avoid string copy in scheduler for const strings

esphome/core/scheduler.cpp

@@ -22,8 +22,17 @@ static const uint32_t MAX_LOGICALLY_DELETED_ITEMS = 10;
 // iterating over them from the loop task is fine; but iterating from any other context requires the lock to be held to
 // avoid the main thread modifying the list while it is being accessed.
 
+void HOT Scheduler::set_timeout(Component *component, const char *name, uint32_t timeout, std::function<void()> func) {
+  return this->set_timeout_(component, name, timeout, func, false);
+}
+
 void HOT Scheduler::set_timeout(Component *component, const std::string &name, uint32_t timeout,
                                 std::function<void()> func) {
+  return this->set_timeout_(component, name, timeout, func, true);
+}
+
+void HOT Scheduler::set_timeout_(Component *component, const std::string &name, uint32_t timeout,
+                                 std::function<void()> func, bool make_copy) {
   const auto now = this->millis_();
 
   if (!name.empty())
@@ -34,7 +43,7 @@ void HOT Scheduler::set_timeout(Component *component, const std::string &name, u
 
   auto item = make_unique<SchedulerItem>();
   item->component = component;
-  item->name = name;
+  item->set_name(name.c_str(), make_copy);
   item->type = SchedulerItem::TIMEOUT;
   item->next_execution_ = now + timeout;
   item->callback = std::move(func);
@@ -49,6 +58,14 @@ bool HOT Scheduler::cancel_timeout(Component *component, const std::string &name
 }
 void HOT Scheduler::set_interval(Component *component, const std::string &name, uint32_t interval,
                                  std::function<void()> func) {
+  this->set_interval_(component, name, interval, func, true);
+}
+void HOT Scheduler::set_interval(Component *component, const char *name, uint32_t interval,
+                                 std::function<void()> func) {
+  this->set_interval_(component, name, interval, func, false);
+}
+void HOT Scheduler::set_interval_(Component *component, const std::string &name, uint32_t interval,
+                                  std::function<void()> func, bool make_copy) {
   const auto now = this->millis_();
 
   if (!name.empty())
@@ -64,7 +81,7 @@ void HOT Scheduler::set_interval(Component *component, const std::string &name,
 
   auto item = make_unique<SchedulerItem>();
   item->component = component;
-  item->name = name;
+  item->set_name(name.c_str(), make_copy);
   item->type = SchedulerItem::INTERVAL;
   item->interval = interval;
   item->next_execution_ = now + offset;
@@ -85,7 +102,7 @@ struct RetryArgs {
   uint8_t retry_countdown;
   uint32_t current_interval;
   Component *component;
-  std::string name;
+  std::string name;  // Keep as std::string since retry uses it dynamically
   float backoff_increase_factor;
   Scheduler *scheduler;
 };
@@ -303,14 +320,16 @@ bool HOT Scheduler::cancel_item_(Component *component, const std::string &name,
   LockGuard guard{this->lock_};
   bool ret = false;
   for (auto &it : this->items_) {
-    if (it->component == component && it->name == name && it->type == type && !it->remove) {
+    const char *item_name = it->get_name();
+    if (it->component == component && item_name != nullptr && name == item_name && it->type == type && !it->remove) {
       to_remove_++;
       it->remove = true;
       ret = true;
     }
   }
   for (auto &it : this->to_add_) {
-    if (it->component == component && it->name == name && it->type == type) {
+    const char *item_name = it->get_name();
+    if (it->component == component && item_name != nullptr && name == item_name && it->type == type) {
       it->remove = true;
       ret = true;
     }

esphome/core/scheduler.h

@@ -12,11 +12,19 @@ class Component;
 
 class Scheduler {
  public:
+  // Public API - accepts std::string for backward compatibility
   void set_timeout(Component *component, const std::string &name, uint32_t timeout, std::function<void()> func);
+  void set_timeout(Component *component, const char *name, uint32_t timeout, std::function<void()> func);
+  void set_timeout_(Component *component, const std::string &name, uint32_t timeout, std::function<void()> func,
+                    bool make_copy);
+
   bool cancel_timeout(Component *component, const std::string &name);
   void set_interval(Component *component, const std::string &name, uint32_t interval, std::function<void()> func);
-  bool cancel_interval(Component *component, const std::string &name);
+  void set_interval(Component *component, const char *name, uint32_t interval, std::function<void()> func);
+  void set_interval_(Component *component, const std::string &name, uint32_t interval, std::function<void()> func,
+                     bool make_copy);
 
+  bool cancel_interval(Component *component, const std::string &name);
   void set_retry(Component *component, const std::string &name, uint32_t initial_wait_time, uint8_t max_attempts,
                  std::function<RetryResult(uint8_t)> func, float backoff_increase_factor = 1.0f);
   bool cancel_retry(Component *component, const std::string &name);
@@ -36,10 +44,65 @@ class Scheduler {
     // with a 16-bit rollover counter to create a 64-bit time that won't roll over for
     // billions of years. This ensures correct scheduling even when devices run for months.
     uint64_t next_execution_;
-    std::string name;
+
+    // Optimized name storage using tagged union
+    union {
+      const char *static_name;  // For string literals (no allocation)
+      char *dynamic_name;       // For allocated strings
+    } name_;
+
     std::function<void()> callback;
-    enum Type : uint8_t { TIMEOUT, INTERVAL } type;
-    bool remove;
+
+    // Bit-packed fields to minimize padding
+    enum Type : uint8_t { TIMEOUT, INTERVAL } type : 1;
+    bool remove : 1;
+    bool owns_name : 1;  // True if name_.dynamic_name needs to be freed
+    // 5 bits padding
+
+    // Constructor
+    SchedulerItem()
+        : component(nullptr),
+          interval(0),
+          next_execution_(0),
+          callback(nullptr),
+          type(TIMEOUT),
+          remove(false),
+          owns_name(false) {
+      name_.static_name = nullptr;
+    }
+
+    // Destructor to clean up dynamic names
+    ~SchedulerItem() {
+      if (owns_name && name_.dynamic_name) {
+        delete[] name_.dynamic_name;
+      }
+    }
+
+    // Helper to get the name regardless of storage type
+    const char *get_name() const { return owns_name ? name_.dynamic_name : name_.static_name; }
+
+    // Helper to set name with proper ownership
+    void set_name(const char *name, bool make_copy = false) {
+      // Clean up old dynamic name if any
+      if (owns_name && name_.dynamic_name) {
+        delete[] name_.dynamic_name;
+      }
+
+      if (name == nullptr || name[0] == '\0') {
+        name_.static_name = nullptr;
+        owns_name = false;
+      } else if (make_copy) {
+        // Make a copy for dynamic strings
+        size_t len = strlen(name);
+        name_.dynamic_name = new char[len + 1];
+        strcpy(name_.dynamic_name, name);
+        owns_name = true;
+      } else {
+        // Use static string directly
+        name_.static_name = name;
+        owns_name = false;
+      }
+    }
 
     static bool cmp(const std::unique_ptr<SchedulerItem> &a, const std::unique_ptr<SchedulerItem> &b);
     const char *get_type_str() {