src/decompression.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public License
   4  * as published by the Free Software Foundation; either version 2
   5  * of the License, or (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  15  *
  16  * See the COPYING file for license information.
  17  *
  18  * Guillaume Chazarain <guichaz@yahoo.fr>
  19  */
  20
  21 /************************************************
  22  * Files decompression (images and collections) *
  23  ************************************************/
  24
  25 #include <unistd.h>             /* read(), pipe(), fork(), execlp() ... */
  26 #include <sys/types.h>          /* pid_t */
  27 #include <signal.h>             /* kill(), SIGTERM */
  28 #include <stdio.h>              /* perror() */
  29 #include <sys/wait.h>           /* waitpid() */
  30 #include <errno.h>              /* errno */
  31
  32 #include "gliv.h"
  33 #include "decompression.h"
  34 #include "collection.h"
  35 #include "loading.h"
  36
  37 typedef struct {
  38     gchar *ext;
  39     gchar *cmd;
  40 } decompressor;
  41
  42 /* Read from the child process. */
  43 static GdkPixbuf *read_image(gint fd, GError ** error)
  44 {
  45     guchar buf[4096];
  46     GdkPixbuf *pixbuf;
  47     GdkPixbufLoader *loader;
  48     gsize size;
  49
  50     loader = gdk_pixbuf_loader_new();
  51
  52     while ((size = read(fd, buf, sizeof(buf))) > 0 || (errno == EINTR)) {
  53         if (size > 0 &&
  54             gdk_pixbuf_loader_write(loader, buf, size, error) == FALSE)
  55             return NULL;
  56     }
  57
  58     if (gdk_pixbuf_loader_close(loader, error) == FALSE)
  59         return NULL;
  60
  61     pixbuf = gdk_pixbuf_loader_get_pixbuf(loader);
  62     if (pixbuf != NULL)
  63         gdk_pixbuf_ref(pixbuf);
  64
  65     g_object_unref(loader);
  66     return pixbuf;
  67 }
  68
  69 /* Exec: "%cmd -c %filename" to send the output to stdout, the parent. */
  70 static void decomp_file(const gchar * cmd, const gchar * filename, gint fd)
  71 {
  72     if (dup2(fd, STDOUT_FILENO) < 0) {
  73         perror("dup2");
  74         return;
  75     }
  76
  77     if (execlp(cmd, cmd, "-c", filename, NULL) < 0) {
  78         perror("execlp");
  79         return;
  80     }
  81 }
  82
  83 static gboolean init_decompression(const gchar * filename, gint * fd,
  84                                    pid_t * pid_ptr)
  85 {
  86     /* *INDENT-OFF* */
  87     static decompressor all_decomp[] = {
  88         { "bz2", "bunzip2"    },
  89         { "gz",  "gunzip"     },
  90         { "z",   "uncompress" },
  91         { NULL,  NULL         }
  92     };
  93     /* *INDENT-ON* */
  94
  95     gint filedes[2];
  96     pid_t pid;
  97     decompressor *decomp;
  98     const gchar *ext;
  99
 100     /* Find the appropriate decompressor. */
 101     ext = get_extension(filename);
 102     if (ext == NULL)
 103         return FALSE;
 104
 105     for (decomp = all_decomp; decomp->ext != NULL; decomp++)
 106         if (!g_ascii_strcasecmp(decomp->ext, ext))
 107             break;
 108
 109     if (decomp->ext == NULL)
 110         /* Decompressor not found. */
 111         return FALSE;
 112
 113     if (pipe(filedes) < 0) {
 114         perror("pipe");
 115         return FALSE;
 116     }
 117
 118     pid = fork();
 119     if (pid < 0) {
 120         perror("fork");
 121         return FALSE;
 122     }
 123
 124     if (pid == 0) {
 125         /* Child */
 126         close(filedes[0]);
 127         decomp_file(decomp->cmd, filename, filedes[1]);
 128         return FALSE;
 129     }
 130
 131     /* Parent */
 132     close(filedes[1]);
 133     *fd = filedes[0];
 134     *pid_ptr = pid;
 135     return TRUE;
 136 }
 137
 138 GdkPixbuf *load_compressed_pixbuf(const gchar * filename, GError ** error)
 139 {
 140     gint fd;
 141     pid_t pid;
 142     GdkPixbuf *pixbuf;
 143
 144     if (init_decompression(filename, &fd, &pid) == FALSE)
 145         return NULL;
 146
 147     pixbuf = read_image(fd, error);
 148     close(fd);
 149     waitpid(pid, NULL, 0);
 150
 151     return pixbuf;
 152 }
 153
 154 gint load_compressed_collection(const gchar * filename, gboolean reverse)
 155 {
 156     gint fd;
 157     pid_t pid;
 158     gint nb_inserted;
 159     FILE *file;
 160
 161     if (init_decompression(filename, &fd, &pid) == FALSE)
 162         return 0;
 163
 164     file = fdopen(fd, "r");
 165     if (file == NULL) {
 166         perror(filename);
 167         kill(pid, SIGTERM);
 168         nb_inserted = 0;
 169     } else
 170         nb_inserted = load_dot_gliv_from_file(file, reverse);
 171
 172     fclose(file);
 173     waitpid(pid, NULL, 0);
 174
 175     return nb_inserted;
 176 }