enh(all): Add [[nodiscard]] and [[maybe_unused]] attributes (addresses #5152)

ActiveRecord/include/Poco/ActiveRecord/ActiveRecord.h

@@ -35,6 +35,7 @@ class ActiveRecordLib_API ActiveRecordBase: public Poco::RefCountedObject
 public:
 	using Ptr = Poco::AutoPtr<ActiveRecordBase>;
 
+	[[nodiscard]]
 	virtual std::string toString() const = 0;
 		/// Returns a string representation of the object for
 		/// debugging purposes. The default implementation returns the ID.
@@ -59,14 +60,17 @@ class ActiveRecordLib_API ActiveRecordBase: public Poco::RefCountedObject
 	void detach();
 		/// Detaches the object from its Context.
 
+	[[nodiscard]]
 	Context::Ptr context() const;
 		/// Returns the Context this object is attached to,
 		/// or a null pointer if the object has not been
 		/// attached to a Context.
 
+	[[nodiscard]]
 	virtual bool isValid() const;
 		/// Returns true iff the object is valid ID, otherwise false.
 
+	[[nodiscard]]
 	bool isAttached() const;
 		/// Returns true iff the object has been attached to a Context, otherwise false.
 

ActiveRecord/include/Poco/ActiveRecord/Context.h

@@ -41,9 +41,11 @@ class ActiveRecordLib_API Context: public Poco::RefCountedObject
 	~Context() = default;
 		/// Destroys the Context.
 
+	[[nodiscard]]
 	Poco::Data::Session& session();
 		/// Returns the database session.
 
+	[[nodiscard]]
 	StatementPlaceholderProvider::Ptr statementPlaceholderProvider() const;
 		/// Returns a new StatementPlaceholderProvider.
 

ActiveRecord/include/Poco/ActiveRecord/IDTraits.h

@@ -39,11 +39,13 @@ class IDTraits<Poco::UInt64>
 public:
 	static constexpr Poco::UInt64 INVALID_ID = std::numeric_limits<Poco::UInt64>::max();
 
+	[[nodiscard]]
 	static bool isValid(Poco::UInt64 id)
 	{
 		return id != INVALID_ID;
 	}
 
+	[[nodiscard]]
 	static std::string toString(Poco::UInt64 id)
 	{
 		return Poco::NumberFormatter::format(id);
@@ -57,11 +59,13 @@ class IDTraits<Poco::Int64>
 public:
 	static constexpr Poco::Int64 INVALID_ID = std::numeric_limits<Poco::Int64>::max();
 
+	[[nodiscard]]
 	static bool isValid(Poco::Int64 id)
 	{
 		return id != INVALID_ID;
 	}
 
+	[[nodiscard]]
 	static std::string toString(Poco::Int64 id)
 	{
 		return Poco::NumberFormatter::format(id);
@@ -75,11 +79,13 @@ class IDTraits<Poco::UInt32>
 public:
 	static constexpr Poco::UInt32 INVALID_ID = std::numeric_limits<Poco::UInt32>::max();
 
+	[[nodiscard]]
 	static bool isValid(Poco::UInt32 id)
 	{
 		return id != INVALID_ID;
 	}
 
+	[[nodiscard]]
 	static std::string toString(Poco::UInt32 id)
 	{
 		return Poco::NumberFormatter::format(id);
@@ -93,11 +99,13 @@ class IDTraits<Poco::Int32>
 public:
 	static const Poco::Int32 INVALID_ID = std::numeric_limits<Poco::Int32>::max();
 
+	[[nodiscard]]
 	static bool isValid(Poco::Int32 id)
 	{
 		return id != INVALID_ID;
 	}
 
+	[[nodiscard]]
 	static std::string toString(Poco::Int32 id)
 	{
 		return Poco::NumberFormatter::format(id);
@@ -111,11 +119,13 @@ class IDTraits<Poco::UInt16>
 public:
 	static constexpr Poco::UInt16 INVALID_ID = std::numeric_limits<Poco::UInt16>::max();
 
+	[[nodiscard]]
 	static bool isValid(Poco::UInt16 id)
 	{
 		return id != INVALID_ID;
 	}
 
+	[[nodiscard]]
 	static std::string toString(Poco::UInt16 id)
 	{
 		return Poco::NumberFormatter::format(id);
@@ -129,11 +139,13 @@ class IDTraits<Poco::Int16>
 public:
 	static constexpr Poco::Int16 INVALID_ID = std::numeric_limits<Poco::Int16>::max();
 
+	[[nodiscard]]
 	static bool isValid(Poco::Int16 id)
 	{
 		return id != INVALID_ID;
 	}
 
+	[[nodiscard]]
 	static std::string toString(Poco::Int16 id)
 	{
 		return Poco::NumberFormatter::format(id);
@@ -147,11 +159,13 @@ class IDTraits<std::string>
 public:
 	static ActiveRecordLib_API const std::string INVALID_ID;
 
