path: root/libdocument/ev-file-helpers.c

/*
 *  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, *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;
}

/**
 * ev_mkstemp:
 * @template: a template string; must contain 'XXXXXX', but not necessarily as a suffix
 * @file_name: a location to store the filename of the temp file
 * @error: a location to store a #GError
 *
 * Creates a temp file in the evince temp directory.
 *
 * Returns: a file descriptor to the newly created temp file name, or %-1
 *   on error with @error filled in
 */
int
ev_mkstemp (const char  *template,
            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, template, 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);
}

/**
 * ev_mkstemp_file:
 * @template: a template string; must contain 'XXXXXX', but not necessarily as a suffix
 * @error: a location to store a #GError
 *
 * Creates a temp #GFile in the evince temp directory. See ev_mkstemp() for more information.
 *
 * Returns: a newly allocated #GFile for the newly created temp file name, or %NULL
 *   on error with @error filled in
 */
GFile *
ev_mkstemp_file (const char        *template,
                 GError           **error)
{
        char *file_name;
        int fd;
        GFile *file;

        fd = ev_mkstemp (template, &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.
 *
 *
 * g_mkdtemp:
 * @tmpl: template directory name
 *
 * Creates a temporary directory. See the mkdtemp() documentation
 * on most UNIX-like systems.
 *
 * The parameter is a string that should follow the rules for
 * mkdtemp() templates, i.e. contain the string "XXXXXX".  g_mkdtemp()
 * is slightly more flexible than mkdtemp() in that the sequence does
 * not have to occur at the very end of the template. The X string
 * will be modified to form the name of a directory that didn't
 * already exist.  The string should be in the GLib file name
 * encoding. Most importantly, on Windows it should be in UTF-8.
 *
 * Return value: If a temporary directory was successfully created,
 * @tmpl will be returned with the XXXXXX string modified in such a
 * way as to make the path unique.  In case of errors, %NULL is
 * returned.
 */
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;
}

/**
 * ev_mkdtemp:
 * @template: a template string; must end in 'XXXXXX'
 * @error: a location to store a #GError
 *
 * Creates a temp directory in the evince temp directory.
 *
 * Returns: a newly allocated string with the temp directory name, or %NULL
 *   on error with @error filled in
 */
gchar *
ev_mkdtemp (const char        *template,
            GError           **error)
{
        const char *tmp;
        char *name;

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

        name = g_build_filename (tmp, template, 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;
}

/**
 * ev_xfer_uri_simple:
 * @from: the source URI
 * @to: the target URI
 * @error: a #GError location to store an error, or %NULL
 *
 * Performs a g_file_copy() from @from to @to.
 *
 * Returns: %TRUE on success, or %FALSE on error with @error filled in
 */
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;
}

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) {
                mime_type = g_content_type_get_mime_type (content_type);
        }

	g_object_unref (file_info);
	return mime_type;
}

static gchar *
get_mime_type_from_data (const gchar *uri, GError **error)
{
#ifndef G_OS_WIN32
	GFile            *file;
	GFileInputStream *input_stream;
	gssize            size_read;
	guchar            buffer[1024];
	gboolean          retval;
	gchar            *content_type, *mime_type;

	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)
		return NULL;

	mime_type = g_content_type_get_mime_type (content_type);
	g_free (content_type);
	return mime_type;
#else
	/*
	 * On Windows, the implementation of g_content_type_guess() is too limited at the moment, so we do not
	 * use it and fall back to get_mime_type_from_uri()
	 */
	return get_mime_type_from_uri (uri, error);
#endif /* G_OS_WIN32 */
}

/**
 * ev_file_get_mime_type:
 * @uri: the URI
 * @fast: whether to use fast MIME type detection
 * @error: a #GError location to store an error, or %NULL
 *
 * Note: on unknown MIME types, this may return NULL without @error
 * being filled in.
 * 
 * Returns: a newly allocated string with the MIME type of the file at
 *   @uri, or %NULL on error or if the MIME type could not be determined
 */
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 */
#define BZIPCOMMAND "bzip2"
#define GZIPCOMMAND "gzip"
#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 ((type == EV_COMPRESSION_BZIP2) ? BZIPCOMMAND : GZIPCOMMAND);
	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.",
			     type == EV_COMPRESSION_BZIP2 ? BZIPCOMMAND : GZIPCOMMAND);
		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 ? "-c" : "-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;
}

/**
 * ev_file_uncompress:
 * @uri: a file URI
 * @type: the compression type
 * @error: a #GError location to store an error, or %NULL
 *
 * Uncompresses the file at @uri.
 *
 * If @type is %EV_COMPRESSION_NONE, it does nothing and returns %NULL.
 *
 * Otherwise, it returns the filename of a
 * temporary file containing the decompressed data from the file at @uri.
 * On error it returns %NULL and fills in @error.
 *
 * It is the caller's responsibility to unlink the temp file after use.
 *
 * Returns: a newly allocated string URI, or %NULL on error
 */
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);
}

/**
 * ev_file_compress:
 * @uri: a file URI
 * @type: the compression type
 * @error: a #GError location to store an error, or %NULL
 *
 * Compresses the file at @uri.
 
 * If @type is %EV_COMPRESSION_NONE, it does nothing and returns %NULL.
 *
 * Otherwise, it returns the filename of a
 * temporary file containing the compressed data from the file at @uri.
 *
 * On error it returns %NULL and fills in @error.
 *
 * It is the caller's responsibility to unlink the temp file after use.
 *
 * Returns: a newly allocated string URI, or %NULL on 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);
}