Can generate config headers without an input file. Closes #549.

2 files changed, 34 insertions, 11 deletions

diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 47f9c7e..ba943e3 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -1887,13 +1887,11 @@ class Interpreter():
     def func_configure_file(self, node, args, kwargs):
         if len(args) > 0:
             raise InterpreterException("configure_file takes only keyword arguments.")
-        if not 'input' in kwargs:
-            raise InterpreterException('Required keyword argument "input" not defined.')
         if not 'output' in kwargs:
             raise InterpreterException('Required keyword argument "output" not defined.')
-        inputfile = kwargs['input']
+        inputfile = kwargs.get('input', None)
         output = kwargs['output']
-        if not isinstance(inputfile, str):
+        if not isinstance(inputfile, (str, type(None))):
             raise InterpreterException('Input must be a string.')
         if not isinstance(output, str):
             raise InterpreterException('Output must be a string.')
@@ -1903,16 +1901,20 @@ class Interpreter():
             conf = kwargs['configuration']
             if not isinstance(conf, ConfigurationDataHolder):
                 raise InterpreterException('Argument "configuration" is not of type configuration_data')
-
-            conffile = os.path.join(self.subdir, inputfile)
-            if conffile not in self.build_def_files:
-                self.build_def_files.append(conffile)
-            os.makedirs(os.path.join(self.environment.build_dir, self.subdir), exist_ok=True)
-            ifile_abs = os.path.join(self.environment.source_dir, self.subdir, inputfile)
             ofile_abs = os.path.join(self.environment.build_dir, self.subdir, output)
-            mesonlib.do_conf_file(ifile_abs, ofile_abs, conf.held_object)
+            if inputfile is not None:
+                conffile = os.path.join(self.subdir, inputfile)
+                if conffile not in self.build_def_files:
+                    self.build_def_files.append(conffile)
+                os.makedirs(os.path.join(self.environment.build_dir, self.subdir), exist_ok=True)
+                ifile_abs = os.path.join(self.environment.source_dir, self.subdir, inputfile)
+                mesonlib.do_conf_file(ifile_abs, ofile_abs, conf.held_object)
+            else:
+                mesonlib.dump_conf_header(ofile_abs, conf.held_object)
             conf.mark_used()
         elif 'command' in kwargs:
+            if 'input' not in kwargs:
+                raise InterpreterException('Required keyword input missing.')
             res = self.func_run_command(node, kwargs['command'], {})
             if res.returncode != 0:
                 raise InterpreterException('Running configure command failed.\n%s\n%s' %
diff --git a/mesonbuild/mesonlib.py b/mesonbuild/mesonlib.py
index fe831bd..584b3b2 100644
--- a/mesonbuild/mesonlib.py
+++ b/mesonbuild/mesonlib.py
@@ -267,6 +267,27 @@ def do_conf_file(src, dst, confdata):
     shutil.copymode(src, dst_tmp)
     replace_if_different(dst, dst_tmp)
 
+def dump_conf_header(ofilename, cdata):
+    with open(ofilename, 'w') as ofile:
+        ofile.write('''/*
+ * Autogenerated by the Meson build system.
+ * Do not edit, your changes will be lost.
+ */
+
+#pragma once
+
+''')
+        for k in sorted(cdata.keys()):
+            v = cdata.get(k)
+            if isinstance(v, bool):
+                if v:
+                    ofile.write('#define %s\n\n' % k)
+                else:
+                    ofile.write('#undef %s\n\n' % k)
+            elif isinstance(v, (int, str)):
+                ofile.write('#define %s %s\n\n' % (k, v))
+            else:
+                raise MesonException('Unknown data type in configuration file entry: ' + k)
 
 def replace_if_different(dst, dst_tmp):
     # If contents are identical, don't touch the file to prevent