 3 [default = false];

  /*
   * Should this field be parsed lazily?  Lazy applies only to message-type
   * fields.  It means that when the outer message is initially parsed, the
   * inner message's contents will not be parsed but instead stored in encoded
   * form.  The inner message will actually be parsed when it is first accessed.
   *
   * This is only a hint.  Implementations are free to choose whether to use
   * eager or lazy parsing regardless of the value of this option.  However,
   * setting this option true suggests that the protocol author believes that
   * using lazy parsing on this field is worth the additional bookkeeping
   * overhead typically needed to implement it.
   *
   * This option does not affect the public interface of any generated code;
   * all method signatures remain the same.  Furthermore, thread-safety of the
   * interface is not affected by this option; const methods remain safe to
   * call from multiple threads concurrently, while non-const methods continue
   * to require exclusive access.
   *
   *
   * Note that implementations may choose not to check required fields within
   * a lazy sub-message.  That is, calling IsInitialized() on the outer message
   * may return true even if the inner message has missing required fields.
   * This is necessary because otherwise the inner message would have to be
   * parsed in order to perform the check, defeating the purpose of lazy
   * parsing.  An implementation which chooses not to check required fields
   * must be consistent about it.  That is, for any particular sub-message, the
   * implementation must either *always* check its required fields, or *never*
   * check its required fields, regardless of whether or not the message has
   * been parsed.
   */
  optional bool lazy = 5 [default = false];

  /*
   * The jstype option determines the JavaScript type used for values of the
   * field.  The option is permitted only for 64 bit integral and fixed types
   * (int64, uint64, sint64, fixed64, sfixed64).  A field with jstype JS_STRING
   * is represented as JavaScript string, which avoids loss of precision that
   * can happen when a large value is converted to a floating point JavaScript.
   * Specifying JS_NUMBER for the jstype causes the generated JavaScript code to
   * use the JavaScript "number" type.  The behavior of the default option
   * JS_NORMAL is implementation dependent.
   *
   * This option is an enum to permit additional types to be added, e.g.
   * goog.math.Integer.
   */
  optional JSType jstype = 6 [default = JS_NORMAL];

  /* For Google-internal migration only. Do not use. */
  optional bool weak = 10 [default = false];

  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  enum CType {
    /* Default mode. */
    STRING = 0;

    CORD = 1;

    STRING_PIECE = 2;
  }

  enum JSType {
    /* Use the default type. */
    JS_NORMAL = 0;

    /* Use JavaScript strings. */
    JS_STRING = 1;

    /* Use JavaScript numbers. */
    JS_NUMBER = 2;
  }

  extensions 1000 to max;

  reserved 4;
}

/* Describes a complete .proto file. */
message FileDescriptorProto {
  optional string name = 1; /* file name, relative to root of source tree */

  optional string package = 2; /* e.g. "foo", "foo.bar", etc. */

  /* Names of files imported by this file. */
  repeated string dependency = 3;

  /* All top-level definitions in this file. */
  repeated DescriptorProto message_type = 4;

  repeated EnumDescriptorProto enum_type = 5;

  repeated ServiceDescriptorProto service = 6;

  repeated FieldDescriptorProto extension = 7;

  optional FileOptions options = 8;

  /*
   * This field contains optional information about the original source code.
   * You may safely remove this entire field without harming runtime
   * functionality of the descriptors -- the information is needed only by
   * development tools.
   */
  optional SourceCodeInfo source_code_info = 9;

  /* Indexes of the public imported files in the dependency list above. */
  repeated int32 public_dependency = 10;

  /*
   * Indexes of the weak imported files in the dependency list.
   * For Google-internal migration only. Do not use.
   */
  repeated int32 weak_dependency = 11;

  /*
   * The syntax of the proto file.
   * The supported values are "proto2" and "proto3".
   */
  optional string syntax = 12;
}

/*
 * The protocol compiler can output a FileDescriptorSet containing the .proto
 * files it parses.
 */
message FileDescriptorSet {
  repeated FileDescriptorProto file = 1;
}

/*
 * ===================================================================
 * Options
 */

