Introduce SimulatorBuilder

[gromacs.git] / src / gromacs / commandline / cmdlinemodulemanager.h

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/*! \libinternal \file
 * \brief
 * Declares gmx::CommandLineModuleManager.
 *
 * \author Teemu Murtola <teemu.murtola@gmail.com>
 * \inlibraryapi
 * \ingroup module_commandline
 */
#ifndef GMX_COMMANDLINE_CMDLINEMODULEMANAGER_H
#define GMX_COMMANDLINE_CMDLINEMODULEMANAGER_H

#include <memory>

#include "gromacs/onlinehelp/ihelptopic.h"
#include "gromacs/utility/classhelpers.h"

namespace gmx
{

class CommandLineModuleGroup;
class CommandLineModuleGroupData;
class CommandLineModuleSettings;
class CommandLineProgramContext;
class ICommandLineModule;
class IFileOutputRedirector;

//! \addtogroup module_commandline
//! \{

//! Smart pointer type for managing a ICommandLineModule.
typedef std::unique_ptr<ICommandLineModule>
    CommandLineModulePointer;

/*! \libinternal \brief
 * Implements a wrapper command-line interface for multiple modules.
 *
 * Typical usage:
 * \code
   int main(int argc, char *argv[])
   {
       gmx::CommandLineProgramContext &programContext = gmx::initForCommandLine(&argc, &argv);
       try
       {
           gmx::CommandLineModuleManager manager("gmx", &programContext);
           // <register all necessary modules>
           int rc = manager.run(argc, argv);
           gmx::finalizeForCommandLine();
           return rc;
       }
       catch (const std::exception &ex)
       {
           gmx::printFatalErrorMessage(stderr, ex);
           return gmx::processExceptionAtExitForCommandLine(ex);
       }
   }
 * \endcode
 *
 * \see page_wrapperbinary
 * \inlibraryapi
 */
class CommandLineModuleManager
{
    public:
        //! Function pointer type for a C main function.
        typedef int (*CMainFunction)(int argc, char *argv[]);
        //! Function pointer to a settings provider.
        typedef void (*InitSettingsFunction)(CommandLineModuleSettings *settings);

        /*! \brief
         * Implements a main() method that runs a single module.
         *
         * \param argc   \c argc passed to main().
         * \param argv   \c argv passed to main().
         * \param module Module to run.
         *
         * This method allows for uniform behavior for binaries that only
         * contain a single module without duplicating any of the
         * implementation from CommandLineModuleManager (startup headers,
         * common options etc.).
         *
         * The signature assumes that \p module construction does not throw
         * (because otherwise the caller would need to duplicate all the
         * exception handling code).  It is possible to move the construction
         * inside the try/catch in this method using an indirection similar to
         * TrajectoryAnalysisCommandLineRunner::runAsMain(), but until that is
         * necessary, the current approach leads to simpler code.
         *
         * Usage:
         * \code
           int main(int argc, char *argv[])
           {
               CustomCommandLineModule module;
               return gmx::CommandLineModuleManager::runAsMainSingleModule(argc, argv, &module);
           }
         * \endcode
         *
         * Does not throw.  All exceptions are caught and handled internally.
         */
        static int runAsMainSingleModule(int argc, char *argv[],
                                         ICommandLineModule *module);
        /*! \brief
         * Implements a main() method that runs a given function.
         *
         * \param argc         \c argc passed to main().
         * \param argv         \c argv passed to main().
         * \param mainFunction The main()-like method to wrap.
         *
         * This method creates a dummy command-line module that does its
         * processing by calling \p mainFunction; see addModuleCMain() for
         * details.  It then runs this module with runAsMainSingleModule().
         * This allows the resulting executable to handle common options and do
         * other common actions (e.g., startup headers) without duplicate code
         * in the main methods.
         *
         * Usage:
         * \code
           int my_main(int argc, char *argv[])
           {
               // <...>
           }

