src/gromacs/utility/datafilefinder.h

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  35 /*! \file
  36  * \brief
  37  * Declares gmx::DataFileFinder and related classes.
  38  *
  39  * \author Teemu Murtola <teemu.murtola@gmail.com>
  40  * \inpublicapi
  41  * \ingroup module_utility
  42  */
  43 #ifndef GMX_UTILITY_LIBFILEFINDER_H
  44 #define GMX_UTILITY_LIBFILEFINDER_H
  45
  46 #include <cstdio>
  47
  48 #include <string>
  49 #include <vector>
  50
  51 #include "gromacs/utility/classhelpers.h"
  52
  53 namespace gmx
  54 {
  55
  56 class DataFileFinder;
  57
  58 /*! \brief
  59  * Search parameters for DataFileFinder.
  60  *
  61  * This class implements a named parameter idiom for DataFileFinder::findFile()
  62  * and DataFileFinder::openFile() to support an easily readable and
  63  * customizable way of searching data files.
  64  *
  65  * By default, the search first considers the current directory, followed by
  66  * specified and default data directories, and an exception is thrown if the
  67  * file could not be found.
  68  * To skip searching in the current directory, use includeCurrentDir().
  69  *
  70  * Methods in this class do not throw.
  71  *
  72  * \inpublicapi
  73  * \ingroup module_utility
  74  */
  75 class DataFileOptions
  76 {
  77     public:
  78         /*! \brief
  79          * Constructs default options for searching for a file with the
  80          * specified name.
  81          *
  82          * \param[in] filename  File name to search for.
  83          *
  84          * This constructor is not explicit to allow passing a simple string to
  85          * DataFileFinder methods to search for the string with the default
  86          * parameters.
  87          */
  88         DataFileOptions(const char *filename)
  89             : filename_(filename), bCurrentDir_(true), bThrow_(true)
  90         {
  91         }
  92         //! \copydoc DataFileOptions(const char *)
  93         DataFileOptions(const std::string &filename)
  94             : filename_(filename.c_str()), bCurrentDir_(true), bThrow_(true)
  95         {
  96         }
  97
  98         //! Sets whether to search in the current (working) directory.
  99         DataFileOptions &includeCurrentDir(bool bInclude)
 100         {
 101             bCurrentDir_ = bInclude;
 102             return *this;
 103         }
 104         //! Sets whether an exception is thrown if the file could not be found.
 105         DataFileOptions &throwIfNotFound(bool bThrow)
 106         {
 107             bThrow_ = bThrow;
 108             return *this;
 109         }
 110
 111     private:
 112         const char *filename_;
 113         bool        bCurrentDir_;
 114         bool        bThrow_;
 115
 116         /*! \brief
 117          * Needed to access the members without otherwise unnecessary accessors.
 118          */
 119         friend class DataFileFinder;
 120 };
 121
 122 /*! \brief
 123  * Information about a data file found by DataFileFinder::enumerateFiles().
 124  *
 125  * \inpublicapi
 126  * \ingroup module_utility
 127  */
 128 struct DataFileInfo
 129 {
 130     //! Initializes the structure with given values.
 131     DataFileInfo(const std::string &dir, const std::string &name, bool bDefault)
 132         : dir(dir), name(name), bFromDefaultDir(bDefault)
 133     {
 134     }
 135
 136     /*! \brief
 137      * Directory from which the file was found.
 138      *
 139      * If the file was found from the current directory, this will be `"."`.
 140      * In other cases, this will be a full path (except if the user-provided
 141      * search path contains relative paths).
 142      */
 143     std::string dir;
 144     /*! \brief
 145      * Name of the file without any directory name.
 146      */
 147     std::string name;
 148     /*! \brief
 149      * Whether the file was found from the default directory.
 150      *
 151      * If `true`, the file was found from the default installation data
 152      * directory, not from the current directory or any user-provided (through
 153      * DataFileFinder::setSearchPathFromEnv()) location.
 154      * \todo
 155      * Consider replacing with an enum that identifies the source (current dir,
 156      * GMXLIB, default).
 157      */
 158     bool        bFromDefaultDir;
 159 };
 160
 161 /*! \brief
 162  * Searches data files from a set of paths.
 163  *
 164  * \inpublicapi
 165  * \ingroup module_utility
 166  */
 167 class DataFileFinder
 168 {
 169     public:
 170         /*! \brief
 171          * Constructs a default data file finder.
 172          *
 173          * The constructed finder searches only in the directory specified by
 174          * the global program context (see IProgramContext), and
 175          * optionally in the current directory.
 176          *
 177          * Does not throw.
 178          */
 179         DataFileFinder();
 180         ~DataFileFinder();
 181
 182         /*! \brief
 183          * Adds search path from an environment variable.
 184          *
 185          * \param[in] envVarName  Name of the environment variable to use.
 186          * \throws std::bad_alloc if out of memory.
 187          *
 188          * If the specified environment variable is set, it is interpreted like
 189          * a `PATH` environment variable on the platform (split at appropriate
 190          * separators), and each path found is added to the search path this
 191          * finder searches.  The added paths take precedence over the default
 192          * directory specified by the global program context, but the current
 193          * directory is searched first.
 194          */
 195         void setSearchPathFromEnv(const char *envVarName);
 196
 197         /*! \brief
 198          * Opens a data file if found.
 199          *
 200          * \param[in] options  Identifies the file to be searched for.
 201          * \returns The opened file handle, or `NULL` if the file could not be
 202          *     found and exceptions were turned off.
 203          * \throws  std::bad_alloc if out of memory.
 204          * \throws  FileIOError if
 205          *   - no such file can be found, and \p options specifies that an
 206          *     exception should be thrown, or
 207          *   - there is an error opening the file (note that a file is skipped
 208          *     during the search if the user does not have rights to open the
 209          *     file at all).
 210          *
 211          * See findFile() for more details.
 212          */
 213         FILE *openFile(const DataFileOptions &options) const;
 214         /*! \brief
 215          * Finds a full path to a data file if found.
 216          *
 217          * \param[in] options  Identifies the file to be searched for.
 218          * \returns Full path to the data file, or an empty string if the file
 219          *     could not be found and exceptions were turned off.
 220          * \throws  std::bad_alloc if out of memory.
 221          * \throws  FileIOError if no such file can be found, and \p options
 222          *     specifies that an exception should be thrown.
 223          *
 224          * Searches for a data file in the search paths configured for the
 225          * finder, as well as in the current directory if so required.
 226          * Returns the full path to the first file found.
 227          */
 228         std::string findFile(const DataFileOptions &options) const;
 229         /*! \brief
 230          * Enumerates files in the data directories.
 231          *
 232          * \param[in] options  Idenfies files to be searched for.
 233          * \returns Information about each found file.
 234          * \throws  std::bad_alloc if out of memory.
 235          * \throws  FileIOError if no such file can be found, and \p options
 236          *     specifies that an exception should be thrown.
 237          *
 238          * Enumerates all files in the data directories that have the
 239          * extension/suffix specified by the file name in \p options.
 240          * Unlike findFile() and openFile(), this only works on files that are
 241          * in the actual data directories, not for any entry within
 242          * subdirectories of those.
 243          * See DataFileInfo for details on what is returned for each found
 244          * file.
 245          * Files from the same directory will be returned as a continuous block
 246          * in the returned vector.
 247          */
 248         std::vector<DataFileInfo> enumerateFiles(const DataFileOptions &options) const;
 249
 250     private:
 251         class Impl;
 252
 253         PrivateImplPointer<Impl> impl_;
 254 };
 255
 256 } // namespace gmx
 257
 258 #endif