/*
 * Each of the definitions above may have "options" attached.  These are
 * just annotations which may cause code to be generated slightly differently
 * or may contain hints for code that manipulates protocol messages.
 *
 * Clients may define custom options as extensions of the *Options messages.
 * These extensions may not yet be known at parsing time, so the parser cannot
 * store the values in them.  Instead it stores them in a field in the *Options
 * message called uninterpreted_option. This field must have the same name
 * across all *Options messages. We then use this field to populate the
 * extensions when we build a descriptor, at which point all protos have been
 * parsed and so all extensions are known.
 *
 * Extension numbers for custom options may be chosen as follows:
 * * For options which will only be used within a single application or
 *   organization, or for experimental options, use field numbers 50000
 *   through 99999.  It is up to you to ensure that you do not use the
 *   same number for multiple options.
 * * For options which will be published and used publicly by multiple
 *   independent entities, e-mail protobuf-global-extension-registry@google.com
 *   to reserve extension numbers. Simply provide your project name (e.g.
 *   Objective-C plugin) and your project website (if available) -- there's no
 *   need to explain how you intend to use them. Usually you only need one
 *   extension number. You can declare multiple options with only one extension
 *   number by putting them in a sub-message. See the Custom Options section of
 *   the docs for examples:
 *   https://developers.google.com/protocol-buffers/docs/proto#options
 *   If this turns out to be popular, a web service will be set up
 *   to automatically assign option numbers.
 */

message FileOptions {
  /*
   * Sets the Java package where classes generated from this .proto will be
   * placed.  By default, the proto package is used, but this is often
   * inappropriate because proto packages do not normally start with backwards
   * domain names.
   */
  optional string java_package = 1;

  /*
   * If set, all the classes from the .proto file are wrapped in a single
   * outer class with the given name.  This applies to both Proto1
   * (equivalent to the old "--one_java_file" option) and Proto2 (where
   * a .proto always translates to a single class, but you may want to
   * explicitly choose the class name).
   */
  optional string java_outer_classname = 8;

  optional OptimizeMode optimize_for = 9 [default = SPEED];

  /*
   * If set true, then the Java code generator will generate a separate .java
   * file for each top-level message, enum, and service defined in the .proto
   * file.  Thus, these types will *not* be nested inside the outer class
   * named by java_outer_classname.  However, the outer class will still be
   * generated to contain the file's getDescriptor() method as well as any
   * top-level extensions defined in the file.
   */
  optional bool java_multiple_files = 10 [default = false];

  /*
   * Sets the Go package where structs generated from this .proto will be
   * placed. If omitted, the Go package will be derived from the following:
   *   - The basename of the package import path, if provided.
   *   - Otherwise, the package statement in the .proto file, if present.
   *   - Otherwise, the basename of the .proto file, without extension.
   */
  optional string go_package = 11;

  /*
   * Should generic services be generated in each language?  "Generic" services
   * are not specific to any particular RPC system.  They are generated by the
   * main code generators in each language (without additional plugins).
   * Generic services were the only kind of service generation supported by
   * early versions of google.protobuf.
   *
   * Generic services are now considered deprecated in favor of using plugins
   * that generate code specific to your particular RPC system.  Therefore,
   * these default to false.  Old code which depends on generic services should
   * explicitly set them to true.
   */
  optional bool cc_generic_services = 16 [default = false];

  optional bool java_generic_services = 17 [default = false];

  optional bool py_generic_services = 18 [default = false];

  /* This option does nothing. */
  optional bool java_generate_equals_and_hash = 20 [deprecated = true];

  /*
   * Is this file deprecated?
   * Depending on the target platform, this can emit Deprecated annotations
   * for everything in the file, or it will be completely ignored; in the very
   * least, this is a formalization for deprecating files.
   */
  optional bool deprecated = 23 [default = false];

  /*
   * If set true, then the Java2 code generator will generate code that
   * throws an exception whenever an attempt is made to assign a non-UTF-8
   * byte sequence to a string field.
   * Message reflection will do the same.
   * However, an extension field still accepts non-UTF-8 byte sequences.
   * This option has no effect on when used with the lite runtime.
   */
  optional bool java_string_check_utf8 = 27 [default = false];

  /*
   * Enables the use of arenas for the proto messages in this file. This applies
   * only to generated classes for C++.
   */
  optional bool cc_enable_arenas = 31 [default = true];

  /*
   * Sets the objective c class prefix which is prepended to all objective c
   * generated classes from this .proto. There is no default.
   */
  optional string objc_class_prefix = 36;

  /* Namespace for generated classes; defaults to the package. */
  optional string csharp_namespace = 37;

  /*
   * By default Swift generators will take the proto package and CamelCase it
   * replacing '.' with underscore and use that to prefix the types/symbols
   * defined. When this options is provided, they will use this value instead
   * to prefix the types/symbols defined.
   */
  optional string swift_prefix = 39;

  /*
   * Sets the php class prefix which is prepended to all php generated classes
   * from this .proto. Default is empty.
   */
  optional string php_class_prefix = 40;

