src/gromacs/utility/programcontext.h

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  35 /*! \file
  36  * \brief
  37  * Declares gmx::IProgramContext and related methods.
  38  *
  39  * \author Teemu Murtola <teemu.murtola@gmail.com>
  40  * \inpublicapi
  41  * \ingroup module_utility
  42  */
  43 #ifndef GMX_UTILITY_PROGRAMCONTEXT_H
  44 #define GMX_UTILITY_PROGRAMCONTEXT_H
  45
  46 namespace gmx
  47 {
  48
  49 //! \addtogroup module_utility
  50 //! \{
  51
  52 /*! \brief
  53  * Provides information about installation prefix (see
  54  * IProgramContext::installationPrefix()).
  55  *
  56  * \inpublicapi
  57  */
  58 struct InstallationPrefixInfo
  59 {
  60     //! Initializes the structure with given values.
  61     InstallationPrefixInfo(const char* path, bool bSource) : path(path), bSourceLayout(bSource) {}
  62
  63     /*! \brief
  64      * Path to the installation prefix of the current \Gromacs instance.
  65      *
  66      * If this is `NULL` or empty, data files cannot be looked up from the
  67      * install tree and \Gromacs functions that access such files may fail.
  68      * This can also contain a path to the source tree (see \a bSourceLayout).
  69      */
  70     const char* const path;
  71     /*! \brief
  72      * Whether \a path points to a source tree -like layout.
  73      *
  74      * For testing, it is useful to read data files from the source tree.
  75      * For such cases, the program context can return the source tree root path
  76      * in \a path, and set this to `true` to indicate that the data files
  77      * should be searched using the layout of the source tree instead of the
  78      * installation.
  79      */
  80     const bool bSourceLayout;
  81 };
  82
  83
  84 /*! \brief
  85  * Provides context information about the program that is calling the library.
  86  *
  87  * This class provides access to information about the program that is
  88  * currently running.  This information is used to provide better information
  89  * to the user, and to locate the \Gromacs data files.
  90  *
  91  * setProgramContext() should be called before any other \Gromacs calls in
  92  * a program (except for gmx::init()).  This avoids thread safety issues, and
  93  * allows nicely formatted error messages.
  94  *
  95  * For thread safety, the implementations of the interface should ensure that
  96  * the returned strings remain valid until the end of the program (see
  97  * getProgramContext() for discussion on deinitialization).  Callers of the
  98  * interface within \Gromacs are prepared for exceptions, but generally
  99  * terminate the program on any exception.  Implementations should avoid
 100  * exception except for truly fatal conditions.
 101  *
 102  * The destructor is protected to signify that the context is never destroyed
 103  * through the interface.
 104  *
 105  * \see getProgramContext()
 106  * \see setProgramContext()
 107  * \inpublicapi
 108  */
 109 class IProgramContext
 110 {
 111 public:
 112     /*! \brief
 113      * Returns the name of the binary as it was invoked without any path.
 114      *
 115      * This is typically `argv[0]` with any leading directory stripped.
 116      * Currently, this should be a valid file name.
 117      */
 118     virtual const char* programName() const = 0;
 119     /*! \brief
 120      * Returns a display name for the program.
 121      *
 122      * For simple programs, this can equal programName().  For the \Gromacs
 123      * `gmx` wrapper binary, this includes the name of the module (e.g.,
 124      * `gmx angle`).  This is used only for informational purposes, and
 125      * there are no constraints on contents, except that it should not be
 126      * `NULL`.
 127      */
 128     virtual const char* displayName() const = 0;
 129     /*! \brief
 130      * Returns the full path of the running binary.
 131      *
 132      * This is mainly used for informational purposes.  There are no
 133      * constraints on contents, except that it should not be `NULL`.
 134      * Currently, this is also used for sanity checks in checkpointing.
 135      *
 136      * The implementation can provide an empty string if the path to the
 137      * binary is not available.  In such a case, the information is not
 138      * shown.
 139      */
 140     virtual const char* fullBinaryPath() const = 0;
 141     /*! \brief
 142      * Returns the installation prefix for \Gromacs.
 143      *
 144      * This path is used to locate the data files that are in `share/top/`
 145      * in the source directory.
 146      * The implementation can provide an empty string if the path is not
 147      * available; in such a case, functions that require data files may
 148      * fail.
 149      *
 150      * The returned structure also contains a flag to indicate whether the
 151      * prefix actually points to the source tree.  This is used for tests
 152      * and to support running binaries directly from the build tree.
 153      */
 154     virtual InstallationPrefixInfo installationPrefix() const = 0;
 155     /*! \brief
 156      * Returns the full command line used to invoke the binary.
 157      *
 158      * The implementation can provide an empty string if no command line is
 159      * available.
 160      */
 161     virtual const char* commandLine() const = 0;
 162
 163 protected:
 164     virtual ~IProgramContext() {}
 165 };
 166
 167 /*! \brief
 168  * Returns the global IProgramContext instance.
 169  *
 170  * \returns The context set with setProgramContext().
 171  *
 172  * If nothing has been set with setProgramContext(), returns a default
 173  * implementation that returns `"GROMACS"` for the program and display names,
 174  * and empty strings for other values.
 175  * The default implementation never throws.
 176  *
 177  * Does not throw.
 178  *
 179  * See setProgramContext() for thread safety notes.  You should not call this
 180  * method in global deinitialization methods (e.g., destructors of global
 181  * variables), since it is very difficult to clean up the state correctly in
 182  * the presence of such calls.  For example, initForCommandLine() assumes that
 183  * such calls do not exist to be able to free the context before exiting.
 184  *
 185  * \see IProgramContext
 186  */
 187 const IProgramContext& getProgramContext();
 188 /*! \brief
 189  * Sets the global IProgramContext instance.
 190  *
 191  * \param[in] context  Program context to set
 192  *     (can be NULL to restore the default context).
 193  *
 194  * The library does not take ownership of \p context.
 195  * The provided object must remain valid until the global instance is changed
 196  * by another call to setProgramContext().
 197  *
 198  * This method is not thread-safe.  It must be the first call to the library
 199  * after gmx::init(), and multi-threaded access is only supported after the
 200  * call completes.  If \Gromacs is getting called from multiple threads, or
 201  * uses multiple threads simultaneously, changing the program context is not
 202  * supported once it is set.
 203  * If the context is cleared at the end of the program, the caller must ensure
 204  * that all other threads have been terminated at this point.
 205  * These constraints simplify the implementation significantly.
 206  *
 207  * Does not throw.
 208  *
 209  * \see IProgramContext
 210  */
 211 void setProgramContext(const IProgramContext* context);
 212
 213 //! \}
 214
 215 } // namespace gmx
 216
 217 #endif