Added file_size and file_content_hex Jinja filters.

Added check if Jinja module exists and appropriate error message to
project generation.

addons/jinja.py

@@ -31,8 +31,19 @@ def _wrap_jinja(orig_jinja):
         return target
     return _wrapped
 
+def _file_size(env, fname: str) -> int:
+    return env.File(fname).get_size()
+
+def _file_content_hex(env, fname: str) -> str:
+    bytes = env.File(fname).get_contents()
+    return ','.join([hex(byte) for byte in bytes])
+
 env.AddMethod(_wrap_jinja(env.Jinja), 'Jinja')
 env.Append(JINJA_FILTERS = {'load_config': _jinja_load_config})
+env.Append(JINJA_GLOBALS = {
+    'file_size': lambda *args: _file_size(env, *args),
+    'file_content_hex': lambda *args: _file_content_hex(env, *args)
+})
 env.Append(JINJA_TEMPLATE_SEARCHPATH = ['data/jinja'])
 env['JINJA_CONFIG_SEARCHPATH'] = [env.Dir('#data/config')]
 Return('env')