fix #514, call_data_callbacks after shared the data

pdi/AUTHORS

@@ -15,7 +15,8 @@ Benoit Martin - CEA (bmartin@cea.fr)
 * Add support for const data in `PDI_share`, `PDI_expose` and `PDI_multi_expose`
 
 Jacques Morice - CEA (jacques.morice@cea.fr)
-* Add Add operator== in Context::Iterator()
+* Add operator== in Context::Iterator()
+* Delay data events in multi_expose when the last data is exposed
 
 François-Xavier Mordant - CEA (francois-xavier.mordant@cea.fr)
 * Fixed CMake issues, internal API enhancement

pdi/CHANGELOG.md

@@ -18,6 +18,8 @@ and this project adheres to
 #### Added
 
 #### Changed
+* Delay data events in multi_expose when the last data is exposed
+  [#514](https://github.com/pdidev/pdi/issues/514)
 
 #### Deprecated
 

pdi/include/pdi/data_descriptor.h

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2015-2024 Commissariat a l'energie atomique et aux energies alternatives (CEA)
+ * Copyright (C) 2015-2026 Commissariat a l'energie atomique et aux energies alternatives (CEA)
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -30,9 +30,14 @@
 #include <paraconf.h>
 
 #include <pdi/pdi_fwd.h>
+#include <pdi/callbacks.h>
+#include <pdi/context.h>
+#include <pdi/data_descriptor.h>
 #include <pdi/datatype_template.h>
 #include <pdi/ref_any.h>
 
+// #include "global_context.h"
+
 namespace PDI {
 
 class PDI_EXPORT Data_descriptor
@@ -85,6 +90,14 @@ class PDI_EXPORT Data_descriptor
 	 */
 	virtual void share(void* data, bool read, bool write) = 0;
 
+	/** Shares some data with PDI
+	 * \param[in,out] data the shared data
+	 * \param read whether read access is granted to other references
+	 * \param write whether write access is granted to other references
+	 * \param delayed_callbacks a class that allow to delay trigger_delayed_data_callbacks for a list of a data
+	 */
+	virtual void share(void* data, bool read, bool write, Delayed_data_callbacks&& delayed_callbacks) = 0;
+
 	/** Shares some data with PDI
 	 * \param[in,out] ref a reference to the shared data
 	 * \param read whether the stored reference should have read access
@@ -93,6 +106,19 @@ class PDI_EXPORT Data_descriptor
 	 */
 	virtual void* share(Ref ref, bool read, bool write) = 0;
 
+	/** Shares some data with PDI
+	 * \param[in,out] ref a reference to the shared data
+	 * \param read whether the stored reference should have read access
+	 * \param write whether the stored reference should have write access
+	 * \param delayed_callbacks a class that allow to delay trigger_delayed_data_callbacks for a list of a data
+	 * \return the just shared buffer
+	 */
+	virtual void* share(Ref ref, bool read, bool write, Delayed_data_callbacks&& delayed_callbacks) = 0;
+
+	/** function to call "data_callbacks" for the shared data.
+	 */
+	virtual void trigger_delayed_data_callbacks() = 0;
+
 	/** Releases ownership of a data shared with PDI. PDI is then responsible to
 	 * free the associated memory whenever necessary.
 	 */

