gst-env.py

   1 #!/usr/bin/env python3
   2
   3 import argparse
   4 import glob
   5 import json
   6 import os
   7 import platform
   8 import re
   9 import shlex
  10 import shutil
  11 import subprocess
  12 import tempfile
  13 import pathlib
  14 import signal
  15 from functools import lru_cache
  16 from pathlib import PurePath, Path
  17
  18 from typing import Any
  19
  20 from scripts.common import get_meson
  21 from scripts.common import git
  22 from scripts.common import win32_get_short_path_name
  23 from scripts.common import get_wine_shortpath
  24
  25 SCRIPTDIR = os.path.dirname(os.path.realpath(__file__))
  26 PREFIX_DIR = os.path.join(SCRIPTDIR, 'prefix')
  27 # Look for the following build dirs: `build` `_build` `builddir`
  28 DEFAULT_BUILDDIR = os.path.join(SCRIPTDIR, 'build')
  29 if not os.path.exists(DEFAULT_BUILDDIR):
  30     DEFAULT_BUILDDIR = os.path.join(SCRIPTDIR, '_build')
  31 if not os.path.exists(DEFAULT_BUILDDIR):
  32     DEFAULT_BUILDDIR = os.path.join(SCRIPTDIR, 'builddir')
  33
  34 TYPELIB_REG = re.compile(r'.*\.typelib$')
  35 SHAREDLIB_REG = re.compile(r'\.so|\.dylib|\.dll')
  36
  37 # libdir is expanded from option of the same name listed in the `meson
  38 # introspect --buildoptions` output.
  39 GSTPLUGIN_FILEPATH_REG_TEMPLATE = r'.*/{libdir}/gstreamer-1.0/[^/]+$'
  40 GSTPLUGIN_FILEPATH_REG = None
  41
  42 BC_RC = '''
  43 BASH_COMPLETION_SCRIPTS="{bash_completions}"
  44 BASH_COMPLETION_PATHS="{bash_completions_paths}"
  45 for p in $BASH_COMPLETION_PATHS; do
  46 for f in $BASH_COMPLETION_SCRIPTS; do
  47   [ -f "$p/$f" ] && . "$p/$f"
  48 done
  49 done
  50 '''
  51 BASH_COMPLETION_PATHS = [SCRIPTDIR + '/subprojects/gstreamer/data/bash-completion/completions']
  52 BASH_COMPLETION_PATHS += [SCRIPTDIR + '/subprojects/gst-devtools/validate/data/bash-completion/completions']
  53
  54
  55 def str_to_bool(value: Any) -> bool:
  56     """Return whether the provided string (or any value really) represents true. Otherwise false.
  57     Just like plugin server stringToBoolean.
  58     """
  59     if not value:
  60         return False
  61     return str(value).lower() in ("y", "yes", "t", "true", "on", "1")
  62
  63
  64 def listify(o):
  65     if isinstance(o, str):
  66         return [o]
  67     if isinstance(o, list):
  68         return o
  69     raise AssertionError('Object {!r} must be a string or a list'.format(o))
  70
  71
  72 def stringify(o):
  73     if isinstance(o, str):
  74         return o
  75     if isinstance(o, list):
  76         if len(o) == 1:
  77             return o[0]
  78         raise AssertionError('Did not expect object {!r} to have more than one element'.format(o))
  79     raise AssertionError('Object {!r} must be a string or a list'.format(o))
  80
  81
  82 def prepend_env_var(env, var, value, sysroot):
  83     if var is None:
  84         return
  85     if value.startswith(sysroot):
  86         value = value[len(sysroot):]
  87     # Try not to exceed maximum length limits for env vars on Windows
  88     if os.name == 'nt':
  89         value = win32_get_short_path_name(value)
  90     env_val = env.get(var, '')
  91     val = os.pathsep + value + os.pathsep
  92     # Don't add the same value twice
  93     if val in env_val or env_val.startswith(value + os.pathsep):
  94         return
  95     env[var] = val + env_val
  96     env[var] = env[var].replace(os.pathsep + os.pathsep, os.pathsep).strip(os.pathsep)
  97
  98
  99 def get_target_install_filename(target, filename):
 100     '''
 101     Checks whether this file is one of the files installed by the target
 102     '''
 103     basename = os.path.basename(filename)
 104     for install_filename in listify(target['install_filename']):
 105         if install_filename.endswith(basename):
 106             return install_filename
 107     return None
 108
 109
 110 def get_pkgconfig_variable_from_pcfile(pcfile, varname):
 111     variables = {}
 112     substre = re.compile('\$\{[^${}]+\}')
 113     with pcfile.open('r', encoding='utf-8') as f:
 114         for line in f:
 115             if '=' not in line:
 116                 continue
 117             key, value = line[:-1].split('=', 1)
 118             subst = {}
 119             for each in substre.findall(value):
 120                 substkey = each[2:-1]
 121                 subst[each] = variables.get(substkey, '')
 122             for k, v in subst.items():
 123                 value = value.replace(k, v)
 124             variables[key] = value
 125     return variables.get(varname, '')
 126
 127
 128 @lru_cache()
 129 def get_pkgconfig_variable(builddir, pcname, varname):
 130     '''
