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https://github.com/zeromq/libzmq.git
synced 2024-12-14 19:13:52 +01:00
refactoring of pipe/swap interaction
This commit is contained in:
parent
42000d2c4f
commit
d90b407115
198
src/pipe.cpp
198
src/pipe.cpp
@ -27,6 +27,7 @@
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zmq::reader_t::reader_t (object_t *parent_, pipe_t *pipe_,
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uint64_t lwm_) :
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object_t (parent_),
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active (true),
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pipe (pipe_),
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writer (NULL),
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lwm (lwm_),
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@ -76,12 +77,14 @@ bool zmq::reader_t::is_delimiter (zmq_msg_t &msg_)
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bool zmq::reader_t::check_read ()
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{
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if (unlikely (terminating))
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if (!active)
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return false;
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// Check if there's an item in the pipe.
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if (!pipe->check_read ())
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if (!pipe->check_read ()) {
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active = false;
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return false;
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}
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// If the next item in the pipe is message delimiter,
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// initiate its termination.
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@ -95,11 +98,13 @@ bool zmq::reader_t::check_read ()
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bool zmq::reader_t::read (zmq_msg_t *msg_)
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{
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if (unlikely (terminating))
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if (!active)
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return false;
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if (!pipe->read (msg_))
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if (!pipe->read (msg_)) {
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active = false;
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return false;
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}
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// If delimiter was read, start termination process of the pipe.
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unsigned char *offset = 0;
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@ -123,6 +128,7 @@ void zmq::reader_t::terminate ()
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if (terminating)
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return;
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active = false;
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terminating = true;
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send_pipe_term (writer);
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}
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@ -130,6 +136,7 @@ void zmq::reader_t::terminate ()
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void zmq::reader_t::process_activate_reader ()
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{
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// Forward the event to the sink (either socket or session).
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active = true;
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sink->activated (this);
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}
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@ -150,38 +157,34 @@ void zmq::reader_t::process_pipe_term_ack ()
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zmq::writer_t::writer_t (object_t *parent_, pipe_t *pipe_, reader_t *reader_,
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uint64_t hwm_, int64_t swap_size_) :
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object_t (parent_),
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active (true),
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pipe (pipe_),
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reader (reader_),
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hwm (hwm_),
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msgs_read (0),
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msgs_written (0),
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msg_store (NULL),
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extra_msg_flag (false),
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stalled (false),
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swap (NULL),
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sink (NULL),
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terminating (false),
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pending_close (false)
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swapping (false),
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pending_delimiter (false),
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terminating (false)
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{
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// Inform reader about the writer.
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reader->set_writer (this);
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// Open the swap file, if required.
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if (swap_size_ > 0) {
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msg_store = new (std::nothrow) msg_store_t (swap_size_);
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if (msg_store != NULL) {
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if (msg_store->init () < 0) {
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delete msg_store;
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msg_store = NULL;
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}
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}
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swap = new (std::nothrow) msg_store_t (swap_size_);
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zmq_assert (swap);
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int rc = swap->init ();
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zmq_assert (rc == 0);
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}
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}
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zmq::writer_t::~writer_t ()
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{
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if (extra_msg_flag)
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zmq_msg_close (&extra_msg);
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delete msg_store;
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if (swap)
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delete swap;
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}
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void zmq::writer_t::set_event_sink (i_writer_events *sink_)
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@ -192,13 +195,26 @@ void zmq::writer_t::set_event_sink (i_writer_events *sink_)
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bool zmq::writer_t::check_write ()
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{
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if (terminating)
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return false;
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if (pipe_full () && (msg_store == NULL || msg_store->full () ||
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extra_msg_flag)) {
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stalled = true;
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// We've already checked and there's no space free for the new message.
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// There's no point in checking once again.
