vpr::SelectorImplBSD Class Reference

BSD Implementation of cross-platform selection interface. More...

#include <vpr/IO/Selector.h>

Inheritance diagram for vpr::SelectorImplBSD:

[legend]Collaboration diagram for vpr::SelectorImplBSD:

[legend]List of all members.

Public Member Functions
bool	addHandle (vpr::IOSys::Handle handle, vpr::Uint16 mask=0)
	Adds the given handle to the selector.
bool	removeHandle (vpr::IOSys::Handle handle)
	Removes a handle from the selector. Sets the event flags going in to the select to mask.
bool	setIn (vpr::IOSys::Handle handle, vpr::Uint16 mask)
	Gets the current in flag mask.
vpr::Uint16	getIn (vpr::IOSys::Handle handle)
	Gets the current out flag mask.
vpr::Uint16	getOut (vpr::IOSys::Handle handle)
	Gets the current "out flag" mask after a call to select().
vpr::ReturnStatus	select (vpr::Uint16 &numWithEvents, const vpr::Interval timeout=vpr::Interval::NoTimeout)
	Select.
vpr::Uint16	getNumHandles ()
	For iteration over the registered handles.
vpr::IOSys::Handle	getHandle (vpr::Uint16 index)
	Gets the handle at the given index within the collection of registered handles.
bool	containsHandle (vpr::IOSys::Handle handle)
	Test if the selector contain the given handle.
Protected Member Functions
std::vector< BSDPollDesc >::iterator	getHandle (int handle)
	Gets the index of the handle given.
Protected Attributes
std::vector< BSDPollDesc >	mPollDescs
	List of Poll Descriptions to pass to select(2).
Classes
struct	BSDPollDesc
	Simple type used for the vector of poll descriptors. More...

---

Detailed Description

BSD Implementation of cross-platform selection interface.

A selector is used to wait on a set of Handles untils any of the events occur that the user is interested in.

Implementation site of the vpr::Selector_t<T> bridge. This class is used as the template parameter to vpr::Selector_t<T> to create the typedef vpr::Selector.

Definition at line 68 of file SelectorImplBSD.h.

---

Member Function Documentation

bool vpr::SelectorImplBSD::addHandle	(	vpr::IOSys::Handle	handle,
		vpr::Uint16	mask = 0
	)

Adds the given handle to the selector.

Precondition:

handle is a valid handle.

handle is added to the handle set, and its mask is initialized using the given value.

Parameters:

	handle	The handle to be added to the selector's handle set.
	mask	The mask used when checking for ready events on the given handle. This argument is optional and defaults to 0 (no events).

Returns:

true is returned if the given handle is added successfully

false is returned otherwise.

Definition at line 66 of file SelectorImplBSD.cpp.

References getHandle(), and mPollDescs.

{
   bool status;

   if ( getHandle(handle) == mPollDescs.end() )
   {
      BSDPollDesc new_desc;
      new_desc.fd        = handle;
      new_desc.in_flags  = mask;
      new_desc.out_flags = 0;

      mPollDescs.push_back(new_desc);
      status = true;
   }
   else
   {
      status = false;
   }

   return status;
}

bool vpr::SelectorImplBSD::removeHandle

(

vpr::IOSys::Handle

handle

)

Removes a handle from the selector. Sets the event flags going in to the select to mask.

Precondition:

handle is in the selector.

Postcondition:

handle is removed from the set of valid handles.

Parameters:

handle

The handle to be removed from the selector's handle set.

Returns:

true is returned if the given handle is removed successfully

false is returned otherwise.

Definition at line 91 of file SelectorImplBSD.cpp.

References getHandle(), and mPollDescs.

bool vpr::SelectorImplBSD::setIn	(	vpr::IOSys::Handle	handle,
		vpr::Uint16	mask
	)

Gets the current in flag mask.

The flags specify which events should be selected for the given handle.

Precondition:

handle has already been registered with this selector.

Postcondition:

handle has its mask updated to use the given value.

Parameters:

	handle	The handle whose mask will be set.
	mask	The mask used when checking for ready events on the given handle.

Definition at line 110 of file SelectorImplBSD.cpp.

