Merge pull request #105 from MightyCreak/fix-subprocess-calls-in-flatpak

Fix subprocess call from within Flatpak

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 ### Fixed
+- Fixed #103: the flatpak app can now call binaries on the host, such as `git`,
+  `svn`, etc. (PR #105)
 
 ## [0.7.0] - 2021-11-16
 

data/diffuserc.in

@@ -2,4 +2,4 @@
 #
 # Copyright (C) 2006-2009 Derrick Moser <derrick_moser@yahoo.com>
 
-import @PKGDATADIR@/syntax/*.syntax
+import @pkgdatadir@/syntax/*.syntax

data/meson.build

@@ -33,7 +33,7 @@ endif
 
 # Diffuse config file
 conf = configuration_data()
-conf.set('PKGDATADIR', pkgdatadir)
+conf.set('pkgdatadir', pkgdatadir)
 
 configure_file(
   input: 'diffuserc.in',

io.github.mightycreak.Diffuse.yml

@@ -8,10 +8,13 @@ finish-args:
   - --socket=fallback-x11
   - --share=ipc
   - --filesystem=home
+  - --talk-name=org.freedesktop.Flatpak
 modules:
   - name: diffuse
     builddir: true
     buildsystem: meson
+    config-opts:
+      - -Duse_flatpak=true
     sources:
       - type: dir
         path: .

meson_options.txt

@@ -0,0 +1 @@
+option('use_flatpak', type: 'boolean', value: false)

src/constants.py.in

@@ -0,0 +1,27 @@
+# Diffuse: a graphical tool for merging and comparing text files.
+#
+# Copyright (C) 2019 Derrick Moser <derrick_moser@yahoo.com>
+# Copyright (C) 2021 Romain Failliot <romain.failliot@foolstep.com>
+#
+# 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.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+APP_NAME = 'Diffuse'
+VERSION = '@VERSION@'
+COPYRIGHT =  '''{copyright} © 2006-2019 Derrick Moser
+{copyright} © 2015-2021 Romain Failliot'''.format(copyright=_("Copyright"))
+WEBSITE = 'https://mightycreak.github.io/diffuse/'
+
+sysconfigdir = '@sysconfigdir@'
+use_flatpak = @use_flatpak@

src/diffuse.in

@@ -23,10 +23,8 @@ import sys
 import gettext
 import locale
 
-VERSION = '@VERSION@'
 pkgdatadir = '@pkgdatadir@'
 localedir = '@localedir@'
-sysconfigdir = '@sysconfigdir@'
 
 sys.path.insert(1, pkgdatadir)
 gettext.install('diffuse', localedir)
@@ -34,4 +32,4 @@ gettext.install('diffuse', localedir)
 if __name__ == '__main__':
     from diffuse import main
 
-    sys.exit(main.main(VERSION, sysconfigdir))
+    sys.exit(main.main())

src/main.py

@@ -26,7 +26,6 @@ import glob
 import re
 import shlex
 import stat
-import subprocess
 import unicodedata
 import webbrowser
 
@@ -53,6 +52,7 @@ from gi.repository import PangoCairo
 from urllib.parse import urlparse
 
 from diffuse import utils
+from diffuse import constants
 
 if not hasattr(__builtins__, 'WindowsError'):
     # define 'WindowsError' so 'except' statements will work on all platforms
@@ -739,7 +739,7 @@ class Preferences:
             [ 'List',
               [ 'Integer', 'tabs_default_panes', 2, _('Default panes'), 2, 16 ],
               [ 'Boolean', 'tabs_always_show', False, _('Always show the tab bar') ],
-              [ 'Boolean', 'tabs_warn_before_quit', True, _('Warn me when closing a tab will quit %s') % utils.APP_NAME ]
+              [ 'Boolean', 'tabs_warn_before_quit', True, _('Warn me when closing a tab will quit %s') % constants.APP_NAME ]
             ],
             _('Regional Settings'),
             [ 'List',
@@ -900,7 +900,7 @@ class Preferences:
                         ss.append(f'{k} "{v_escaped}"\n')
                 ss.sort()
                 f = open(self.path, 'w')
-                f.write(f'# This prefs file was generated by {utils.APP_NAME} {utils.VERSION}.\n\n')
+                f.write(f'# This prefs file was generated by {constants.APP_NAME} {constants.VERSION}.\n\n')
                 for s in ss:
                     f.write(s)
                 f.close()
@@ -1225,66 +1225,6 @@ def safeRelativePath(abspath1, name, prefs, cygwin_pref):
 def bashEscape(s):
     return "'" + s.replace("'", "'\\''") + "'"
 