pdi/include/pdi/delayed_data_callbacks.h

@@ -0,0 +1,128 @@
+/*******************************************************************************
+ * Copyright (C) 2026 Commissariat a l'energie atomique et aux energies alternatives (CEA)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * * Neither the name of CEA nor the names of its contributors may be used to
+ *   endorse or promote products derived from this software without specific
+ *   prior written permission.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ ******************************************************************************/
+
+#ifndef PDI_DELAYED_DATA_CALLBACK_H_
+#define PDI_DELAYED_DATA_CALLBACK_H_
+
+#include <string>
+#include <vector>
+
+#include <pdi/pdi_fwd.h>
+#include "pdi/context.h"
+#include "pdi/datatype.h"
+#include "pdi/error.h"
+#include "pdi/plugin.h"
+#include "pdi/ref_any.h"
+#include "pdi/scalar_datatype.h"
+#include <pdi/context.h>
+#include <pdi/data_descriptor.h>
+#include <pdi/datatype_template.h>
+#include <pdi/ref_any.h>
+
+#include <data_descriptor_impl.h>
+
+#include "global_context.h"
+
+namespace PDI {
+
+class PDI_EXPORT Delayed_data_callbacks
+{
+	/// friend class Global_context;
+	std::vector<std::string> m_datanames;
+
+	/// The context this descriptor is part of
+	Global_context& m_context;
+
+public:
+	/// constructor used in:
+	///     - the case of PDI_multi_expose
+	///     - when a user want to define is own "Delayed_data_callbacks" object
+	/// Remark: This constructor doesn't work if PDI_init is not called.
+	Delayed_data_callbacks(Global_context& ctx)
+		: m_datanames{}
+		, m_context{ctx}
+	{}
+
+	// In the destructor, we need to throw an error message in case of the callback on the data doesn't work (trigger function)
+	//  (example: error in the config.yml for a plugin, error due to external library incompatibility)
+	~Delayed_data_callbacks() noexcept(false)
+	{
+		try {
+			this->trigger();
+		} catch (Error& e) {
+			if (std::uncaught_exceptions()) {
+				// An exception is throwing. Print simple message to avoid std::terminate.
+				m_context.logger().error("Error in the destructor of Delayed_data_callbacks, {}", e.what());
+			} else {
+				// No exception is throwing. Throw an error.
+				throw Error(e.status(), "Error in the destructor of Delayed_data_callbacks, {}", e.what());
+			}
+		} catch (const std::exception& e) {
+			if (std::uncaught_exceptions()) {
+				// An exception is throwing. Print simple message to avoid std::terminate.
+				m_context.logger().error("Error in the destructor of Delayed_data_callbacks, {}", e.what());
+			} else {
+				// No exception is throwing. Throw an error.
+				m_context.logger().error("Error in the destructor of Delayed_data_callbacks.");
+				throw;
+			}
+		} catch (...) {
+			if (std::uncaught_exceptions()) {
+				// An exception is throwing. Print simple message to avoid std::terminate.
+				m_context.logger().error("Error in the destructor of Delayed_data_callbacks.");
+			} else {
+				// No exception is throwing. Throw an error.
+				m_context.logger().error("Error in the destructor of Delayed_data_callbacks.");
+				throw;
+			}
+		}
+	}
+
+	// add element to the list
+	void add_dataname(const std::string& name) { m_datanames.emplace_back(name); }
+
+	// trigger_delayed_data_callbacks()
+	void trigger()
+	try {
+		int i = 0;
+		size_t number_of_elements = m_datanames.size();
+		for (auto&& element_name: m_datanames) {
+			m_context.logger().trace("Trigger data callback `{}' ({}/{})", element_name.c_str(), ++i, number_of_elements);
+			m_context[element_name.c_str()].trigger_delayed_data_callbacks();
+		}
+		this->cancel(); // clear the m_datanames
+	} catch (Error& e) {
+		this->cancel(); // clear the m_datanames
+		throw Error(e.status(), "Error in trigger data callback: `{}'", e.what());
+	} catch (...) {
+		this->cancel(); // clear the m_datanames
+		throw;
+	}
+
+	// clear the element in the list
+	void cancel() { m_datanames.clear(); }
+}; // class Delayed_data_callbacks
+
+} // namespace PDI
+#endif // PDI_DELAYED_DATA_CALLBACK_H_

pdi/include/pdi/pdi_fwd.h

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2015-2025 Commissariat a l'energie atomique et aux energies alternatives (CEA)
+ * Copyright (C) 2015-2026 Commissariat a l'energie atomique et aux energies alternatives (CEA)
  * Copyright (C) 2021 Institute of Bioorganic Chemistry Polish Academy of Science (PSNC)
  * All rights reserved.
  *
@@ -79,6 +79,11 @@ using Datatype_template_sptr = std::shared_ptr<const Datatype_template>;
 
 using Datatype_sptr = std::shared_ptr<const Datatype>;
 
+/**
+ * A class to delayed the moment to call call_data_callback
+*/
+class Delayed_data_callbacks;
+
 /** A data descriptors with a name and a value, it contains an implicit type
  * template that is used when exposing untyped data
  */

pdi/src/data_descriptor_impl.cxx

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2015-2024 Commissariat a l'energie atomique et aux energies alternatives (CEA)
+ * Copyright (C) 2015-2026 Commissariat a l'energie atomique et aux energies alternatives (CEA)
  * Copyright (C) 2021 Institute of Bioorganic Chemistry Polish Academy of Science (PSNC)
  * All rights reserved.
  *
@@ -32,6 +32,7 @@
 
 #include "pdi/context.h"
 #include "pdi/datatype.h"
+#include "pdi/delayed_data_callbacks.h"
 #include "pdi/error.h"
 #include "pdi/plugin.h"
 #include "pdi/ref_any.h"
@@ -151,13 +152,47 @@ bool Data_descriptor_impl::empty()
 	return m_refs.empty();
 }
 
