Add macro_name option to configure_file

Allow macro_name to be speficied as a parameter to configure_file().
This allows C macro-style include guards to be added to
configure_file()'s output when a template file is not given. This change
simplifies the creation of configure files that define macros with
dynamic names and want the C-style include guards.

1 files changed, 14 insertions, 5 deletions

diff --git a/mesonbuild/utils/universal.py b/mesonbuild/utils/universal.py
index 7f0f385..1d0e382 100644
--- a/mesonbuild/utils/universal.py
+++ b/mesonbuild/utils/universal.py
@@ -1351,7 +1351,7 @@ CONF_C_PRELUDE = '''/*
  * Do not edit, your changes will be lost.
  */
 
-#pragma once
+{}
 
 '''
 
@@ -1360,10 +1360,16 @@ CONF_NASM_PRELUDE = '''; Autogenerated by the Meson build system.
 
 '''
 
-def _dump_c_header(ofile: T.TextIO, cdata: ConfigurationData, output_format: Literal['c', 'nasm']) -> None:
+def _dump_c_header(ofile: T.TextIO,
+                   cdata: ConfigurationData,
+                   output_format: Literal['c', 'nasm'],
+                   macro_name: T.Optional[str]) -> None:
     format_desc: T.Callable[[str], str]
     if output_format == 'c':
-        prelude = CONF_C_PRELUDE
+        if macro_name:
+            prelude = CONF_C_PRELUDE.format('#ifndef {0}\n#define {0}'.format(macro_name))
+        else:
+            prelude = CONF_C_PRELUDE.format('#pragma once')
         prefix = '#'
         format_desc = lambda desc: f'/* {desc} */\n'
     else:  # nasm
@@ -1385,17 +1391,20 @@ def _dump_c_header(ofile: T.TextIO, cdata: ConfigurationData, output_format: Lit
             ofile.write(f'{prefix}define {k} {v}\n\n')
         else:
             raise MesonException('Unknown data type in configuration file entry: ' + k)
+    if output_format == 'c' and macro_name:
+        ofile.write('#endif\n')
 
 
 def dump_conf_header(ofilename: str, cdata: ConfigurationData,
-                     output_format: Literal['c', 'nasm', 'json']) -> None:
+                     output_format: Literal['c', 'nasm', 'json'],
+                     macro_name: T.Optional[str]) -> None:
     ofilename_tmp = ofilename + '~'
     with open(ofilename_tmp, 'w', encoding='utf-8') as ofile:
         if output_format == 'json':
             data = {k: v[0] for k, v in cdata.values.items()}
             json.dump(data, ofile, sort_keys=True)
         else:  # c, nasm
-            _dump_c_header(ofile, cdata, output_format)
+            _dump_c_header(ofile, cdata, output_format, macro_name)
 
     replace_if_different(ofilename, ofilename_tmp)