References getHandle(), and mPollDescs.

vpr::Uint16 vpr::SelectorImplBSD::getIn

(

vpr::IOSys::Handle

handle

)

Gets the current out flag mask.

Precondition:

handle has already been added to the selector using addHandle().

Parameters:

handle

The handle whose "in" event flags will be returned.

Returns:

A bitmask value representing the "in flags" of handle.

Definition at line 129 of file SelectorImplBSD.cpp.

References getHandle(), and mPollDescs.

vpr::Uint16 vpr::SelectorImplBSD::getOut

(

vpr::IOSys::Handle

handle

)

Gets the current "out flag" mask after a call to select().

The value returned will be the bitwise OR of the "out flags". These state which of the operations named "in flags" were found to be ready.

Precondition:

select() has been called.

Parameters:

handle

The handle whose "out" event flags will be returned.

Returns:

A bitmask value representing the "out flags" of handle. These flags state which requested events were detected for handle.

Definition at line 148 of file SelectorImplBSD.cpp.

References getHandle(), and mPollDescs.

{
   vpr::Uint16 flags;
   std::vector<BSDPollDesc>::iterator i = getHandle(handle);

   if ( mPollDescs.end() == i )
   {
      // XXX: This is VERY bad thing to do.  Need to have an error code instead
      flags = 0;
   }
   else
   {
      flags = (*i).out_flags;
   }

   return flags;
}

vpr::ReturnStatus vpr::SelectorImplBSD::select	(	vpr::Uint16 &	numWithEvents,
		const vpr::Interval	timeout = vpr::Interval::NoTimeout
	)

Select.

Parameters:

	numWithEvents	Upon completion, this holds the number of items that have events.
	timeout	The interval to wait for an event to be raised. This argument is optional and defaults to vpr::Interval::NoTimeout (wait until an event is detected withotu timing out). Passing vpr::Interval::NoWait effects a poll on the registered handles and returns immediately.

Returns:

vpr::ReturnStatus::Succeed is returned if at least one event was detected within the timeout interval.

vpr::ReturnStatus::Timeout is returned if no events were detected before the timeout expired or if vpr::Interval::NoWait was passed. In this case, numWithEvents should be checked for a value greater than 0.

vpr::ReturnStatus::Fail is returned if the select failed.

Definition at line 169 of file SelectorImplBSD.cpp.

References errno, vpr::SelectorBase::Except, vpr::ReturnStatus::Fail, mPollDescs, vpr::Interval::msec(), vpr::Interval::NoTimeout, vpr::Interval::NoWait, vpr::SelectorBase::Read, vpr::ReturnStatus::setCode(), vpr::ReturnStatus::Timeout, and vpr::SelectorBase::Write.

{
   vpr::ReturnStatus ret_val;
   int result, last_fd;
   fd_set read_set, write_set, exception_set;
   std::vector<BSDPollDesc>::iterator i;
   struct timeval timeout_obj;

   // Zero everything out before doing anything else.
   FD_ZERO(&read_set);
   FD_ZERO(&write_set);
   FD_ZERO(&exception_set);

   last_fd = -1;

   for ( i = mPollDescs.begin(); i != mPollDescs.end(); ++i )
   {
      (*i).out_flags = 0;

      if ( (*i).in_flags & SelectorBase::Read )
      {
         FD_SET((*i).fd, &read_set);
      }

      if ( (*i).in_flags & SelectorBase::Write )
      {
         FD_SET((*i).fd, &write_set);
      }

      if ( (*i).in_flags & SelectorBase::Except )
      {
         FD_SET((*i).fd, &exception_set);
      }

      // Find the highest-valued file descriptor.
      if ( last_fd < (*i).fd )
      {
         last_fd = (*i).fd;
      }
   }

   if ( timeout == vpr::Interval::NoWait )
   {
      timeout_obj.tv_sec  = 0;
      timeout_obj.tv_usec = 0;
   }
   else
   {
      // Apparently select(2) doesn't like if the microsecond member has a
      // time larger than 1 second, so if timeout (given in milliseconds) is
      // larger than 1000, we have to split it up between the seconds and
      // microseconds members.
      if ( timeout.msec() >= 1000 )
      {
         timeout_obj.tv_sec  = timeout.msec() / 1000;
         timeout_obj.tv_usec = (timeout.msec() % 1000) * 1000000;
      }
      else
      {
         timeout_obj.tv_sec  = 0;
         timeout_obj.tv_usec = timeout.msec() * 1000;
      }
   }