 131     Parsing isn't perfect, but it's good enough.
 132     '''
 133     pcfile = Path(builddir) / 'meson-private' / (pcname + '.pc')
 134     if pcfile.is_file():
 135         return get_pkgconfig_variable_from_pcfile(pcfile, varname)
 136     return subprocess.check_output(['pkg-config', pcname, '--variable=' + varname],
 137                                    universal_newlines=True, encoding='utf-8')
 138
 139
 140 def is_gio_module(target, filename, builddir):
 141     if target['type'] != 'shared module':
 142         return False
 143     install_filename = get_target_install_filename(target, filename)
 144     if not install_filename:
 145         return False
 146     giomoduledir = PurePath(get_pkgconfig_variable(builddir, 'gio-2.0', 'giomoduledir'))
 147     fpath = PurePath(install_filename)
 148     if fpath.parent != giomoduledir:
 149         return False
 150     return True
 151
 152
 153 def is_library_target_and_not_plugin(target, filename):
 154     '''
 155     Don't add plugins to PATH/LD_LIBRARY_PATH because:
 156     1. We don't need to
 157     2. It causes us to exceed the PATH length limit on Windows and Wine
 158     '''
 159     if target['type'] != 'shared library':
 160         return False
 161     # Check if this output of that target is a shared library
 162     if not SHAREDLIB_REG.search(filename):
 163         return False
 164     # Check if it's installed to the gstreamer plugin location
 165     install_filename = get_target_install_filename(target, filename)
 166     if not install_filename:
 167         return False
 168     global GSTPLUGIN_FILEPATH_REG
 169     if GSTPLUGIN_FILEPATH_REG is None:
 170         GSTPLUGIN_FILEPATH_REG = re.compile(GSTPLUGIN_FILEPATH_REG_TEMPLATE)
 171     if GSTPLUGIN_FILEPATH_REG.search(install_filename.replace('\\', '/')):
 172         return False
 173     return True
 174
 175
 176 def is_binary_target_and_in_path(target, filename, bindir):
 177     if target['type'] != 'executable':
 178         return False
 179     # Check if this file installed by this target is installed to bindir
 180     install_filename = get_target_install_filename(target, filename)
 181     if not install_filename:
 182         return False
 183     fpath = PurePath(install_filename)
 184     if fpath.parent != bindir:
 185         return False
 186     return True
 187
 188
 189 def get_wine_subprocess_env(options, env):
 190     with open(os.path.join(options.builddir, 'meson-info', 'intro-buildoptions.json')) as f:
 191         buildoptions = json.load(f)
 192
 193     prefix, = [o for o in buildoptions if o['name'] == 'prefix']
 194     path = os.path.normpath(os.path.join(prefix['value'], 'bin'))
 195     prepend_env_var(env, "PATH", path, options.sysroot)
 196     wine_path = get_wine_shortpath(
 197         options.wine.split(' '),
 198         [path] + env.get('WINEPATH', '').split(';')
 199     )
 200     if options.winepath:
 201         wine_path += ';' + options.winepath
 202     env['WINEPATH'] = wine_path
 203     env['WINEDEBUG'] = 'fixme-all'
 204
 205     return env
 206
 207
 208 def setup_gdb(options):
 209     python_paths = set()
 210
 211     if not shutil.which('gdb'):
 212         return python_paths
 213
 214     bdir = pathlib.Path(options.builddir).resolve()
 215     for libpath, gdb_path in [
 216             (os.path.join("subprojects", "gstreamer", "gst"),
 217              os.path.join("subprojects", "gstreamer", "libs", "gst", "helpers")),
 218             (os.path.join("subprojects", "glib", "gobject"), None),
 219             (os.path.join("subprojects", "glib", "glib"), None)]:
 220
 221         if not gdb_path:
 222             gdb_path = libpath
 223
 224         autoload_path = (pathlib.Path(bdir) / 'gdb-auto-load').joinpath(*bdir.parts[1:]) / libpath
 225         autoload_path.mkdir(parents=True, exist_ok=True)
