[nfc] Pass tags to triggers by reference and keep the listener list in static storage (#19902)

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

esphome/components/nfc/__init__.py

@@ -7,7 +7,8 @@ nfc_ns = cg.esphome_ns.namespace("nfc")
 
 Nfcc = nfc_ns.class_("Nfcc")
 NfcTag = nfc_ns.class_("NfcTag")
+NfcTagConstRef = NfcTag.operator("ref").operator("const")
 NfcTagListener = nfc_ns.class_("NfcTagListener")
 NfcOnTagTrigger = nfc_ns.class_(
-    "NfcOnTagTrigger", automation.Trigger.template(cg.std_string, NfcTag)
+    "NfcOnTagTrigger", automation.Trigger.template(cg.std_string, NfcTagConstRef)
 )

esphome/components/nfc/automation.h

@@ -7,7 +7,8 @@
 
 namespace esphome::nfc {
 
-class NfcOnTagTrigger final : public Trigger<std::string, NfcTag> {
+/// Fires with the formatted UID and the tag itself; the tag is passed by reference so no copy is made per trigger
+class NfcOnTagTrigger final : public Trigger<std::string, const NfcTag &> {
  public:
   void process(const std::unique_ptr<NfcTag> &tag);
 };

esphome/components/nfc/binary_sensor/__init__.py

@@ -20,7 +20,6 @@ NfcTagBinarySensor = nfc_ns.class_(
     binary_sensor.BinarySensor,
     cg.Component,
     NfcTagListener,
-    cg.Parented.template(Nfcc),
 )
 
 
@@ -59,12 +58,15 @@ CONFIG_SCHEMA = cv.All(
 )
 
 
+_request_listener_slot = cg.slot_counter("NFC_TAG_LISTENER_COUNT")
+
+
 async def to_code(config: ConfigType) -> None:
     var = await binary_sensor.new_binary_sensor(config)
     await cg.register_component(var, config)
-    await cg.register_parented(var, config[CONF_NFCC_ID])
 
     hub = await cg.get_variable(config[CONF_NFCC_ID])
+    _request_listener_slot(str(hub))
     cg.add(hub.register_listener(var))
     if CONF_NDEF_CONTAINS in config:
         cg.add(var.set_ndef_match_string(config[CONF_NDEF_CONTAINS]))

esphome/components/nfc/binary_sensor/nfc_binary_sensor.cpp

@@ -7,10 +7,7 @@ namespace esphome::nfc {
 
 static const char *const TAG = "nfc.binary_sensor";
 
-void NfcTagBinarySensor::setup() {
-  this->parent_->register_listener(this);
-  this->publish_initial_state(false);
-}
+void NfcTagBinarySensor::setup() { this->publish_initial_state(false); }
 
 void NfcTagBinarySensor::dump_config() {
   std::string match_str = "name";

esphome/components/nfc/binary_sensor/nfc_binary_sensor.h

@@ -8,10 +8,7 @@
 
 namespace esphome::nfc {
 
-class NfcTagBinarySensor final : public binary_sensor::BinarySensor,
-                                 public Component,
-                                 public NfcTagListener,
-                                 public Parented<Nfcc> {
+class NfcTagBinarySensor final : public binary_sensor::BinarySensor, public Component, public NfcTagListener {
  public:
   void setup() override;
   void dump_config() override;

esphome/components/nfc/nfc.h

@@ -83,10 +83,12 @@ class NfcTagListener {
 
 class Nfcc {
  public:
+#ifdef NFC_TAG_LISTENER_COUNT
   void register_listener(NfcTagListener *listener) { this->tag_listeners_.push_back(listener); }
 
  protected:
-  std::vector<NfcTagListener *> tag_listeners_;
+  StaticVector<NfcTagListener *, NFC_TAG_LISTENER_COUNT> tag_listeners_;
+#endif
 };
 
 }  // namespace esphome::nfc

esphome/components/nfc/nfc_helpers.cpp

@@ -4,14 +4,14 @@ namespace esphome::nfc {
 
 static const char *const TAG = "nfc.helpers";
 