   // If timeout is 0, this will be the same as polling the descriptors.  To
   // get no timeout, NULL must be passed to select(2).
   result = ::select(last_fd + 1, &read_set, &write_set, &exception_set,
                     (timeout != vpr::Interval::NoTimeout) ? &timeout_obj : NULL);

   // D'oh!
   if ( -1 == result )
   {
      fprintf(stderr, "SelectorImplBSD::select: Error selecting: %s\n",
              strerror(errno));
      numWithEvents = 0;
      ret_val.setCode(ReturnStatus::Fail);
   }
   // Timeout.
   else if ( 0 == result )
   {
      numWithEvents = 0;
      ret_val.setCode(ReturnStatus::Timeout);
   }
   // We got one!
   else
   {
      for ( i = mPollDescs.begin(); i != mPollDescs.end(); ++i )
      {
         if ( FD_ISSET((*i).fd, &read_set) )
         {
            (*i).out_flags |= SelectorBase::Read;
         }

         if ( FD_ISSET((*i).fd, &write_set) )
         {
            (*i).out_flags |= SelectorBase::Write;
         }

         if ( FD_ISSET((*i).fd, &exception_set) )
         {
            (*i).out_flags |= SelectorBase::Except;
         }
      }

      numWithEvents = result;
   }

   return ret_val;
}

vpr::Uint16 vpr::SelectorImplBSD::getNumHandles

(

)

[inline]

For iteration over the registered handles.

Returns:

An unsigned value stating how many handles have been registered.

Definition at line 174 of file SelectorImplBSD.h.

References mPollDescs.

   {
      return mPollDescs.size();
   }

vpr::IOSys::Handle vpr::SelectorImplBSD::getHandle

(

vpr::Uint16

index

)

[inline]

Gets the handle at the given index within the collection of registered handles.

The index is determined by the order of handle addition using addHandle().

Parameters:

index

The index of the desired handle.

Returns:

A vpr::IOSys::Handle object representing the registered handle at the given index.

Definition at line 189 of file SelectorImplBSD.h.

References mPollDescs.

Referenced by addHandle(), containsHandle(), getIn(), getOut(), removeHandle(), and setIn().

   {
      return mPollDescs[index].fd;
   }

bool vpr::SelectorImplBSD::containsHandle

(

vpr::IOSys::Handle

handle

)

[inline]

Test if the selector contain the given handle.

Parameters:

handle

The handle of interest.

Returns:

true is returned if handle was previously registered with this selector.

false is returned if the handle has not been registered.

Definition at line 203 of file SelectorImplBSD.h.

References getHandle(), and mPollDescs.

   {
      return (getHandle(handle) != mPollDescs.end());
   }

std::vector< SelectorImplBSD::BSDPollDesc >::iterator vpr::SelectorImplBSD::getHandle

(

int

handle

)

[protected]

Gets the index of the handle given.

Returns:

.end() is returned if the given index is not found
Otherwise, the index to the handle in mPollDescs is returned.

Definition at line 283 of file SelectorImplBSD.cpp.

References mPollDescs.

{
   // XXX: Should probably be replaced by a map in the future for speed

   for ( std::vector<BSDPollDesc>::iterator i=mPollDescs.begin();
       i != mPollDescs.end();++i )
   {
      if ( (*i).fd == handle )
         return i;
   }

   return mPollDescs.end();
}

---

Member Data Documentation

std::vector<BSDPollDesc> vpr::SelectorImplBSD::mPollDescs [protected]

List of Poll Descriptions to pass to select(2).

Definition at line 226 of file SelectorImplBSD.h.

Referenced by addHandle(), containsHandle(), getHandle(), getIn(), getNumHandles(), getOut(), removeHandle(), select(), and setIn().

---

The documentation for this class was generated from the following files:

• SelectorImplBSD.h
• SelectorImplBSD.cpp

---