-# use popen to read the output of a command
-def popenRead(dn, cmd, prefs, bash_pref, success_results=None):
-    if success_results is None:
-        success_results = [ 0 ]
-    if utils.isWindows() and prefs.getBool(bash_pref):
-        # launch the command from a bash shell is requested
-        cmd = [ prefs.convertToNativePath('/bin/bash.exe'), '-l', '-c', 'cd {}; {}'.format(bashEscape(dn), ' '.join([ bashEscape(arg) for arg in cmd ])) ]
-        dn = None
-    # use subprocess.Popen to retrieve the file contents
-    if utils.isWindows():
-        info = subprocess.STARTUPINFO()
-        info.dwFlags |= subprocess.STARTF_USESHOWWINDOW
-        info.wShowWindow = subprocess.SW_HIDE
-    else:
-        info = None
-    proc = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=dn, startupinfo=info)
-    proc.stdin.close()
-    proc.stderr.close()
-    fd = proc.stdout
-    # read the command's output
-    s = fd.read()
-    fd.close()
-    if proc.wait() not in success_results:
-        raise IOError('Command failed.')
-    return s
-
-# use popen to read the output of a command
-def popenReadLines(dn, cmd, prefs, bash_pref, success_results=None):
-    return strip_eols(splitlines(popenRead(dn, cmd, prefs, bash_pref, success_results).decode('utf-8', errors='ignore')))
-
-# simulate use of popen with xargs to read the output of a command
-def popenXArgsReadLines(dn, cmd, args, prefs, bash_pref):
-    # os.sysconf() is only available on Unix
-    if hasattr(os, 'sysconf'):
-        maxsize = os.sysconf('SC_ARG_MAX')
-        maxsize -= sum([ len(k) + len(v) + 2 for k, v in os.environ.items() ])
-    else:
-        # assume the Window's limit to CreateProcess()
-        maxsize = 32767
-    maxsize -= sum([ len(k) + 1 for k in cmd ])
-
-    ss = []
-    i, s, a = 0, 0, []
-    while i < len(args):
-        f = (len(a) == 0)
-        if f:
-            # start a new command line
-            a = cmd[:]
-        elif s + len(args[i]) + 1 <= maxsize:
-            f = True
-        if f:
-            # append another argument to the current command line
-            a.append(args[i])
-            s += len(args[i]) + 1
-            i += 1
-        if i == len(args) or not f:
-            ss.extend(popenReadLines(dn, a, prefs, bash_pref))
-            s, a = 0, []
-    return ss
-
 # utility class to help support Git and Monotone
 # represents a set of files and folders of interest for "git status" or
 # "mtn automate inventory"
@@ -1361,7 +1301,7 @@ class _Bzr:
             isabs |= os.path.isabs(name)
             args.append(safeRelativePath(self.root, name, prefs, 'bzr_cygwin'))
         # run command
-        ss = popenReadLines(self.root, args, prefs, 'bzr_bash')
+        ss = utils.popenReadLines(self.root, args, prefs, 'bzr_bash')
         # parse response
         prev = 'before:' + rev
         fs = _VcsFolderSet(names)
@@ -1441,7 +1381,7 @@ class _Bzr:
         prev = '-1'
         fs = _VcsFolderSet(names)
         added, modified, removed, renamed = {}, {}, {}, {}
-        for s in popenReadLines(self.root, args, prefs, 'bzr_bash'):
+        for s in utils.popenReadLines(self.root, args, prefs, 'bzr_bash'):
             # parse response
             if len(s) < 5:
                 continue
@@ -1498,7 +1438,7 @@ class _Bzr:
         return result
 
     def getRevision(self, prefs, name, rev):
-        return popenRead(self.root, [ prefs.getString('bzr_bin'), 'cat', '--name-from-revision', '-r', rev, safeRelativePath(self.root, name, prefs, 'bzr_cygwin') ], prefs, 'bzr_bash')
+        return utils.popenRead(self.root, [ prefs.getString('bzr_bin'), 'cat', '--name-from-revision', '-r', rev, safeRelativePath(self.root, name, prefs, 'bzr_cygwin') ], prefs, 'bzr_bash')
 
