Queue.cpp

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#include <sstream>
 
#include "Queue.h"
#include "madara/knowledge/ContextGuard.h"
 
bool madara::knowledge::containers::Queue::enqueue(
    const knowledge::KnowledgeRecord& record)
{
  bool result(false);
 
  if (context_)
  {
    ContextGuard context_guard(*context_);
    MADARA_GUARD_TYPE guard(mutex_);
 
    if (count_ < 0)
      count_ = 0;
 
    // avoid double retrieval of count_ during check
    knowledge::KnowledgeRecord::Integer count = *count_;
 
    if (context_ && name_ != "" && queue_.size() > 0 &&
        count < (KnowledgeRecord::Integer)queue_.size())
    {
      // there's no point in signaling inside of a locked context
      if (!settings_.signal_changes)
        settings_.signal_changes = false;
 
      knowledge::KnowledgeRecord::Integer tail = *tail_;
 
      context_->set(queue_.vector_[tail], record, settings_);
      tail_ = increment(tail, 1);
      ++count_;
    }
  }
 
  // now that we no longer have a lock on context, signal
  if (context_)
    context_->signal();
 
  return result;
}
 
madara::knowledge::KnowledgeRecord
madara::knowledge::containers::Queue::dequeue(bool wait)
{
  madara::knowledge::KnowledgeRecord result;
 
  if (context_ && name_ != "")
  {
    ContextGuard context_guard(*context_);
    MADARA_GUARD_TYPE guard(mutex_);
 
    if (wait)
    {
      while (count_ <= 0)
        context_->wait_for_change(true);
    }
 
    if (count_ > 0)
    {
      knowledge::KnowledgeRecord::Integer head = *head_;
 
      result = context_->get(queue_.vector_[head], settings_);
 
      head_ = increment(head, 1);
      --count_;
    }
  }
 
  // now that we no longer have a lock on context, signal
  if (context_)
    context_->signal();
 
  return result;
}
 
void madara::knowledge::containers::Queue::set_name(
    const std::string& var_name, KnowledgeBase& knowledge)
{
  KnowledgeUpdateSettings keep_local(true);
  context_ = &(knowledge.get_context());
 
  ContextGuard context_guard(*context_);
  MADARA_GUARD_TYPE guard(mutex_);
 
  name_ = var_name;
 
  this->count_.set_name(var_name + ".count", knowledge);
  this->head_.set_name(var_name + ".head", knowledge);
  this->tail_.set_name(var_name + ".tail", knowledge);
  this->queue_.set_name(var_name, knowledge);
}
 
void madara::knowledge::containers::Queue::set_name(
    const std::string& var_name, Variables& knowledge)
{
  KnowledgeUpdateSettings keep_local(true);
  context_ = knowledge.get_context();
 
  ContextGuard context_guard(*context_);
  MADARA_GUARD_TYPE guard(mutex_);
 
  name_ = var_name;
 
  this->count_.set_name(var_name + ".count", knowledge);
  this->head_.set_name(var_name + ".head", knowledge);
  this->tail_.set_name(var_name + ".tail", knowledge);
  this->queue_.set_name(var_name, knowledge);
}