 226         for gdb_helper in glob.glob(str(bdir / gdb_path / "*-gdb.py")):
 227             python_paths.add(str(bdir / gdb_path))
 228             python_paths.add(os.path.join(options.srcdir, gdb_path))
 229             try:
 230                 if os.name == 'nt':
 231                     shutil.copy(gdb_helper, str(autoload_path / os.path.basename(gdb_helper)))
 232                 else:
 233                     os.symlink(gdb_helper, str(autoload_path / os.path.basename(gdb_helper)))
 234             except (FileExistsError, shutil.SameFileError):
 235                 pass
 236
 237     gdbinit_line = 'add-auto-load-scripts-directory {}\n'.format(bdir / 'gdb-auto-load')
 238     try:
 239         with open(os.path.join(options.srcdir, '.gdbinit'), 'r') as f:
 240             if gdbinit_line in f.readlines():
 241                 return python_paths
 242     except FileNotFoundError:
 243         pass
 244
 245     with open(os.path.join(options.srcdir, '.gdbinit'), 'a') as f:
 246         f.write(gdbinit_line)
 247
 248     return python_paths
 249
 250
 251 def is_bash_completion_available(options):
 252     return os.path.exists(os.path.join(options.builddir, 'subprojects/gstreamer/data/bash-completion/helpers/gst'))
 253
 254
 255 def get_subprocess_env(options, gst_version):
 256     env = os.environ.copy()
 257
 258     env["CURRENT_GST"] = os.path.normpath(SCRIPTDIR)
 259     env["GST_VERSION"] = gst_version
 260     prepend_env_var(env, "GST_VALIDATE_SCENARIOS_PATH", os.path.normpath(
 261         "%s/subprojects/gst-devtools/validate/data/scenarios" % SCRIPTDIR),
 262         options.sysroot)
 263     env["GST_VALIDATE_PLUGIN_PATH"] = os.path.normpath(
 264         "%s/subprojects/gst-devtools/validate/plugins" % options.builddir)
 265     prepend_env_var(env, "GST_VALIDATE_APPS_DIR", os.path.normpath(
 266         "%s/subprojects/gst-editing-services/tests/validate" % SCRIPTDIR),
 267         options.sysroot)
 268     env["GST_ENV"] = 'gst-' + gst_version
 269     env["GST_REGISTRY"] = os.path.normpath(options.builddir + "/registry.dat")
 270     prepend_env_var(env, "PATH", os.path.normpath(
 271         "%s/subprojects/gst-devtools/validate/tools" % options.builddir),
 272         options.sysroot)
 273
 274     prepend_env_var(env, "GST_VALIDATE_SCENARIOS_PATH", os.path.normpath(
 275         "%s/subprojects/gst-examples/webrtc/check/validate/scenarios" %
 276         SCRIPTDIR), options.sysroot)
 277     prepend_env_var(env, "GST_VALIDATE_APPS_DIR", os.path.normpath(
 278         "%s/subprojects/gst-examples/webrtc/check/validate/apps" %
 279         SCRIPTDIR), options.sysroot)
 280
 281     if options.wine:
 282         return get_wine_subprocess_env(options, env)
 283
 284     prepend_env_var(env, "PATH", os.path.join(SCRIPTDIR, 'meson'),
 285         options.sysroot)
 286
 287     env["GST_PLUGIN_SYSTEM_PATH"] = ""
 288     env["GST_PLUGIN_SCANNER"] = os.path.normpath(
 289         "%s/subprojects/gstreamer/libs/gst/helpers/gst-plugin-scanner" % options.builddir)
 290     env["GST_PTP_HELPER"] = os.path.normpath(
 291         "%s/subprojects/gstreamer/libs/gst/helpers/gst-ptp-helper" % options.builddir)
 292
 293     if os.name == 'nt':
 294         lib_path_envvar = 'PATH'
 295     elif platform.system() == 'Darwin':
 296         # RPATH is sufficient on macOS, and DYLD_LIBRARY_PATH can cause issues with dynamic linker path priority
 297         lib_path_envvar = None
 298     else:
 299         lib_path_envvar = 'LD_LIBRARY_PATH'
 300
 301     prepend_env_var(env, "GST_PLUGIN_PATH", os.path.join(SCRIPTDIR, 'subprojects',
 302                                                         'gst-python', 'plugin'),
 303                     options.sysroot)
 304     prepend_env_var(env, "GST_PLUGIN_PATH", os.path.join(PREFIX_DIR, 'lib',
 305                                                         'gstreamer-1.0'),
 306                     options.sysroot)