 def _get_bzr_repo(path, prefs):
     p = _find_parent_dir_with(path, '.bzr')
@@ -1547,7 +1487,7 @@ class _Cvs:
         prev = 'BASE'
         fs = _VcsFolderSet(names)
         modified = {}
-        for s in popenReadLines(self.root, args, prefs, 'cvs_bash'):
+        for s in utils.popenReadLines(self.root, args, prefs, 'cvs_bash'):
             # parse response
             if len(s) < 3 or s[0] not in 'ACMR':
                 continue
@@ -1571,10 +1511,10 @@ class _Cvs:
     def getRevision(self, prefs, name, rev):
         if rev == 'BASE' and not os.path.exists(name):
             # find revision for removed files
-            for s in popenReadLines(self.root, [ prefs.getString('cvs_bin'), 'status', safeRelativePath(self.root, name, prefs, 'cvs_cygwin') ], prefs, 'cvs_bash'):
+            for s in utils.popenReadLines(self.root, [ prefs.getString('cvs_bin'), 'status', safeRelativePath(self.root, name, prefs, 'cvs_cygwin') ], prefs, 'cvs_bash'):
                 if s.startswith('   Working revision:\t-'):
                     rev = s.split('\t')[1][1:]
-        return popenRead(self.root, [ prefs.getString('cvs_bin'), '-Q', 'update', '-p', '-r', rev, safeRelativePath(self.root, name, prefs, 'cvs_cygwin') ], prefs, 'cvs_bash')
+        return utils.popenRead(self.root, [ prefs.getString('cvs_bin'), '-Q', 'update', '-p', '-r', rev, safeRelativePath(self.root, name, prefs, 'cvs_cygwin') ], prefs, 'cvs_bash')
 
 def _get_cvs_repo(path, prefs):
     if os.path.isdir(os.path.join(path, 'CVS')):
@@ -1608,7 +1548,7 @@ class _Darcs:
                 args.append(safeRelativePath(self.root, name, prefs, 'darcs_cygwin'))
         # run command
         # 'darcs whatsnew' will return 1 if there are no changes
-        ss = popenReadLines(self.root, args, prefs, 'darcs_bash', [0, 1])
+        ss = utils.popenReadLines(self.root, args, prefs, 'darcs_bash', [0, 1])
         # parse response
         i, n = 0, len(ss)
         if mods:
@@ -1701,7 +1641,7 @@ class _Darcs:
         except ValueError:
             args.extend([ '-h', rev ])
         args.append(safeRelativePath(self.root, name, prefs, 'darcs_cygwin'))
-        return popenRead(self.root, args, prefs, 'darcs_bash')
+        return utils.popenRead(self.root, args, prefs, 'darcs_bash')
 
 def _get_darcs_repo(path, prefs):
     p = _find_parent_dir_with(path, '_darcs')
@@ -1727,7 +1667,7 @@ class _Git:
         prev = rev + '^'
         fs = _VcsFolderSet(names)
         modified = {}
-        for s in popenReadLines(self.root, args, prefs, 'git_bash'):
+        for s in utils.popenReadLines(self.root, args, prefs, 'git_bash'):
             # parse response
             if len(s) < 2 or s[0] not in 'ADM':
                 continue
@@ -1762,7 +1702,7 @@ class _Git:
         fs = _VcsFolderSet(names)
         modified, renamed = {}, {}
         # 'git status' will return 1 when a commit would fail
-        for s in popenReadLines(self.root, args, prefs, 'git_bash', [0, 1]):
+        for s in utils.popenReadLines(self.root, args, prefs, 'git_bash', [0, 1]):
             # parse response
             if len(s) < 3:
                 continue
@@ -1828,13 +1768,13 @@ class _Git:
         return result
 
     def getRevision(self, prefs, name, rev):
-        return popenRead(self.root, [ prefs.getString('git_bin'), 'show', '{}:{}'.format(rev, relpath(self.root, os.path.abspath(name)).replace(os.sep, '/')) ], prefs, 'git_bash')
+        return utils.popenRead(self.root, [ prefs.getString('git_bin'), 'show', '{}:{}'.format(rev, relpath(self.root, os.path.abspath(name)).replace(os.sep, '/')) ], prefs, 'git_bash')
 
