pathexpand.cc

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/*
    Copyright (C) 2013-2014 Paul Davis

    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 of the License, 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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <vector>
#include <iostream>
#include <climits>
#include <cerrno>
#include <cstdlib>

#include <regex.h>

#include <glibmm/fileutils.h>
#include <glibmm/miscutils.h>

#include "pbd/compose.h"
#include "pbd/debug.h"
#include "pbd/pathexpand.h"
#include "pbd/strsplit.h"
#include "pbd/tokenizer.h"

using std::string;
using std::vector;

#ifdef COMPILER_MINGW

#include <stdio.h>
#include <stdlib.h>
#include <glibmm.h>

/****************************************************************
 * Emulate POSIX realpath() using Win32 _fullpath() since realpath()
 * is not available.
 *
 * Returns:
 *    On Success: A pointer to the resolved (absolute) path
 *    On Failure: 0 (NULL)
 */

static char* 
realpath (const char *original_path, char resolved_path[_MAX_PATH+1])
{
        char *rpath = 0;
        bool bIsSymLink = false; // We'll probably need to test the incoming path
                                 // to find out if it points to a Windows shortcut
                                 // (or a hard link) and set this appropriately.

        if (bIsSymLink) {
                // At the moment I'm not sure if Windows '_fullpath()' is directly
                // equivalent to POSIX 'realpath()' - in as much as the latter will
                // resolve the supplied path if it happens to point to a symbolic
                // link ('_fullpath()' probably DOESN'T do this but I'm not really
                // sure if Ardour needs such functionality anyway). Therefore we'll
                // possibly need to add that functionality here at a later date.
        } else {
                char temp[(_MAX_PATH+1)*6]; // Allow for maximum length of a path in wchar characters
                
                // POSIX 'realpath()' requires that the buffer size is at
                // least PATH_MAX+1, so assume that the user knew this !!

                rpath = _fullpath (temp, Glib::locale_from_utf8 (original_path).c_str(), _MAX_PATH);

                if (0 != rpath) {
                        snprintf (resolved_path, _MAX_PATH+1, "%s", Glib::locale_to_utf8 (temp).c_str());
                }
                        
        }
        
        return (rpath);
}

#endif  // COMPILER_MINGW

string
PBD::canonical_path (const std::string& path)
{
        char buf[PATH_MAX+1];

        if (realpath (path.c_str(), buf) == NULL) {
                DEBUG_TRACE (DEBUG::FileUtils,
                                string_compose("PBD::canonical_path: Unable to resolve %1: %2\n", path, g_strerror(errno)));
                return path;
        }

        DEBUG_TRACE (DEBUG::FileUtils,
                        string_compose("PBD::canonical_path %1 resolved to: %2\n", path, string(buf)));

        return string (buf);
}

string
PBD::path_expand (string path)
{
        if (path.empty()) {
                return path;
        }

        /* tilde expansion */

        if (path[0] == '~') {
                if (path.length() == 1) {
                        return Glib::get_home_dir();
                }

                if (path[1] == '/') {
                        path.replace (0, 1, Glib::get_home_dir());
                } else {
                        /* can't handle ~roger, so just leave it */
                }
        }

        /* now do $VAR substitution, since wordexp isn't reliable */

        regex_t compiled_pattern;
        const int nmatches = 100;
        regmatch_t matches[nmatches];
        
        if (regcomp (&compiled_pattern, "\\$([a-zA-Z_][a-zA-Z0-9_]*|\\{[a-zA-Z_][a-zA-Z0-9_]*\\})", REG_EXTENDED)) {
                std::cerr << "bad regcomp\n";
                return path;
        }

        while (true) { 

                if (regexec (&compiled_pattern, path.c_str(), nmatches, matches, 0)) {
                        break;
                }
                
                /* matches[0] gives the entire match */
                
                string match = path.substr (matches[0].rm_so, matches[0].rm_eo - matches[0].rm_so);
                
                /* try to get match from the environment */

                if (match[1] == '{') {
                        /* ${FOO} form */
                        match = match.substr (2, match.length() - 3);
                }

                char* matched_value = getenv (match.c_str());

                if (matched_value) {
                        path.replace (matches[0].rm_so, matches[0].rm_eo - matches[0].rm_so, matched_value);
                } else {
                        path.replace (matches[0].rm_so, matches[0].rm_eo - matches[0].rm_so, string());
                }

                /* go back and do it again with whatever remains after the
                 * substitution 
                 */
        }

        regfree (&compiled_pattern);

        /* canonicalize */

        return canonical_path (path);
}

string
PBD::search_path_expand (string path)
{
        if (path.empty()) {
                return path;
        }

        vector<string> s;
        vector<string> n;

        split (path, s, G_SEARCHPATH_SEPARATOR);

        for (vector<string>::iterator i = s.begin(); i != s.end(); ++i) {
                string exp = path_expand (*i);
                if (!exp.empty()) {
                        n.push_back (exp);
                }
        }

        string r;

        for (vector<string>::iterator i = n.begin(); i != n.end(); ++i) {
                if (!r.empty()) {
                        r += G_SEARCHPATH_SEPARATOR;
                }
                r += *i;
        }

        return r;
}

std::vector <std::string>
PBD::parse_path(std::string path, bool check_if_exists)
{
        vector <std::string> pathlist;
        vector <std::string> tmp;
        PBD::tokenize (path, string(G_SEARCHPATH_SEPARATOR_S), std::back_inserter (tmp));

        for(vector<std::string>::const_iterator i = tmp.begin(); i != tmp.end(); ++i) {
                if ((*i).empty()) continue;
                std::string dir;
#ifndef PLATFORM_WINDOWS
                if ((*i).substr(0,1) == "~") {
                        dir = Glib::build_filename(Glib::get_home_dir(), (*i).substr(1));
                }
                else
#endif
                {
                        dir = *i;
                }
                if (!check_if_exists || Glib::file_test (dir, Glib::FILE_TEST_IS_DIR)) {
                        pathlist.push_back(dir);
                }
        }
  return pathlist;
}