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if (unlikely (!active))
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return false;
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if (unlikely (swapping)) {
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if (unlikely (swap->full ())) {
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active = false;
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return false;
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}
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}
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else {
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if (unlikely (pipe_full ())) {
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if (swap)
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swapping = true;
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else {
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active = false;
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return false;
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}
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}
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}
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return true;
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@ -206,58 +222,44 @@ bool zmq::writer_t::check_write ()
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bool zmq::writer_t::write (zmq_msg_t *msg_)
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{
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if (terminating)
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if (unlikely (!check_write ()))
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return false;
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if (!check_write ())
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return false;
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if (pipe_full ()) {
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if (msg_store->store (msg_)) {
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if (!(msg_->flags & ZMQ_MSG_MORE))
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msg_store->commit ();
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} else {
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extra_msg = *msg_;
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extra_msg_flag = true;
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}
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}
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else {
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pipe->write (*msg_, msg_->flags & ZMQ_MSG_MORE);
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if (unlikely (swapping)) {
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bool stored = swap->store (msg_);
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zmq_assert (stored);
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if (!(msg_->flags & ZMQ_MSG_MORE))
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msgs_written++;
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swap->commit ();
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return true;
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}
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pipe->write (*msg_, msg_->flags & ZMQ_MSG_MORE);
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if (!(msg_->flags & ZMQ_MSG_MORE))
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msgs_written++;
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return true;
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}
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void zmq::writer_t::rollback ()
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{
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if (extra_msg_flag && extra_msg.flags & ZMQ_MSG_MORE) {
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zmq_msg_close (&extra_msg);
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extra_msg_flag = false;
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// Remove incomplete message from the swap.
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if (unlikely (swapping)) {
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swap->rollback ();
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return;
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}
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if (msg_store != NULL)
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msg_store->rollback ();
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// Remove incomplete message from the pipe.
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zmq_msg_t msg;
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// Remove all incomplete messages from the pipe.
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while (pipe->unwrite (&msg)) {
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zmq_assert (msg.flags & ZMQ_MSG_MORE);
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zmq_msg_close (&msg);
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msgs_written--;
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}
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if (stalled && check_write ()) {
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stalled = false;
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zmq_assert (sink);
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sink->activated (this);
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}
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}
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void zmq::writer_t::flush ()
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{
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if (!pipe->flush ())
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// In the swapping mode, flushing is automatically handled by swap object.
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if (!swapping && !pipe->flush ())
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send_activate_reader (reader);
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}
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@ -267,19 +269,20 @@ void zmq::writer_t::terminate ()
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if (terminating)
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return;
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if (msg_store == NULL || (msg_store->empty () && !extra_msg_flag))
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write_delimiter ();
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else
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pending_close = true;
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}
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// Mark the pipe as not available for writing.
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active = false;
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void zmq::writer_t::write_delimiter ()
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{
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// Rollback any unfinished messages.
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rollback ();
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// Push delimiter into the pipe.
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// Trick the compiler to belive that the tag is a valid pointer.
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if (swapping) {
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pending_delimiter = true;
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return;
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}
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// Push delimiter into the pipe. Trick the compiler to belive that
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// the tag is a valid pointer. Note that watermarks are not checked
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// thus the delimiter can be written even though the pipe is full.
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zmq_msg_t msg;
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const unsigned char *offset = 0;
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msg.content = (void*) (offset + ZMQ_DELIMITER);
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@ -290,44 +293,47 @@ void zmq::writer_t::write_delimiter ()
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void zmq::writer_t::process_activate_writer (uint64_t msgs_read_)
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{
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zmq_msg_t msg;
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// Store the reader's message sequence number.
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msgs_read = msgs_read_;
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if (msg_store) {
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// Move messages from backing store into pipe.
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while (!pipe_full () && !msg_store->empty ()) {
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msg_store->fetch(&msg);
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// Write message into the pipe.
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// If we are in the swapping mode, we have some messages in the swap.
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// Given that pipe is now ready for writing we can move part of the
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// swap into the pipe.
