[build-script] Factor out helper for validating the args.

Author: ddunbar

utils/build-script

@@ -68,10 +68,55 @@ def call_without_sleeping(command, dry_run=False):
 class BuildScriptInvocation(object):
     """Represent a single build script invocation."""
 
+    @staticmethod
+    def validate_arguments(toolchain, args):
+        if toolchain.cc is None or toolchain.cxx is None:
+            diagnostics.fatal(
+                "can't find clang (please install clang-3.5 or a "
+                "later version)")
+
+        if toolchain.cmake is None:
+            diagnostics.fatal("can't find CMake (please install CMake)")
+
+        if args.distcc:
+            if toolchain.distcc is None:
+                diagnostics.fatal(
+                    "can't find distcc (please install distcc)")
+            if toolchain.distcc_pump is None:
+                diagnostics.fatal(
+                    "can't find distcc-pump (please install distcc-pump)")
+
+        if args.host_target is None or args.stdlib_deployment_targets is None:
+            diagnostics.fatal("unknown operating system")
+
+        if args.symbols_package:
+            if not os.path.isabs(args.symbols_package):
+                print(
+                    '--symbols-package must be an absolute path '
+                    '(was \'{}\')'.format(args.symbols_package))
+                return 1
+            if not args.install_symroot:
+                diagnostics.fatal(
+                    "--install-symroot is required when specifying "
+                    "--symbols-package.")
+
+        if args.android:
+            if args.android_ndk is None or \
+                    args.android_api_level is None or \
+                    args.android_icu_uc is None or \
+                    args.android_icu_uc_include is None or \
+                    args.android_icu_i18n is None or \
+                    args.android_icu_i18n_include is None:
+                diagnostics.fatal(
+                    "when building for Android, --android-ndk, "
+                    "--android-ndk-version, --android-icu-uc, "
+                    "--android-icu-uc-include, --android-icu-i18n, "
+                    "and --android-icu-i18n-include must be specified")
+
     @staticmethod
     def apply_default_arguments(toolchain, args):
         """Preprocess an argument set to apply default behaviors."""
-        
+
         # Build cmark if any cmark-related options were specified.
         if (args.cmark_build_variant is not None):
             args.build_cmark = True
@@ -237,7 +282,7 @@ class BuildScriptInvocation(object):
         if args.android:
             args.stdlib_deployment_targets.append(
                 StdlibDeploymentTarget.Android.armv7)
-    
+
     def __init__(self, toolchain, args):
         self.toolchain = toolchain
         self.args = args
@@ -286,7 +331,7 @@ class BuildScriptInvocation(object):
         # Create local shadows, for convenience.
         args = self.args
         toolchain = self.toolchain
-        
+
         cmake = CMake(args=args,
                       toolchain=self.toolchain)
 
@@ -454,8 +499,8 @@ class BuildScriptInvocation(object):
                     args.install_prefix),
             ]
 
-        # If we have extra_swift_args, combine all of them together and then add
-        # them as one command.
+        # If we have extra_swift_args, combine all of them together and then
+        # add them as one command.
         if args.extra_swift_args:
             impl_args += [
                 "--extra-swift-args",
@@ -468,7 +513,7 @@ class BuildScriptInvocation(object):
                 "--extra-cmake-options=%s" % ' '.join(
                     pipes.quote(opt) for opt in args.extra_cmake_options)
             ]
-            
+
         if args.lto:
             impl_args += [
                 "--llvm-enable-lto",
@@ -493,13 +538,12 @@ class BuildScriptInvocation(object):
 
         return impl_args
 
+
 # Main entry point for the preset mode.
 def main_preset():
     parser = argparse.ArgumentParser(
         formatter_class=argparse.RawDescriptionHelpFormatter,
-        description=
-
-        """Builds Swift using a preset.""")
+        description="""Builds Swift using a preset.""")
     parser.add_argument(
         "-n", "--dry-run",
         help="print the commands that would be executed, but do not execute "
@@ -1469,51 +1513,12 @@ details of the setups of other systems or automated environments.""")
     if args.cmake is not None:
         toolchain.cmake = args.cmake
 
-    if toolchain.cc is None or toolchain.cxx is None:
-        diagnostics.fatal(
-            "can't find clang (please install clang-3.5 or a later version)")
-
-    if toolchain.cmake is None:
-        diagnostics.fatal("can't find CMake (please install CMake)")
-
-    if args.distcc:
-        if toolchain.distcc is None:
-            diagnostics.fatal(
-                "can't find distcc (please install distcc)")
-        if toolchain.distcc_pump is None:
-            diagnostics.fatal(
-                "can't find distcc-pump (please install distcc-pump)")
-
-    if args.host_target is None or args.stdlib_deployment_targets is None:
-        diagnostics.fatal("unknown operating system")
-
-    if args.symbols_package:
-        if not os.path.isabs(args.symbols_package):
-            print(
-                '--symbols-package must be an absolute path '
-                '(was \'{}\')'.format(args.symbols_package))
-            return 1
-        if not args.install_symroot:
-            diagnostics.fatal(
-                "--install-symroot is required when specifying "
-                "--symbols-package.")
-
-    if args.android:
-        if args.android_ndk is None or \
-                args.android_api_level is None or \
-                args.android_icu_uc is None or \
-                args.android_icu_uc_include is None or \
-                args.android_icu_i18n is None or \
-                args.android_icu_i18n_include is None:
-            diagnostics.fatal("when building for Android, --android-ndk, "
-                              "--android-ndk-version, --android-icu-uc, "
-                              "--android-icu-uc-include, --android-icu-i18n, "
-                              "and --android-icu-i18n-include must be "
-                              "specified")
+    # Validate the arguments.
+    BuildScriptInvocation.validate_arguments(toolchain, args)
 
     # Preprocess the arguments to apply defaults.
     BuildScriptInvocation.apply_default_arguments(toolchain, args)
-            
+
     # Create the build script invocation.
     invocation = BuildScriptInvocation(toolchain, args)