 307     prepend_env_var(env, "GST_PLUGIN_PATH", os.path.join(options.builddir, 'subprojects',
 308                                                          'libnice', 'gst'),
 309                     options.sysroot)
 310     prepend_env_var(env, "GST_VALIDATE_SCENARIOS_PATH",
 311                     os.path.join(PREFIX_DIR, 'share', 'gstreamer-1.0',
 312                                  'validate', 'scenarios'),
 313                     options.sysroot)
 314     prepend_env_var(env, "GI_TYPELIB_PATH", os.path.join(PREFIX_DIR, 'lib',
 315                                                          'lib', 'girepository-1.0'),
 316                     options.sysroot)
 317     prepend_env_var(env, "PKG_CONFIG_PATH", os.path.join(PREFIX_DIR, 'lib', 'pkgconfig'),
 318                     options.sysroot)
 319
 320     # gst-indent
 321     prepend_env_var(env, "PATH", os.path.join(SCRIPTDIR, 'scripts'),
 322                     options.sysroot)
 323
 324     # tools: gst-launch-1.0, gst-inspect-1.0
 325     prepend_env_var(env, "PATH", os.path.join(options.builddir, 'subprojects',
 326                                               'gstreamer', 'tools'),
 327                     options.sysroot)
 328     # plugin scanner and generator
 329     prepend_env_var(env, "PATH", os.path.join(options.builddir, 'subprojects',
 330                                               'gstreamer', 'docs'),
 331                     options.sysroot)
 332     prepend_env_var(env, "PATH", os.path.join(options.builddir, 'subprojects',
 333                                               'gst-plugins-base', 'tools'),
 334                     options.sysroot)
 335
 336     # Library and binary search paths
 337     prepend_env_var(env, "PATH", os.path.join(PREFIX_DIR, 'bin'),
 338                     options.sysroot)
 339     if lib_path_envvar != 'PATH':
 340         prepend_env_var(env, lib_path_envvar, os.path.join(PREFIX_DIR, 'lib'),
 341                         options.sysroot)
 342         prepend_env_var(env, lib_path_envvar, os.path.join(PREFIX_DIR, 'lib64'),
 343                         options.sysroot)
 344     elif 'QMAKE' in os.environ:
 345         # There's no RPATH on Windows, so we need to set PATH for the qt5 DLLs
 346         prepend_env_var(env, 'PATH', os.path.dirname(os.environ['QMAKE']),
 347                         options.sysroot)
 348
 349     meson = get_meson()
 350     targets_s = subprocess.check_output(meson + ['introspect', options.builddir, '--targets'])
 351     targets = json.loads(targets_s.decode())
 352     paths = set()
 353     mono_paths = set()
 354     srcdir_path = pathlib.Path(options.srcdir)
 355
 356     build_options_s = subprocess.check_output(meson + ['introspect', options.builddir, '--buildoptions'])
 357     build_options = json.loads(build_options_s.decode())
 358     libdir, = [o['value'] for o in build_options if o['name'] == 'libdir']
 359     libdir = PurePath(libdir)
 360     prefix, = [o['value'] for o in build_options if o['name'] == 'prefix']
 361     bindir, = [o['value'] for o in build_options if o['name'] == 'bindir']
 362     prefix = PurePath(prefix)
 363     bindir = prefix / bindir
 364
 365     global GSTPLUGIN_FILEPATH_REG_TEMPLATE
 366     GSTPLUGIN_FILEPATH_REG_TEMPLATE = GSTPLUGIN_FILEPATH_REG_TEMPLATE.format(libdir=libdir.as_posix())
 367
 368     for target in targets:
 369         filenames = listify(target['filename'])
 370         if not target['installed']:
 371             continue
 372         for filename in filenames:
 373             root = os.path.dirname(filename)
 374             if srcdir_path / "subprojects/gst-devtools/validate/plugins" in (srcdir_path / root).parents:
 375                 continue
 376             if filename.endswith('.dll'):
 377                 mono_paths.add(os.path.join(options.builddir, root))
 378             if TYPELIB_REG.search(filename):
