[uart] Keep debug delimiters and event match data in shared PROGMEM tables

esphome/components/uart/__init__.py

@@ -274,7 +274,9 @@ DEBUG_SCHEMA = cv.Schema(
                 cv.Optional(
                     CONF_TIMEOUT, default=AFTER_DEFAULTS[CONF_TIMEOUT]
                 ): cv.positive_time_period_milliseconds,
-                cv.Optional(CONF_DELIMITER): cv.templatable(validate_raw_data),
+                cv.Optional(CONF_DELIMITER): cv.templatable(
+                    cv.All(validate_raw_data, cv.Length(max=255))
+                ),
             }
         ),
         cv.Optional(
@@ -345,12 +347,11 @@ async def debug_to_code(config, parent):
     after = config[CONF_AFTER]
     cg.add(trigger.set_after_bytes(after[CONF_BYTES]))
     cg.add(trigger.set_after_timeout(after[CONF_TIMEOUT]))
-    if CONF_DELIMITER in after:
-        data = after[CONF_DELIMITER]
-        if isinstance(data, bytes):
-            data = list(data)
-        for byte in after[CONF_DELIMITER]:
-            cg.add(trigger.add_delimiter_byte(byte))
+    if delimiter := after.get(CONF_DELIMITER):
+        table = cg.shared_progmem_array(
+            "uart_debug_delimiter", cg.uint8, [int(b) for b in delimiter]
+        )
+        cg.add(trigger.set_after_delimiter(table, len(delimiter)))
     if config[CONF_DUMMY_RECEIVER]:
         dummy = cg.new_Pvariable(config[CONF_DUMMY_RECEIVER_ID], parent)
         await cg.register_component(dummy, {})

esphome/components/uart/event/__init__.py

@@ -1,8 +1,7 @@
 import esphome.codegen as cg
 from esphome.components import event, uart
 import esphome.config_validation as cv
-from esphome.const import CONF_EVENT_TYPES, CONF_ID
-from esphome.core import ID
+from esphome.const import CONF_EVENT_TYPES
 from esphome.types import ConfigType
 
 from .. import uart_ns
@@ -12,6 +11,7 @@ CODEOWNERS = ["@eoasmxd"]
 DEPENDENCIES = ["uart"]
 
 UARTEvent = uart_ns.class_("UARTEvent", event.Event, uart.UARTDevice, cg.Component)
+UARTEventMatcher = uart_ns.struct("UARTEventMatcher")
 
 
 def validate_event_types(value) -> list[tuple[str, str | list[int]]]:
@@ -56,6 +56,8 @@ def validate_event_types(value) -> list[tuple[str, str | list[int]]]:
 
     if not processed:
         raise cv.Invalid("event_types must contain at least one event mapping.")
+    if any(len(data) > 0xFFFF for _, data in processed):
+        raise cv.Invalid("Event match data can be at most 65535 bytes.")
 
     return processed
 
@@ -77,14 +79,27 @@ async def to_code(config: ConfigType) -> None:
     var = await event.new_event(config, event_types=event_names)
     await cg.register_component(var, config)
     await uart.register_uart_device(var, config)
-    for i, (event_name, match_data) in enumerate(config[CONF_EVENT_TYPES]):
-        if isinstance(match_data, str):
-            match_data = [ord(c) for c in match_data]
-
-        match_data_var_id = ID(
-            f"match_data_{config[CONF_ID]}_{i}", is_declaration=True, type=cg.uint8
+    matchers = []
+    max_len = 0
+    for event_name, match_data in config[CONF_EVENT_TYPES]:
+        match_data = (
+            [ord(c) for c in match_data]
+            if isinstance(match_data, str)
+            else [int(b) for b in match_data]
         )
-        match_data_var = cg.static_const_array(
-            match_data_var_id, cg.ArrayInitializer(*match_data)
+        data = (
+            cg.shared_progmem_array("uart_event_match", cg.uint8, match_data)
+            if match_data
+            else cg.nullptr
         )
-        cg.add(var.add_event_matcher(event_name, match_data_var, len(match_data)))
+        matchers.append(
+            cg.StructInitializer(
+                UARTEventMatcher,
+                ("event_name", event_name),
+                ("data", data),
+                ("data_len", len(match_data)),
+            )
+        )
+        max_len = max(max_len, len(match_data))
+    table = cg.shared_progmem_array("uart_event_matchers", UARTEventMatcher, matchers)
+    cg.add(var.set_matchers(table, len(matchers), max_len))

esphome/components/uart/event/uart_event.cpp

@@ -1,6 +1,6 @@
 #include "uart_event.h"
+#include "esphome/core/hal.h"
 #include "esphome/core/log.h"
-#include <algorithm>
 