-bool has_ha_tag_ndef(NfcTag &tag) { return !get_ha_tag_ndef(tag).empty(); }
+bool has_ha_tag_ndef(const NfcTag &tag) { return !get_ha_tag_ndef(tag).empty(); }
 
-std::string get_ha_tag_ndef(NfcTag &tag) {
+std::string get_ha_tag_ndef(const NfcTag &tag) {
   if (!tag.has_ndef_message()) {
     return std::string();
   }
-  auto message = tag.get_ndef_message();
-  auto records = message->get_records();
+  const auto &message = tag.get_ndef_message();
+  const auto &records = message->get_records();
   for (const auto &record : records) {
     std::string payload = record->get_payload();
     size_t pos = payload.find(HA_TAG_ID_PREFIX);

esphome/components/nfc/nfc_helpers.h

@@ -8,8 +8,8 @@ static const char HA_TAG_ID_EXT_RECORD_TYPE[] = "android.com:pkg";
 static const char HA_TAG_ID_EXT_RECORD_PAYLOAD[] = "io.homeassistant.companion.android";
 static const char HA_TAG_ID_PREFIX[] = "https://www.home-assistant.io/tag/";
 
-std::string get_ha_tag_ndef(NfcTag &tag);
+std::string get_ha_tag_ndef(const NfcTag &tag);
 std::string get_random_ha_tag_ndef();
-bool has_ha_tag_ndef(NfcTag &tag);
+bool has_ha_tag_ndef(const NfcTag &tag);
 
 }  // namespace esphome::nfc

esphome/components/nfc/nfc_tag.h

@@ -42,9 +42,10 @@ class NfcTag {
   }
 
   NfcTagUid &get_uid() { return this->uid_; };
-  const std::string &get_tag_type() { return this->tag_type_; };
-  bool has_ndef_message() { return this->ndef_message_ != nullptr; };
-  const std::shared_ptr<NdefMessage> &get_ndef_message() { return this->ndef_message_; };
+  const NfcTagUid &get_uid() const { return this->uid_; };
+  const std::string &get_tag_type() const { return this->tag_type_; };
+  bool has_ndef_message() const { return this->ndef_message_ != nullptr; };
+  const std::shared_ptr<NdefMessage> &get_ndef_message() const { return this->ndef_message_; };
   void set_ndef_message(std::unique_ptr<NdefMessage> ndef_message) { this->ndef_message_ = std::move(ndef_message); };
 
  protected:

esphome/components/pn532/__init__.py

@@ -66,7 +66,7 @@ async def setup_pn532(var: MockObj, config: ConfigType) -> None:
         _request_ontag_trigger_slot(str(var))
         cg.add(var.register_ontag_trigger(trigger))
         await automation.build_automation(
-            trigger, [(cg.std_string, "x"), (nfc.NfcTag, "tag")], conf
+            trigger, [(cg.std_string, "x"), (nfc.NfcTagConstRef, "tag")], conf
         )
 
     for conf in config.get(CONF_ON_TAG_REMOVED, []):
@@ -74,7 +74,7 @@ async def setup_pn532(var: MockObj, config: ConfigType) -> None:
         _request_ontagremoved_trigger_slot(str(var))
         cg.add(var.register_ontagremoved_trigger(trigger))
         await automation.build_automation(
-            trigger, [(cg.std_string, "x"), (nfc.NfcTag, "tag")], conf
+            trigger, [(cg.std_string, "x"), (nfc.NfcTagConstRef, "tag")], conf
         )
 
     await automation.build_callback_automations(var, config, _CALLBACK_AUTOMATIONS)

esphome/components/pn71xx/__init__.py

@@ -144,7 +144,7 @@ async def setup_pn71xx(var: MockObj, config: ConfigType) -> None:
         _request_ontag_trigger_slot(str(var))
         cg.add(var.register_ontag_trigger(trigger))
         await automation.build_automation(
-            trigger, [(cg.std_string, "x"), (nfc.NfcTag, "tag")], conf
+            trigger, [(cg.std_string, "x"), (nfc.NfcTagConstRef, "tag")], conf
         )
 