 379                 prepend_env_var(env, "GI_TYPELIB_PATH",
 380                                 os.path.join(options.builddir, root),
 381                                 options.sysroot)
 382             elif is_library_target_and_not_plugin(target, filename):
 383                 prepend_env_var(env, lib_path_envvar,
 384                                 os.path.join(options.builddir, root),
 385                                 options.sysroot)
 386             elif is_binary_target_and_in_path(target, filename, bindir):
 387                 paths.add(os.path.join(options.builddir, root))
 388             elif is_gio_module(target, filename, options.builddir):
 389                 prepend_env_var(env, 'GIO_EXTRA_MODULES',
 390                                 os.path.join(options.builddir, root),
 391                                 options.sysroot)
 392
 393     # Search for the Plugin paths file either in the build directory root
 394     # or check if gstreamer is a subproject of another project
 395     for sub_directories in [[], ['subprojects', 'gstreamer']]:
 396         plugin_paths = os.path.join(options.builddir, *sub_directories, 'GstPluginsPath.json')
 397         if os.path.exists(plugin_paths):
 398             with open(plugin_paths) as f:
 399                 for plugin_path in json.load(f):
 400                     prepend_env_var(env, 'GST_PLUGIN_PATH', plugin_path,
 401                                     options.sysroot)
 402             break
 403
 404     # Sort to iterate in a consistent order (`set`s and `hash`es are randomized)
 405     for p in sorted(paths):
 406         prepend_env_var(env, 'PATH', p, options.sysroot)
 407
 408     if os.name != 'nt':
 409         for p in sorted(mono_paths):
 410             prepend_env_var(env, "MONO_PATH", p, options.sysroot)
 411
 412     presets = set()
 413     encoding_targets = set()
 414     python_dirs = setup_gdb(options)
 415     overrides_dirs = set()
 416     if '--installed' in subprocess.check_output(meson + ['introspect', '-h']).decode():
 417         installed_s = subprocess.check_output(meson + ['introspect', options.builddir, '--installed'])
 418         for path, installpath in json.loads(installed_s.decode()).items():
 419             installpath_parts = pathlib.Path(installpath).parts
 420
 421             # We want to add all python modules to the PYTHONPATH
 422             # in a manner consistent with the way they would be imported:
 423             # For example if the source path /home/meh/foo/bar.py
 424             # is to be installed in /usr/lib/python/site-packages/foo/bar.py,
 425             # we want to add /home/meh to the PYTHONPATH.
 426             # This will only work for projects where the paths to be installed
 427             # mirror the installed directory layout, for example if the path
 428             # is /home/meh/baz/bar.py and the install path is
 429             # /usr/lib/site-packages/foo/bar.py , we will not add anything
 430             # to PYTHONPATH, but the current approach works with pygobject
 431             # and gst-python at least.
 432             if 'site-packages' in installpath_parts:
 433                 install_subpath = os.path.join(*installpath_parts[installpath_parts.index('site-packages') + 1:])
 434                 if path.endswith(install_subpath):
 435                     if os.path.commonprefix(["gi/overrides", install_subpath]):
 436                         overrides_dirs.add(os.path.dirname(path))
 437                     else:
 438                         python_dirs.add(path[:len(install_subpath) * -1])
 439
 440             if path.endswith('.prs'):
 441                 presets.add(os.path.dirname(path))
 442             elif path.endswith('.gep'):
 443                 encoding_targets.add(
 444                     os.path.abspath(os.path.join(os.path.dirname(path), '..')))
