[light] Add zero-copy support for API effect commands (#12384)

esphome/components/api/api.proto

@@ -579,7 +579,7 @@ message LightCommandRequest {
   bool has_flash_length = 16;
   uint32 flash_length = 17;
   bool has_effect = 18;
-  string effect = 19;
+  string effect = 19 [(pointer_to_buffer) = true];
   uint32 device_id = 28 [(field_ifdef) = "USE_DEVICES"];
 }
 

esphome/components/api/api_connection.cpp

@@ -533,7 +533,7 @@ void APIConnection::light_command(const LightCommandRequest &msg) {
   if (msg.has_flash_length)
     call.set_flash_length(msg.flash_length);
   if (msg.has_effect)
-    call.set_effect(msg.effect);
+    call.set_effect(reinterpret_cast<const char *>(msg.effect), msg.effect_len);
   call.perform();
 }
 #endif

esphome/components/api/api_pb2.cpp

@@ -611,9 +611,12 @@ bool LightCommandRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
 }
 bool LightCommandRequest::decode_length(uint32_t field_id, ProtoLengthDelimited value) {
   switch (field_id) {
-    case 19:
+    case 19: {
-      this->effect = value.as_string();
+      // Use raw data directly to avoid allocation
+      this->effect = value.data();
+      this->effect_len = value.size();
       break;
+    }
     default:
       return false;
   }

esphome/components/api/api_pb2.h

@@ -840,7 +840,7 @@ class LightStateResponse final : public StateResponseProtoMessage {
 class LightCommandRequest final : public CommandProtoMessage {
  public:
   static constexpr uint8_t MESSAGE_TYPE = 32;
-  static constexpr uint8_t ESTIMATED_SIZE = 112;
+  static constexpr uint8_t ESTIMATED_SIZE = 122;
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "light_command_request"; }
 #endif
@@ -869,7 +869,8 @@ class LightCommandRequest final : public CommandProtoMessage {
   bool has_flash_length{false};
   uint32_t flash_length{0};
   bool has_effect{false};
-  std::string effect{};
+  const uint8_t *effect{nullptr};
+  uint16_t effect_len{0};
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif

esphome/components/api/api_pb2_dump.cpp

@@ -999,7 +999,9 @@ void LightCommandRequest::dump_to(std::string &out) const {
   dump_field(out, "has_flash_length", this->has_flash_length);
   dump_field(out, "flash_length", this->flash_length);
   dump_field(out, "has_effect", this->has_effect);
-  dump_field(out, "effect", this->effect);
+  out.append("  effect: ");
+  out.append(format_hex_pretty(this->effect, this->effect_len));
+  out.append("\n");
 #ifdef USE_DEVICES
   dump_field(out, "device_id", this->device_id);
 #endif

esphome/components/light/light_call.cpp

@@ -504,8 +504,8 @@ color_mode_bitmask_t LightCall::get_suitable_color_modes_mask_() {
 #undef KEY
 }
 
-LightCall &LightCall::set_effect(const std::string &effect) {
+LightCall &LightCall::set_effect(const char *effect, size_t len) {
-  if (strcasecmp(effect.c_str(), "none") == 0) {
+  if (len == 4 && strncasecmp(effect, "none", 4) == 0) {
     this->set_effect(0);
     return *this;
   }
@@ -513,15 +513,16 @@ LightCall &LightCall::set_effect(const std::string &effect) {
   bool found = false;
   for (uint32_t i = 0; i < this->parent_->effects_.size(); i++) {
     LightEffect *e = this->parent_->effects_[i];
+    const char *name = e->get_name();
 
-    if (strcasecmp(effect.c_str(), e->get_name()) == 0) {
+    if (strncasecmp(effect, name, len) == 0 && name[len] == '\0') {
       this->set_effect(i + 1);
       found = true;
       break;
     }
   }
   if (!found) {
-    ESP_LOGW(TAG, "'%s': no such effect '%s'", this->parent_->get_name().c_str(), effect.c_str());
+    ESP_LOGW(TAG, "'%s': no such effect '%.*s'", this->parent_->get_name().c_str(), (int) len, effect);
   }
   return *this;
 }

esphome/components/light/light_call.h

@@ -129,7 +129,9 @@ class LightCall {
   /// Set the effect of the light by its name.
   LightCall &set_effect(optional<std::string> effect);
   /// Set the effect of the light by its name.
-  LightCall &set_effect(const std::string &effect);
+  LightCall &set_effect(const std::string &effect) { return this->set_effect(effect.data(), effect.size()); }
+  /// Set the effect of the light by its name and length (zero-copy from API).
+  LightCall &set_effect(const char *effect, size_t len);
   /// Set the effect of the light by its internal index number (only for internal use).
   LightCall &set_effect(uint32_t effect_number);
   LightCall &set_effect(optional<uint32_t> effect_number);