path: root/ace/Message_Block.cpp

// Message_Block.cpp
// $Id$

#define ACE_BUILD_DLL
#include "ace/Message_Block.h"
#include "ace/Service_Config.h"

#if !defined (__ACE_INLINE__)
#include "ace/Message_Block.i"
#endif /* __ACE_INLINE__ */

ACE_ALLOC_HOOK_DEFINE(ACE_Message_Block)

void
ACE_Message_Block::data_block (ACE_Data_Block *db)
{
  ACE_TRACE ("ACE_Data_Block::data_block");
  if (this->data_block_ != 0)
    // This call passes a 0 into release since we don't want to delete
    // <this> at this point.
    this->data_block_->release (0);

  this->data_block_ = db;

  // Set the read and write pointers in the <Message_Block> to point
  // to the buffer in the <ACE_Data_Block>.
  this->rd_ptr (this->data_block ()->base ());
  this->wr_ptr (this->data_block ()->base ());
}

int
ACE_Message_Block::copy (const char *buf, size_t n)
{
  ACE_TRACE ("ACE_Message_Block::copy");
  // Note that for this to work correct, end() *must* be >= wr_ptr().
  size_t len = size_t (this->end () - this->wr_ptr ());

  if (len < n)
    return -1;
  else
    {
      (void) ACE_OS::memcpy (this->wr_ptr (), buf, n);
      this->wr_ptr (n);
      return 0;
    }
}

int
ACE_Message_Block::copy (const char *buf)
{
  ACE_TRACE ("ACE_Message_Block::copy");
  // Note that for this to work correct, end() *must* be >= wr_ptr().
  size_t len = size_t (this->end () - this->wr_ptr ());
  size_t buflen = ACE_OS::strlen (buf) + 1;

  if (len < buflen)
    return -1;
  else
    {
      (void) ACE_OS::memcpy (this->wr_ptr (), buf, buflen);
      this->wr_ptr (buflen);
      return 0;
    }
}

void
ACE_Data_Block::dump (void) const
{
  ACE_TRACE ("ACE_Data_Block::dump");
  ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
  ACE_DEBUG ((LM_DEBUG, 
	     "-----( Message Block )-----\n"
	     "type_ = %d\n"
	     "cur_size_ = %u\n"
	     "max_size_ = %u\n"
	     "flags_ = %u\n"
	     "base_ = %u\n"
	     "locking_strategy_ = %u\n"
	     "reference_count_ = %u\n"
	     "---------------------------\n",
	     this->type_, 
	     this->cur_size_, 
	     this->max_size_,
	     this->flags_, 
	     this->base_,
	     this->locking_strategy_,
	     this->reference_count_));
  this->allocator_strategy_->dump ();
  ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
}

void
ACE_Message_Block::dump (void) const
{
  ACE_TRACE ("ACE_Message_Block::dump");
  ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
  ACE_DEBUG ((LM_DEBUG, 
	     "-----( Message Block )-----\n"
	     "priority_ = %d\n"
	     "next_ = %u\n"
	     "prev_ = %u\n"
	     "cont_ = %u\n"	      
	     "rd_ptr_ = %u\n"
	     "wr_ptr_ = %u\n"
	     "---------------------------\n",
	     this->priority_, 
	     this->next_, 
	     this->prev_,
	     this->cont_,
	     this->rd_ptr_, 
	     this->wr_ptr_));
  this->data_block ()->dump ();
  ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
}

int
ACE_Data_Block::size (size_t length)
{
  ACE_TRACE ("ACE_Data_Block::size");

  if (length < this->max_size_)
    this->cur_size_ = length;
  else
    {
      char *buf;
      
      ACE_ALLOCATOR_RETURN (buf, 
			    (char *) this->allocator_strategy_->malloc (length), 
			    -1);