+	[[nodiscard]]
 	static bool isValid(const std::string& id)
 	{
 		return !id.empty();
 	}
 
+	[[nodiscard]]
 	static std::string toString(const std::string& id)
 	{
 		return id;
@@ -165,11 +179,13 @@ class IDTraits<Poco::UUID>
 public:
 	static ActiveRecordLib_API const Poco::UUID INVALID_ID;
 
+	[[nodiscard]]
 	static bool isValid(const Poco::UUID& id)
 	{
 		return !id.isNull();
 	}
 
+	[[nodiscard]]
 	static std::string toString(const Poco::UUID& id)
 	{
 		return id.toString();

ActiveRecord/include/Poco/ActiveRecord/Query.h

@@ -116,6 +116,7 @@ class Query
 		return *this;
 	}
 
+	[[nodiscard]]
 	std::vector<typename ActRec::Ptr> execute()
 		/// Execute the query and return a vector with the
 		/// results.
@@ -147,6 +148,7 @@ class Query
 		return result;
 	}
 
+	[[nodiscard]]
 	std::size_t totalResults() const
 		/// In case of a paged query, returns the total number of results
 		/// that would be returned without paging.

ActiveRecord/include/Poco/ActiveRecord/StatementPlaceholderProvider.h

@@ -30,6 +30,8 @@ class ActiveRecordLib_API StatementPlaceholderProvider
 	using Ptr = std::unique_ptr<StatementPlaceholderProvider>;
 
 	virtual void reset() = 0;
+
+	[[nodiscard]]
 	virtual std::string next() = 0;
 
 	virtual ~StatementPlaceholderProvider();
@@ -40,6 +42,8 @@ class ActiveRecordLib_API DefaultStatementPlaceholderProvider: public StatementP
 {
 public:
 	void reset();
+
+	[[nodiscard]]
 	std::string next();
 };
 
@@ -48,6 +52,8 @@ class ActiveRecordLib_API PostgresStatementPlaceholderProvider: public Statement
 {
 public:
 	void reset();
+
+	[[nodiscard]]
 	std::string next();
 
 private:

ApacheConnector/include/ApacheApplication.h

@@ -31,9 +31,11 @@ class ApacheApplication: public Poco::Util::Application
 		/// Initializes the application if called for the first
 		/// time; does nothing in later calls.
 
+	[[nodiscard]]
 	ApacheRequestHandlerFactory& factory();
 		/// Returns the ApacheRequestHandlerFactory.
 
+	[[nodiscard]]
 	static ApacheApplication& instance();
 		/// Returns the application instance.
 

ApacheConnector/include/ApacheConnector.h

@@ -26,6 +26,7 @@ class ApacheRequestRec
 	ApacheRequestRec(request_rec* _pRec);
 		/// Creates the ApacheRequestRec;
 
+	[[nodiscard]]
 	bool haveRequestBody();
 		/// Returns true if the request contains a body.
 
@@ -56,6 +57,7 @@ class ApacheRequestRec
 		/// Copies the request uri and header fields from the Apache request
 		/// to the ApacheServerRequest.
 
+	[[nodiscard]]
 	bool secure();
 		/// Returns true if the request is using a secure
 		/// connection. Returns false if no secure connection

ApacheConnector/include/ApacheRequestHandlerFactory.h

@@ -28,9 +28,11 @@ class ApacheRequestHandlerFactory: public Poco::Net::HTTPRequestHandlerFactory
 	~ApacheRequestHandlerFactory();
 		/// Destructor of the ApacheRequestHandlerFactory
 
+	[[nodiscard]]
 	Poco::Net::HTTPRequestHandler* createRequestHandler(const Poco::Net::HTTPServerRequest& request);
 		/// Creates a new request handler for the given HTTP request.
 
+	[[nodiscard]]
 	bool mustHandle(const std::string& uri);
 		/// Returns 1 if the given uri must be handled by the
 		/// poco_mapper module, 0 otherwise.

ApacheConnector/include/ApacheServerRequest.h

@@ -35,29 +35,36 @@ class ApacheServerRequest: public Poco::Net::HTTPServerRequest
 	~ApacheServerRequest();
 		/// Destroys the ApacheServerRequest.
 
+	[[nodiscard]]
 	std::istream& stream();
 		/// Returns the input stream for reading
 		/// the request body.
 		///
 		/// The stream is valid until the HTTPServerRequest
 		/// object is destroyed.
 
+	[[nodiscard]]
 	bool expectContinue() const;
 		/// Returns true if the client expects a
 		/// 100 Continue response.
 
+	[[nodiscard]]
 	const Poco::Net::SocketAddress& clientAddress() const;
 		/// Returns the client's address.
 