 def _get_git_repo(path, prefs):
     if 'GIT_DIR' in os.environ:
         try:
             d = path
-            ss = popenReadLines(d, [ prefs.getString('git_bin'), 'rev-parse', '--show-prefix' ], prefs, 'git_bash')
+            ss = utils.popenReadLines(d, [ prefs.getString('git_bin'), 'rev-parse', '--show-prefix' ], prefs, 'git_bash')
             if len(ss) > 0:
                 # be careful to handle trailing slashes
                 d = d.split(os.sep)
@@ -1873,7 +1813,7 @@ class _Hg:
     def _getPreviousRevision(self, prefs, rev):
         if rev is None:
             if self.working_rev is None:
-                ss = popenReadLines(self.root, [ prefs.getString('hg_bin'), 'id', '-i', '-t' ], prefs, 'hg_bash')
+                ss = utils.popenReadLines(self.root, [ prefs.getString('hg_bin'), 'id', '-i', '-t' ], prefs, 'hg_bash')
                 if len(ss) != 1:
                     raise IOError('Unknown working revision')
                 ss = ss[0].split(' ')
@@ -1901,7 +1841,7 @@ class _Hg:
         prev = self._getPreviousRevision(prefs, rev)
         fs = _VcsFolderSet(names)
         modified = {}
-        for s in popenReadLines(self.root, args, prefs, 'hg_bash'):
+        for s in utils.popenReadLines(self.root, args, prefs, 'hg_bash'):
             # parse response
             if len(s) < 3 or s[0] not in 'AMR':
                 continue
@@ -1928,7 +1868,7 @@ class _Hg:
         return self._getCommitTemplate(prefs, names, [ 'status', '-q' ], None)
 
     def getRevision(self, prefs, name, rev):
-        return popenRead(self.root, [ prefs.getString('hg_bin'), 'cat', '-r', rev, safeRelativePath(self.root, name, prefs, 'hg_cygwin') ], prefs, 'hg_bash')
+        return utils.popenRead(self.root, [ prefs.getString('hg_bin'), 'cat', '-r', rev, safeRelativePath(self.root, name, prefs, 'hg_cygwin') ], prefs, 'hg_bash')
 
 def _get_hg_repo(path, prefs):
     p = _find_parent_dir_with(path, '.hg')
@@ -1947,7 +1887,7 @@ class _Mtn:
     def getCommitTemplate(self, prefs, rev, names):
         # build command
         vcs_bin = prefs.getString('mtn_bin')
-        ss = popenReadLines(self.root, [ vcs_bin, 'automate', 'select', '-q', rev ], prefs, 'mtn_bash')
+        ss = utils.popenReadLines(self.root, [ vcs_bin, 'automate', 'select', '-q', rev ], prefs, 'mtn_bash')
         if len(ss) != 1:
             raise IOError('Ambiguous revision specifier')
         args = [ vcs_bin, 'automate', 'get_revision', ss[0] ]
@@ -1959,7 +1899,7 @@ class _Mtn:
         # run command
         prev = None
         removed, added, modified, renamed = {}, {}, {}, {}
-        ss = popenReadLines(self.root, args, prefs, 'mtn_bash')
+        ss = utils.popenReadLines(self.root, args, prefs, 'mtn_bash')
         i = 0
         while i < len(ss):
             # process results
@@ -2002,7 +1942,7 @@ class _Mtn:
         if removed or renamed:
             # remove directories
             removed_dirs = set()
-            for s in popenReadLines(self.root, [ vcs_bin, 'automate', 'get_manifest_of', prev ], prefs, 'mtn_bash'):
+            for s in utils.popenReadLines(self.root, [ vcs_bin, 'automate', 'get_manifest_of', prev ], prefs, 'mtn_bash'):
                 s = shlex.split(s)
                 if len(s) > 1 and s[0] == 'dir':
                     removed_dirs.add(s[1])
@@ -2049,7 +1989,7 @@ class _Mtn:
             isabs |= os.path.isabs(name)
         # build list of interesting files
         prev = 'h:'
-        ss = popenReadLines(self.root, args, prefs, 'mtn_bash')
+        ss = utils.popenReadLines(self.root, args, prefs, 'mtn_bash')
         removed, added, modified, renamed = {}, {}, {}, {}
         i = 0
         while i < len(ss):
@@ -2110,7 +2050,7 @@ class _Mtn:
         return result
 
     def getRevision(self, prefs, name, rev):
-        return popenRead(self.root, [ prefs.getString('mtn_bin'), 'automate', 'get_file_of', '-q', '-r', rev, safeRelativePath(self.root, name, prefs, 'mtn_cygwin') ], prefs, 'mtn_bash')
+        return utils.popenRead(self.root, [ prefs.getString('mtn_bin'), 'automate', 'get_file_of', '-q', '-r', rev, safeRelativePath(self.root, name, prefs, 'mtn_cygwin') ], prefs, 'mtn_bash')
 
