ev-file-helpers.c

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/*
 *  Copyright (C) 2002 Jorn Baayen
 *  Copyright © 2009 Christian Persch
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <config.h>

#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

#include <glib.h>
#include <glib/gstdio.h>
#include <glib/gi18n-lib.h>

#include "ev-file-helpers.h"

static gchar *tmp_dir = NULL;

/*
 * ev_dir_ensure_exists:
 * @dir: the directory name
 * @mode: permissions to use when creating the directory
 * @error: a location to store a #GError
 *
 * Create @dir recursively with permissions @mode.
 *
 * Returns: %TRUE on success, or %FALSE on error with @error filled in
 */
static gboolean
_ev_dir_ensure_exists (const gchar *dir,
                       int          mode,
                       GError     **error)
{
        int errsv;
        char *display_name;

        g_return_val_if_fail (dir != NULL, FALSE);

        errno = 0;
    if (g_mkdir_with_parents (dir, mode) == 0)
        return TRUE;

        errsv = errno;
    if (errsv == EEXIST && g_file_test (dir, G_FILE_TEST_IS_DIR))
                return TRUE;

        display_name = g_filename_display_name (dir);
        g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
                     "Failed to create directory '%s': %s",
                     display_name, g_strerror (errsv));
        g_free (display_name);

    return FALSE;
}

/*
 * _ev_tmp_dir:
 * @error: a location to store a #GError
 *
 * Returns the tmp directory.
 *
 * Returns: the tmp directory, or %NULL with @error filled in if the
 *   directory could not be created
 */
static const char *
_ev_tmp_dir (GError **error)
{

        if (tmp_dir == NULL) {
                gchar *dirname;
                const gchar *prgname;

                prgname = g_get_prgname ();
                dirname = g_strdup_printf ("%s-%u", prgname ? prgname : "unknown", getpid ());
                tmp_dir = g_build_filename (g_get_tmp_dir (), dirname, NULL);
                g_free (dirname);
        }

        if (!_ev_dir_ensure_exists (tmp_dir, 0700, error))
                return NULL;

    return tmp_dir;
}

void
_ev_file_helpers_init (void)
{
}

void
_ev_file_helpers_shutdown (void)
{   
    if (tmp_dir != NULL)    
        g_rmdir (tmp_dir);

    g_free (tmp_dir);
    tmp_dir = NULL;
}

int
ev_mkstemp (const char  *tmpl,
            char       **file_name,
            GError     **error)
{
        const char *tmp;
        char *name;
        int fd;

        if ((tmp = _ev_tmp_dir (error)) == NULL)
              return -1;

        name = g_build_filename (tmp, tmpl, NULL);
        fd = g_mkstemp (name);

        if (fd == -1) {
        int errsv = errno;

                g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
                             _("Failed to create a temporary file: %s"),
                             g_strerror (errsv));

                g_free (name);
                return -1;
        }

        if (file_name)
                *file_name = name;

        return fd;
}

static void
close_fd_cb (gpointer fdptr)
{
        int fd = GPOINTER_TO_INT (fdptr);

        close (fd);
}

GFile *
ev_mkstemp_file (const char        *tmpl,
                 GError           **error)
{
        char *file_name;
        int fd;
        GFile *file;

        fd = ev_mkstemp (tmpl, &file_name, error);
        if (fd == -1)
                return NULL;

        file = g_file_new_for_path (file_name);
        g_free (file_name);

        g_object_set_data_full (G_OBJECT (file), "ev-mkstemp-fd",
                                GINT_TO_POINTER (fd), (GDestroyNotify) close_fd_cb);

        return file;
}

/*
 * This function is copied from
 * http://bugzilla.gnome.org/show_bug.cgi?id=524831
 * and renamed from g_mkdtemp to _ev_g_mkdtemp.
 *
 * If/when this function gets added to glib, it can be removed from
 * evince' sources.
 */
static gchar *
_ev_g_mkdtemp (gchar *tmpl)
{
  static const char letters[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  static const int NLETTERS = sizeof (letters) - 1;
  static int counter = 0;
  char *XXXXXX;
  GTimeVal tv;
  glong value;
  int count;

  /* find the last occurrence of "XXXXXX" */
  XXXXXX = g_strrstr (tmpl, "XXXXXX");

  if (!XXXXXX || strncmp (XXXXXX, "XXXXXX", 6))
    {
      errno = EINVAL;
      return NULL;
    }

  /* Get some more or less random data.  */
  g_get_current_time (&tv);
  value = (tv.tv_usec ^ tv.tv_sec) + counter++;

  for (count = 0; count < 100; value += 7777, ++count)
    {
      glong v = value;

      /* Fill in the random bits.  */
      XXXXXX[0] = letters[v % NLETTERS];
      v /= NLETTERS;
      XXXXXX[1] = letters[v % NLETTERS];
      v /= NLETTERS;
      XXXXXX[2] = letters[v % NLETTERS];
      v /= NLETTERS;
      XXXXXX[3] = letters[v % NLETTERS];
      v /= NLETTERS;
      XXXXXX[4] = letters[v % NLETTERS];
      v /= NLETTERS;
      XXXXXX[5] = letters[v % NLETTERS];