  /*
   * Use this option to change the namespace of php generated classes. Default
   * is empty. When this option is empty, the package name will be used for
   * determining the namespace.
   */
  optional string php_namespace = 41;

  optional bool php_generic_services = 42 [default = false];

  /*
   * Use this option to change the namespace of php generated metadata classes.
   * Default is empty. When this option is empty, the proto file name will be
   * used for determining the namespace.
   */
  optional string php_metadata_namespace = 44;

  /*
   * Use this option to change the package of ruby generated classes. Default
   * is empty. When this option is not set, the package name will be used for
   * determining the ruby package.
   */
  optional string ruby_package = 45;

  /*
   * The parser stores options it doesn't recognize here.
   * See the documentation for the "Options" section above.
   */
  repeated UninterpretedOption uninterpreted_option = 999;

  /* Generated classes can be optimized for speed or code size. */
  enum OptimizeMode {
    SPEED = 1; /* Generate complete code for parsing, serialization, */

    /* etc. */
    CODE_SIZE = 2; /* Use ReflectionOps to implement these methods. */

    LITE_RUNTIME = 3; /* Generate code using MessageLite and the lite runtime. */
  }

  extensions 1000 to max;

  reserved 38;
}

/*
 * Describes the relationship between generated code and its original source
 * file. A GeneratedCodeInfo message is associated with only one generated
 * source file, but may contain references to different source .proto files.
 */
message GeneratedCodeInfo {
  /*
   * An Annotation connects some span of text in generated code to an element
   * of its generating .proto file.
   */
  repeated Annotation annotation = 1;

  message Annotation {
    /*
     * Identifies the element in the original source .proto file. This field
     * is formatted the same as SourceCodeInfo.Location.path.
     */
    repeated int32 path = 1 [packed = true];

    /* Identifies the filesystem path to the original source .proto. */
    optional string source_file = 2;

    /*
     * Identifies the starting offset in bytes in the generated code
     * that relates to the identified object.
     */
    optional int32 begin = 3;

    /*
     * Identifies the ending offset in bytes in the generated code that
     * relates to the identified offset. The end offset should be one past
     * the last relevant byte (so the length of the text = end - begin).
     */
    optional int32 end = 4;
  }
}

message MessageOptions {
  /*
   * Set true to use the old proto1 MessageSet wire format for extensions.
   * This is provided for backwards-compatibility with the MessageSet wire
   * format.  You should not use this for any other reason:  It's less
   * efficient, has fewer features, and is more complicated.
   *
   * The message must be defined exactly as follows:
   *   message Foo {
   *     option message_set_wire_format = true;
   *     extensions 4 to max;
   *   }
   * Note that the message cannot have any defined fields; MessageSets only
   * have extensions.
   *
   * All extensions of your type must be singular messages; e.g. they cannot
   * be int32s, enums, or repeated messages.
   *
   * Because this is an option, the above two restrictions are not enforced by
   * the protocol compiler.
   */
  optional bool message_set_wire_format = 1 [default = false];

  /*
   * Disables the generation of the standard "descriptor()" accessor, which can
   * conflict with a field of the same name.  This is meant to make migration
   * from proto1 easier; new code should avoid fields named "descriptor".
   */
  optional bool no_standard_descriptor_accessor = 2 [default = false];

  /*
   * Is this message deprecated?
   * Depending on the target platform, this can emit Deprecated annotations
   * for the message, or it will be completely ignored; in the very least,
   * this is a formalization for deprecating messages.
   */
  optional bool deprecated = 3 [default = false];

  /*
   * Whether the message is an automatically generated map entry type for the
   * maps field.
   *
   * For maps fields:
   *     map<KeyType, ValueType> map_field = 1;
   * The parsed descriptor looks like:
   *     message MapFieldEntry {
   *         option map_entry = true;
   *         optional KeyType key = 1;
   *         optional ValueType value = 2;
   *     }
   *     repeated MapFieldEntry map_field = 1;
   *
   * Implementations may choose not to generate the map_entry=true message, but
   * use a native map in the target language to hold the keys and values.
   * The reflection APIs in such implementations still need to work as
   * if the field is a repeated message field.
   *
   * NOTE: Do not set the option in .proto files. Always use the maps syntax
   * instead. The option should only be implicitly set by the proto compiler
   * parser.
   */
  optional bool map_entry = 7;

  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  extensions 1000 to max;

  reserved 8, 9;
}

/* Describes a method of a service. */
message MethodDescriptorProto {
  optional string name = 1;

