src/gromacs/utility/futil.h

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  37 /*! \file
  38  * \brief
  39  * Low-level wrappers for OS-specific file handling with some \Gromacs
  40  * customizations.
  41  *
  42  * \inpublicapi
  43  * \ingroup module_utility
  44  */
  45 #ifndef GMX_UTILITY_FUTIL_H
  46 #define GMX_UTILITY_FUTIL_H
  47
  48 #include <climits>
  49 #include <cstdio>
  50
  51 #include <string>
  52
  53 #include "gromacs/utility/basedefinitions.h"
  54 #include "gromacs/utility/fileptr.h"
  55
  56 /*! \def GMX_PATH_MAX
  57  * \brief
  58  * Maximum path length, if the OS provides one, otherwise a fixed constant.
  59  */
  60 #ifdef PATH_MAX
  61 #    define GMX_PATH_MAX PATH_MAX
  62 #elif defined MAX_PATH
  63 #    define GMX_PATH_MAX MAX_PATH
  64 #else
  65 #    define GMX_PATH_MAX 4096
  66 #endif
  67
  68 /** \Gromacs definition to use instead of `off_t`. */
  69 typedef int64_t gmx_off_t;
  70
  71 /*! \brief
  72  * Turn off buffering for output files (which is default) for debugging
  73  * purposes.
  74  *
  75  * This only has effect on files opened with gmx_ffopen().
  76  */
  77 void gmx_disable_file_buffering();
  78
  79 /*! \brief
  80  * Enables backups with the specified number of maximum backups.
  81  *
  82  * If \p count == 0, disables backups.  If not called, this is the default.
  83  * If \p count == -1, reads the count from an environment variable.
  84  *
  85  * This is not currently thread-safe, as it is only called during
  86  * initialization code.
  87  */
  88 void gmx_set_max_backup_count(int count);
  89
  90 /*! \brief
  91  * Check whether a path exists.
  92  *
  93  * \returns `TRUE` when \p fname exists.
  94  *
  95  * Note that this returns `TRUE` even if \p fname is a directory instead of a
  96  * file.
  97  */
  98 gmx_bool gmx_fexist(const std::string& fname);
  99
 100 /*! \brief
 101  * Makes a backup of file if the file exists.
 102  */
 103 void make_backup(const std::string& file);
 104
 105 /*! \brief
 106  * Opens a file, with \Gromacs-specific additions.
 107  *
 108  * If the file is in compressed format, opens a pipe which uncompresses the
 109  * file on the fly.  For this to work, gmx_ffclose() and frewind() should
 110  * always be used for files opened with gmx_ffopen() instead of fclose() and
 111  * rewind().  For compressed files, the \p file parameter should be passed
 112  * without the compressed extension; if that file is not found, then a few
 113  * compression extensions are tried.
 114  * Creates a backup if a file opened for writing already exists before
 115  * overwriting it.
 116  * A fatal error results if the file cannot be opened, for whatever reason.
 117  */
 118 FILE* gmx_ffopen(const std::string& file, const char* mode);
 119
 120 /** Closes a file opened with gmx_ffopen(). */
 121 int gmx_ffclose(FILE* fp);
 122
 123 /*! \brief
 124  * Wraps rewind() for files opened with gmx_ffopen().
 125  *
 126  * A fatal error results if this function is called for a pipe (a compressed
 127  * input file).
 128  */
 129 void frewind(FILE* fp);
 130
 131 /** OS-independent 64-bit fseek().
 132  *
 133  * \return 0 when successful, or -1 (and set errno) in case of error.
 134  */
 135 int gmx_fseek(FILE* stream, gmx_off_t offset, int whence);
 136
 137 /** OS-independent 64-bit ftell().
 138  *
 139  * \return The current offset when successful, or -1 (and set errno) in case of error.
 140  */
 141 gmx_off_t gmx_ftell(FILE* stream);
 142
 143 /** OS-independent truncate(). */
 144 int gmx_truncate(const std::string& filename, gmx_off_t length);
 145
 146 namespace gmx
 147 {
 148
 149 /*! \brief
 150  * Finds full path for a library file.
