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)
  62         : path(path), bSourceLayout(bSource)
  63     {
  64     }
  65
  66     /*! \brief
  67      * Path to the installation prefix of the current \Gromacs instance.
  68      *
  69      * If this is `NULL` or empty, data files cannot be looked up from the
  70      * install tree and \Gromacs functions that access such files may fail.
  71      * This can also contain a path to the source tree (see \a bSourceLayout).
  72      */
  73     const char *const path;
  74     /*! \brief
  75      * Whether \a path points to a source tree -like layout.
  76      *
  77      * For testing, it is useful to read data files from the source tree.
  78      * For such cases, the program context can return the source tree root path
  79      * in \a path, and set this to `true` to indicate that the data files
  80      * should be searched using the layout of the source tree instead of the
  81      * installation.
  82      */
  83     const bool        bSourceLayout;
  84 };
  85
  86
  87 /*! \brief
  88  * Provides context information about the program that is calling the library.
  89  *
  90  * This class provides access to information about the program that is
  91  * currently running.  This information is used to provide better information
  92  * to the user, and to locate the \Gromacs data files.
  93  *
  94  * setProgramContext() should be called before any other \Gromacs calls in
  95  * a program (except for gmx::init()).  This avoids thread safety issues, and
  96  * allows nicely formatted error messages.
  97  *
  98  * For thread safety, the implementations of the interface should ensure that
  99  * the returned strings remain valid until the end of the program (see
 100  * getProgramContext() for discussion on deinitialization).  Callers of the
 101  * interface within \Gromacs are prepared for exceptions, but generally
 102  * terminate the program on any exception.  Implementations should avoid
 103  * exception except for truly fatal conditions.
 104  *
 105  * The destructor is protected to signify that the context is never destroyed
 106  * through the interface.
 107  *
 108  * \see getProgramContext()
 109  * \see setProgramContext()
 110  * \inpublicapi
 111  */
 112 class IProgramContext
 113 {
 114     public:
 115         /*! \brief
 116          * Returns the name of the binary as it was invoked without any path.
 117          *
 118          * This is typically `argv[0]` with any leading directory stripped.
 119          * Currently, this should be a valid file name.
 120          */
 121         virtual const char *programName() const = 0;
 122         /*! \brief
 123          * Returns a display name for the program.
 124          *
 125          * For simple programs, this can equal programName().  For the \Gromacs
 126          * `gmx` wrapper binary, this includes the name of the module (e.g.,
 127          * `gmx angle`).  This is used only for informational purposes, and
 128          * there are no constraints on contents, except that it should not be
 129          * `NULL`.
 130          */
 131         virtual const char *displayName() const = 0;
 132         /*! \brief
 133          * Returns the full path of the running binary.
 134          *
 135          * This is mainly used for informational purposes.  There are no
 136          * constraints on contents, except that it should not be `NULL`.
 137          * Currently, this is also used for sanity checks in checkpointing.
 138          *
 139          * The implementation can provide an empty string if the path to the
 140          * binary is not available.  In such a case, the information is not
 141          * shown.
 142          */
 143         virtual const char *fullBinaryPath() const = 0;
 144         /*! \brief
 145          * Returns the installation prefix for \Gromacs.
 146          *
 147          * This path is used to locate the data files that are in `share/top/`
 148          * in the source directory.
 149          * The implementation can provide an empty string if the path is not
 150          * available; in such a case, functions that require data files may
 151          * fail.
 152          *
 153          * The returned structure also contains a flag to indicate whether the
 154          * prefix actually points to the source tree.  This is used for tests
 155          * and to support running binaries directly from the build tree.
 156          */
 157         virtual InstallationPrefixInfo installationPrefix() const = 0;
 158         /*! \brief
 159          * Returns the full command line used to invoke the binary.
 160          *
 161          * The implementation can provide an empty string if no command line is
 162          * available.
 163          */
 164         virtual const char *commandLine() const = 0;
 165
 166     protected:
 167         virtual ~IProgramContext() {}
 168 };
 169
 170 /*! \brief
 171  * Returns the global IProgramContext instance.
 172  *
 173  * \returns The context set with setProgramContext().
 174  *
 175  * If nothing has been set with setProgramContext(), returns a default
 176  * implementation that returns `"GROMACS"` for the program and display names,
 177  * and empty strings for other values.
 178  * The default implementation never throws.
 179  *
 180  * Does not throw.
 181  *
 182  * See setProgramContext() for thread safety notes.  You should not call this
 183  * method in global deinitialization methods (e.g., destructors of global
 184  * variables), since it is very difficult to clean up the state correctly in
 185  * the presence of such calls.  For example, initForCommandLine() assumes that
 186  * such calls do not exist to be able to free the context before exiting.
 187  *
 188  * \see IProgramContext
 189  */
 190 const IProgramContext &getProgramContext();
 191 /*! \brief
 192  * Sets the global IProgramContext instance.
 193  *
 194  * \param[in] context  Program context to set
 195  *     (can be NULL to restore the default context).
 196  *
 197  * The library does not take ownership of \p context.
 198  * The provided object must remain valid until the global instance is changed
 199  * by another call to setProgramContext().
 200  *
 201  * This method is not thread-safe.  It must be the first call to the library
 202  * after gmx::init(), and multi-threaded access is only supported after the
 203  * call completes.  If \Gromacs is getting called from multiple threads, or
 204  * uses multiple threads simultaneously, changing the program context is not
 205  * supported once it is set.
 206  * If the context is cleared at the end of the program, the caller must ensure
 207  * that all other threads have been terminated at this point.
 208  * These constraints simplify the implementation significantly.
 209  *
 210  * Does not throw.
 211  *
 212  * \see IProgramContext
 213  */
 214 void setProgramContext(const IProgramContext *context);
 215
 216 //! \}
 217
 218 } // namespace gmx
 219
 220 #endif