URIs vs. half-baked URIs (was Filesel drag and drop)

[Darin Adler <darin bentspoon com>]

On Thursday, August 2, 2001, at 02:33  PM, Alex Larsson wrote:

> +static gchar *
> +uri_extract_filename (const gchar* uri)
> +{
> +  /* file uri with a hostname */
> +  if (strncmp(uri, "file://", strlen("file://"))==0)
> +    {
> +      const char *hostname = &uri[strlen("file://")];
> +      char *p = strchr (hostname,'/');
> +
> +      /* if we can't find the '/' this uri is bad */
> +      if(!p)
> +	return NULL;
> +
> +      return g_strdup (p);
> +
> +      /* if the file doesn't have the //, we take it containing
> +	 a local path */
> +    }
> +  else if (strncmp (uri, "file:", strlen("file:"))==0)
> +    {
> +      const char *path = &uri[strlen("file:")];
> +      /* if empty bad */
> +      if (!*path)
> +	return NULL;
> +      return g_strdup (path);
> +    }
> +  return NULL;
> +}

I know this kind of code is already in GNOME, but eventually we have to 
distinguish real URIs from half-baked URIs: paths with "file:" or 
"file://<hostname>" prefixes but without URI escaping. The code above 
strips the prefix (ignoring the hostname) and then uses the rest as a path.
 This won't work for files with "%" characters in their name, it won't 
work properly if the URIs have "%" escape sequences in them, and it will 
do the wrong thing for URIs with host names (other than the current host) 
in them.

I don't mean to pick on Alex, he just happened to be the one who posted 
the code, but this is a real problem. At some point we have to start 
distinguishing between places that use real URIs and places that use these 
kinds of half-baked URIs if we want to be able to drag files that have "%" 
characters in the file name.

An easy way to do this correctly for code that can have a gnome-vfs 
dependency is to use gnome_vfs_get_local_path_from_uri or 
gnome_vfs_get_uri_from_local_path. Maybe we should put these two functions 
into glib or somewhere in gtk since it's *so* easy and common to get them 
wrong, and they affect drag and drop.

Relevant functions to look at to see the problem in existing GNOME code 
are gnome_uri_list_extract_filenames, which extracts paths from URIs in 
this same half-baked way, and add_one_compatible_uri from eel-dnd.c which 
goes out of its way to construct half-baked URIs that 
gnome_uri_list_extract_filenames can deal with.

    -- Darin

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