 def _get_mtn_repo(path, prefs):
     p = _find_parent_dir_with(path, '_MTN')
@@ -2125,7 +2065,7 @@ class _Rcs:
     def getFileTemplate(self, prefs, name):
         args = [ prefs.getString('rcs_bin_rlog'), '-L', '-h', safeRelativePath(self.root, name, prefs, 'rcs_cygwin') ]
         rev = ''
-        for line in popenReadLines(self.root, args, prefs, 'rcs_bash'):
+        for line in utils.popenReadLines(self.root, args, prefs, 'rcs_bash'):
             if line.startswith('head: '):
                 rev = line[6:]
         return [ (name, rev), (name, None) ]
@@ -2201,7 +2141,7 @@ class _Rcs:
         args = [ safeRelativePath(self.root, k, prefs, 'rcs_cygwin') for k in r ]
         # run command
         r, k = {}, ''
-        for line in popenXArgsReadLines(self.root, cmd, args, prefs, 'rcs_bash'):
+        for line in utils.popenXArgsReadLines(self.root, cmd, args, prefs, 'rcs_bash'):
             # parse response
             if line.startswith('Working file: '):
                 k = prefs.convertToNativePath(line[14:])
@@ -2214,7 +2154,7 @@ class _Rcs:
         return [ [ (k, r[k]), (k, None) ] for k in sorted(r.keys()) ]
 
     def getRevision(self, prefs, name, rev):
-        return popenRead(self.root, [ prefs.getString('rcs_bin_co'), '-p', '-q', '-r' + rev, safeRelativePath(self.root, name, prefs, 'rcs_cygwin') ], prefs, 'rcs_bash')
+        return utils.popenRead(self.root, [ prefs.getString('rcs_bin_co'), '-p', '-q', '-r' + rev, safeRelativePath(self.root, name, prefs, 'rcs_cygwin') ], prefs, 'rcs_bash')
 
 def _get_rcs_repo(path, prefs):
     if os.path.isdir(os.path.join(path, 'RCS')):
@@ -2265,7 +2205,7 @@ class _Svn:
             vcs, prefix = self._getVcs(), self._getURLPrefix()
             n = len(prefix)
             args = [ prefs.getString(vcs + '_bin'), 'info' ]
-            for s in popenReadLines(self.root, args, prefs, vcs + '_bash'):
+            for s in utils.popenReadLines(self.root, args, prefs, vcs + '_bash'):
                 if s.startswith(prefix):
                     self.url = s[n:]
                     break
@@ -2312,7 +2252,7 @@ class _Svn:
         # run command
         fs = _VcsFolderSet(names)
         modified, added, removed = {}, set(), set()
-        for s in popenReadLines(self.root, args, prefs, vcs_bash):
+        for s in utils.popenReadLines(self.root, args, prefs, vcs_bash):
             status = self._parseStatusLine(s)
             if status is None:
                 continue
@@ -2368,7 +2308,7 @@ class _Svn:
             # determine which are directories
             added = {}
             for p, v in m.items():
-                for s in popenReadLines(self.root, [ vcs_bin, 'list', '-r', rev, '{}/{}'.format(self._getURL(prefs), p.replace(os.sep, '/')) ], prefs, vcs_bash):
+                for s in utils.popenReadLines(self.root, [ vcs_bin, 'list', '-r', rev, '{}/{}'.format(self._getURL(prefs), p.replace(os.sep, '/')) ], prefs, vcs_bash):
                     if s in v:
                         # confirmed as added file
                         k = os.path.join(self.root, os.path.join(p, s))
@@ -2394,7 +2334,7 @@ class _Svn:
                 m[d].add(b)
             removed_dir, removed = set(), {}
             for p, v in m.items():
-                for s in popenReadLines(self.root, [ vcs_bin, 'list', '-r', prev, '{}/{}'.format(self._getURL(prefs), p.replace(os.sep, '/')) ], prefs, vcs_bash):
+                for s in utils.popenReadLines(self.root, [ vcs_bin, 'list', '-r', prev, '{}/{}'.format(self._getURL(prefs), p.replace(os.sep, '/')) ], prefs, vcs_bash):
                     if s.endswith('/'):
                         s = s[:-1]
                         if s in v:
@@ -2412,7 +2352,7 @@ class _Svn:
                 tmp = removed_dir
                 removed_dir = set()
                 for p in tmp:
-                    for s in popenReadLines(self.root, [ vcs_bin, 'list', '-r', prev, '{}/{}'.format(self._getURL(prefs), p.replace(os.sep, '/')) ], prefs, vcs_bash):
+                    for s in utils.popenReadLines(self.root, [ vcs_bin, 'list', '-r', prev, '{}/{}'.format(self._getURL(prefs), p.replace(os.sep, '/')) ], prefs, vcs_bash):
                         if s.endswith('/'):
                             # confirmed item as directory
                             removed_dir.add(os.path.join(p, s[:-1]))
@@ -2441,8 +2381,8 @@ class _Svn:
     def getRevision(self, prefs, name, rev):
         vcs_bin = prefs.getString('svn_bin')
         if rev in [ 'BASE', 'COMMITTED', 'PREV' ]:
-            return popenRead(self.root, [ vcs_bin, 'cat', '{}@{}'.format(safeRelativePath(self.root, name, prefs, 'svn_cygwin'), rev) ], prefs, 'svn_bash')
+            return utils.popenRead(self.root, [ vcs_bin, 'cat', '{}@{}'.format(safeRelativePath(self.root, name, prefs, 'svn_cygwin'), rev) ], prefs, 'svn_bash')
-        return popenRead(self.root, [ vcs_bin, 'cat', '{}/{}@{}'.format(self._getURL(prefs), relpath(self.root, os.path.abspath(name)).replace(os.sep, '/'), rev) ], prefs, 'svn_bash')
+        return utils.popenRead(self.root, [ vcs_bin, 'cat', '{}/{}@{}'.format(self._getURL(prefs), relpath(self.root, os.path.abspath(name)).replace(os.sep, '/'), rev) ], prefs, 'svn_bash')
 