 445
 446             if path.endswith('gstomx.conf'):
 447                 prepend_env_var(env, 'GST_OMX_CONFIG_DIR', os.path.dirname(path),
 448                                 options.sysroot)
 449
 450         for p in sorted(presets):
 451             prepend_env_var(env, 'GST_PRESET_PATH', p, options.sysroot)
 452
 453         for t in sorted(encoding_targets):
 454             prepend_env_var(env, 'GST_ENCODING_TARGET_PATH', t, options.sysroot)
 455
 456     # Check if meson has generated -uninstalled pkgconfig files
 457     meson_uninstalled = pathlib.Path(options.builddir) / 'meson-uninstalled'
 458     if meson_uninstalled.is_dir():
 459         prepend_env_var(env, 'PKG_CONFIG_PATH', str(meson_uninstalled), options.sysroot)
 460
 461     for python_dir in sorted(python_dirs):
 462         prepend_env_var(env, 'PYTHONPATH', python_dir, options.sysroot)
 463
 464     for python_dir in sorted(overrides_dirs):
 465         prepend_env_var(env, '_GI_OVERRIDES_PATH', python_dir, options.sysroot)
 466
 467     mesonpath = os.path.join(SCRIPTDIR, "meson")
 468     if os.path.join(mesonpath):
 469         # Add meson/ into PYTHONPATH if we are using a local meson
 470         prepend_env_var(env, 'PYTHONPATH', mesonpath, options.sysroot)
 471
 472     # Ensure that gst-python/gi is used first
 473     prepend_env_var(env, "PYTHONPATH", os.path.join(SCRIPTDIR, 'subprojects', 'gst-python'),
 474                     options.sysroot)
 475
 476     # For devhelp books
 477     if 'XDG_DATA_DIRS' not in env or not env['XDG_DATA_DIRS']:
 478         # Preserve default paths when empty
 479         prepend_env_var(env, 'XDG_DATA_DIRS', '/usr/local/share/:/usr/share/', '')
 480
 481     prepend_env_var(env, 'XDG_DATA_DIRS', os.path.join(options.builddir,
 482                                                        'subprojects',
 483                                                        'gst-docs',
 484                                                        'GStreamer-doc'),
 485                     options.sysroot)
 486
 487     if 'XDG_CONFIG_DIRS' not in env or not env['XDG_CONFIG_DIRS']:
 488         # Preserve default paths when empty
 489         prepend_env_var(env, 'XDG_CONFIG_DIRS', '/etc/local/xdg:/etc/xdg', '')
 490
 491     prepend_env_var(env, "XDG_CONFIG_DIRS", os.path.join(PREFIX_DIR, 'etc', 'xdg'),
 492                     options.sysroot)
 493
 494     return env
 495
 496
 497 def get_windows_shell():
 498     command = ['powershell.exe', '-noprofile', '-executionpolicy', 'bypass', '-file',
 499         os.path.join(SCRIPTDIR, 'data', 'misc', 'cmd_or_ps.ps1')]
 500     result = subprocess.check_output(command)
 501     return result.decode().strip()
 502
 503
 504 if __name__ == "__main__":
 505     parser = argparse.ArgumentParser(prog="gst-env")
 506
 507     parser.add_argument("--builddir",
 508                         default=DEFAULT_BUILDDIR,
 509                         help="The meson build directory")
 510     parser.add_argument("--srcdir",
 511                         default=SCRIPTDIR,
 512                         help="The top level source directory")
 513     parser.add_argument("--sysroot",
 514                         default='',
 515                         help="The sysroot path used during cross-compilation")
 516     parser.add_argument("--wine",
 517                         default='',
 518                         help="Build a wine env based on specified wine command")
 519     parser.add_argument("--winepath",
 520                         default='',
 521                         help="Extra path to set to WINEPATH.")
 522     parser.add_argument("--only-environment",
 523                         action='store_true',
 524                         default=False,
 525                         help="Do not start a shell, only print required environment.")
 526     options, args = parser.parse_known_args()
 527
 528     if not os.path.exists(options.builddir):
 529         print("GStreamer not built in %s\n\nBuild it and try again" %
 530               options.builddir)
 531         exit(1)
 532     options.builddir = os.path.abspath(options.builddir)
 533
 534     if not os.path.exists(options.srcdir):
 535         print("The specified source dir does not exist" %
 536               options.srcdir)
 537         exit(1)
 538
 539     # The following incantation will retrieve the current branch name.