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if (swapping) {
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zmq_msg_t msg;
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while (!pipe_full () && !swap->empty ()) {
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swap->fetch(&msg);
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pipe->write (msg, msg.flags & ZMQ_MSG_MORE);
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if (!(msg.flags & ZMQ_MSG_MORE))
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msgs_written++;
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}
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if (extra_msg_flag) {
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if (!pipe_full ()) {
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pipe->write (extra_msg, extra_msg.flags & ZMQ_MSG_MORE);
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if (!(extra_msg.flags & ZMQ_MSG_MORE))
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msgs_written++;
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extra_msg_flag = false;
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}
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else if (msg_store->store (&extra_msg)) {
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if (!(extra_msg.flags & ZMQ_MSG_MORE))
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msg_store->commit ();
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extra_msg_flag = false;
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}
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}
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if (pending_close && msg_store->empty () && !extra_msg_flag) {
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write_delimiter ();
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pending_close = false;
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}
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flush ();
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if (!pipe->flush ())
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send_activate_reader (reader);
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}
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if (stalled) {
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stalled = false;
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// There are no more messages in the swap. We can switch into
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// standard in-memory mode.
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if (swap->empty ()) {
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swapping = false;
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// Push delimiter into the pipe. Trick the compiler to belive that
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// the tag is a valid pointer. Note that watermarks are not checked
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// thus the delimiter can be written even though the pipe is full.
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if (pending_delimiter) {
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zmq_msg_t msg;
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const unsigned char *offset = 0;
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msg.content = (void*) (offset + ZMQ_DELIMITER);
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msg.flags = 0;
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pipe->write (msg, false);
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flush ();
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return;
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}
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}
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// If the writer was non-active before, let's make it active
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// (available for writing messages to).
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if (!active) {
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active = true;
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zmq_assert (sink);
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sink->activated (this);
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}
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39
src/pipe.hpp
39
src/pipe.hpp
@ -87,6 +87,9 @@ namespace zmq
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// Returns true if the message is delimiter; false otherwise.
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static bool is_delimiter (zmq_msg_t &msg_);
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// True, if pipe can be read from.
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bool active;
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// The underlying pipe.
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pipe_t *pipe;
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@ -127,8 +130,8 @@ namespace zmq
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void set_event_sink (i_writer_events *endpoint_);
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// Checks whether a message can be written to the pipe.
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// If writing the message would cause high watermark to be
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// exceeded, the function returns false.
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// If writing the message would cause high watermark and (optionally)
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// swap to be exceeded, the function returns false.
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bool check_write ();
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// Writes a message to the underlying pipe. Returns false if the
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@ -150,17 +153,17 @@ namespace zmq
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uint64_t hwm_, int64_t swap_size_);
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~writer_t ();
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void process_activate_writer (uint64_t msgs_read_);
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// Command handlers.
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void process_activate_writer (uint64_t msgs_read_);
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void process_pipe_term ();
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// Tests whether the pipe is already full.
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// Tests whether underlying pipe is already full. The swap is not
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// taken into account.
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bool pipe_full ();
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// Write special message to the pipe so that the reader
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// can find out we are finished.
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void write_delimiter ();
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// True, if this object can be written to. Undelying ypipe may be full
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// but as long as there's swap space available, this flag is true.
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bool active;
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// The underlying pipe.
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pipe_t *pipe;
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@ -178,26 +181,24 @@ namespace zmq
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// Number of messages we have written so far.
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uint64_t msgs_written;
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// Pointer to backing store. If NULL, messages are always
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// Pointer to the message swap. If NULL, messages are always
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// kept in main memory.
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msg_store_t *msg_store;
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bool extra_msg_flag;
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zmq_msg_t extra_msg;
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// True iff the last attempt to write a message has failed.
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bool stalled;
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msg_store_t *swap;
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// Sink for the events (either the socket or the session).
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i_writer_events *sink;
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// If true, swap is active. New messages are to be written to the swap.
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bool swapping;
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// If true, there's a delimiter to be written to the pipe after the
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// swap is empied.
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bool pending_delimiter;
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// True is 'terminate' method was called of 'pipe_term' command
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// arrived from the reader.
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bool terminating;
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bool pending_close;
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writer_t (const writer_t&);
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void operator = (const writer_t&);
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};
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