           int main(int argc, char *argv[])
           {
               return gmx::CommandLineModuleManager::runAsMainCMain(argc, argv, &my_main);
           }
         * \endcode
         *
         * Does not throw.  All exceptions are caught and handled internally.
         */
        static int runAsMainCMain(int argc, char *argv[],
                                  CMainFunction mainFunction);
        /*! \brief
         * Implements a main() method that runs a given function with custom
         * settings.
         *
         * This method does the same as runAsMainCMain(), but additionally
         * calls \p settingsFunction to initialize CommandLineModuleSettings.
         * This allows specifying, e.g., a different default nice level.
         */
        static int runAsMainCMainWithSettings(int argc, char *argv[],
                                              CMainFunction mainFunction,
                                              InitSettingsFunction settingsFunction);

        /*! \brief
         * Initializes a command-line module manager.
         *
         * \param[in] binaryName     Name of the running binary
         *     (without Gromacs binary suffix or .exe on Windows).
         * \param     programContext Program information for the running binary.
         * \throws    std::bad_alloc if out of memory.
         *
         * \p binaryName is used to detect when the binary is run through a
         * symlink, and automatically invoke a matching module in such a case.
         *
         * \p programInfo is non-const to allow the manager to amend it based
         * on the actual module that is getting executed.
         */
        CommandLineModuleManager(const char                *binaryName,
                                 CommandLineProgramContext *programContext);
        ~CommandLineModuleManager();

        /*! \brief
         * Sets the module manager to quiet mode: don't print anything.
         *
         * \param[in] bQuiet  Whether the module manager should remain silent.
         *
         * Normally, the module manager prints out some information to `stderr`
         * before it starts the module and after it finishes.  This removes
         * that output, which is useful in particular for unit tests so that
         * they don't spam `stderr`.
         */
        void setQuiet(bool bQuiet);
        /*! \brief
         * Redirects the output of the module manager to a file.
         *
         * \param[in] output  File redirector to use for output.
         *
         * Normally, the module manager prints explicitly requested text such
         * as help output to `stdout`, but this method can be used to redirect
         * that output to a file.  For exporting help from the module manager,
         * several files are written, and can be redirected with this method as
         * well.
         *
         * This is used for unit tests, either to keep them quiet or to verify
         * that output.  To keep implementation options open, behavior with
         * `output == NULL` is undefined and should not be relied on.
         * For tests, there should only be need to call this a single time,
         * right after creating the manager.
         */
        void setOutputRedirector(IFileOutputRedirector *output);

        /*! \brief
         * Makes the manager always run a single module.
         *
         * \param     module  Module to run.
         *
         * This method disables all mechanisms for selecting a module, and
         * directly passes all command-line arguments to \p module.
         * Help arguments are an exception: these are still recognized by the
         * manager and translated into a call to
         * ICommandLineModule::writeHelp().
         *
         * This is public mainly for unit testing purposes; for other code,
         * runAsMainSingleModule() typically provides the desired
         * functionality.
         *
         * Does not throw.
         */
        void setSingleModule(ICommandLineModule *module);
        /*! \brief
         * Adds a given module to this manager.
         *
         * \param   module  Module to add.
         * \throws  std::bad_alloc if out of memory.
         *
         * The manager takes ownership of the object.
         *
         * This method is public mostly for testing purposes; for typical uses,
         * registerModule() is a more convenient way of adding modules.
         *
         * \see registerModule()
         */
        void addModule(CommandLineModulePointer module);
        /*! \brief
         * Adds a module that runs a given main()-like function.
         *
         * \param[in] name             Name for the module.
         * \param[in] shortDescription One-line description for the module.
         * \param[in] mainFunction     Main function to wrap.
         * \throws    std::bad_alloc if out of memory.
         *
         * There is normally no need to call this method outside the Gromacs
         * library.  User code usually wants to use runAsMainCMain().
         *
         * \p name and \p shortDescription should be string constants, or the
         * caller should otherwise ensure that they stay in scope for the
         * duration the CommandLineModuleManager object exists.
         * \p mainFunction should call parse_common_args() to process its
         * command-line arguments.
         */
        void addModuleCMain(const char *name, const char *shortDescription,
                            CMainFunction mainFunction);
        /*! \brief
         * Adds a module that runs a given main()-like function with custom
         * settings.
         *
         * This method does the same as runAsMainCMain(), but additionally
         * calls \p settingsFunction to initialize CommandLineModuleSettings.
         * This allows specifying, e.g., a different default nice level.
         */
        void addModuleCMainWithSettings(const char *name, const char *shortDescription,
                                        CMainFunction mainFunction,
                                        InitSettingsFunction settingsFunction);
        /*! \brief
         * Registers a module of a certain type to this manager.
         *
         * \tparam  Module  Type of module to register.
         * \throws  std::bad_alloc if out of memory.
         *
         * \p Module must be default-constructible and implement
         * ICommandLineModule.
         *
         * This method is provided as a convenient alternative to addModule()
         * for cases where each module is implemented by a different type
         * (which should be the case for typical situations outside unit
         * tests).
         */
        template <class Module>
        void registerModule()
        {
            addModule(CommandLineModulePointer(new Module));
        }