 def _get_svn_repo(path, prefs):
     p = _find_parent_dir_with(path, '.svn')
@@ -2472,7 +2412,7 @@ class _Svk(_Svn):
         return str(int(rev) - 1)
 
     def getRevision(self, prefs, name, rev):
-        return popenRead(self.root, [ prefs.getString('svk_bin'), 'cat', '-r', rev, '{}/{}'.format(self._getURL(prefs), relpath(self.root, os.path.abspath(name)).replace(os.sep, '/')) ], prefs, 'svk_bash')
+        return utils.popenRead(self.root, [ prefs.getString('svk_bin'), 'cat', '-r', rev, '{}/{}'.format(self._getURL(prefs), relpath(self.root, os.path.abspath(name)).replace(os.sep, '/')) ], prefs, 'svk_bash')
 
 def _get_svk_repo(path, prefs):
     name = path
@@ -6548,7 +6488,7 @@ class SearchDialog(Gtk.Dialog):
 
 # convenience method to request confirmation when closing the last tab
 def confirmTabClose(parent):
-    dialog = utils.MessageDialog(parent, Gtk.MessageType.WARNING, _('Closing this tab will quit %s.') % (utils.APP_NAME, ))
+    dialog = utils.MessageDialog(parent, Gtk.MessageType.WARNING, _('Closing this tab will quit %s.') % (constants.APP_NAME, ))
     end = (dialog.run() == Gtk.ResponseType.OK)
     dialog.destroy()
     return end
@@ -6642,17 +6582,17 @@ class AboutDialog(Gtk.AboutDialog):
     def __init__(self):
         Gtk.AboutDialog.__init__(self)
         self.set_logo_icon_name('io.github.mightycreak.Diffuse')
-        self.set_program_name(utils.APP_NAME)
+        self.set_program_name(constants.APP_NAME)
-        self.set_version(utils.VERSION)
+        self.set_version(constants.VERSION)
         self.set_comments(_('Diffuse is a graphical tool for merging and comparing text files.'))
-        self.set_copyright(utils.COPYRIGHT)
+        self.set_copyright(constants.COPYRIGHT)
-        self.set_website(utils.WEBSITE)
+        self.set_website(constants.WEBSITE)
         self.set_authors([ 'Derrick Moser <derrick_moser@yahoo.com>',
                            'Romain Failliot <romain.failliot@foolstep.com>' ])
         self.set_translator_credits(_('translator-credits'))
         license_text = [
-            utils.APP_NAME + ' ' + utils.VERSION + '\n\n',
+            constants.APP_NAME + ' ' + constants.VERSION + '\n\n',
-            utils.COPYRIGHT + '\n\n',
+            constants.COPYRIGHT + '\n\n',
             _('''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
@@ -6898,7 +6838,7 @@ class Diffuse(Gtk.Window):
             if self.headers[f].has_edits:
                 # warn users of any unsaved changes they might lose
                 dialog = Gtk.MessageDialog(self.get_toplevel(), Gtk.DialogFlags.DESTROY_WITH_PARENT, Gtk.MessageType.WARNING, Gtk.ButtonsType.NONE, _('Save changes before loading the new file?'))
-                dialog.set_title(utils.APP_NAME)
+                dialog.set_title(constants.APP_NAME)
                 dialog.add_button(Gtk.STOCK_CANCEL, Gtk.ResponseType.CANCEL)
                 dialog.add_button(Gtk.STOCK_NO, Gtk.ResponseType.REJECT)
                 dialog.add_button(Gtk.STOCK_YES, Gtk.ResponseType.OK)
@@ -7444,7 +7384,7 @@ class Diffuse(Gtk.Window):
         menuspecs.append([ _('_Help'), [
                      [_('_Help Contents...'), self.help_contents_cb, None, Gtk.STOCK_HELP, 'help_contents'],
                      [],
-                     [_('_About %s...') % (utils.APP_NAME, ), self.about_cb, None, Gtk.STOCK_ABOUT, 'about'] ] ])
+                     [_('_About %s...') % (constants.APP_NAME, ), self.about_cb, None, Gtk.STOCK_ABOUT, 'about'] ] ])
 
