Tighten up scope after the previous patch avoided using
internals.  This will also make it easier to change
internal implementation without having to chase down quite
as many impacted callers or worrying about two files getting
implementations out of sync.

* src/conf/object_event_private.h
(virObjectEventCallbackListAddID, virObjectEventQueueClear)
(virObjectEventStateLock, virObjectEventStateUnlock)
(virObjectEventTimer): Drop prototype.
(_virObjectEventCallbackList, _virObjectEventState)
(_virObjectEventCallback): Move...
* src/conf/object_event.c: ...here.
(virObjectEventCallbackListAddID, virObjectEventQueueClear)
(virObjectEventStateLock, virObjectEventStateUnlock)
(virObjectEventTimer): Mark private.
Signed-off-by: NEric Blake <eblake@redhat.com>

Right now, the older virConnectDomainEventRegister (takes a
function pointer, returns 0 on success) and the newer
virConnectDomainEventRegisterID (takes an eventID, returns a
callbackID) share the underlying implementation (the older
API ends up consuming a callbackID for eventID 0 under the
hood).  We implemented that by a lot of copy and pasted
code between object_event.c and domain_event.c, according to
whether we are dealing with a function pointer or an eventID.
However, our copy and paste is not symmetric.  Consider this
sequence:

id1 = virConnectDomainEventRegisterAny(conn, dom,
   VIR_DOMAIN_EVENT_ID_LIFECYCLE,
   VIR_DOMAIN_EVENT_CALLBACK(callback), NULL, NULL);
virConnectDomainEventRegister(conn, callback, NULL, NULL);
virConnectDomainEventDeregister(conn, callback);
virConnectDomainEventDeregsiterAny(conn, id1);

the first three calls would succeed, but the third call ended
up nuking the id1 callbackID (the per-domain new-style handler),
then the fourth call failed with an error about an unknown
callbackID, leaving us with the global handler (old-style) still
live and receiving events.  It required another old-style
deregister to clean up the mess.  Root cause was that
virDomainEventCallbackList{Remove,MarkDelete} were only
checking for function pointer match, rather than also checking
for whether the registration was global.

Rather than playing with the guts of object_event ourselves
in domain_event, it is nicer to add a mapping function for the
internal callback id, then share common code for event removal.
For now, the function-to-id mapping is used only internally;
I thought about whether a new public API to let a user learn
the callback would be useful, but decided exposing this to the
user is probably a disservice, since we already publicly
document that they should avoid the old style, and since this
patch already demonstrates that older libvirt versions have
weird behavior when mixing old and new styles.

And like all good bug fix patches, I enhanced the testsuite,
validating that the changes in tests/ expose the failure
without the rest of the patch.

* src/conf/object_event.c (virObjectEventCallbackLookup)
(virObjectEventStateCallbackID): New functions.
(virObjectEventCallbackLookup): Use helper function.
* src/conf/object_event_private.h (virObjectEventStateCallbackID):
Declare new function.
* src/conf/domain_event.c (virDomainEventStateRegister)
(virDomainEventStateDeregister): Let common code handle the
complexity.
(virDomainEventCallbackListRemove)
(virDomainEventCallbackListMarkDelete)
(virDomainEventCallbackListAdd): Drop unused functions.
* tests/objecteventtest.c (testDomainCreateXMLMixed): New test.
Signed-off-by: NEric Blake <eblake@redhat.com>

We might as well take advantage of viralloc.h instead of open-coding
array management ourselves.  While at it, I simplified several
places that were doing repetitive pointer chasing to use an
intermediate variable for legibility (some other places remain,
but they will disapper in later refactoring patches).

* src/conf/object_event_private.h (_virObjectEventCallbackList):
Use size_t for count.
* src/conf/object_event.c (_virObjectEventQueue): Likewise.
(virObjectEventCallbackListRemoveID): Use VIR_DELETE_ELEMENT.
(virObjectEventQueuePush, virObjectEventCallbackListAddID): Use
VIR_APPEND_ELEMENT.
(virObjectEventCallbackListEventID)
(virObjectEventStateDispatchCallbacks): Simplify code.
Signed-off-by: NEric Blake <eblake@redhat.com>

No need to use an int that only ever stores 0 and 1.

* src/conf/object_event_private.h (_virObjectEventCallback):
Change deleted to bool.
* src/conf/object_event.c (virObjectEventDispatchMatchCallback):
Switch return type to bool.
(virObjectEventCallbackListMarkDeleteID): Update client.
* src/conf/domain_event.c (virDomainEventCallbackListMarkDelete):
Likewise.

Any file with access to object_event_private.h also has access to
the internals of virObjectEvent, without needing an accessor
function.  Not to mention the accessor function was doing type
checks that would always succeed.

* src/conf/object_event_private.h (virObjectEventGetEventID): Drop.
* src/conf/object_event.c (virObjectEventGetEventID): Drop.
(virObjectEventDispatchMatchCallback): Simplify caller.
* src/conf/domain_event.c (virDomainEventDispatchDefaultFunc):
Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

While working on events, I found a number of minor issues; I'm
hoisting these to the front rather than doing it piecemeal in
the patches where I first noticed bad or missing documentation.

* src/conf/object_event.c: Fix grammar, document all parameters
of public functions, wrap some long lines.
* src/conf/object_event.h: Likewise.
* src/conf/network_event.c: Likewise.
* src/conf/domain_event.c: Likewise (except for the large number
of event creation functions).
* src/libvirt_private.cyms (conf/object_event.h): Split...
(conf/network_event.h): ...to account for new file.
Signed-off-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The event namespace concept is mostly redundant information.
With the re-written dispatcher, the namespace is only used
for equality comparisons between event IDs. This can be solved
by just comparing virClassPtr instances instead.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of having the object event code have to know about each
type of event and their dispatch functions, associate a dispatch
function with the object instance. The dispatch code can thus be
significantly simplified.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

While running objecteventtest, it was found that valgrind pointed out the
following memory leak:

==13464== 5 bytes in 1 blocks are definitely lost in loss record 7 of 134
==13464==    at 0x4A0887C: malloc (vg_replace_malloc.c:270)
==13464==    by 0x341F485E21: strdup (strdup.c:42)
==13464==    by 0x4CAE28F: virStrdup (virstring.c:554)
==13464==    by 0x4CF3CBE: virObjectEventCallbackListAddID (object_event.c:286)
==13464==    by 0x4CF49CA: virObjectEventStateRegisterID (object_event.c:729)
==13464==    by 0x4CF73FE: virDomainEventStateRegisterID (domain_event.c:1424)
==13464==    by 0x4D7358F: testConnectDomainEventRegisterAny (test_driver.c:6032)
==13464==    by 0x4D600C8: virConnectDomainEventRegisterAny (libvirt.c:19128)
==13464==    by 0x402409: testDomainStartStopEvent (objecteventtest.c:232)
==13464==    by 0x403451: virtTestRun (testutils.c:138)
==13464==    by 0x402012: mymain (objecteventtest.c:395)
==13464==    by 0x403AF2: virtTestMain (testutils.c:593)
==13464==

Hitting this should be pretty rare, but at least developers will know
that they are providing a weird event ID. Otherwise for namespace that
are added in the normal way, gcc will raise a warning about unhandled
case in the switch.

Define the public API for (de-)registering network events
and the callbacks for receiving lifecycle events. The lifecycle
event includes a 'detail' parameter to match the domain lifecycle
event data, but this is currently unused.

The network events related code goes into its own set of internal
files src/conf/network_event.[ch]