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

[Kieran Bingham]

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.

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}});
 }
 
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_;
+
 	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 -%}
 
 
-- 
2.25.1