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//
// 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 <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()
{
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
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