     for conf in config.get(CONF_ON_TAG_REMOVED, []):
@@ -152,7 +152,7 @@ async def setup_pn71xx(var: MockObj, config: ConfigType) -> None:
         _request_ontagremoved_trigger_slot(str(var))
         cg.add(var.register_ontagremoved_trigger(trigger))
         await automation.build_automation(
-            trigger, [(cg.std_string, "x"), (nfc.NfcTag, "tag")], conf
+            trigger, [(cg.std_string, "x"), (nfc.NfcTagConstRef, "tag")], conf
         )
 
     await automation.build_callback_automations(var, config, _CALLBACK_AUTOMATIONS)

esphome/components/pn71xx/pn71xx.cpp

@@ -569,9 +569,11 @@ void PN71xx::erase_tag_(const uint8_t tag_index) {
       trigger->process(this->discovered_endpoint_[tag_index].tag);
     }
 #endif
+#ifdef NFC_TAG_LISTENER_COUNT
     for (auto *listener : this->tag_listeners_) {
       listener->tag_off(*this->discovered_endpoint_[tag_index].tag);
     }
+#endif
     char uid_buf[nfc::FORMAT_UID_BUFFER_SIZE];
     ESP_LOGI(TAG, "Tag %s removed", nfc::format_uid_to(uid_buf, this->discovered_endpoint_[tag_index].tag->get_uid()));
     // keep the remaining entries in order; selecting_endpoint_ indexes into this list
@@ -908,9 +910,11 @@ void PN71xx::process_rf_intf_activated_oid_(nfc::NciMessage &rx) {  // an endpoi
             trigger->process(working_endpoint.tag);
           }
 #endif
+#ifdef NFC_TAG_LISTENER_COUNT
           for (auto *listener : this->tag_listeners_) {
             listener->tag_on(*working_endpoint.tag);
           }
+#endif
           working_endpoint.trig_called = true;
           break;
         }

esphome/core/defines.h

@@ -141,6 +141,7 @@
 #define MICRONOVA_LISTENER_COUNT 1
 #define USE_MICRONOVA_WRITER
 #define MK2PVROUTER_LISTENER_COUNT 1
+#define NFC_TAG_LISTENER_COUNT 1
 #define PN532_BINARY_SENSOR_COUNT 1
 #define PN532_ON_TAG_REMOVED_TRIGGER_COUNT 1
 #define PN532_ON_TAG_TRIGGER_COUNT 1

tests/components/pn532_spi/common.yaml

@@ -1,6 +1,15 @@
 pn532_spi:
   id: pn532_nfcc_spi
   cs_pin: ${cs_pin}
+  on_tag:
+    then:
+      - delay: 10ms
+      - lambda: |-
+          ESP_LOGD("test", "%s %zu %d %d", tag.get_tag_type().c_str(), tag.get_uid().size(), tag.has_ndef_message(),
+                   nfc::has_ha_tag_ndef(tag));
+  on_tag_removed:
+    then:
+      - lambda: ESP_LOGD("test", "%s", tag.get_tag_type().c_str());
 
 binary_sensor:
   - platform: pn532

tests/components/pn7160_spi/common.yaml

@@ -24,8 +24,19 @@ pn7160_spi:
   emulation_message: https://www.home-assistant.io/tag/pulse_ce
   tag_ttl: 1000ms
   on_tag:
-    - logger.log: "Tag"
+    then:
+      - delay: 10ms
+      - lambda: |-
+          ESP_LOGD("test", "%s %zu %d %s", tag.get_tag_type().c_str(), tag.get_uid().size(), tag.has_ndef_message(),
+                   nfc::get_ha_tag_ndef(tag).c_str());
   on_tag_removed:
-    - logger.log: "Tag removed"
+    then:
+      - lambda: ESP_LOGD("test", "%s", tag.get_tag_type().c_str());
   on_emulated_tag_scan:
     - logger.log: "Tag emulated"
+
+binary_sensor:
+  - platform: nfc
+    nfcc_id: nfcc_pn7160_spi
+    name: Pulse tag
+    ndef_contains: pulse