      /* tmpl is in UTF-8 on Windows, thus use g_mkdir() */
      if (g_mkdir (tmpl, 0700) == 0)
        return tmpl;

      if (errno != EEXIST)
         /* Any other error will apply also to other names we might
         *  try, and there are 2^32 or so of them, so give up now.
         */
         return NULL;
    }

  /* We got out of the loop because we ran out of combinations to try.  */
  errno = EEXIST;
  return NULL;
}

gchar *
ev_mkdtemp (const char        *tmpl,
            GError           **error)
{
        const char *tmp;
        char *name;

        if ((tmp = _ev_tmp_dir (error)) == NULL)
              return NULL;

        name = g_build_filename (tmp, tmpl, NULL);
        if (_ev_g_mkdtemp (name) == NULL) {
        int errsv = errno;

                g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
                             _("Failed to create a temporary directory: %s"),
                             g_strerror (errsv));

                g_free (name);
                return NULL;
        }

        return name;
}

/* Remove a local temp file created by evince */
void
ev_tmp_filename_unlink (const gchar *filename)
{
    if (!filename)
        return;

    if (!tmp_dir)
        return;

    if (g_str_has_prefix (filename, tmp_dir)) {
        g_unlink (filename);
    }
}

void
ev_tmp_file_unlink (GFile *file)
{
    gboolean res;
    GError  *error = NULL;

    if (!file)
        return;
    
    res = g_file_delete (file, NULL, &error);
    if (!res) {
        char *uri;
        
        uri = g_file_get_uri (file);
        g_warning ("Unable to delete temp file %s: %s\n", uri, error->message);
        g_free (uri);
        g_error_free (error);
    }
}

void
ev_tmp_uri_unlink (const gchar *uri)
{
    GFile *file;
    
    if (!uri)
        return;
    
    file = g_file_new_for_uri (uri);
    if (!g_file_is_native (file)) {
        g_warning ("Attempting to delete non native uri: %s\n", uri);
        g_object_unref (file);
        return;
    }
    
    ev_tmp_file_unlink (file);
    g_object_unref (file);
}

gboolean
ev_file_is_temp (GFile *file)
{
    gchar   *path;
    gboolean retval;

    if (!g_file_is_native (file))
        return FALSE;

    path = g_file_get_path (file);
    if (!path)
        return FALSE;

    retval = g_str_has_prefix (path, g_get_tmp_dir ());
    g_free (path);

    return retval;
}

gboolean
ev_xfer_uri_simple (const char *from,
            const char *to,
            GError     **error)
{
    GFile *source_file;
    GFile *target_file;
    gboolean result;
    
    if (!from)
        return TRUE;

        g_return_val_if_fail (to != NULL, TRUE);

    source_file = g_file_new_for_uri (from);
    target_file = g_file_new_for_uri (to);
    
    result = g_file_copy (source_file, target_file,
                  G_FILE_COPY_TARGET_DEFAULT_PERMS |
                  G_FILE_COPY_OVERWRITE,
                  NULL, NULL, NULL, error);

    g_object_unref (target_file);
    g_object_unref (source_file);
    
    return result;
}

gboolean
ev_file_copy_metadata (const char *from,
                       const char *to,
                       GError     **error)
{
        GFile *source_file;
        GFile *target_file;
        gboolean result;

        g_return_val_if_fail (from != NULL, FALSE);
        g_return_val_if_fail (to != NULL, FALSE);

        source_file = g_file_new_for_uri (from);
        target_file = g_file_new_for_uri (to);

        result = g_file_copy_attributes (source_file, target_file,
                                         G_FILE_COPY_ALL_METADATA |
                                         G_FILE_COPY_TARGET_DEFAULT_PERMS,
                                         NULL, error);

        g_object_unref (target_file);
        g_object_unref (source_file);

        return result;
}

static gchar *
get_mime_type_from_uri (const gchar *uri, GError **error)
{
    GFile       *file;
    GFileInfo   *file_info;
    const gchar *content_type;
        gchar       *mime_type = NULL;

    file = g_file_new_for_uri (uri);
    file_info = g_file_query_info (file,
                       G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
                       0, NULL, error);
    g_object_unref (file);

    if (file_info == NULL)
        return NULL;

    content_type = g_file_info_get_content_type (file_info);
    if (content_type != NULL) {
                mime_type = g_content_type_get_mime_type (content_type);
        }
        if (mime_type == NULL) {
                g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                                     _("Unknown MIME Type"));
        }

    g_object_unref (file_info);
    return mime_type;
}

static gchar *
get_mime_type_from_data (const gchar *uri, GError **error)
{
    GFile            *file;
    GFileInputStream *input_stream;
    gssize            size_read;
    guchar            buffer[1024];
    gboolean          retval;
    gchar            *content_type;
        gchar            *mime_type = NULL;

