[libcamera-devel] [PATCH v3 01/11] utils: ipc: proxy: Track IPA with a state machine

[Laurent Pinchart]

On Fri, Mar 26, 2021 at 11:50:10AM +0900, paul.elder at ideasonboard.com wrote:
> Hi Kieran,
> 
> On Thu, Mar 25, 2021 at 01:42:21PM +0000, Kieran Bingham wrote:
> > Asynchronous tasks can only be submitted while the IPA is running.
> > 
> > Further more, the shutdown sequence can not be tracked with a simple
> > running flag. We can also be in the state 'Stopping' where we have not
> > yet completed all events, but we must not commence anything new.
> > 
> > Refactor the running_ boolean into a stateful enum to track this.
> 
> Ooh, good idea!
> 
> > 
> > Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> > ---
> >  .../libcamera_templates/module_ipa_proxy.cpp.tmpl         | 8 ++++----
> >  .../libcamera_templates/module_ipa_proxy.h.tmpl           | 8 +++++++-
> >  .../generators/libcamera_templates/proxy_functions.tmpl   | 7 +++++--
> >  3 files changed, 16 insertions(+), 7 deletions(-)
> > 
> > diff --git a/utils/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl b/utils/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl
> > index e3b541db4e36..dd0f4d3f64b6 100644
> > --- a/utils/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl
> > +++ b/utils/ipc/generators/libcamera_templates/module_ipa_proxy.cpp.tmpl
> > @@ -45,7 +45,7 @@ namespace {{ns}} {
> >  {%- endif %}
> >  
> >  {{proxy_name}}::{{proxy_name}}(IPAModule *ipam, bool isolate)
> > -	: IPAProxy(ipam), running_(false),
> > +	: IPAProxy(ipam), state_(Stopped),
> >  	  isolate_(isolate), seq_(0)
> >  {
> >  	LOG(IPAProxy, Debug)
> > @@ -155,7 +155,7 @@ void {{proxy_name}}::recvMessage(const IPCMessage &data)
> >  
> >  	return {{ "_ret" if method|method_return_value != "void" }};
> >  {%- elif method.mojom_name == "start" %}
> > -	running_ = true;
> > +	state_ = Running;
> >  	thread_.start();
> >  
> >  	{{ "return " if method|method_return_value != "void" -}}
> > @@ -173,7 +173,7 @@ void {{proxy_name}}::recvMessage(const IPCMessage &data)
> >  	{%- endfor -%}
> >  );
> >  {% elif method|is_async %}
> > -	ASSERT(running_);
> > +	ASSERT(state_ == Running);
> >  	proxy_.invokeMethod(&ThreadProxy::{{method.mojom_name}}, ConnectionTypeQueued,
> >  	{%- for param in method|method_param_names -%}
> >  		{{param}}{{- ", " if not loop.last}}
> > @@ -226,7 +226,7 @@ void {{proxy_name}}::recvMessage(const IPCMessage &data)
> >  {% for method in interface_event.methods %}
> >  {{proxy_funcs.func_sig(proxy_name, method, "Thread")}}
> >  {
> > -	ASSERT(running_);
> > +	ASSERT(state_ != Stopped);
> >  	{{method.mojom_name}}.emit({{method.parameters|params_comma_sep}});
> >  }
> 
> As mentioned on irc, I think we need to copy these over to the IPC
> versions too, but that can be done on top.
> >  
> > diff --git a/utils/ipc/generators/libcamera_templates/module_ipa_proxy.h.tmpl b/utils/ipc/generators/libcamera_templates/module_ipa_proxy.h.tmpl
> > index efb09a180b90..e33c26492d91 100644
> > --- a/utils/ipc/generators/libcamera_templates/module_ipa_proxy.h.tmpl
> > +++ b/utils/ipc/generators/libcamera_templates/module_ipa_proxy.h.tmpl
> > @@ -104,7 +104,13 @@ private:
> >  		{{interface_name}} *ipa_;
> >  	};
> >  
> > -	bool running_;
> > +	enum {{proxy_name}}States {
> > +		Stopped,
> > +		Stopping,
> > +		Running,
> > +	};
> > +	enum {{proxy_name}}States state_;
> > +
> 
> Since these are the same for all IPAProxies, should we put them in
> ipa_proxy.h in the base IPAProxy class instead?

I like this.

> With or without the suggested change,
> 
> Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
> 
> >  	Thread thread_;
> >  	ThreadProxy proxy_;
> >  	std::unique_ptr<{{interface_name}}> ipa_;
> > diff --git a/utils/ipc/generators/libcamera_templates/proxy_functions.tmpl b/utils/ipc/generators/libcamera_templates/proxy_functions.tmpl
> > index 8addc2fad0a8..09394a4fec83 100644
> > --- a/utils/ipc/generators/libcamera_templates/proxy_functions.tmpl
> > +++ b/utils/ipc/generators/libcamera_templates/proxy_functions.tmpl
> > @@ -23,9 +23,12 @@
> >   # \brief Generate function body for IPA stop() function for thread
> >   #}
> >  {%- macro stop_thread_body() -%}
> > -	if (!running_)
> > +	ASSERT(state_ != Stopping);
> > +	if (state_ != Running)
> >  		return;
> >  
> > +	state_ = Stopping;
> > +
> >  	proxy_.invokeMethod(&ThreadProxy::stop, ConnectionTypeBlocking);
> >  
> >  	thread_.exit();
> > @@ -33,7 +36,7 @@
> >  
> >  	Thread::current()->dispatchMessages(Message::Type::InvokeMessage);
> >  
> > -	running_ = false;
> > +	state_ = Stopped;
> >  {%- endmacro -%}
> >  
> >  

-- 
Regards,

Laurent Pinchart