The shared reference count was not shared but copied. msg_t cannot
store the refcnt itsef but has to store a pointer to an externally
allocated (shared) refcnter. The changes to lmsg are reverted to
use content_t again. Howver, this introduces an allocation in v2_decoder
when creating the message which can be avoided. When allocating the reception
buffer, space is allocated for the maximum number of reference counts
(8192 / max_vsm_size = 8192/64 = 128 zmq:atomic_counter objects). This
increases the buffer by 128*sizeof(atomic_counter) = 128*4 = 512 bytes only.
When creating a message, the refcnt member is set to the address of one of the
pre-allocated atomic_counter_t objects. To do so, a new msg_t type zcmsg
is introduced because msg::copy must discriminate between the message types
when releasing memory.
With a msg_t size of 64 bytes, it becomes possible to embedd the content_t's members
struct for large messages directly in the msg_t. This saves the dynamic allocation
of content_t obejcts when using msg_t::init_data.
content_t contains a zmq::atomic_counter_t object which is not a POD in C++98
and thus it cannot be used as a member of the union u. To bypass this, C++11
is used which has relaxed rules for POD and atomic_counter is a C++11-POD. An
alternative would have been to make atomic_counter a classical POD by removing
constructors and all private member functions, i.e. have a struct and free functions
to manipulate it.
A new msg_t::init function is added which decides to either to copy the data for size<64 bytes
or use msg_t::init_data to do zero-copy initialization.
Of course people still "can" distributed the sources under the
LGPLv3. However we provide COPYING.LESSER with additional grants.
Solution: specify these grants in the header of each source file.
Increasing it would have at least two benefits -
* More messages would be 'VSM' messages, so it would reduce allocation
overhead a bit.
* Remove any chance of false sharing of things that are, by design,
pushed by value onto a ypipe_t<msg_t> which is shared between two threads.
The only downside I see is slightly increased memory consumption on memory
constrained applications.
- Full discussion of this rationale is part of issue #1295
- copy and move message operations are updated to maintain proper
reference count of properties object
- zmq_msg_gets updated to use i_properties interface to fetch property
value
- setter/getter added to msg_t class
The get_credential () member function returns
credential for the last peer we received message for.
The idea is that this function is used to implement user-level API.
* Command names changed from null terminated to length-specified
* Command frames use the correct flag (bit 2)
* test_stream acts as test case for command frames
* Some code cleanups
Copyrights had become ads for Sustrik's corporate sponsors, going against the original
agreement to share copyrights with the community (that agreement was: one line stating
iMatix copyright + one reference to AUTHORS file). The proliferation of corporate ads
is also unfair to the many individual authors. I've removed ALL corporate title from
the source files so the copyright statements can now be centralized in AUTHORS and
source files can be properly updated on an annual basis.
When a peer reconnects, the router socket receives an identity
message containing this peer id. When this happens, the current
implementation crashes.
This patch makes a router socket to silently ignore all identity
messages coming from reconnected peers.
However, the "durable socket" behaviour wasn't re-added.
Identities are used solely for routing in REQ/REP pattern.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
GENERIC allows to use 0MQ as a dumb networking framework.
It provides user with connect/disconnect notifications.
Also, each inbound message is labeled by ID of the connection
it originated from. Outbound messages should be labeled by
the ID of the connection to send them to.
To distinguish connect/disconnect notifications from common
messages, COMMAND flag was introduced.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Till now the VSM buffer was aligned to 16 bit boundary
which could possibly cause problems on RISC architectures
when accessing the message data in unsafe manner.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
So far there was no distinction between message parts used by 0MQ
and message parts used by user. Now, the message parts used by 0MQ
are marked as 'LABEL'.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
This patch addresses serveral issues:
1. It gathers message related functionality scattered over whole
codebase into a single class.
2. It makes zmq_msg_t an opaque datatype. Internals of the class
don't pollute zmq.h header file.
3. zmq_msg_t size decreases from 48 to 32 bytes. That saves ~33%
of memory in scenarios with large amount of small messages.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
