/********************************************************************
 * filesystem.c
 *
 * This is the source file for the sys-filesystem package for Ruby.
 * This is for UNIX platforms only.
 ********************************************************************/
#include <ruby.h>

#include <sys/types.h>
#include <sys/statvfs.h>

#ifdef HAVE_SYS_MNTTAB_H

/* Solaris */
#include <sys/mnttab.h>
#define MNTENT	mnttab
#define START_MNT(F,M) fopen(F,M)
#define GET_MNT(FP,MP) (getmntent(FP,MP) == 0)
#define END_MNT(F) fclose(F)
#define MOUNTLIST	"/etc/mnttab"

#else

/* All other flavors of UNIX */
#include <mntent.h>
#define MNTENT	mntent
#define START_MNT(F,M) setmntent(F,M)
#define GET_MNT(FP,MP) ((MP = getmntent(FP)) != NULL)
#define END_MNT(F) endmntent(F)
#define MOUNTLIST	"/etc/mtab"

#endif

VALUE mSys, cFilesys, cStat;

/* call-seq:
 *    Filesystem.stat(path)
 *
 * Returns a a Filesystem::Stat object containing information about the +path+
 * file system.
 */
static VALUE fs_stat(VALUE klass, VALUE v_path){
   VALUE v_stat;
   struct statvfs fs;
   char* path = StringValuePtr(v_path);

   if(statvfs(path, &fs) < 0)
      rb_sys_fail("statvfs");

   v_stat = rb_funcall(cStat, rb_intern("new"), 0, 0);

   rb_iv_set(v_stat, "@path", v_path);
   rb_iv_set(v_stat, "@block_size", ULONG2NUM(fs.f_bsize));
   rb_iv_set(v_stat, "@fragment_size", ULONG2NUM(fs.f_frsize));
   rb_iv_set(v_stat, "@blocks", LONG2NUM(fs.f_blocks));
   rb_iv_set(v_stat, "@blocks_free", LONG2NUM(fs.f_bfree));
   rb_iv_set(v_stat, "@blocks_available", LONG2NUM(fs.f_bavail));
   rb_iv_set(v_stat, "@files", LONG2NUM(fs.f_files));
   rb_iv_set(v_stat, "@files_free", LONG2NUM(fs.f_ffree));
   rb_iv_set(v_stat, "@files_available", LONG2NUM(fs.f_favail));
   rb_iv_set(v_stat, "@filesystem_id", ULONG2NUM(fs.f_fsid));
   rb_iv_set(v_stat, "@flags", ULONG2NUM(fs.f_flag));
   rb_iv_set(v_stat, "@name_max", ULONG2NUM(fs.f_namemax));

#ifdef HAVE_ST_F_BASETYPE
   rb_iv_set(v_stat, "@base_type", rb_str_new2(fs.f_basetype));
#endif

   return rb_obj_freeze(v_stat);
}

/* Convenient methods for converting bytes to kilobytes, megabytes or
 * gigabytes.
 */

/*
 * call-seq:
 *    <tt>fix</tt>.to_kb
 *
 * Returns +fix+ in terms of kilobytes.
 */
static VALUE fixnum_to_kb(VALUE self){
   return ULL2NUM(NUM2ULONG(self) / 1024);
}

/*
 * call-seq:
 *    <tt>fix</tt>.to_mb
 *
 * Returns +fix+ in terms of megabytes.
 */
static VALUE fixnum_to_mb(VALUE self){
   return ULL2NUM(NUM2ULONG(self) / 1048576);
}

/*
 * call-seq:
 *    <tt>fix</tt>.to_gb
 *
 * Returns +fix+ in terms of gigabytes.
 */
static VALUE fixnum_to_gb(VALUE self){
   return ULL2NUM(NUM2ULONG(self) / 1073741824);
}

void Init_filesystem(){
   /* Classes and Modules */
   mSys     = rb_define_module("Sys");
   cFilesys = rb_define_class_under(mSys, "Filesystem", rb_cObject);
   cStat    = rb_define_class_under(cFilesys, "Stat", rb_cObject);

   /* Singleton methods */
   rb_define_singleton_method(cFilesys, "stat", fs_stat, 1);

   /* Stat accessors */

   /* The path of the file system */
   rb_define_attr(cStat, "path", 1, 0);

   /* The preferred system block size */
   rb_define_attr(cStat, "block_size", 1, 0);

   /* The fragment size, i.e. fundamental file system block size */
   rb_define_attr(cStat, "fragment_size", 1, 0);

   /* The total number of +fragment_size+ blocks in the file system */
   rb_define_attr(cStat, "blocks", 1, 0);

   /* The total number of free blocks in the file system */
   rb_define_attr(cStat, "blocks_free", 1, 0);

   /* The number of free blocks available to unprivileged processes */
   rb_define_attr(cStat, "blocks_available", 1, 0);

   /* The total number of files/inodes that can be created */
   rb_define_attr(cStat, "files", 1, 0);

   /* The total number of free files/inodes on the file system */
   rb_define_attr(cStat, "files_free", 1, 0);

   /* The number of free files/inodes available to unprivileged processes */
   rb_define_attr(cStat, "files_available", 1, 0);

   /* The file system identifier */
   rb_define_attr(cStat, "filesystem_id", 1, 0);

   /* The file system type, e.g. UFS */
   rb_define_attr(cStat, "base_type", 1, 0);

   /* A bit mask of flags.  See the <tt>Constants</tt> for a list of flags */
   rb_define_attr(cStat, "flags", 1, 0);

   /* The maximum length of a file name permitted on the file system */
   rb_define_attr(cStat, "name_max", 1, 0);

   /* Constants */

   /* The version of this package */
   rb_define_const(cFilesys, "VERSION", rb_str_new2("0.1.0"));

   /* Read only file system */
   rb_define_const(cStat, "RDONLY", INT2FIX(ST_RDONLY));

   /* File system does not support suid or sgid semantics */
   rb_define_const(cStat, "NOSUID", INT2FIX(ST_NOSUID));

#ifdef ST_NOTRUNC
   /* File system does not truncate file names longer than +name_max+ */
   rb_define_const(cStat, "NOTRUNC", INT2FIX(ST_NOTRUNC));
#endif

   /* Aliases */
   rb_define_alias(cStat, "inodes", "files");
   rb_define_alias(cStat, "inodes_free", "files_free");
   rb_define_alias(cStat, "inodes_available", "files_available");

   /* Convenient methods for Fixnum */
   rb_define_method(rb_cFixnum, "to_kb", fixnum_to_kb, 0);
   rb_define_method(rb_cFixnum, "to_mb", fixnum_to_mb, 0);
   rb_define_method(rb_cFixnum, "to_gb", fixnum_to_gb, 0);
}