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pva/client.h Allow callbacks to unref Operations

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Keep a local (internal) shared_ptr whenever
user callbacks are run.  This allows user
callbacks to drop (reset()/dtor) Operations
or Monitors safely.

Ref must to captured before mutex is locked,
which is safe as the internal weak_ptr is
not changed after build() (despite being non-const)
This commit is contained in:
Michael Davidsaver
2018-06-29 11:19:24 -07:00
parent f29ef3121e
commit 80db41f1c4
4 changed files with 19 additions and 2 deletions
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7
src/client/clientMonitor.cpp
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@@ -84,6 +84,9 @@ struct Monitor::Impl : public pva::MonitorRequester,
{
operation_type::shared_pointer temp;
{
// keepalive for safety in case callback wants to destroy us
std::tr1::shared_ptr<Monitor::Impl> keepalive(internal_shared_from_this());
Guard G(mutex);
last.reset();
@@ -111,6 +114,7 @@ struct Monitor::Impl : public pva::MonitorRequester,
pva::MonitorPtr const & operation,
pvd::StructureConstPtr const & structure) OVERRIDE FINAL
{
std::tr1::shared_ptr<Monitor::Impl> keepalive(internal_shared_from_this());
Guard G(mutex);
if(!cb || started || done) return;
@@ -140,6 +144,7 @@ struct Monitor::Impl : public pva::MonitorRequester,
virtual void channelDisconnect(bool destroy) OVERRIDE FINAL
{
std::tr1::shared_ptr<Monitor::Impl> keepalive(internal_shared_from_this());
Guard G(mutex);
if(!cb || done) return;
event.message = "Disconnect";
@@ -149,6 +154,7 @@ struct Monitor::Impl : public pva::MonitorRequester,
virtual void monitorEvent(pva::MonitorPtr const & monitor) OVERRIDE FINAL
{
std::tr1::shared_ptr<Monitor::Impl> keepalive(internal_shared_from_this());
Guard G(mutex);
if(!cb || done) return;
event.message.clear();
@@ -158,6 +164,7 @@ struct Monitor::Impl : public pva::MonitorRequester,
virtual void unlisten(pva::MonitorPtr const & monitor) OVERRIDE FINAL
{
std::tr1::shared_ptr<Monitor::Impl> keepalive(internal_shared_from_this());
Guard G(mutex);
if(!cb || done) return;
done = true;