      ACE_OS::memcpy (buf, this->base_, this->cur_size_);
      if (ACE_BIT_DISABLED (this->flags_, ACE_Message_Block::DONT_DELETE))
	this->allocator_strategy_->free ((void *) this->base_);
      else
	// We now assume ownership.
	ACE_CLR_BITS (this->flags_, ACE_Message_Block::DONT_DELETE);

      this->max_size_ = length;
      this->cur_size_ = length;
      this->base_ = buf;
    }
  return 0;
}

int
ACE_Message_Block::size (size_t length)
{
  ACE_TRACE ("ACE_Message_Block::size");
  char *old_base = this->data_block ()->base ();

  // Resize the underlying <ACE_Data_Block>.
  if (this->data_block ()->size (length) == -1)
    return -1;

  // Reset the read and write pointers if we've changed the underlying
  // memory buffer.
  else if (this->data_block ()->base () != old_base)
    {
      // Compute the old deltas...
      int r_delta = this->rd_ptr_ - old_base;
      int w_delta = this->wr_ptr_ - old_base;

      // ... and use them to initialize the new deltas.
      this->rd_ptr_ = this->data_block ()->base () + r_delta;
      this->wr_ptr_ = this->data_block ()->base () + w_delta;
    }
  return 0;
}

ACE_Data_Block::~ACE_Data_Block (void)
{
  // Sanity check...
  ACE_ASSERT (this->reference_count_ <= 1);

  // Just to be safe...
  this->reference_count_ = 0;

  if (ACE_BIT_DISABLED (this->flags_, ACE_Message_Block::DONT_DELETE))
    {
      this->allocator_strategy_->free ((void *) this->base_);
      this->base_ = 0;
    }
}

ACE_Message_Block::~ACE_Message_Block (void)
{
  ACE_TRACE ("ACE_Message_Block::~ACE_Message_Block");

  // Free up all the continuation messages.
  if (this->cont_)
    {
      this->cont_->release ();
      this->cont_ = 0;
    }

  this->prev_ = 0;
  this->next_ = 0;

  // This must come last since it may delete <this>.
  if (this->data_block ())
    this->data_block ()->release (this);
}

ACE_Data_Block::ACE_Data_Block (void)
  : type_ (ACE_Message_Block::MB_DATA),
    cur_size_ (0),
    max_size_ (0),
    flags_ (ACE_Message_Block::DONT_DELETE),
    base_ (0),
    allocator_strategy_ (0),
    locking_strategy_ (0),
    reference_count_ (1)
{
  ACE_TRACE ("ACE_Data_Block::ACE_Data_Block");
}

ACE_Data_Block::ACE_Data_Block (size_t size,
				ACE_Message_Block::ACE_Message_Type msg_type,
				const char *msg_data, 
				ACE_Allocator *allocator_strategy,
				ACE_Lock *locking_strategy,
				ACE_Message_Block::Message_Flags flags)
  : type_ (msg_type),
    cur_size_ (size),
    max_size_ (size),
    flags_ (flags),
    base_ ((char *) msg_data),
    allocator_strategy_ (allocator_strategy),
    locking_strategy_ (locking_strategy),
    reference_count_ (1)
{
  ACE_TRACE ("ACE_Data_Block::ACE_Data_Block");

  // If the user didn't pass one in, let's use the
  // <ACE_Service_Config::alloc>.
  if (this->allocator_strategy_ == 0)
    ACE_ALLOCATOR (this->allocator_strategy_, ACE_Service_Config::alloc ());

  if (msg_data == 0)
    ACE_ALLOCATOR (this->base_, 
		   (char *) this->allocator_strategy_->malloc (size));
  else
    this->base_ = (char *) msg_data;
}

ACE_Message_Block::ACE_Message_Block (const char *data,
				      size_t size)
{
  ACE_TRACE ("ACE_Message_Block::ACE_Message_Block");

  if (this->init_i (size,    // size
		    MB_DATA, // type
		    0,       // cont
		    data,    // data
		    0,       // allocator
		    0,       // locking strategy
		    ACE_Message_Block::DONT_DELETE, // flags
		    0, // priority
		    0) == -1) // data block
    ACE_ERROR ((LM_ERROR, "ACE_Message_Block"));
}

