src/viewer/growbuf.c

   1 /*
   2    Internal file viewer for the Midnight Commander
   3    Function for work with growing bufers
   4
   5    Copyright (C) 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003,
   6    2004, 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
   7
   8    Written by: 1994, 1995, 1998 Miguel de Icaza
   9    1994, 1995 Janne Kukonlehto
  10    1995 Jakub Jelinek
  11    1996 Joseph M. Hinkle
  12    1997 Norbert Warmuth
  13    1998 Pavel Machek
  14    2004 Roland Illig <roland.illig@gmx.de>
  15    2005 Roland Illig <roland.illig@gmx.de>
  16    2009 Slava Zanko <slavazanko@google.com>
  17    2009 Andrew Borodin <aborodin@vmail.ru>
  18    2009 Ilia Maslakov <il.smind@gmail.com>
  19
  20    This file is part of the Midnight Commander.
  21
  22    The Midnight Commander is free software; you can redistribute it
  23    and/or modify it under the terms of the GNU General Public License as
  24    published by the Free Software Foundation; either version 2 of the
  25    License, or (at your option) any later version.
  26
  27    The Midnight Commander is distributed in the hope that it will be
  28    useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  29    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  30    General Public License for more details.
  31
  32    You should have received a copy of the GNU General Public License
  33    along with this program; if not, write to the Free Software
  34    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  35    MA 02110-1301, USA.
  36  */
  37
  38 #include <config.h>
  39 #include <errno.h>
  40
  41 #include "lib/global.h"
  42 #include "src/wtools.h"
  43
  44 #include "lib/vfs/mc-vfs/vfs.h"
  45
  46 #include "internal.h"
  47
  48 /* Block size for reading files in parts */
  49 #define VIEW_PAGE_SIZE          ((size_t) 8192)
  50
  51 /*** global variables ****************************************************************************/
  52
  53 /*** file scope macro definitions ****************************************************************/
  54
  55 /*** file scope type declarations ****************************************************************/
  56
  57 /*** file scope variables ************************************************************************/
  58
  59 /*** file scope functions ************************************************************************/
  60
  61 /*** public functions ****************************************************************************/
  62
  63 /* --------------------------------------------------------------------------------------------- */
  64
  65 void
  66 mcview_growbuf_init (mcview_t * view)
  67 {
  68     view->growbuf_in_use = TRUE;
  69     view->growbuf_blockptr = g_ptr_array_new ();
  70     view->growbuf_lastindex = VIEW_PAGE_SIZE;
  71     view->growbuf_finished = FALSE;
  72 }
  73
  74 /* --------------------------------------------------------------------------------------------- */
  75
  76 void
  77 mcview_growbuf_free (mcview_t * view)
  78 {
  79     assert (view->growbuf_in_use);
  80
  81     g_ptr_array_foreach (view->growbuf_blockptr, (GFunc) g_free, NULL);
  82
  83     (void) g_ptr_array_free (view->growbuf_blockptr, TRUE);
  84
  85     view->growbuf_blockptr = NULL;
  86     view->growbuf_in_use = FALSE;
  87 }
  88
  89 /* --------------------------------------------------------------------------------------------- */
  90
  91 off_t
  92 mcview_growbuf_filesize (mcview_t * view)
  93 {
  94     assert (view->growbuf_in_use);
  95
  96     if (view->growbuf_blockptr->len == 0)
  97         return 0;
  98     else
  99         return ((off_t) view->growbuf_blockptr->len - 1) * VIEW_PAGE_SIZE + view->growbuf_lastindex;
 100 }
 101
 102 /* --------------------------------------------------------------------------------------------- */
 103
 104 /* Copies the output from the pipe to the growing buffer, until either
 105  * the end-of-pipe is reached or the interval [0..ofs) of the growing
 106  * buffer is completely filled. */
 107 void
 108 mcview_growbuf_read_until (mcview_t * view, off_t ofs)
 109 {
 110     ssize_t nread;
 111     byte *p;
 112     size_t bytesfree;
 113     gboolean short_read;
 114
