// // NestedDiagnosticContext.h // // Library: Foundation // Package: Core // Module: NestedDiagnosticContext // // Definition of the NestedDiagnosticContext class. // // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH. // and Contributors. // // SPDX-License-Identifier: BSL-1.0 // #ifndef Foundation_NestedDiagnosticContext_INCLUDED #define Foundation_NestedDiagnosticContext_INCLUDED #include "Poco/Foundation.h" #include #include namespace Poco { class NDCScope; class Foundation_API NestedDiagnosticContext /// This class implements a Nested Diagnostic Context (NDC), /// as described in Neil Harrison's article "Patterns for Logging /// Diagnostic Messages" in "Pattern Languages of Program Design 3" /// (Addison-Wesley). /// /// A NDC maintains a stack of context information, consisting of /// an informational string (e.g., a method name), as well as an /// optional source code line number and file name. /// NDCs are especially useful for tagging log messages with /// context information which is very helpful in a multithreaded /// server scenario. /// Every thread has its own private NDC, which is automatically /// created when needed and destroyed when the thread terminates. /// /// The NDCScope (or NDC::Scope) class can be used to automatically /// push information at the beginning of a scope, and to pop it /// at the end. /// The poco_ndc(info) macro augments the information with a /// source code line number and file name. { public: typedef NDCScope Scope; NestedDiagnosticContext(); /// Creates the NestedDiagnosticContext. NestedDiagnosticContext(const NestedDiagnosticContext& ctx); /// Copy constructor. ~NestedDiagnosticContext(); /// Destroys the NestedDiagnosticContext. NestedDiagnosticContext& operator = (const NestedDiagnosticContext& ctx); /// Assignment operator. void push(const std::string& info); /// Pushes a context (without line number and filename) onto the stack. void push(const std::string& info, LineNumber line, const char* filename); /// Pushes a context (including line number and filename) /// onto the stack. Filename must be a static string, such as the /// one produced by the __FILE__ preprocessor macro. void pop(); /// Pops the top-most context off the stack. int depth() const; /// Returns the depth (number of contexts) of the stack. std::string toString() const; /// Returns the stack as a string with entries /// delimited by colons. The string does not contain /// line numbers and filenames. void dump(std::ostream& ostr) const; /// Dumps the stack (including line number and filenames) /// to the given stream. The entries are delimited by /// a newline. void dump(std::ostream& ostr, const std::string& delimiter) const; /// Dumps the stack (including line number and filenames) /// to the given stream. void clear(); /// Clears the NDC stack. static NestedDiagnosticContext& current(); /// Returns the current thread's NDC. private: struct Context { std::string info; const char* file; LineNumber line; }; typedef std::vector Stack; Stack _stack; }; typedef NestedDiagnosticContext NDC; class Foundation_API NDCScope /// This class can be used to automatically push a context onto /// the NDC stack at the beginning of a scope, and to pop /// the context at the end of the scope. { public: NDCScope(const std::string& info); /// Pushes a context on the stack. NDCScope(const std::string& info, LineNumber line, const char* filename); /// Pushes a context on the stack. ~NDCScope(); /// Pops the top-most context off the stack. }; // // inlines // inline NDCScope::NDCScope(const std::string& info) { NestedDiagnosticContext::current().push(info); } inline NDCScope::NDCScope(const std::string& info, LineNumber line, const char* filename) { NestedDiagnosticContext::current().push(info, line, filename); } inline NDCScope::~NDCScope() { try { NestedDiagnosticContext::current().pop(); } catch (...) { poco_unexpected(); } } // // helper macros // #define poco_ndc(func) \ Poco::NDCScope _theNdcScope(#func, __LINE__, __FILE__) #if defined(_DEBUG) #define poco_ndc_dbg(func) \ Poco::NDCScope _theNdcScope(#func, __LINE__, __FILE__) #else #define poco_ndc_dbg(func) #endif } // namespace Poco #endif // Foundation_NestedDiagnosticContext_INCLUDED