[utils] Inline caffeinate logic into sole client.

- This eliminates the last client of `SwiftBuildSupport.check_call`, which is
   now replaced by `swift_build_support.shell.call`.

 - Part of SR-237.

utils/SwiftBuildSupport.py

@@ -18,7 +18,6 @@ except ImportError:
     import configparser as ConfigParser
 
 import os
-import platform
 import subprocess
 import sys
 
@@ -70,28 +69,6 @@ SWIFT_BUILD_ROOT = os.environ.get(
     "SWIFT_BUILD_ROOT", os.path.join(SWIFT_SOURCE_ROOT, "build"))
 
 
-def check_call(args, print_command=False, verbose=False, disable_sleep=False):
-    if disable_sleep:
-        if platform.system() == 'Darwin':
-            # Don't mutate the caller's copy of the arguments.
-            args = list(args)
-            args.insert(0, "caffeinate")
-
-    if print_command:
-        print(os.getcwd() + "$ " + shell.quote_command(args))
-        sys.stdout.flush()
-    try:
-        return subprocess.check_call(args)
-    except subprocess.CalledProcessError as e:
-        diagnostics.fatal(
-            "command terminated with a non-zero exit status " +
-            str(e.returncode) + ", aborting")
-    except OSError as e:
-        diagnostics.fatal(
-            "could not execute '" + shell.quote_command(args) +
-            "': " + e.strerror)
-
-
 def check_output(args, print_command=False, verbose=False):
     if print_command:
         print(os.getcwd() + "$ " + shell.quote_command(args))

utils/build-script

@@ -28,7 +28,6 @@ from SwiftBuildSupport import (
     HOME,
     SWIFT_BUILD_ROOT,
     SWIFT_SOURCE_ROOT,
-    check_call,
     get_all_preset_names,
     get_preset_options,
 )  # noqa (E402 module level import not at top of file)
@@ -51,6 +50,21 @@ from swift_build_support.workspace import Workspace  # noqa(E402)
 from swift_build_support.workspace import compute_build_subdir  # noqa(E402)
 
 
+def call_without_sleeping(command, dry_run=False):
+    """
+    Execute a command during which system sleep is disabled.
+
+    By default, this ignores the state of the `shell.dry_run` flag.
+    """
+
+    # Disable system sleep, if possible.
+    if platform.system() == 'Darwin':
+        # Don't mutate the caller's copy of the arguments.
+        command = ["caffeinate"] + list(command)
+
+    shell.call(command, dry_run=dry_run, print_command=False)
+
+
 # Main entry point for the preset mode.
 def main_preset():
     parser = argparse.ArgumentParser(
@@ -124,7 +138,7 @@ def main_preset():
         "using preset '" + args.preset + "', which expands to \n\n" +
         shell.quote_command(build_script_args) + "\n")
 
-    check_call(build_script_args, disable_sleep=True)
+    call_without_sleeping(build_script_args)
 
     return 0
 
@@ -1429,8 +1443,7 @@ details of the setups of other systems or automated environments.""")
     if args.dry_run:
         build_script_impl_args += ["--dry-run"]
 
-    check_call([build_script_impl] + build_script_impl_args,
-               disable_sleep=True)
+    call_without_sleeping([build_script_impl] + build_script_impl_args)
 
     if args.symbols_package:
         print('--- Creating symbols package ---')