wrapper: add common development wrapper

wrapper.py.in

@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+
+"""
+Runs an application in a manner that allows it to discover various engine
+resources that may be in unexpected locations.
+
+In particular: this allows running an application 'in-tree' under a debugger
+with dependencies and resources out of line.
+
+The base assumption is that this is probably a special circumstance and hence
+should be run reasonably verbose but not interfere with a probable debugger
+session.
+"""
+
+import platform
+import os
+import subprocess
+import sys
+
+# We need these ASAN options set so that nVidia's driver doesn't force an
+# immediate halt.
+#
+# invalid_pointer_pairs gives overly verbose reports from deep within some
+# core dependencies so it's not enabled by default.
+asan_options = {
+    'protect_shadow_gap': 0,
+    'detect_stack_use_after_return': 1,
+    #'detect_invalid_pointer_pairs': 1,
+}
+
+
+# A path that contains our application, the resources, and the runtime
+# configuration.
+#
+# It is probably assumed that the root will directly contain a 'config.json';
+# but there's a definitely an assumption that we won't travel deeper into a
+# hierarchy without foreknowledge that we're dealing with a good path, so don't
+# set this to something stupid like '/'.
+#
+# By default we find the first path below us that contains a 'config.json'
+# file under the assumption this script sits within a game directory structure.
+
+def find_root(init, default):
+    cursor = init
+
+    while True:
+        if os.path.isfile(os.path.join(cursor, 'config.json')):
+            return cursor
+
+        parent = os.path.dirname(cursor)
+        if parent == cursor:
+            return default
+
+        cursor = parent
+
+root = os.path.abspath(os.path.dirname(__file__))
+root = find_root(root, default=root)
+
+
+defaults = {
+    # don't break terrifically often, given we're probably running a debugger,
+    # but write a lot of information to the console.
+    'BREAK_LEVEL': 'CRITICAL',
+    'LOG_LEVEL': 'DEBUG',
+
+    'CL_VENDOR_IGNORE': 'intel64.icd',
+
+    'ROOT': root,
+
+    'ASAN_OPTIONS': ':'.join (f"{k}={v}" for k,v in asan_options.items())
+}
+
+# Overwrite our defaults with the current environment. This ensures a user can
+# override any of the above variables easily from the commandline.
+
+env = defaults.copy()
+env.update(os.environ)
+
+# Windows has its own unique rules for library lookups. We record the
+# environment variable which effects path lookups and the separator and the
+# target directory for Windows and for every single other system we're likely
+# to ever deal with...
+if platform.system() == 'Windows':
+    separator = ';'
+    depsdir = ['bin']
+    searchvar = 'PATH'
+else:
+    separator = ':'
+    depsdir = ['lib', 'lib64']
+    searchvar = 'LD_LIBRARY_PATH'
+
+
+# append the in-tree dependencies to the library path
+search = separator.join(
+    "@CMAKE_CURRENT_BINARY_DIR@/deps/" + i for i in depsdir
+)
+
+if searchvar in env:
+    env[searchvar] = search + separator + env[searchvar]
+else:
+    env[searchvar] = search
+
+# It's probably unnecessary to pipe std
+res = subprocess.run(sys.argv[1:], env=env, stderr=sys.stderr, stdout=sys.stdout)
+sys.exit(res.returncode)