add json output format to configure file

docs/markdown/snippets/json_output_format.md

@@ -0,0 +1,5 @@
+## Added 'json' output_format to configure_file()
+
+When no input file is specified, [[configure_file]] can now
+generate a `json` file from given [[@cfg_data]]. 
+Field descriptions are not preserved in the json file.

docs/yaml/functions/configure_file.yaml

@@ -134,7 +134,7 @@ kwargs:
       The format of the output to generate when no input
       was specified. It defaults to `c`, in which case preprocessor directives
       will be prefixed with `#`, you can also use `nasm`, in which case the
-      prefix will be `%`.
+      prefix will be `%`. *(since 1.3.0)* `json` format can also be used.
 
   encoding:
     type: str

mesonbuild/interpreter/interpreter.py

@@ -2594,8 +2594,8 @@ class Interpreter(InterpreterBase, HoldableObject):
         KwargInfo('install_dir', (str, bool), default='',
                   validator=lambda x: 'must be `false` if boolean' if x is True else None),
         OUTPUT_KW,
-        KwargInfo('output_format', str, default='c', since='0.47.0',
-                  validator=in_set_validator({'c', 'nasm'})),
+        KwargInfo('output_format', str, default='c', since='0.47.0', since_values={'json': '1.3.0'},
+                  validator=in_set_validator({'c', 'json', 'nasm'})),
     )
     def func_configure_file(self, node: mparser.BaseNode, args: T.List[TYPE_var],
                             kwargs: kwtypes.ConfigureFile):

mesonbuild/interpreter/kwargs.py

@@ -286,7 +286,7 @@ class ConfigureFile(TypedDict):
     output: str
     capture: bool
     format: T.Literal['meson', 'cmake', 'cmake@']
-    output_format: T.Literal['c', 'nasm']
+    output_format: T.Literal['c', 'json', 'nasm']
     depfile: T.Optional[str]
     install: T.Optional[bool]
     install_dir: T.Union[str, T.Literal[False]]

mesonbuild/utils/universal.py

@@ -32,6 +32,7 @@ import textwrap
 import copy
 import pickle
 import errno
+import json
 
 from mesonbuild import mlog
 from .core import MesonException, HoldableObject
@@ -1361,34 +1362,43 @@ CONF_NASM_PRELUDE = '''; Autogenerated by the Meson build system.
 
 '''
 
-def dump_conf_header(ofilename: str, cdata: 'ConfigurationData', output_format: Literal['c', 'nasm']) -> None:
+def _dump_c_header(ofile: T.TextIO, cdata: ConfigurationData, output_format: Literal['c', 'nasm']) -> None:
+    format_desc: T.Callable[[str], str]
     if output_format == 'c':
         prelude = CONF_C_PRELUDE
         prefix = '#'
-    else:
+        format_desc = lambda desc: f'/* {desc} */\n'
+    else:  # nasm
         prelude = CONF_NASM_PRELUDE
         prefix = '%'
+        format_desc = lambda desc: '; ' + '\n; '.join(desc.splitlines()) + '\n'
+
+    ofile.write(prelude)
+    for k in sorted(cdata.keys()):
+        (v, desc) = cdata.get(k)
+        if desc:
+            ofile.write(format_desc(desc))
+        if isinstance(v, bool):
+            if v:
+                ofile.write(f'{prefix}define {k}\n\n')
+            else:
+                ofile.write(f'{prefix}undef {k}\n\n')
+        elif isinstance(v, (int, str)):
+            ofile.write(f'{prefix}define {k} {v}\n\n')
+        else:
+            raise MesonException('Unknown data type in configuration file entry: ' + k)
+
 
+def dump_conf_header(ofilename: str, cdata: ConfigurationData,
+                     output_format: Literal['c', 'nasm', 'json']) -> None:
     ofilename_tmp = ofilename + '~'
     with open(ofilename_tmp, 'w', encoding='utf-8') as ofile:
-        ofile.write(prelude)
-        for k in sorted(cdata.keys()):
-            (v, desc) = cdata.get(k)
-            if desc:
-                if output_format == 'c':
-                    ofile.write('/* %s */\n' % desc)
-                elif output_format == 'nasm':
-                    for line in desc.split('\n'):
-                        ofile.write('; %s\n' % line)
-            if isinstance(v, bool):
-                if v:
-                    ofile.write(f'{prefix}define {k}\n\n')
-                else:
-                    ofile.write(f'{prefix}undef {k}\n\n')
-            elif isinstance(v, (int, str)):
-                ofile.write(f'{prefix}define {k} {v}\n\n')
-            else:
-                raise MesonException('Unknown data type in configuration file entry: ' + k)
+        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)
+
     replace_if_different(ofilename, ofilename_tmp)
 
 

test cases/common/269 configure file output format/compare.py

@@ -0,0 +1,5 @@
+import sys
+
+with open(sys.argv[1], 'r', encoding='utf-8') as f, open(sys.argv[2], 'r', encoding='utf-8') as g:
+    if f.read() != g.read():
+        sys.exit('contents are not equal')

test cases/common/269 configure file output format/expected/config.h

@@ -0,0 +1,21 @@
+/*
+ * Autogenerated by the Meson build system.
+ * Do not edit, your changes will be lost.
+ */
+
+#pragma once
+
+#define bool
+
+#undef false
+
+/* ultimate question of life, the universe, and everything */
+#define int 42
+
+/* This is
+a multiline
+description */
+#define str "hello world!"
+
+#define unquoted float
+

test cases/common/269 configure file output format/expected/config.json

@@ -0,0 +1 @@
+{"bool": true, "false": false, "int": 42, "str": "\"hello world!\"", "unquoted": "float"}

test cases/common/269 configure file output format/expected/config.nasm

@@ -0,0 +1,17 @@
+; Autogenerated by the Meson build system.
+; Do not edit, your changes will be lost.
+
+%define bool
+
+%undef false
+
+; ultimate question of life, the universe, and everything
+%define int 42
+
+; This is
+; a multiline
+; description
+%define str "hello world!"
+
+%define unquoted float
+

test cases/common/269 configure file output format/meson.build

@@ -0,0 +1,38 @@
+project('configure file output format')
+
+data = configuration_data()
+data.set_quoted('str', 'hello world!', description: '''This is
+a multiline
+description''')
+data.set('unquoted', 'float')
+data.set('int', 42, description: 'ultimate question of life, the universe, and everything')
+data.set('bool', true)
+data.set('false', false)
+
+config_h = configure_file(
+    configuration: data,
+    output_format: 'c',
+    output: 'config.h'
+)
+
+config_nasm = configure_file(
+    configuration: data,
+    output_format: 'nasm',
+    output: 'config.nasm'
+)
+
+config_json = configure_file(
+    configuration: data,
+    output_format: 'json',
+    output: 'config.json'
+)
+
+py = find_program('python3')
+compare_py = files('compare.py')
+expected_config_h = files('expected/config.h')
+expected_config_nasm = files('expected/config.nasm')
+expected_config_json = files('expected/config.json')
+
+test('c_output', py, args: [compare_py, expected_config_h, config_h])
+test('nasm_output', py, args: [compare_py, expected_config_nasm, config_nasm])
+test('json_output', py, args: [compare_py, expected_config_json, config_json])