 151  *
 152  * Searches in the configured library directories for \c filename. If
 153  * \c bAddCWD is true, searches first in the current directory. Fatal
 154  * error results if the file is not found in any location and \c
 155  * bFatal is true.
 156  */
 157 std::string findLibraryFile(const std::string& filename, bool bAddCWD = true, bool bFatal = true);
 158 //! \copydoc findLibraryFile(const std::string &, bool, bool)
 159 std::string findLibraryFile(const char* filename, bool bAddCWD = true, bool bFatal = true);
 160
 161 /*! \brief
 162  * Opens a library file for reading in an RAII-style `FILE` handle.
 163  *
 164  * Works as findLibraryFile(), except that it opens the file and
 165  * returns a file handle.
 166  */
 167 FilePtr openLibraryFile(const std::string& filename, bool bAddCWD = true, bool bFatal = true);
 168 //! \copydoc openLibraryFile(const std::string &, bool, bool)
 169 FilePtr openLibraryFile(const char* filename, bool bAddCWD = true, bool bFatal = true);
 170
 171 } // namespace gmx
 172
 173 /*! \brief
 174  * Creates unique name for temp file (wrapper around mkstemp) and opens it.
 175  *
 176  * \p buf should be at least 7 bytes long
 177  */
 178 FILE* gmx_fopen_temporary(char* buf);
 179
 180 /*! \brief
 181  * Creates unique name for temp file (wrapper around mkstemp).
 182  *
 183  * \p buf should be at least 7 bytes long
 184  */
 185 void gmx_tmpnam(char* buf);
 186
 187 /*! \brief
 188  * OS-independent rename().
 189  *
 190  * Renames/moves a file atomically, if the OS makes that available.
 191  */
 192 int gmx_file_rename(const char* oldname, const char* newname);
 193
 194 /*! \brief
 195  * Copies a file (data only) oldname to newname.
 196  *
 197  * If \p copy_if_empty is `FALSE`, the file won't be copied if it's empty.
 198  */
 199 int gmx_file_copy(const char* oldname, const char* newname, gmx_bool copy_if_empty);
 200
 201 /*! \brief
 202  * OS-independent fsync().
 203  *
 204  * Only use this during checkpointing!
 205  */
 206 int gmx_fsync(FILE* fp);
 207
 208 /*! \brief
 209  * OS-independent chdir().
 210  *
 211  * Exits with a fatal error if changing the directory fails.
 212  */
 213 void gmx_chdir(const char* directory);
 214 /*! \brief
 215  * OS-independent getcwd().
 216  *
 217  * Exits with a fatal error if the call fails.
 218  */
 219 void gmx_getcwd(char* buffer, size_t size);
 220
 221 namespace gmx
 222 {
 223
 224 class DataFileFinder;
 225
 226 /*! \brief
 227  * Gets a finder for locating data files from share/top/.
 228  *
 229  * \returns Finder set with setLibraryFileFinder(), or a default finder.
 230  *
 231  * If setLibraryFileFinder() has not been called (or a `NULL` finder has been
 232  * set), a default finder is returned.
 233  * The default finder searches data files from the directory identified by the
 234  * global program context; it does not respect GMXLIB environment variable.
 235  * Calling initForCommandLine() sets a finder that respects GMXLIB.
 236  *
 237  * Does not throw.
 238  *
 239  * See setLibraryFileFinder() for thread safety.
 240  *
 241  * \ingroup module_utility
 242  */
 243 const DataFileFinder& getLibraryFileFinder();
 244 /*! \brief
 245  * Sets a finder for location data files from share/top/.
 246  *
 247  * \param[in] finder  finder to set
 248  *     (can be NULL to restore the default finder).
 249  *
 250  * The library does not take ownership of \p finder.
 251  * The provided object must remain valid until the global instance is changed
 252  * by another call to setLibraryFileFinder().
 253  *
 254  * The global instance is used by findLibraryFile() and openLibraryFile().
 255  *
 256  * This method is not thread-safe.  See setProgramContext(); the same
 257  * constraints apply here as well.
 258  *
 259  * Does not throw.
 260  */
 261 void setLibraryFileFinder(const DataFileFinder* finder);
 262
 263 } // namespace gmx
 264
 265 #endif