        /*! \brief
         * Adds a group for modules to use in help output.
         *
         * \param[in] title  Short title for the group.
         * \returns   Handle that can be used to add modules to the group.
         * \throws    std::bad_alloc if out of memory.
         *
         * Creates a group that is used to structure the list of all modules in
         * help output.  Modules are added to the group using the returned
         * object.
         */
        CommandLineModuleGroup addModuleGroup(const char *title);

        /*! \brief
         * Makes given help topic available through the manager's help module.
         *
         * \param[in]  topic  Help topic to add.
         * \throws     std::bad_alloc if out of memory.
         *
         * The manager takes ownership of the help topic.
         */
        void addHelpTopic(HelpTopicPointer topic);

        /*! \brief
         * Runs a module based on given command line.
         *
         * \param[in] argc  Number of elements in \p argv.
         * \param[in] argv  Command-line arguments.
         * \throws   unspecified  Throws any exception that the selected module
         *      throws.
         * \returns  Exit code for the program.
         * \retval   0 on successful termination.
         * \retval   2 if no module is specified, or if the module is not found.
         *
         * Runs the module whose name matches \p argv[1].
         */
        int run(int argc, char *argv[]);

    private:
        class Impl;

        PrivateImplPointer<Impl> impl_;
};

/*! \libinternal \brief
 * Handle to add content to a group added with
 * CommandLineModuleManager::addModuleGroup().
 *
 * This class only provides a public interface to construct a module group for
 * CommandLineModuleManager, and has semantics similar to a pointer: copies all
 * point to the same group.  The actual state of the group is maintained in an
 * internal implementation class.
 *
 * \inlibraryapi
 */
class CommandLineModuleGroup
{
    public:
        /*! \cond internal */
        //! Shorthand for the implementation type that holds all the data.
        typedef CommandLineModuleGroupData Impl;

        //! Creates a new group (only called by CommandLineModuleManager).
        explicit CommandLineModuleGroup(Impl *impl) : impl_(impl) {}
        //! \endcond

        /*! \brief
         * Adds a module to this group.
         *
         * \param[in] name  Name of the module.
         * \throws    std::bad_alloc if out of memory.
         *
         * This works as addModuleWithDescription(), but uses the short
         * description of the module itself as the description.
         *
         * \see addModuleWithDescription()
         */
        void addModule(const char *name);
        /*! \brief
         * Adds a module to this group with a custom description.
         *
         * \param[in] name        Name of the module.
         * \param[in] description Description of the module in this group.
         * \throws    std::bad_alloc if out of memory.
         *
         * \p name must name a module added into the CommandLineModuleManager.
         * It is possible to add the same module into multiple groups.
         */
        void addModuleWithDescription(const char *name, const char *description);

    private:
        //! Pointer to the data owned by CommandLineModuleManager.
        Impl                     *impl_;
};

//! \}

} // namespace gmx

#endif