+void Data_descriptor_impl::trigger_delayed_data_callbacks()
+try {
+	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
+	if (m_refs.empty() || (m_refs.size() == 1 && metadata())) {
+		throw State_error{"Cannot call trigger_delayed_data_callbacks on a non shared value: : `{}'", m_name};
+	}
+	try {
+		m_context.callbacks().call_data_callbacks(m_name, ref());
+	} catch (const exception&) {
+		m_refs.pop();
+		throw;
+	} catch (...) {
+		m_context.logger().trace("Error in trigger_delayed_data_callbacks\n");
+		m_refs.pop();
+		throw;
+	}
+
+	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
+} catch (Error& e) {
+	throw Error(e.status(), "Unable to execute data_callbacks on data `{}', {}", name(), e.what());
+}
+
+
 void Data_descriptor_impl::share(void* data, bool read, bool write)
+try {
+	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
+
+	share(data, read, write, Delayed_data_callbacks(m_context));
+
+	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
+} catch (Error& e) {
+	throw;
+}
+
+void Data_descriptor_impl::share(void* data, bool read, bool write, Delayed_data_callbacks&& delayed_callbacks)
 try {
 	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
 	Ref r{data, &free, m_type->evaluate(m_context), read, write};
 	try {
 		m_context.logger().trace("Sharing `{}' Ref with rights: R = {}, W = {}", m_name, read, write);
-		share(r, false, false);
+		share(r, false, false, std::move(delayed_callbacks));
 	} catch (...) {
 		// on error, do not free the data as would be done automatically otherwise
 		r.release();
@@ -170,6 +205,17 @@ try {
 }
 
 void* Data_descriptor_impl::share(Ref data_ref, bool read, bool write)
+try {
+	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
+	return share(data_ref, read, write, Delayed_data_callbacks(m_context));
+} catch (Error& e) {
+	throw Error(e.status(), "Unable to share `{}', {}", name(), e.what());
+	;
+} catch (...) {
+	throw std::runtime_error("void* Data_descriptor_impl::share(Ref data_ref, bool read, bool write)");
+}
+
+void* Data_descriptor_impl::share(Ref data_ref, bool read, bool write, Delayed_data_callbacks&& delayed_callbacks)
 try {
 	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
 	// metadata must provide read access
@@ -201,12 +247,7 @@ try {
 		throw Right_error{"Unable to grant requested rights"};
 	}
 
-	try {
-		m_context.callbacks().call_data_callbacks(m_name, ref());
-	} catch (const exception&) {
-		m_refs.pop();
-		throw;
-	}
+	delayed_callbacks.add_dataname(m_name);
 
 	assert((!metadata() || !m_refs.empty()) && "metadata descriptors should always keep a placeholder");
 	return result;

pdi/src/data_descriptor_impl.h

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2015-2024 Commissariat a l'energie atomique et aux energies alternatives (CEA)
+ * Copyright (C) 2015-2026 Commissariat a l'energie atomique et aux energies alternatives (CEA)
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -43,8 +43,10 @@ namespace PDI {
 class PDI_EXPORT Data_descriptor_impl: public Data_descriptor
 {
 	friend class Global_context;
+	friend class Delayed_data_callback;
 	friend class Descriptor_test_handler;
 
+
 	struct PDI_NO_EXPORT Ref_holder;
 
 	/// The context this descriptor is part of
@@ -59,7 +61,6 @@ class PDI_EXPORT Data_descriptor_impl: public Data_descriptor
 
 	bool m_metadata;
 
-
 	/** Create an empty descriptor
 	 */
 	Data_descriptor_impl(Global_context& ctx, const char* name);
@@ -91,12 +92,17 @@ class PDI_EXPORT Data_descriptor_impl: public Data_descriptor
 
 	void share(void* data, bool read, bool write) override;
 
+	void share(void* data, bool read, bool write, Delayed_data_callbacks&& delayed_callbacks) override;
+
 	void* share(Ref ref, bool read, bool write) override;
 
+	void* share(Ref ref, bool read, bool write, Delayed_data_callbacks&& delayed_callbacks) override;
+
+	void trigger_delayed_data_callbacks() override;
+
 	void release() override;
 
 	void* reclaim() override;
-
 }; // class Data_descriptor
 
 } // namespace PDI

pdi/src/global_context.h

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2015-2025 Commissariat a l'energie atomique et aux energies alternatives (CEA)
+ * Copyright (C) 2015-2026 Commissariat a l'energie atomique et aux energies alternatives (CEA)
  * Copyright (C) 2021 Institute of Bioorganic Chemistry Polish Academy of Science (PSNC)
  * All rights reserved.
  *
@@ -49,6 +49,7 @@ namespace PDI {
 class PDI_EXPORT Global_context: public Context
 {
 private:
+	friend class Delayed_data_callbacks;
 	friend class Data_descriptor_impl;
 
 	/// The singleton Context instance