ACE_Message_Block::ACE_Message_Block (void)
{
  ACE_TRACE ("ACE_Message_Block::ACE_Message_Block");

  if (this->init_i (0,       // size
		    MB_DATA, // type
		    0,       // cont
		    0,       // data
		    0,       // allocator
		    0,       // locking strategy
		    ACE_Message_Block::DONT_DELETE, // flags
		    0, // priority
		    0) == -1) // data block
    ACE_ERROR ((LM_ERROR, "ACE_Message_Block"));
}

ACE_Message_Block::ACE_Message_Block (size_t size,
				      ACE_Message_Type msg_type,
				      ACE_Message_Block *msg_cont, 
				      const char *msg_data, 
				      ACE_Allocator *allocator_strategy,
				      ACE_Lock *locking_strategy,
				      u_long priority)
{
  ACE_TRACE ("ACE_Message_Block::ACE_Message_Block");

  if (this->init_i (size, 
		    msg_type, 
		    msg_cont, 
		    msg_data, 
		    allocator_strategy, 
		    locking_strategy,
		    msg_data ? ACE_Message_Block::DONT_DELETE : 0,
		    priority,
		    0) == -1) // data block
    ACE_ERROR ((LM_ERROR, "ACE_Message_Block"));
}

int
ACE_Message_Block::init (size_t size, 
			 ACE_Message_Type msg_type, 
			 ACE_Message_Block *msg_cont, 
			 const char *msg_data,
			 ACE_Allocator *allocator_strategy,
			 ACE_Lock *locking_strategy,
			 u_long priority)
{
  ACE_TRACE ("ACE_Message_Block::init");

  return this->init_i (size, 
		       msg_type, 
		       msg_cont, 
		       msg_data,
		       allocator_strategy, 
		       locking_strategy,
		       msg_data ? ACE_Message_Block::DONT_DELETE : 0,
		       priority,
		       0); // data block
}

int
ACE_Message_Block::init (const char *data,
			 size_t size)
{
  ACE_TRACE ("ACE_Message_Block::init");
  // Should we also initialize all the other fields, as well?

  return this->init_i (size,    // size
		       MB_DATA, // type
		       0,       // cont
		       data,    // data
		       0,       // allocator
		       0,       // locking strategy
		       ACE_Message_Block::DONT_DELETE,  // flags
		       0,  // priority
		       0); // data block
}

ACE_Message_Block::ACE_Message_Block (size_t size, 
				      ACE_Message_Type msg_type, 
				      ACE_Message_Block *msg_cont, 
				      const char *msg_data,
				      ACE_Allocator *allocator_strategy,
				      ACE_Lock *locking_strategy,
				      Message_Flags flags,
				      u_long priority,
				      ACE_Data_Block *db)
{
  ACE_TRACE ("ACE_Message_Block::ACE_Message_Block");

  if (this->init_i (size, 
		    msg_type, 
		    msg_cont, 
		    msg_data,
		    allocator_strategy, 
		    locking_strategy,
		    flags,
		    priority,
		    db) == -1)
    ACE_ERROR ((LM_ERROR, "ACE_Message_Block"));
}

ACE_Message_Block::ACE_Message_Block (ACE_Data_Block *data_block)
{
  ACE_TRACE ("ACE_Message_Block::ACE_Message_Block");
  
  if (this->init_i (0,         // size
		    MB_NORMAL, // type
		    0,         // cont
		    0,         // data
		    0,         // allocator
		    0,         // locking strategy
		    0,         // flags
		    0,         // priority
		    data_block) == -1) // data block
    ACE_ERROR ((LM_ERROR, "ACE_Message_Block"));
}

