Revert of [NaCl SDK] Remove create_nmf dependency on NACL_SDK_ROOT env var

native_client_sdk/src/tools/create_nmf.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Tool for automatically creating .nmf files from .nexe/.pexe/.bc executables.
 
 As well as creating the nmf file this tool can also find and stage
 any shared libraries dependencies that the executables might have.
 """
@@ skipping 448 matching lines @@
       else:
         canonicalized.append([unquoted[0], unquoted[2], unquoted[4]])
     else:
       err.write('Bad key:arch:url tuple for --extra-files: ' + kv + '\n')
   if seen_error:
     return None
   return canonicalized
 
 
 def GetSDKRoot():
-  """Returns the root directory of the NaCl SDK.
+  """Determine current NACL_SDK_ROOT, either via the environment variable
+  itself, or by attempting to derive it from the location of this script.
   """
-  # This script should be installed in NACL_SDK_ROOT/tools. Assert that
-  # the 'toolchain' folder exists within this directory in case, for
-  # example, this script is moved to a different location.
-  # During the Chrome build this script is sometimes run outside of
-  # of an SDK but in these cases it should always be run with --objdump=
-  # and --no-default-libpath which avoids the need to call this function.
-  sdk_root = os.path.dirname(SCRIPT_DIR)
-  assert(os.path.exists(os.path.join(sdk_root, 'toolchain')))
+  sdk_root = os.environ.get('NACL_SDK_ROOT')
+  if not sdk_root:
+    sdk_root = os.path.dirname(SCRIPT_DIR)
+    if not os.path.exists(os.path.join(sdk_root, 'toolchain')):
+      return None
+
   return sdk_root
 
 
 def FindObjdumpExecutable():
   """Derive path to objdump executable to use for determining shared
   object dependencies.
   """
+  sdk_root = GetSDKRoot()
+  if not sdk_root:
+    return None
+
   osname = getos.GetPlatform()
-  toolchain = os.path.join(GetSDKRoot(), 'toolchain', '%s_x86_glibc' % osname)
+  toolchain = os.path.join(sdk_root, 'toolchain', '%s_x86_glibc' % osname)
   objdump = os.path.join(toolchain, 'bin', 'x86_64-nacl-objdump')
   if osname == 'win':
     objdump += '.exe'
 
   if not os.path.exists(objdump):
     sys.stderr.write('WARNING: failed to find objdump in default '
                      'location: %s' % objdump)
     return None
 
   return objdump
 
 
 def GetDefaultLibPath(config):
   """Derive default library path to use when searching for shared
   objects.  This currently include the toolchain library folders
   as well as the top level SDK lib folder and the naclports lib
   folder.  We include both 32-bit and 64-bit library paths.
   """
   assert(config in ('Debug', 'Release'))
   sdk_root = GetSDKRoot()
+  if not sdk_root:
+    # TOOD(sbc): output a warning here?  We would also need to suppress
+    # the warning when run from the chromium build.
+    return []
 
   osname = getos.GetPlatform()
   libpath = [
     # Core toolchain libraries
     'toolchain/%s_x86_glibc/x86_64-nacl/lib' % osname,
     'toolchain/%s_x86_glibc/x86_64-nacl/lib32' % osname,
     # naclports installed libraries
     'toolchain/%s_x86_glibc/x86_64-nacl/usr/lib' % osname,
     'toolchain/%s_x86_glibc/i686-nacl/usr/lib' % osname,
     # SDK bundle libraries
@@ skipping 48 matching lines @@
                       metavar='DIRECTORY')
   parser.add_argument('--no-arch-prefix', action='store_true',
                       help='Don\'t put shared libraries in the lib32/lib64 '
                       'directories. Instead, they will be put in the same '
                       'directory as the .nexe that matches its architecture.')
   parser.add_argument('-t', '--toolchain', help='Legacy option, do not use')
   parser.add_argument('-n', '--name', dest='name',
                       help='Rename FOO as BAR',
                       action='append', default=[], metavar='FOO,BAR')
   parser.add_argument('-x', '--extra-files',
-                      help='Add extra key:file tuple to the "files"'
-                           ' section of the .nmf',
+                      help=('Add extra key:file tuple to the "files"' +
+                            ' section of the .nmf'),
                       action='append', default=[], metavar='FILE')
   parser.add_argument('-O', '--pnacl-optlevel',
                       help='Set the optimization level to N in PNaCl manifests',
                       metavar='N')
   parser.add_argument('--pnacl-debug-optlevel',
                       help='Set the optimization level to N for debugging '
                            'sections in PNaCl manifests',
                       metavar='N')
   parser.add_argument('-v', '--verbose',
                       help='Verbose output', action='store_true')
@@ skipping 67 matching lines @@
                  lib_path=options.lib_path,
                  extra_files=canonicalized,
                  lib_prefix=options.lib_prefix,
                  nexe_prefix=options.nexe_prefix,
                  no_arch_prefix=options.no_arch_prefix,
                  remap=remap,
                  pnacl_optlevel=pnacl_optlevel,
                  pnacl_debug_optlevel=pnacl_debug_optlevel,
                  nmf_root=nmf_root)
 
-  if options.output is None:
+  if not options.output:
     sys.stdout.write(nmf.GetJson())
   else:
     with open(options.output, 'w') as output:
       output.write(nmf.GetJson())
 
   if options.stage_dependencies and not nmf.pnacl:
     Trace('Staging dependencies...')
     nmf.StageDependencies(options.stage_dependencies)
 
   return 0
 
 
 if __name__ == '__main__':
   try:
     rtn = main(sys.argv[1:])
   except Error, e:
     sys.stderr.write('%s: %s\n' % (os.path.basename(__file__), e))
     rtn = 1
   except KeyboardInterrupt:
     sys.stderr.write('%s: interrupted\n' % os.path.basename(__file__))
     rtn = 1
   sys.exit(rtn)