 115     assert (view->growbuf_in_use);
 116
 117     if (view->growbuf_finished)
 118         return;
 119
 120     short_read = FALSE;
 121     while (mcview_growbuf_filesize (view) < ofs || short_read)
 122     {
 123         if (view->growbuf_lastindex == VIEW_PAGE_SIZE)
 124         {
 125             /* Append a new block to the growing buffer */
 126             byte *newblock = g_try_malloc (VIEW_PAGE_SIZE);
 127             if (newblock == NULL)
 128                 return;
 129
 130             g_ptr_array_add (view->growbuf_blockptr, newblock);
 131             view->growbuf_lastindex = 0;
 132         }
 133         p = g_ptr_array_index (view->growbuf_blockptr,
 134                                view->growbuf_blockptr->len - 1) + view->growbuf_lastindex;
 135
 136         bytesfree = VIEW_PAGE_SIZE - view->growbuf_lastindex;
 137
 138         if (view->datasource == DS_STDIO_PIPE)
 139         {
 140             nread = fread (p, 1, bytesfree, view->ds_stdio_pipe);
 141             if (nread == 0)
 142             {
 143                 view->growbuf_finished = TRUE;
 144                 (void) pclose (view->ds_stdio_pipe);
 145                 mcview_display (view);
 146                 close_error_pipe (D_NORMAL, NULL);
 147                 view->ds_stdio_pipe = NULL;
 148                 return;
 149             }
 150         }
 151         else
 152         {
 153             assert (view->datasource == DS_VFS_PIPE);
 154             do
 155             {
 156                 nread = mc_read (view->ds_vfs_pipe, p, bytesfree);
 157             }
 158             while (nread == -1 && errno == EINTR);
 159             if (nread == -1 || nread == 0)
 160             {
 161                 view->growbuf_finished = TRUE;
 162                 (void) mc_close (view->ds_vfs_pipe);
 163                 view->ds_vfs_pipe = -1;
 164                 return;
 165             }
 166         }
 167         short_read = ((size_t) nread < bytesfree);
 168         view->growbuf_lastindex += nread;
 169     }
 170 }
 171
 172 /* --------------------------------------------------------------------------------------------- */
 173
 174 gboolean
 175 mcview_get_byte_growing_buffer (mcview_t * view, off_t byte_index, int *retval)
 176 {
 177     off_t pageno;
 178     off_t pageindex;
 179
 180     if (retval)
 181         *retval = -1;
 182
 183     pageno = byte_index / VIEW_PAGE_SIZE;
 184     pageindex = byte_index % VIEW_PAGE_SIZE;
 185
 186     assert (view->growbuf_in_use);
 187
 188     if (pageno < 0)
 189         return FALSE;
 190
 191     mcview_growbuf_read_until (view, byte_index + 1);
 192     if (view->growbuf_blockptr->len == 0)
 193         return FALSE;
 194     if (pageno < view->growbuf_blockptr->len - 1)
 195     {
 196         if (retval)
 197             *retval = *((byte *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex));
 198         return TRUE;
 199     }
 200     if (pageno == view->growbuf_blockptr->len - 1 && pageindex < (off_t) view->growbuf_lastindex)
 201     {
 202         if (retval)
 203             *retval = *((byte *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex));
 204         return TRUE;
 205     }
 206     return FALSE;
 207 }
 208
 209 /* --------------------------------------------------------------------------------------------- */
 210
 211 char *
 212 mcview_get_ptr_growing_buffer (mcview_t * view, off_t byte_index)
 213 {
 214     off_t pageno = byte_index / VIEW_PAGE_SIZE;
 215     off_t pageindex = byte_index % VIEW_PAGE_SIZE;
 216
 217     assert (view->growbuf_in_use);
 218
 219     if (pageno < 0)
 220         return NULL;
 221
 222     mcview_growbuf_read_until (view, byte_index + 1);
 223     if (view->growbuf_blockptr->len == 0)
 224         return NULL;
 225     if (pageno < view->growbuf_blockptr->len - 1)
 226         return (char *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex);
 227     if (pageno == view->growbuf_blockptr->len - 1 && pageindex < (off_t) view->growbuf_lastindex)
 228         return (char *) (g_ptr_array_index (view->growbuf_blockptr, pageno) + pageindex);
 229     return NULL;
 230 }
 231
 232 /* --------------------------------------------------------------------------------------------- */