ContextBuilder: solve context close bug using reference count

- added reference count to ContextBuilder to keep track of how many external references to the M2k context are present. When the last reference is removed, the M2k context can be closed. - contexts should be closed in the reverse order they were opened: contextClose() -> iio_context_destroy() to avoid pointer errors. - based on context ownership, the user of the API is responsible of deinitalizing resources. Signed-off-by: Adrian Stanea <[email protected]>
analogdevicesinc · Sep 27, 2023 · 0c78649 · 0c78649
1 parent 7b31a3d
commit 0c78649
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Showing 4 changed files with 55 additions and 12 deletions.
diff --git a/include/libm2k/contextbuilder.hpp b/include/libm2k/contextbuilder.hpp
@@ -114,6 +114,9 @@ class LIBM2K_API ContextBuilder {
 		bool ownsContext = false);
 	static bool m_disable_logging;
 
+	static std::map<std::string, int> reference_count;
+	static void updateReferenceCount(std::string uri);	
+	static Context* sarchInConnectedDevices(std::string uri);
 };
 
 /**

diff --git a/src/context_impl.cpp b/src/context_impl.cpp
@@ -460,3 +460,9 @@ void ContextImpl::setContextOwnership(bool ownsContext)
 {
         m_ownsContext = ownsContext;
 }
+
+bool ContextImpl::getContextOwnership()
+{
+	return m_ownsContext;
+}
+
diff --git a/src/context_impl.hpp b/src/context_impl.hpp
@@ -91,6 +91,7 @@ class ContextImpl : public virtual Context {
 	struct iio_context *getIioContext() override;
 	void setTimeout(unsigned int timeout) override;
 	void setContextOwnership(bool ownsContext);
+	bool getContextOwnership();
 
 protected:
 	struct iio_context* m_context;

diff --git a/src/contextbuilder.cpp b/src/contextbuilder.cpp
@@ -56,6 +56,7 @@ std::map<ContextTypes, std::string> ContextBuilder::m_dev_name_map = {
 };
 
 bool ContextBuilder::m_disable_logging = true;
+std::map<std::string, int> ContextBuilder::reference_count = {};
 
 ContextBuilder::ContextBuilder()
 {
@@ -135,6 +136,7 @@ Context* ContextBuilder::buildContext(ContextTypes type, std::string uri,
 			struct iio_context* ctx, bool sync, bool ownsContext) // enum Device Name
 {
 	std::string name = m_dev_name_map.at(type);
+	updateReferenceCount(uri);
 	switch (type) {
 		case CtxM2K:
 		{
@@ -158,17 +160,38 @@ Context* ContextBuilder::buildContext(ContextTypes type, std::string uri,
 	}
 }
 
+void ContextBuilder::updateReferenceCount(std::string uri)
+{
+	if(reference_count.find(uri) == reference_count.end()) {
+		reference_count[uri] = 1;
+	} else {
+		reference_count[uri]++;
+	}	
+}
+
+Context* ContextBuilder::sarchInConnectedDevices(std::string uri)
+{
+	for (Context* dev : s_connectedDevices) {
+		if (dev->getUri() == std::string(uri)) {
+			updateReferenceCount(uri);
+			return dev;
+		}
+	}
+	return nullptr;	
+}
+
+
 Context* ContextBuilder::contextOpen(const char *uri)
 {
+	Context* dev = nullptr;
 	if (m_disable_logging) {
 		enableLogging(false);
 	}
 	LIBM2K_LOG(INFO, "libm2k version: " + getVersion());
 
-	for (Context* dev : s_connectedDevices) {
-		if (dev->getUri() == std::string(uri)) {
-			return dev;
-		}
+	dev = sarchInConnectedDevices(uri);
+	if (dev) {
+		return dev;
 	}
 
 	struct iio_context* ctx = iio_create_context_from_uri(uri);
@@ -192,14 +215,15 @@ Context* ContextBuilder::contextOpen(const char *uri)
 
 	ContextTypes dev_type = ContextBuilder::identifyContext(ctx);
 
-	Context* dev = buildContext(dev_type, std::string(uri), ctx, true, true);
+	dev = buildContext(dev_type, std::string(uri), ctx, true, true);
 	s_connectedDevices.push_back(dev);
 
 	return dev;
 }
 
 Context* ContextBuilder::contextOpen(struct iio_context* ctx, const char* uri)
 {
+	Context* dev = nullptr;
     if (m_disable_logging) {
         enableLogging(false);
     }
@@ -221,10 +245,9 @@ Context* ContextBuilder::contextOpen(struct iio_context* ctx, const char* uri)
 		LIBM2K_LOG(INFO, "Firmware version: " + std::string(hw_fw_version));
 	}
 
-	for (Context* dev : s_connectedDevices) {
-		if (dev->getUri() == std::string(uri)) {
-			return dev;
-		}
+	dev = sarchInConnectedDevices(uri);
+	if (dev) {
+		return dev;
 	}
 
 	if (!ctx) {
@@ -233,7 +256,7 @@ Context* ContextBuilder::contextOpen(struct iio_context* ctx, const char* uri)
 
 	ContextTypes dev_type = ContextBuilder::identifyContext(ctx);
 
-	Context* dev = buildContext(dev_type, std::string(uri), ctx, true);
+	dev = buildContext(dev_type, std::string(uri), ctx, true);
 	s_connectedDevices.push_back(dev);
 
 	return dev;
@@ -298,13 +321,23 @@ M2k *ContextBuilder::m2kOpen()
 
 void ContextBuilder::contextClose(Context* device, bool deinit)
 {
+	std::string uri = device->getUri();
+	bool isDeviceCached = reference_count.find(uri) != reference_count.end();
+	if(isDeviceCached) {
+		reference_count[uri]--;
+		if(reference_count[uri] != 0) 
+			return;
+	}
+
 	s_connectedDevices.erase(std::remove(s_connectedDevices.begin(),
 					     s_connectedDevices.end(),
 					     device), s_connectedDevices.end());
 	try {
-		if (deinit) {
+		ContextImpl* ctx_impl = dynamic_cast<ContextImpl*>(device);
+		if (deinit && !ctx_impl->getContextOwnership())
+			device->deinitialize();
+		else if (deinit)
 			device->deinitialize();
-		}
 	} catch (std::exception &e ){
 		delete device;
 		THROW_M2K_EXCEPTION("Context deinit: " + std::string(e.what()), libm2k::EXC_RUNTIME_ERROR);