         # used to disable menu events when switching tabs
         self.menu_update_depth = 0
@@ -7561,7 +7501,7 @@ class Diffuse(Gtk.Window):
                 ss.append(f'{k} {v}\n')
             ss.sort()
             f = open(statepath, 'w')
-            f.write(f"# This state file was generated by {utils.APP_NAME} {utils.VERSION}.\n\n")
+            f.write(f"# This state file was generated by {constants.APP_NAME} {constants.VERSION}.\n\n")
             for s in ss:
                 f.write(s)
             f.close()
@@ -7601,7 +7541,7 @@ class Diffuse(Gtk.Window):
                                    buttons=Gtk.ButtonsType.NONE,
                                    text=_('Some files have unsaved changes.  Select the files to save before closing.'))
         dialog.set_resizable(True)
-        dialog.set_title(utils.APP_NAME)
+        dialog.set_title(constants.APP_NAME)
         # add list of files with unsaved changes
         sw = Gtk.ScrolledWindow.new()
         sw.set_policy(Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.AUTOMATIC)
@@ -7688,7 +7628,7 @@ class Diffuse(Gtk.Window):
     # update window's title
     def updateTitle(self, viewer):
         title = self.notebook.get_tab_label(viewer).get_text()
-        self.set_title(f'{title} - {utils.APP_NAME}')
+        self.set_title(f'{title} - {constants.APP_NAME}')
 
     # update the message in the status bar
     def setStatus(self, s):
@@ -8172,7 +8112,7 @@ class Diffuse(Gtk.Window):
                     del parts[-1]
         if help_url is None:
             # no local help file is available, show on-line help
-            help_url = utils.WEBSITE + 'manual.html'
+            help_url = constants.WEBSITE + 'manual.html'
             # ask for localised manual
             if utils.lang is not None:
                 help_url += '?lang=' + utils.lang
@@ -8193,17 +8133,15 @@ GObject.signal_new('reload', Diffuse.FileDiffViewer.PaneHeader, GObject.SignalFl
 GObject.signal_new('save', Diffuse.FileDiffViewer.PaneHeader, GObject.SignalFlags.RUN_LAST, GObject.TYPE_NONE, ())
 GObject.signal_new('save-as', Diffuse.FileDiffViewer.PaneHeader, GObject.SignalFlags.RUN_LAST, GObject.TYPE_NONE, ())
 
-def main(version, sysconfigdir):
+def main():
     # app = Application()
     # return app.run(sys.argv)
 
-    utils.VERSION = version
-
     args = sys.argv
     argc = len(args)
 
     if argc == 2 and args[1] in [ '-v', '--version' ]:
-        print('%s %s\n%s' % (utils.APP_NAME, utils.VERSION, utils.COPYRIGHT))
+        print('%s %s\n%s' % (constants.APP_NAME, constants.VERSION, constants.COPYRIGHT))
         sys.exit(0)
     if argc == 2 and args[1] in [ '-h', '-?', '--help' ]:
         print(_('''Usage:
@@ -8270,7 +8208,7 @@ Display Options:
         if utils.isWindows():
             rc_file = os.path.join(utils.bin_dir, 'diffuserc')
         else:
-            rc_file = os.path.join(utils.bin_dir, f'{sysconfigdir}/diffuserc')
+            rc_file = os.path.join(utils.bin_dir, f'{constants.sysconfigdir}/diffuserc')
         for rc_file in rc_file, os.path.join(rc_dir, 'diffuserc'):
             if os.path.isfile(rc_file):
                 rc_files.append(rc_file)

src/meson.build

@@ -10,6 +10,7 @@ conf.set('VERSION', meson.project_version())
 conf.set('localedir', join_paths(get_option('prefix'), get_option('localedir')))
 conf.set('pkgdatadir', pkgdatadir)
 conf.set('sysconfigdir', sysconfdir)
+conf.set('use_flatpak', get_option('use_flatpak'))
 
 configure_file(
   input: 'diffuse.in',
@@ -19,6 +20,14 @@ configure_file(
   install_dir: get_option('bindir')
 )
 