 540     try:
 541         gst_version = git("rev-parse", "--symbolic-full-name", "--abbrev-ref", "HEAD",
 542                           repository_path=options.srcdir).strip('\n')
 543     except subprocess.CalledProcessError:
 544         gst_version = "unknown"
 545
 546     if options.wine:
 547         gst_version += '-' + os.path.basename(options.wine)
 548
 549     env = get_subprocess_env(options, gst_version)
 550     if not args:
 551         if os.name == 'nt':
 552             shell = get_windows_shell()
 553             if shell == 'powershell.exe':
 554                 args = ['powershell.exe']
 555                 args += ['-NoLogo', '-NoExit']
 556                 prompt = 'function global:prompt {  "[gst-' + gst_version + '"+"] PS " + $PWD + "> "}'
 557                 args += ['-Command', prompt]
 558             else:
 559                 args = [os.environ.get("COMSPEC", r"C:\WINDOWS\system32\cmd.exe")]
 560                 args += ['/k', 'prompt [gst-{}] $P$G'.format(gst_version)]
 561         else:
 562             args = [os.environ.get("SHELL", os.path.realpath("/bin/sh"))]
 563         if args[0].endswith('bash') and not str_to_bool(os.environ.get("GST_BUILD_DISABLE_PS1_OVERRIDE", r"FALSE")):
 564             # Let the GC remove the tmp file
 565             tmprc = tempfile.NamedTemporaryFile(mode='w')
 566             bashrc = os.path.expanduser('~/.bashrc')
 567             if os.path.exists(bashrc):
 568                 with open(bashrc, 'r') as src:
 569                     shutil.copyfileobj(src, tmprc)
 570             tmprc.write('\nexport PS1="[gst-%s] $PS1"' % gst_version)
 571             tmprc.flush()
 572             if is_bash_completion_available(options):
 573                 bash_completions_files = []
 574                 for p in BASH_COMPLETION_PATHS:
 575                     if os.path.exists(p):
 576                         bash_completions_files += os.listdir(path=p)
 577                 bc_rc = BC_RC.format(bash_completions=' '.join(bash_completions_files), bash_completions_paths=' '.join(BASH_COMPLETION_PATHS))
 578                 tmprc.write(bc_rc)
 579                 tmprc.flush()
 580             args.append("--rcfile")
 581             args.append(tmprc.name)
 582         elif args[0].endswith('fish'):
 583             # Ignore SIGINT while using fish as the shell to make it behave
 584             # like other shells such as bash and zsh.
 585             # See: https://gitlab.freedesktop.org/gstreamer/gst-build/issues/18
 586             signal.signal(signal.SIGINT, lambda x, y: True)
 587             # Set the prompt
 588             args.append('--init-command')
 589             prompt_cmd = '''functions --copy fish_prompt original_fish_prompt
 590             function fish_prompt
 591                 echo -n '[gst-{}] '(original_fish_prompt)
 592             end'''.format(gst_version)
 593             args.append(prompt_cmd)
 594         elif args[0].endswith('zsh'):
 595             tmpdir = tempfile.TemporaryDirectory()
 596             # Let the GC remove the tmp file
 597             tmprc = open(os.path.join(tmpdir.name, '.zshrc'), 'w')
 598             zshrc = os.path.expanduser('~/.zshrc')
 599             if os.path.exists(zshrc):
 600                 with open(zshrc, 'r') as src:
 601                     shutil.copyfileobj(src, tmprc)
 602             tmprc.write('\nexport PROMPT="[gst-{}] $PROMPT"'.format(gst_version))
 603             tmprc.flush()
 604             env['ZDOTDIR'] = tmpdir.name
 605     try:
 606         if options.only_environment:
 607             for name, value in env.items():
 608                 print('{}={}'.format(name, shlex.quote(value)))
 609                 print('export {}'.format(name))
 610         else:
 611             if os.environ.get("CI_PROJECT_NAME"):
 612                 print("Ignoring SIGINT when running on the CI,"
 613                       " as we get spurious sigint in there for some reason.")
 614                 signal.signal(signal.SIGINT, signal.SIG_IGN)
 615             exit(subprocess.call(args, close_fds=False, env=env))
 616
 617     except subprocess.CalledProcessError as e:
 618         exit(e.returncode)