+	[[nodiscard]]
 	const Poco::Net::SocketAddress& serverAddress() const;
 		/// Returns the server's address.
 
+	[[nodiscard]]
 	const Poco::Net::HTTPServerParams& serverParams() const;
 		/// Returns a reference to the server parameters.
 
+	[[nodiscard]]
 	Poco::Net::HTTPServerResponse& response() const;
 		/// Returns a reference to the associated response
 
+	[[nodiscard]]
 	bool secure() const;
 		/// Returns true if the request is using a secure
 		/// connection. Returns false if no secure connection

ApacheConnector/include/ApacheServerResponse.h

@@ -98,6 +98,7 @@ class ApacheServerResponse: public Poco::Net::HTTPServerResponse
 		/// and sets the "WWW-Authenticate" header field
 		/// according to the given realm.
 
+	[[nodiscard]]
 	bool sent() const;
 		/// Returns true if the response (header) has been sent.
 

ApacheConnector/include/ApacheStream.h

@@ -59,6 +59,7 @@ class ApacheIOS: public virtual std::ios
 		///
 		/// Flushes the buffer, but does not close the socket.
 
+	[[nodiscard]]
 	ApacheStreamBuf* rdbuf();
 		/// Returns a pointer to the internal ApacheStreamBuf.
 

CppParser/include/Poco/CppParser/Attributes.h

@@ -46,36 +46,43 @@ class CppParser_API Attributes
 	Attributes& operator = (const Attributes& attrs);
 		/// Assignment operator.
 
+	[[nodiscard]]
 	bool has(const std::string& name) const;
 		/// Returns true if an attribute with the given name exists.
 
+	[[nodiscard]]
 	std::string getString(const std::string& name) const;
 		/// Returns the attribute's value as a string.
 		///
 		/// Throws a Poco::NotFoundException if the attribute does not exist.
 
+	[[nodiscard]]
 	std::string getString(const std::string& name, const std::string& defaultValue) const;
 		/// Returns the attribute's value as a string, if it exists.
 		/// Returns the defaultValue if the attribute does not exist.
 
+	[[nodiscard]]
 	int getInt(const std::string& name) const;
 		/// Returns the attribute's value as an integer.
 		///
 		/// Throws a Poco::NotFoundException if the attribute does not exist.
 		/// Throws a Poco::SyntaxException if the stored value is not an integer.
 
+	[[nodiscard]]
 	int getInt(const std::string& name, int defaultValue) const;
 		/// Returns the attribute's value as an integer, if it exists.
 		/// Returns the defaultValue if the attribute does not exist.
 		///
 		/// Throws a Poco::SyntaxException if the stored value is not an integer.
 
+	[[nodiscard]]
 	bool getBool(const std::string& name) const;
 		/// Returns the attribute's value as a boolean.
 		/// The returned value is 'true', iff the stored value is not "false".
 		///
 		/// Throws a Poco::NotFoundException if the attribute does not exist.
 
+	[[nodiscard]]
 	bool getBool(const std::string& name, bool defaultValue) const;
 		/// Returns the attribute's value as a boolean, if it exists.
 		/// The returned value is 'true', iff the stored value is not "false".
@@ -87,10 +94,15 @@ class CppParser_API Attributes
 		/// Removes the attribute with the given name.
 		/// Does nothing if the attribute does not exist.
 
+	[[nodiscard]]
 	const std::string& operator [] (const std::string& name) const;
+
+	[[nodiscard]]
 	std::string& operator [] (const std::string& name);
 
+	[[nodiscard]]
 	Iterator begin() const;
+	[[nodiscard]]
 	Iterator end() const;
 
 	void clear();

CppParser/include/Poco/CppParser/AttributesParser.h

@@ -62,9 +62,14 @@ class CppParser_API AttributesParser
 	const Poco::Token* parseComplexAttribute(const Token* pNext, const std::string& id);
 	const Poco::Token* parseIdentifier(const Poco::Token* pNext, std::string& id);
 	const Poco::Token* next();
+
+	[[nodiscard]]
 	static bool isIdentifier(const Poco::Token* pToken);
+	[[nodiscard]]
 	static bool isOperator(const Poco::Token* pToken, int kind);
+	[[nodiscard]]
 	static bool isLiteral(const Poco::Token* pToken);
+	[[nodiscard]]
 	static bool isEOF(const Poco::Token* pToken);
 
 private:

CppParser/include/Poco/CppParser/BuiltIn.h

@@ -35,7 +35,9 @@ class CppParser_API BuiltIn: public Symbol
 	~BuiltIn();
 		/// Destroys the BuiltIn.
 
+	[[nodiscard]]
 	Symbol::Kind kind() const;
+	[[nodiscard]]
 	std::string toString() const;
 };