 namespace esphome::uart {
 
@@ -12,13 +12,6 @@ void UARTEvent::dump_config() { LOG_EVENT("", "UART Event", this); }
 
 void UARTEvent::loop() { this->read_data_(); }
 
-void UARTEvent::add_event_matcher(const char *event_name, const uint8_t *match_data, size_t match_data_len) {
-  this->matchers_.push_back({event_name, match_data, match_data_len});
-  if (match_data_len > this->max_matcher_len_) {
-    this->max_matcher_len_ = match_data_len;
-  }
-}
-
 void UARTEvent::read_data_() {
   while (this->available()) {
     uint8_t data;
@@ -26,12 +19,18 @@ void UARTEvent::read_data_() {
     this->buffer_.push_back(data);
 
     bool match_found = false;
-    for (const auto &matcher : this->matchers_) {
+    for (uint16_t i = 0; i < this->matcher_count_; i++) {
+      const UARTEventMatcher &matcher = this->matchers_[i];
       if (this->buffer_.size() < matcher.data_len) {
         continue;
       }
 
-      if (std::equal(matcher.data, matcher.data + matcher.data_len, this->buffer_.end() - matcher.data_len)) {
+      const uint8_t *tail = this->buffer_.data() + this->buffer_.size() - matcher.data_len;
+      size_t pos = 0;
+      // The pattern may be in flash, which ESP8266 can only read a byte at a time through progmem_read_byte
+      while (pos < matcher.data_len && progmem_read_byte(matcher.data + pos) == tail[pos])
+        pos++;
+      if (pos == matcher.data_len) {
         this->trigger(matcher.event_name);
         this->buffer_.clear();
         match_found = true;

esphome/components/uart/event/uart_event.h

@@ -1,31 +1,50 @@
 #pragma once
 
 #include "esphome/core/component.h"
+#include "esphome/core/defines.h"
 #include "esphome/components/event/event.h"
 #include "esphome/components/uart/uart.h"
+#include <type_traits>
 #include <vector>
 
 namespace esphome::uart {
 
+/// An event type and the byte pattern that fires it; `data` may point to PROGMEM.
+struct UARTEventMatcher {
+  const char *event_name;
+  const uint8_t *data;
+  size_t data_len;
+};
+// Codegen keeps the matchers in a flash table read with plain loads, which ESP8266 only allows for whole words.
+static_assert(std::is_same_v<decltype(UARTEventMatcher::event_name), const char *>,
+              "UARTEventMatcher fields must stay word sized");
+static_assert(std::is_same_v<decltype(UARTEventMatcher::data), const uint8_t *>,
+              "UARTEventMatcher fields must stay word sized");
+static_assert(std::is_same_v<decltype(UARTEventMatcher::data_len), size_t>,
+              "UARTEventMatcher fields must stay word sized");
+#ifdef USE_ESP8266
+static_assert(sizeof(UARTEventMatcher) == 3 * sizeof(uint32_t), "UARTEventMatcher is read from flash with word loads");
+#endif
+
 class UARTEvent final : public event::Event, public UARTDevice, public Component {
  public:
   void setup() override;
   void loop() override;
   void dump_config() override;
 
-  void add_event_matcher(const char *event_name, const uint8_t *match_data, size_t match_data_len);
+  /// `matchers` is a codegen PROGMEM table that must outlive the component.
+  void set_matchers(const UARTEventMatcher *matchers, uint16_t count, uint16_t max_len) {
+    this->matchers_ = matchers;
+    this->matcher_count_ = count;
+    this->max_matcher_len_ = max_len;
+  }
 
  protected:
-  struct EventMatcher {
-    const char *event_name;
-    const uint8_t *data;
-    size_t data_len;
-  };
-
   void read_data_();
-  std::vector<EventMatcher> matchers_;
+  const UARTEventMatcher *matchers_{nullptr};
   std::vector<uint8_t> buffer_;
-  size_t max_matcher_len_ = 0;
+  uint16_t matcher_count_{0};
+  uint16_t max_matcher_len_{0};
 };
 
