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//

// NestedDiagnosticContext.h

//

// $Id: //poco/1.3/Foundation/include/Poco/NestedDiagnosticContext.h#1 $

//

// Library: Foundation

// Package: Core

// Module:  NestedDiagnosticContext

//

// Definition of the NestedDiagnosticContext class.

//

// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.

// and Contributors.

//

// Permission is hereby granted, free of charge, to any person or organization

// obtaining a copy of the software and accompanying documentation covered by

// this license (the "Software") to use, reproduce, display, distribute,

// execute, and transmit the Software, and to prepare derivative works of the

// Software, and to permit third-parties to whom the Software is furnished to

// do so, all subject to the following:

// 

// The copyright notices in the Software and this entire statement, including

// the above license grant, this restriction and the following disclaimer,

// must be included in all copies of the Software, in whole or in part, and

// all derivative works of the Software, unless such copies or derivative

// works are solely in the form of machine-executable object code generated by

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// 

// 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, TITLE AND NON-INFRINGEMENT. IN NO EVENT

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//

#ifndef Foundation_NestedDiagnosticContext_INCLUDED

#define Foundation_NestedDiagnosticContext_INCLUDED

#include "Poco/Foundation.h"

#include <vector>

#include <ostream>

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, int 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;

                int         line;

        };

        typedef std::vector<Context> 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, int 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, int line, const char* filename)

{

        NestedDiagnosticContext::current().push(info, line, filename);

}

inline NDCScope::~NDCScope()

{

        NestedDiagnosticContext::current().pop();

}

//

// 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