    file = g_file_new_for_uri (uri);
    
    input_stream = g_file_read (file, NULL, error);
    if (!input_stream) {
        g_object_unref (file);
        return NULL;
    }

    size_read = g_input_stream_read (G_INPUT_STREAM (input_stream),
                     buffer, sizeof (buffer), NULL, error);
    if (size_read == -1) {
        g_object_unref (input_stream);
        g_object_unref (file);
        return NULL;
    }

    retval = g_input_stream_close (G_INPUT_STREAM (input_stream), NULL, error);

    g_object_unref (input_stream);
    g_object_unref (file);
    if (!retval)
        return NULL;

    content_type = g_content_type_guess (NULL, /* no filename */
                         buffer, size_read,
                         NULL);
        if (content_type == NULL) {
                g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                                     _("Unknown MIME Type"));
                return NULL;
        }

#ifndef G_OS_WIN32
       /* On Windows, the implementation of g_content_type_guess() is
        * sometimes too limited, so we do use get_mime_type_from_uri()
        * as a fallback */
       if (strcmp (content_type, "*") == 0) {
               g_free (content_type);
               return get_mime_type_from_uri (uri, error);
       }
#endif /* G_OS_WIN32 */

        mime_type = g_content_type_get_mime_type (content_type);
        g_free (content_type);

        if (mime_type == NULL) {
                g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                                     _("Unknown MIME Type"));
        }

    return mime_type;
}

gchar *
ev_file_get_mime_type (const gchar *uri,
               gboolean     fast,
               GError     **error)
{
    return fast ? get_mime_type_from_uri (uri, error) : get_mime_type_from_data (uri, error);
}

/* Compressed files support */

static const char *compressor_cmds[] = {
  NULL,
  "bzip2",
  "gzip",
  "xz"
};

#define N_ARGS      4
#define BUFFER_SIZE 1024

static gchar *
compression_run (const gchar       *uri,
         EvCompressionType  type,
         gboolean           compress, 
         GError           **error)
{
    gchar *argv[N_ARGS];
    gchar *uri_dst = NULL;
    gchar *filename, *filename_dst = NULL;
    gchar *cmd;
    gint   fd, pout;
    GError *err = NULL;

    if (type == EV_COMPRESSION_NONE)
        return NULL;

    cmd = g_find_program_in_path (compressor_cmds[type]);
    if (!cmd) {
        /* FIXME: better error codes! */
        /* FIXME: i18n later */
        g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
                 "Failed to find the \"%s\" command in the search path.",
                             compressor_cmds[type]);
        return NULL;
    }

    filename = g_filename_from_uri (uri, NULL, error);
    if (!filename) {
        g_free (cmd);
        return NULL;
    }

        fd = ev_mkstemp ("comp.XXXXXX", &filename_dst, error);
    if (fd == -1) {
        g_free (cmd);
        g_free (filename);

        return NULL;
    }

    argv[0] = cmd;
    argv[1] = compress ? (char *) "-c" : (char *) "-cd";
    argv[2] = filename;
    argv[3] = NULL;

    if (g_spawn_async_with_pipes (NULL, argv, NULL,
                      G_SPAWN_STDERR_TO_DEV_NULL,
                      NULL, NULL, NULL,
                      NULL, &pout, NULL, &err)) {
        GIOChannel *in, *out;
        gchar buf[BUFFER_SIZE];
        GIOStatus read_st, write_st;
        gsize bytes_read, bytes_written;

        in = g_io_channel_unix_new (pout);
        g_io_channel_set_encoding (in, NULL, NULL);
        out = g_io_channel_unix_new (fd);
        g_io_channel_set_encoding (out, NULL, NULL);

        do {
            read_st = g_io_channel_read_chars (in, buf,
                               BUFFER_SIZE,
                               &bytes_read,
                               error);
            if (read_st == G_IO_STATUS_NORMAL) {
                write_st = g_io_channel_write_chars (out, buf,
                                     bytes_read,
                                     &bytes_written,
                                     error);
                if (write_st == G_IO_STATUS_ERROR)
                    break;
            } else if (read_st == G_IO_STATUS_ERROR) {
                break;
            }
        } while (bytes_read > 0);

        g_io_channel_unref (in);
        g_io_channel_unref (out);
    }

    close (fd);

    if (err) {
        g_propagate_error (error, err);
    } else {
        uri_dst = g_filename_to_uri (filename_dst, NULL, error);
    }

    g_free (cmd);
    g_free (filename);
    g_free (filename_dst);

    return uri_dst;
}

gchar *
ev_file_uncompress (const gchar       *uri,
            EvCompressionType  type,
            GError           **error)
{
    g_return_val_if_fail (uri != NULL, NULL);

    return compression_run (uri, type, FALSE, error);
}

gchar *
ev_file_compress (const gchar       *uri,
          EvCompressionType  type,
          GError           **error)
{
    g_return_val_if_fail (uri != NULL, NULL);

    return compression_run (uri, type, TRUE, error);
}