 }  // namespace esphome::uart

esphome/components/uart/uart_debugger.cpp

@@ -3,6 +3,7 @@
 
 #include <vector>
 #include "uart_debugger.h"
+#include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
@@ -44,15 +45,15 @@ void UARTDebugger::store_byte_(UARTDirection direction, uint8_t byte) {
 }
 
 void UARTDebugger::trigger_after_delimiter_(uint8_t byte) {
-  if (this->after_delimiter_.empty() || !this->has_buffered_bytes_()) {
+  if (this->after_delimiter_len_ == 0 || !this->has_buffered_bytes_()) {
     return;
   }
-  if (this->after_delimiter_[this->after_delimiter_pos_] != byte) {
+  if (progmem_read_byte(this->after_delimiter_ + this->after_delimiter_pos_) != byte) {
     this->after_delimiter_pos_ = 0;
     return;
   }
   this->after_delimiter_pos_++;
-  if (this->after_delimiter_pos_ == this->after_delimiter_.size()) {
+  if (this->after_delimiter_pos_ == this->after_delimiter_len_) {
     this->fire_trigger_();
     this->after_delimiter_pos_ = 0;
   }

esphome/components/uart/uart_debugger.h

@@ -36,11 +36,13 @@ class UARTDebugger final : public Component, public Trigger<UARTDirection, std::
   /// this timeout, logging will be triggered.
   void set_after_timeout(uint32_t timeout) { this->after_timeout_ = timeout; }
 
-  /// Add a delimiter byte. This can be called multiple times to setup a
-  /// multi-byte delimiter (a typical example would be '\r\n').
-  /// When the constructed byte sequence is found in the data stream,
-  /// logging will be triggered.
-  void add_delimiter_byte(uint8_t byte) { this->after_delimiter_.push_back(byte); }
+  /// Set a delimiter byte sequence (a typical example would be '\r\n').
+  /// When the sequence is found in the data stream, logging will be triggered.
+  /// `delimiter` is a codegen PROGMEM table that must outlive the debugger.
+  void set_after_delimiter(const uint8_t *delimiter, uint8_t len) {
+    this->after_delimiter_ = delimiter;
+    this->after_delimiter_len_ = len;
+  }
 
   void set_debug_prefix(const char *prefix) { this->debug_prefix_ = StringRef(prefix); }
 
@@ -51,8 +53,9 @@ class UARTDebugger final : public Component, public Trigger<UARTDirection, std::
   size_t after_bytes_;
   uint32_t after_timeout_;
   uint32_t last_time_{};
-  std::vector<uint8_t> after_delimiter_{};
-  size_t after_delimiter_pos_{};
+  const uint8_t *after_delimiter_{nullptr};
+  uint8_t after_delimiter_len_{0};
+  uint8_t after_delimiter_pos_{0};
   bool is_triggering_{false};
   StringRef debug_prefix_{};
 

tests/component_tests/uart/config/debug_event_tables.yaml

@@ -0,0 +1,34 @@
+esphome:
+  name: test
+
+esp8266:
+  board: esp01_1m
+
+uart:
+  - id: uart_a
+    tx_pin: GPIO1
+    rx_pin: GPIO3
+    baud_rate: 9600
+    debug:
+      after:
+        delimiter: "\r\n"
+  - id: uart_b
+    tx_pin: GPIO2
+    baud_rate: 9600
+    debug:
+      after:
+        delimiter: [0x0D, 0x0A]
+
+event:
+  - platform: uart
+    uart_id: uart_a
+    name: Event A
+    event_types:
+      - "start": "*A#"
+      - "stop": [0x2A, 0x42, 0x23]
+  - platform: uart
+    uart_id: uart_a
+    name: Event B
+    event_types:
+      - "start": "*A#"
+      - "stop": [0x2A, 0x42, 0x23]

tests/component_tests/uart/test_debug_event_tables.py

@@ -0,0 +1,27 @@
+"""uart debug delimiters and uart event patterns live in shared PROGMEM tables."""
+
+from collections.abc import Callable
+from pathlib import Path
+import re
+
+
+def test_debug_delimiter_and_event_matchers_use_shared_tables(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+) -> None:
+    main_cpp = generate_main(component_config_path("debug_event_tables.yaml"))
+
+    # "\r\n" and [0x0D, 0x0A] are the same bytes, so both debuggers share one table
+    delimiters = re.findall(r"->set_after_delimiter\((\w+), 2\);", main_cpp)
+    assert len(delimiters) == 2
+    assert delimiters[0] == delimiters[1]
+    assert "add_delimiter_byte" not in main_cpp
+
+    # Both events have the same patterns, so they share the byte tables and the matcher table
+    patterns = re.findall(r"static constexpr uint8_t uart_event_match\w*\[\]", main_cpp)
+    assert len(patterns) == 2
+    calls = re.findall(r"->set_matchers\((\w+), 2, 3\);", main_cpp)
+    assert len(calls) == 2
+    assert calls[0] == calls[1]
+    assert main_cpp.count("static constexpr uart::UARTEventMatcher") == 1
+    assert "add_event_matcher" not in main_cpp