CodeDweller/faults.hpp

// faults.hpp
//
// Copyright (C) 2004-2020 MicroNeil Research Corporation.
//
// This software is released under the MIT license. See LICENSE.TXT.
//
// Faults and Checks are classes we can use in place of assert() to handle
// unreasonable or necessary conditions in our code. They are constructed with
// friendly descriptions (and optionally error codes) and then used just
// like assert() would be used-- except they are designed to remain in the
// production code. After all, assert() is a C (not C++) concept.
//
// A ...Check(test_expression) activates when the test_expression is not true.
// A ...Fault(text_expression) activates when the test_expression is true.
//
// An Abort...() sends it's description to cerr then aborts (no cleanup).
// An Exit...() sends it's description to cerr then exits with a result code.
// A Runtime...() throws a runtime_error (self) with it's description in what().
// A Logic...() throws a logic_error (self) with it's description in what().

#pragma once

#include <stdexcept>
#include <cstdlib>
#include <iostream>
#include <string>

namespace codedweller {

const int DefaultExitCode = EXIT_FAILURE;                                       // Use this when no code is provided.

class AbortCheck {                                                              // If this check is false we will abort.

  private:

    const std::string myDescription;                                            // This is what I have to say.

  public:

    AbortCheck(const std::string& Text) : myDescription(Text) {}                // I am constructed with a description

    void operator()(bool X) const {                                             // Apply me like assert(exp)
        if(false == X) {                                                        // If the expression is false then we
            std::cerr << myDescription << std::endl;                            // failed the check so we display our
            abort();                                                            // description and abort.
        }
    }

    const std::string Description() { return myDescription; }                   // You can ask for my Description.
};

class AbortFault {                                                              // If this fault occurs we will abort.

  private:

    const std::string myDescription;                                            // This is what I have to say.

  public:

    AbortFault(const std::string& Text) :  myDescription(Text) {}               // I am constructed with a description

    void operator()(bool X) const {                                             // Apply me like assert(! exp)
        if(true == X) {                                                         // If the expression is true then we
            std::cerr << myDescription << std::endl;                                 // have a fault so we display our fault
            abort();                                                            // description and abort.
        }
    }

    const std::string Description() const { return myDescription; }             // You can ask for my Description.
};

class ExitCheck {                                                               // If this check is false we will exit.

  private:

    const std::string myDescription;                                            // This is what I have to say.
    const int myExitCode;                                                       // This is what I send to exit().

  public:

    ExitCheck(const std::string& Text, int Code=DefaultExitCode) :              // I am constructed with a description
      myDescription(Text), myExitCode(Code) {}                                  // and (optionlly) an exit code.

    void operator()(bool X) const {                                             // Apply me like assert(exp)
        if(false == X) {                                                        // If the expression is false then we
            std::cerr << myDescription << std::endl;                            // failed the check so we display our
            exit(myExitCode);                                                   // description and exit with our code.
        }
    }

    const std::string Description() { return myDescription; }                   // You can ask for my Description.
    const int ExitCode() { return myExitCode; }                                 // You can ask for my ExitCode.
};

class ExitFault {                                                               // If this fault occurs we will exit.

  private:

    const std::string myDescription;                                            // This is what I have to say.
    const int myExitCode;                                                       // This is what I send to exit().

  public:

    ExitFault(const std::string& Text, int Code=DefaultExitCode) :              // I am constructed with a description
      myDescription(Text), myExitCode(Code) {}                                  // and (optionlly) an exit code.

    void operator()(bool X) const {                                             // Apply me like assert(! exp)
        if(true == X) {                                                         // If the expression is true then we
            std::cerr << myDescription << std::endl;                            // have a fault so we display our fault
            exit(myExitCode);                                                   // description and exit with our code.
        }
    }

    const std::string Description() const { return myDescription; }             // You can ask for my Description.
    const int ExitCode() const { return myExitCode; }                           // You can ask for my ExitCode.
};

class RuntimeCheck : public std::runtime_error {                                // Throw if this check fails.

  public:

    RuntimeCheck(const std::string& Text) : std::runtime_error(Text) {}         // Construct me with a description.

    void operator()(bool X) const {                                             // Apply me like assert(exp)
        if(false == X) {                                                        // If the expression is false then we
            throw *this;                                                        // failed the check so we throw.
        }
    }
};

class RuntimeFault : public std::runtime_error {                                // Throw if we find this fault.

  public:

    RuntimeFault(const std::string& Text) : std::runtime_error(Text) {}         // Construct me with a description.

    void operator()(bool X) const {                                             // Apply me like assert(exp)
        if(true == X) {                                                         // If the expression is true then we
            throw *this;                                                        // found the fault so we throw.
        }
    }
};

class LogicCheck : public std::logic_error {                                    // Throw if this check fails.

  public:

    LogicCheck(const std::string& Text) : std::logic_error(Text) {}             // Construct me with a description.

    void operator()(bool X) const {                                             // Apply me like assert(exp)
        if(false == X) {                                                        // If the expression is false then we
            throw *this;                                                        // failed the check so we throw.
        }
    }
};

class LogicFault : public std::logic_error {                                    // Throw if we find this fault.

  public:

    LogicFault(const std::string& Text) : std::logic_error(Text) {}             // Construct me with a description.

    void operator()(bool X) const {                                             // Apply me like assert(exp)
        if(true == X) {                                                         // If the expression is true then we
            throw *this;                                                        // found the fault so we throw.
        }
    }
};

} // End namespace codedweller