int
ACE_Message_Block::init_i (size_t size, 
			   ACE_Message_Type msg_type, 
			   ACE_Message_Block *msg_cont, 
			   const char *msg_data,
			   ACE_Allocator *allocator_strategy,
			   ACE_Lock *locking_strategy,
			   Message_Flags flags,
			   u_long priority,
			   ACE_Data_Block *db)
{
  ACE_TRACE ("ACE_Message_Block::init_i");

  this->priority_ = priority;
  this->cont_ = msg_cont;
  this->next_ = 0;
  this->prev_ = 0;
  this->data_block_ = 0;

  if (db == 0)
    // Allocate the <ACE_Data_Block> portion, which is reference
    // counted.
    ACE_NEW_RETURN (db,
		    ACE_Data_Block (size,
				    msg_type,
				    msg_data,
				    allocator_strategy,
				    locking_strategy,
				    flags),
		    -1);

  // Reset the data_block_ pointer.
  this->data_block (db);
  return 0;
}

ACE_Data_Block *
ACE_Data_Block::release_i (ACE_Message_Block *mb)
{
  ACE_TRACE ("ACE_Data_Block::release");

  ACE_ASSERT (this->reference_count_ >= 0);

  ACE_Data_Block *result = 0;

  this->reference_count_--;

  if (this->reference_count_ == 0)
    {
      delete this;

      if (mb != 0)
	{
	  // We need to delete <mb> here since the lock will be held
	  // correctly at this point, which protects against race
	  // conditions in multi-threaded programs.  Note that we must
	  // reset <mb->data_block_> to 0 or else we'll end up in
	  // infinite recursion.
	  mb->data_block_ = 0;
	  delete mb;
	}
    }
  else // if (this->reference_count_ > 0)
    result = this;

  return result;
}

ACE_Data_Block *
ACE_Data_Block::release (ACE_Message_Block *mb)
{
  ACE_TRACE ("ACE_Data_Block::release");

  // If there's a locking strategy then we need to acquire the lock
  // before decrementing the count.
  if (this->locking_strategy_)
    {
      ACE_GUARD_RETURN (ACE_Lock, ace_mon, *this->locking_strategy_, 0);

      return this->release_i (mb);
    }
  else
    return this->release_i (mb);
}

ACE_Message_Block *
ACE_Message_Block::release (void)
{
  ACE_TRACE ("ACE_Message_Block::release");

  if (this->data_block ()->release (this) == 0)
    return 0;
  else
    return this;
}

/* static */ ACE_Message_Block *
ACE_Message_Block::release (ACE_Message_Block *mb)
{
  ACE_TRACE ("ACE_Message_Block::release");

  if (mb != 0)
    return mb->release ();
  else
    return 0;
}

ACE_Data_Block *
ACE_Data_Block::duplicate (void) 
{
  ACE_TRACE ("ACE_Data_Block::duplicate");

  // Create a new <ACE_Message_Block>, but share the <base_> pointer
  // data (i.e., don't copy that).
  if (this->locking_strategy_)
    {
      // We need to acquire the lock before incrementing the count.
      ACE_GUARD_RETURN (ACE_Lock, ace_mon, *this->locking_strategy_, 0);
      this->reference_count_++;
    }
  else
    this->reference_count_++;

  return this;
}

ACE_Message_Block *
ACE_Message_Block::duplicate (void) const
{
  ACE_TRACE ("ACE_Message_Block::duplicate");

  ACE_Message_Block *nb;

  // Create a new <ACE_Message_Block> that contains unique copies of
  // the message block fields, but a reference counted duplicate of
  // the <ACE_Data_Block>.
  ACE_NEW_RETURN (nb, 
		  ACE_Message_Block (0, // size
				     ACE_Message_Type (0), // type
				     0, // cont
				     0, // data
				     0, // allocator
				     0, // locking strategy
				     0, // flags
				     this->priority_, // priority
				     // Get a pointer to a
				     // "duplicated" <ACE_Data_Block>
				     // (will simply increment the
				     // reference count).
				     this->data_block ()->duplicate ()), // data block
		  0);

