template_text.h

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#pragma once
 
#include "esphome/components/text/text.h"
#include "esphome/core/automation.h"
#include "esphome/core/component.h"
#include "esphome/core/preferences.h"
#include "esphome/core/template_lambda.h"
 
namespace esphome {
namespace template_ {
 
// We keep this separate so we don't have to template and duplicate
// the text input for each different size flash allocation.
class TemplateTextSaverBase {
 public:
  virtual bool save(const std::string &value) { return true; }
 
  virtual void setup(uint32_t id, std::string &value) {}
 
 protected:
  ESPPreferenceObject pref_;
  std::string prev_;
};
 
template<uint8_t SZ> class TextSaver : public TemplateTextSaverBase {
 public:
  bool save(const std::string &value) override {
    int diff = value.compare(this->prev_);
    if (diff != 0) {
      // If string is bigger than the allocation, do not save it.
      // We don't need to waste ram setting prev_value either.
      int size = value.size();
      if (size <= SZ) {
        // Make it into a length prefixed thing
        unsigned char temp[SZ + 1];
        memcpy(temp + 1, value.c_str(), size);
        // SZ should be pre checked at the schema level, it can't go past the char range.
        temp[0] = ((unsigned char) size);
        this->pref_.save(&temp);
        this->prev_.assign(value);
        return true;
      }
    }
    return false;
  }
 
  // Make the preference object.  Fill the provided location with the saved data
  // If it is available, else leave it alone
  void setup(uint32_t id, std::string &value) override {
    this->pref_ = global_preferences->make_preference<uint8_t[SZ + 1]>(id);
 
    char temp[SZ + 1];
    bool hasdata = this->pref_.load(&temp);
 
    if (hasdata) {
      value.assign(temp + 1, (size_t) temp[0]);
    }
 
    this->prev_.assign(value);
  }
};
 
class TemplateText final : public text::Text, public PollingComponent {
 public:
  template<typename F> void set_template(F &&f) { this->f_.set(std::forward<F>(f)); }
 
  void setup() override;
  void update() override;
  void dump_config() override;
  float get_setup_priority() const override { return setup_priority::HARDWARE; }
 
  Trigger<std::string> *get_set_trigger() const { return this->set_trigger_; }
  void set_optimistic(bool optimistic) { this->optimistic_ = optimistic; }
  void set_initial_value(const std::string &initial_value) { this->initial_value_ = initial_value; }
  void set_value_saver(TemplateTextSaverBase *restore_value_saver) { this->pref_ = restore_value_saver; }
 
 protected:
  void control(const std::string &value) override;
  bool optimistic_ = false;
  std::string initial_value_;
  Trigger<std::string> *set_trigger_ = new Trigger<std::string>();
  TemplateLambda<std::string> f_{};
 
  TemplateTextSaverBase *pref_ = nullptr;
};
 
}  // namespace template_
}  // namespace esphome