Add snippets.symbol_visibility_header() method

Defining public API in a cross platform library is painful, especially
on Windows. Since every library have to define pretty much the same
macros, better do it in Meson.

1 files changed, 101 insertions, 0 deletions

diff --git a/mesonbuild/modules/snippets.py b/mesonbuild/modules/snippets.py
new file mode 100644
index 000000000..f93a754a8
--- /dev/null
+++ b/mesonbuild/modules/snippets.py
@@ -0,0 +1,101 @@
+# Copyright 2025 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+import textwrap
+import typing as T
+
+from pathlib import Path
+
+from . import NewExtensionModule, ModuleInfo
+from ..interpreterbase import KwargInfo, typed_kwargs, typed_pos_args
+from ..interpreter.type_checking import NoneType
+from .. import mesonlib
+
+if T.TYPE_CHECKING:
+    from typing_extensions import TypedDict
+    from . import ModuleState
+
+    class SymbolVisibilityHeaderKW(TypedDict):
+        namespace: T.Optional[str]
+        api: T.Optional[str]
+        compilation: T.Optional[str]
+        static_compilation: T.Optional[str]
+        static_only: bool
+
+
+class SnippetsModule(NewExtensionModule):
+
+    INFO = ModuleInfo('snippets', '1.10.0')
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.methods.update({
+            'symbol_visibility_header': self.symbol_visibility_header_method,
+        })
+
+    @typed_kwargs('snippets.symbol_visibility_header',
+                  KwargInfo('namespace', (str, NoneType)),
+                  KwargInfo('api', (str, NoneType)),
+                  KwargInfo('compilation', (str, NoneType)),
+                  KwargInfo('static_compilation', (str, NoneType)),
+                  KwargInfo('static_only', (bool, NoneType)))
+    @typed_pos_args('snippets.symbol_visibility_header', str)
+    def symbol_visibility_header_method(self, state: ModuleState, args: T.Tuple[str], kwargs: 'SymbolVisibilityHeaderKW') -> mesonlib.File:
+        header_name = args[0]
+        namespace = kwargs['namespace'] or state.project_name
+        namespace = mesonlib.underscorify(namespace).upper()
+        if namespace[0].isdigit():
+            namespace = f'_{namespace}'
+        api = kwargs['api'] or f'{namespace}_API'
+        compilation = kwargs['compilation'] or f'{namespace}_COMPILATION'
+        static_compilation = kwargs['static_compilation'] or f'{namespace}_STATIC_COMPILATION'
+        static_only = kwargs['static_only']
+        if static_only is None:
+            default_library = state.get_option('default_library')
+            static_only = default_library == 'static'
+        content = textwrap.dedent('''\
+            // SPDX-license-identifier: 0BSD OR CC0-1.0 OR WTFPL OR Apache-2.0 OR LGPL-2.0-or-later
+            #pragma once
+            ''')
+        if static_only:
+            content += textwrap.dedent(f'''
+                #ifndef {static_compilation}
+                #  define {static_compilation}
+                #endif /* {static_compilation} */
+                ''')
+        content += textwrap.dedent(f'''
+            #if (defined(_WIN32) || defined(__CYGWIN__)) && !defined({static_compilation})
+            #  define {api}_EXPORT __declspec(dllexport)
+            #  define {api}_IMPORT __declspec(dllimport)
+            #elif __GNUC__ >= 4
+            #  define {api}_EXPORT __attribute__((visibility("default")))
+            #  define {api}_IMPORT
+            #else
+            #  define {api}_EXPORT
+            #  define {api}_IMPORT
+            #endif
+
+            #ifdef {compilation}
+            #  define {api} {api}_EXPORT extern
+            #else
+            #  define {api} {api}_IMPORT extern
+            #endif
+            ''')
+        header_path = Path(state.environment.get_build_dir(), state.subdir, header_name)
+        header_path.write_text(content, encoding='utf-8')
+        return mesonlib.File.from_built_file(state.subdir, header_name)
+
+def initialize(*args: T.Any, **kwargs: T.Any) -> SnippetsModule:
+    return SnippetsModule()