  /*
   * Input and output type names.  These are resolved in the same way as
   * FieldDescriptorProto.type_name, but must refer to a message type.
   */
  optional string input_type = 2;

  optional string output_type = 3;

  optional MethodOptions options = 4;

  /* Identifies if client streams multiple client messages */
  optional bool client_streaming = 5 [default = false];

  /* Identifies if server streams multiple server messages */
  optional bool server_streaming = 6 [default = false];
}

message MethodOptions {
  /*
   * Note:  Field numbers 1 through 32 are reserved for Google's internal RPC
   *   framework.  We apologize for hoarding these numbers to ourselves, but
   *   we were already using them long before we decided to release Protocol
   *   Buffers.
   */

  /*
   * Is this method deprecated?
   * Depending on the target platform, this can emit Deprecated annotations
   * for the method, or it will be completely ignored; in the very least,
   * this is a formalization for deprecating methods.
   */
  optional bool deprecated = 33 [default = false];

  optional IdempotencyLevel idempotency_level = 34 [default = IDEMPOTENCY_UNKNOWN];

  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  /*
   * Is this method side-effect-free (or safe in HTTP parlance), or idempotent,
   * or neither? HTTP based RPC implementation may choose GET verb for safe
   * methods, and PUT verb for idempotent methods instead of the default POST.
   */
  enum IdempotencyLevel {
    IDEMPOTENCY_UNKNOWN = 0;

    NO_SIDE_EFFECTS = 1; /* implies idempotent */

    IDEMPOTENT = 2; /* idempotent, but may have side effects */
  }

  extensions 1000 to max;
}

/* Describes a oneof. */
message OneofDescriptorProto {
  optional string name = 1;

  optional OneofOptions options = 2;
}

message OneofOptions {
  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  extensions 1000 to max;
}

/* Describes a service. */
message ServiceDescriptorProto {
  optional string name = 1;

  repeated MethodDescriptorProto method = 2;

  optional ServiceOptions options = 3;
}

message ServiceOptions {
  /*
   * Note:  Field numbers 1 through 32 are reserved for Google's internal RPC
   *   framework.  We apologize for hoarding these numbers to ourselves, but
   *   we were already using them long before we decided to release Protocol
   *   Buffers.
   */

  /*
   * Is this service deprecated?
   * Depending on the target platform, this can emit Deprecated annotations
   * for the service, or it will be completely ignored; in the very least,
   * this is a formalization for deprecating services.
   */
  optional bool deprecated = 33 [default = false];

  /* The parser stores options it doesn't recognize here. See above. */
  repeated UninterpretedOption uninterpreted_option = 999;

  extensions 1000 to max;
}

/*
 * ===================================================================
 * Optional source code info
 */

/*
 * Encapsulates information about the original source file from which a
 * FileDescriptorProto was generated.
 */
message SourceCodeInfo {
  /*
   * A Location identifies a piece of source code in a .proto file which
   * corresponds to a particular definition.  This information is intended
   * to be useful to IDEs, code indexers, documentation generators, and similar
   * tools.
   *
   * For example, say we have a file like:
   *   message Foo {
   *     optional string foo = 1;
   *   }
   * Let's look at just the field definition:
   *   optional string foo = 1;
   *   ^       ^^     ^^  ^  ^^^
   *   a       bc     de  f  ghi
   * We have the following locations:
   *   span   path               represents
   *   [a,i)  [ 4, 0, 2, 0 ]     The whole field definition.
   *   [a,b)  [ 4, 0, 2, 0, 4 ]  The label (optional).
   *   [c,d)  [ 4, 0, 2, 0, 5 ]  The type (string).
   *   [e,f)  [ 4, 0, 2, 0, 1 ]  The name (foo).
   *   [g,h)  [ 4, 0, 2, 0, 3 ]  The number (1).
   *
   * Notes:
   * - A location may refer to a repeated field itself (i.e. not to any
   *   particular index within it).  This is used whenever a set of elements are
   *   logically enclosed in a single code segment.  For example, an entire
   *   extend block (possibly containing multiple extension definitions) will
   *   have an outer location whose path refers to the "extensions" repeated
   *   field without an index.
   * - Multiple locations may have the same path.  This happens when a single
   *   logical declaration is spread out across multiple places.  The most
   *   obvious example is the "extend" block again -- there may be multiple
   *   extend blocks in the same scope, each of which will have the same path.
   * - A location's span is not always a subset of its parent's span.  For
   *   example, the "extendee" of an extension declaration appears at the
   *   beginning of the "extend" block and is shared by all extensions within
   *   the block.
   * - Just because a location's span is a subset of some other location's span
   *   does not mean that it is a descendant.  For example, a "group" defines
   *   both a type and a field in a single declaration.  Thus, the locations
   *   corresponding to the type and field and their components will overlap.
   * - Code which tries to interpret locations should probably be designed to
   *   ignore those that it doesn't understand, as more types of locations could
   *   be recorded in the future.
   */
  repeated Location location = 1;

