esphome/esphome/components/api/api_options.proto

syntax = "proto2";
import "google/protobuf/descriptor.proto";


enum APISourceType {
    SOURCE_BOTH = 0;
    SOURCE_SERVER = 1;
    SOURCE_CLIENT = 2;
}

message void {}

extend google.protobuf.MethodOptions {
    optional bool needs_setup_connection = 1038 [default=true];
    optional bool needs_authentication = 1039 [default=true];
}

extend google.protobuf.MessageOptions {
    optional uint32 id = 1036 [default=0];
    optional APISourceType source = 1037 [default=SOURCE_BOTH];
    optional string ifdef = 1038;
    optional bool log = 1039 [default=true];
    optional bool no_delay = 1040 [default=false];
    optional string base_class = 1041;
    optional bool inline_encode = 1042 [default=false];
    optional bool speed_optimized = 1043 [default=false];
}

extend google.protobuf.FieldOptions {
    optional string field_ifdef = 1042;
    optional uint32 fixed_array_size = 50007;
    optional bool fixed_array_skip_zero = 50009 [default=false];
    optional string fixed_array_size_define = 50010;
    optional string fixed_array_with_length_define = 50011;

    // pointer_to_buffer: Use pointer instead of array for fixed-size byte fields
    // When set, the field will be declared as a pointer (const uint8_t *data)
    // instead of an array (uint8_t data[N]). This allows zero-copy on decode
    // by pointing directly to the protobuf buffer. The buffer must remain valid
    // until the message is processed (which is guaranteed for stack-allocated messages).
    optional bool pointer_to_buffer = 50012 [default=false];

    // container_pointer: Zero-copy optimization for repeated fields.
    //
    // When container_pointer is set on a repeated field, the generated message will
    // store a pointer to an existing container instead of copying the data into the
    // message's own repeated field. This eliminates heap allocations and improves performance.
    //
    // Requirements for safe usage:
    // 1. The source container must remain valid until the message is encoded
    // 2. Messages must be encoded immediately (which ESPHome does by default)
    // 3. The container type must match the field type exactly
    //
    // Supported container types:
    // - "std::vector<T>" for most repeated fields
    // - "std::set<T>" for unique/sorted data
    // - Full type specification required for enums (e.g., "std::set<climate::ClimateMode>")
    //
    // Example usage in .proto file:
    //   repeated string supported_modes = 12 [(container_pointer) = "std::set"];
    //   repeated ColorMode color_modes = 13 [(container_pointer) = "std::set<light::ColorMode>"];
    //
    // The corresponding C++ code must provide const reference access to a container
    // that matches the specified type and remains valid during message encoding.
    // This is typically done through methods returning const T& or special accessor
    // methods like get_options() or supported_modes_for_api_().
    optional string container_pointer = 50001;

    // fixed_vector: Use FixedVector instead of std::vector for repeated fields
    // When set, the repeated field will use FixedVector<T> which requires calling
    // init(size) before adding elements. This eliminates std::vector template overhead
    // and is ideal when the exact size is known before populating the array.
    optional bool fixed_vector = 50013 [default=false];

    // container_pointer_no_template: Use a non-template container type for repeated fields
    // Similar to container_pointer, but for containers that don't take template parameters.
    // The container type is used as-is without appending element type.
    // The container must have:
    // - begin() and end() methods returning iterators
    // - empty() method
    // Example: [(container_pointer_no_template) = "light::ColorModeMask"]
    //   generates: const light::ColorModeMask *supported_color_modes{};
    optional string container_pointer_no_template = 50014;

    // packed_buffer: Expose raw packed buffer instead of decoding into container
    // When set on a packed repeated field, the generated code stores a pointer
    // to the raw protobuf buffer instead of decoding values. This enables
    // zero-copy passthrough when the consumer can decode on-demand.
    // The field must be a packed repeated field (packed=true).
    // Generates three fields:
    //   - const uint8_t *<field>_data_{nullptr};
    //   - uint16_t <field>_length_{0};
    //   - uint16_t <field>_count_{0};
    optional bool packed_buffer = 50015 [default=false];

    // force: Always encode this field, even when its value equals the proto3 default.
    // Skips the zero/empty check in calculate_size() and encode(), using the _force
    // variant of the calc_ method. Use on fields that are almost always non-default
    // to eliminate dead branches on hot paths.
    optional bool force = 50016 [default=false];

    // max_value: Maximum value a field can have.
    // When max_value < 128, the code generator emits constant-size calculations
    // and direct byte writes instead of varint branching, since the encoded varint
    // is guaranteed to be 1 byte.
    optional uint32 max_value = 50017;

    // max_data_length: Maximum length of a string or bytes field.
    // When max_data_length < 128, the code generator emits constant-size
    // length varint calculations and direct byte writes, since the length
    // varint is guaranteed to be 1 byte.
    optional uint32 max_data_length = 50018;

    // mac_address: Field is a 48-bit MAC address stored in a uint64.
    // Emits encode_varint_raw_48bit which has a 7-byte fast path that avoids
    // the per-byte loop when the upper bits are non-zero (the common case
    // for real MAC addresses, since OUIs occupy the top 24 bits).
    optional bool mac_address = 50019 [default=false];

    // track_presence: Track whether this message-typed field was present on the wire.
    // Generates a `bool has_<field>{false};` member on the decoding side that is set
    // to true when the field arrives, so an all-default submessage can be told apart
    // from an absent one (e.g. a UTC ParsedTimezone, which is all zeros).
    optional bool track_presence = 50020 [default=false];
}