1 files changed, 82 insertions, 0 deletions
diff --git a/platform_methods.py b/platform_methods.py
new file mode 100644
index 0000000000..4300216427
--- /dev/null
+++ b/platform_methods.py
@@ -0,0 +1,82 @@
+import os
+import sys
+import json
+import uuid
+import functools
+import subprocess
+
+# NOTE: The multiprocessing module is not compatible with SCons due to conflict on cPickle
+
+if sys.version_info[0] < 3:
+    JSON_SERIALIZABLE_TYPES = (bool, int, long, float, basestring)
+else:
+    JSON_SERIALIZABLE_TYPES = (bool, int, float, str)
+
+
+def run_in_subprocess(builder_function):
+
+    @functools.wraps(builder_function)
+    def wrapper(target, source, env):
+
+        # Convert SCons Node instances to absolute paths
+        target = [node.srcnode().abspath for node in target]
+        source = [node.srcnode().abspath for node in source]
+
+        # Short circuit on non-Windows platforms, no need to run in subprocess
+        if sys.platform not in ('win32', 'cygwin'):
+            return builder_function(target, source, env)
+
+        # Identify module
+        module_name = builder_function.__module__
+        function_name = builder_function.__name__
+        module_path = sys.modules[module_name].__file__
+        if module_path.endswith('.pyc') or module_path.endswith('.pyo'):
+            module_path = module_path[:-1]
+
+        # Subprocess environment
+        subprocess_env = os.environ.copy()
+        subprocess_env['PYTHONPATH'] = os.pathsep.join([os.getcwd()] + sys.path)
+
+        # Keep only JSON serializable environment items
+        filtered_env = dict(
+            (key, value)
+            for key, value in env.items()
+            if isinstance(value, JSON_SERIALIZABLE_TYPES)
+        )
+
+        # Save parameters
+        args = (target, source, filtered_env)
+        data = dict(fn=function_name, args=args)
+        json_path = os.path.join(os.environ['TMP'], uuid.uuid4().hex + '.json')
+        with open(json_path, 'wt') as json_file:
+            json.dump(data, json_file, indent=2)
+        json_file_size = os.stat(json_path).st_size
+
+        print('Executing builder function in subprocess: '
+              'module_path=%r, parameter_file=%r, parameter_file_size=%r, target=%r, source=%r' % (
+               module_path, json_path, json_file_size, target, source))
+        try:
+            exit_code = subprocess.call([sys.executable, module_path, json_path], env=subprocess_env)
+        finally:
+            try:
+                os.remove(json_path)
+            except (OSError, IOError) as e:
+                # Do not fail the entire build if it cannot delete a temporary file
+                print('WARNING: Could not delete temporary file: path=%r; [%s] %s' %
+                      (json_path, e.__class__.__name__, e))
+
+        # Must succeed
+        if exit_code:
+            raise RuntimeError(
+                'Failed to run builder function in subprocess: module_path=%r; data=%r' % (module_path, data))
+
+    return wrapper
+
+
+def subprocess_main(namespace):
+
+    with open(sys.argv[1]) as json_file:
+        data = json.load(json_file)
+
+    fn = namespace[data['fn']]
+    fn(*data['args'])