  message Location {
    /*
     * Identifies which part of the FileDescriptorProto was defined at this
     * location.
     *
     * Each element is a field number or an index.  They form a path from
     * the root FileDescriptorProto to the place where the definition.  For
     * example, this path:
     *   [ 4, 3, 2, 7, 1 ]
     * refers to:
     *   file.message_type(3)  // 4, 3
     *       .field(7)         // 2, 7
     *       .name()           // 1
     * This is because FileDescriptorProto.message_type has field number 4:
     *   repeated DescriptorProto message_type = 4;
     * and DescriptorProto.field has field number 2:
     *   repeated FieldDescriptorProto field = 2;
     * and FieldDescriptorProto.name has field number 1:
     *   optional string name = 1;
     *
     * Thus, the above path gives the location of a field name.  If we removed
     * the last element:
     *   [ 4, 3, 2, 7 ]
     * this path refers to the whole field declaration (from the beginning
     * of the label to the terminating semicolon).
     */
    repeated int32 path = 1 [packed = true];

    /*
     * Always has exactly three or four elements: start line, start column,
     * end line (optional, otherwise assumed same as start line), end column.
     * These are packed into a single field for efficiency.  Note that line
     * and column numbers are zero-based -- typically you will want to add
     * 1 to each before displaying to a user.
     */
    repeated int32 span = 2 [packed = true];

    // If this SourceCodeInfo represents a complete declaration, these are any
    // comments appearing before and after the declaration which appear to be
    // attached to the declaration.
    //
    // A series of line comments appearing on consecutive lines, with no other
    // tokens appearing on those lines, will be treated as a single comment.
    //
    // leading_detached_comments will keep paragraphs of comments that appear
    // before (but not connected to) the current element. Each paragraph,
    // separated by empty lines, will be one comment element in the repeated
    // field.
    //
    // Only the comment content is provided; comment markers (e.g. //) are
    // stripped out.  For block comments, leading whitespace and an asterisk
    // will be stripped from the beginning of each line other than the first.
    // Newlines are included in the output.
    //
    // Examples:
    //
    //   optional int32 foo = 1;  // Comment attached to foo.
    //   // Comment attached to bar.
    //   optional int32 bar = 2;
    //
    //   optional string baz = 3;
    //   // Comment attached to baz.
    //   // Another line attached to baz.
    //
    //   // Comment attached to qux.
    //   //
    //   // Another line attached to qux.
    //   optional double qux = 4;
    //
    //   // Detached comment for corge. This is not leading or trailing comments
    //   // to qux or corge because there are blank lines separating it from
    //   // both.
    //
    //   // Detached comment for corge paragraph 2.
    //
    //   optional string corge = 5;
    //   /* Block comment attached
    //    * to corge.  Leading asterisks
    //    * will be removed. */
    //   /* Block comment attached to
    //    * grault. */
    //   optional int32 grault = 6;
    //
    //   // ignored detached comments.
    optional string leading_comments = 3;

    optional string trailing_comments = 4;

    repeated string leading_detached_comments = 6;
  }
}

/*
 * A message representing a option the parser does not recognize. This only
 * appears in options protos created by the compiler::Parser class.
 * DescriptorPool resolves these when building Descriptor objects. Therefore,
 * options protos in descriptor objects (e.g. returned by Descriptor::options(),
 * or produced by Descriptor::CopyTo()) will never have UninterpretedOptions
 * in them.
 */
message UninterpretedOption {
  repeated NamePart name = 2;

  /*
   * The value of the uninterpreted option, in whatever type the tokenizer
   * identified it as during parsing. Exactly one of these should be set.
   */
  optional string identifier_value = 3;

  optional uint64 positive_int_value = 4;

  optional int64 negative_int_value = 5;

  optional double double_value = 6;

  optional bytes string_value = 7;

  optional string aggregate_value = 8;

  /*
   * The name of the uninterpreted option.  Each string represents a segment in
   * a dot-separated name.  is_extension is true iff a segment represents an
   * extension (denoted with parentheses in options specs in .proto files).
   * E.g.,{ ["foo", false], ["bar.baz", true], ["qux", false] } represents
   * "foo.(bar.baz).qux".
   */
  message NamePart {
    required string name_part = 1;

    required bool is_extension = 2;
  }
}