+configure_file(
+  input: 'constants.py.in',
+  output: 'constants.py',
+  configuration: conf,
+  install: true,
+  install_dir: moduledir
+)
+
 diffuse_sources = [
   '__init__.py',
   'main.py',

src/utils.py

@@ -20,12 +20,15 @@
 import os
 import sys
 import locale
+import subprocess
 
 import gi
 
 gi.require_version('Gtk', '3.0')
 from gi.repository import Gtk
 
+from diffuse import constants
+
 # convenience class for displaying a message dialogue
 class MessageDialog(Gtk.MessageDialog):
     def __init__(self, parent, type, s):
@@ -61,6 +64,71 @@ def make_subdirs(p, ss):
                 pass
     return p
 
+def useFlatpak():
+    return constants.use_flatpak
+
+# use popen to read the output of a command
+def popenRead(dn, cmd, prefs, bash_pref, success_results=None):
+    if success_results is None:
+        success_results = [ 0 ]
+    if isWindows() and prefs.getBool(bash_pref):
+        # launch the command from a bash shell is requested
+        cmd = [ prefs.convertToNativePath('/bin/bash.exe'), '-l', '-c', 'cd {}; {}'.format(bashEscape(dn), ' '.join([ bashEscape(arg) for arg in cmd ])) ]
+        dn = None
+    # use subprocess.Popen to retrieve the file contents
+    if isWindows():
+        info = subprocess.STARTUPINFO()
+        info.dwFlags |= subprocess.STARTF_USESHOWWINDOW
+        info.wShowWindow = subprocess.SW_HIDE
+    else:
+        info = None
+    if useFlatpak():
+        cmd = [ 'flatpak-spawn', '--host' ] + cmd
+    proc = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=dn, startupinfo=info)
+    proc.stdin.close()
+    proc.stderr.close()
+    fd = proc.stdout
+    # read the command's output
+    s = fd.read()
+    fd.close()
+    if proc.wait() not in success_results:
+        raise IOError('Command failed.')
+    return s
+
+# use popen to read the output of a command
+def popenReadLines(dn, cmd, prefs, bash_pref, success_results=None):
+    return strip_eols(splitlines(popenRead(dn, cmd, prefs, bash_pref, success_results).decode('utf-8', errors='ignore')))
+
+# simulate use of popen with xargs to read the output of a command
+def popenXArgsReadLines(dn, cmd, args, prefs, bash_pref):
+    # os.sysconf() is only available on Unix
+    if hasattr(os, 'sysconf'):
+        maxsize = os.sysconf('SC_ARG_MAX')
+        maxsize -= sum([ len(k) + len(v) + 2 for k, v in os.environ.items() ])
+    else:
+        # assume the Window's limit to CreateProcess()
+        maxsize = 32767
+    maxsize -= sum([ len(k) + 1 for k in cmd ])
+
+    ss = []
+    i, s, a = 0, 0, []
+    while i < len(args):
+        f = (len(a) == 0)
+        if f:
+            # start a new command line
+            a = cmd[:]
+        elif s + len(args[i]) + 1 <= maxsize:
+            f = True
+        if f:
+            # append another argument to the current command line
+            a.append(args[i])
+            s += len(args[i]) + 1
+            i += 1
+        if i == len(args) or not f:
+            ss.extend(popenReadLines(dn, a, prefs, bash_pref))
+            s, a = 0, []
+    return ss
+
 # use the program's location as a starting place to search for supporting files
 # such as icon and help documentation
 if hasattr(sys, 'frozen'):
@@ -85,9 +153,3 @@ if isWindows():
     else:
         if lang is not None:
             os.environ['LANG'] = lang
-
-APP_NAME = 'Diffuse'
-VERSION = '0.0.0'
-COPYRIGHT =  '''{copyright} © 2006-2019 Derrick Moser
-{copyright} © 2015-2021 Romain Failliot'''.format(copyright=_("Copyright"))
-WEBSITE = 'https://mightycreak.github.io/diffuse/'