  // Set the read and write pointers in the new <Message_Block> to the
  // same relative offset as in the existing <Message_Block>.  Note
  // that we are assuming that the data_block()->base() pointer
  // doesn't change when it's duplicated.
  nb->rd_ptr (this->rd_ptr_ - this->data_block ()->base ());
  nb->wr_ptr (this->wr_ptr_ - this->data_block ()->base ());

  // Increment the reference counts of all the continuation messages.
  if (this->cont_)
    {
      nb->cont_ = this->cont_->duplicate ();

      // If things go wrong, release all of our resources and return
      // 0.
      if (nb->cont_ == 0)
	{
	  nb->release ();
	  nb = 0;
	}
    }

  return nb;
}

ACE_Message_Block *
ACE_Message_Block::duplicate (ACE_Message_Block *mb)
{
  ACE_TRACE ("ACE_Message_Block::duplicate");
  if (mb == 0)
    return 0;
  else
    return mb->duplicate ();
}

ACE_Data_Block *
ACE_Data_Block::clone (ACE_Message_Block::Message_Flags mask) const
{
  ACE_TRACE ("ACE_Data_Block::clone");

  // You always want to clear this one to prevent memory leaks but you
  // might add some others later.
  const ACE_Message_Block::Message_Flags always_clear = 
    ACE_Message_Block::DONT_DELETE; 

  ACE_Data_Block *nb;

  ACE_NEW_RETURN (nb, 
		  ACE_Data_Block (this->max_size_, // size
				  this->type_,     // type
				  0,               // data
				  this->allocator_strategy_, // allocator
				  this->locking_strategy_, // locking strategy
				  this->flags_), // flags
		  0);

  // Copy all of the payload memory into the new object.
  ACE_OS::memcpy (nb->base_, this->base_, this->max_size_);

  // Set new flags minus the mask...
  nb->clr_flags (mask | always_clear);
  return nb;
}

ACE_Message_Block *
ACE_Message_Block::clone (Message_Flags mask) const
{
  ACE_TRACE ("ACE_Message_Block::clone");
  
  // Get a pointer to a "cloned" <ACE_Data_Block> (will copy the
  // values rather than increment the reference count).

  ACE_Data_Block *db = this->data_block ()->clone (mask);
  
  if (db == 0)
    return 0;

  ACE_Message_Block *nb = 
    new ACE_Message_Block (0, // size
			   ACE_Message_Type (0), // type
			   0, // cont
			   0, // data
			   0, // allocator
			   0, // locking strategy
			   0, // flags
			   this->priority_, // priority
			   db); // data_block
  if (nb == 0)
    {
      db->release ();
      return 0;
    }
		 
  // Set the read and write pointers in the new <Message_Block> to the
  // same relative offset as in the existing <Message_Block>.
  nb->rd_ptr (this->rd_ptr_ - this->data_block ()->base ());
  nb->wr_ptr (this->wr_ptr_ - this->data_block ()->base ());

  // Clone all the continuation messages if necessary.
  if (nb->cont_ != 0 
      && (nb->cont_ = nb->cont_->clone (mask)) == 0)
    {
      nb->release ();
      return 0;
    }
  return nb;
}

// This is private.
ACE_Message_Block &
ACE_Message_Block::operator= (const ACE_Message_Block &)
{
  ACE_TRACE ("ACE_Message_Block::operator=");
  return *this;
}

#if defined (ACE_TEMPLATES_REQUIRE_SPECIALIZATION)
// These specializations aren't needed for the ACE library because
// Service_Config.cpp has them:
//
// template class ACE_Malloc <ACE_LOCAL_MEMORY_POOL, ACE_Null_Mutex>;
// template class ACE_Allocator_Adapter <ACE_Malloc <ACE_LOCAL_MEMORY_POOL, ACE_Null_Mutex> >;
#endif /* ACE_TEMPLATES_REQUIRE_SPECIALIZATION */