Add support for C/C++, improve Obj-C handling (#129)

* Expand list of C extensions, ignore CppCompile for now

* Add support for C/C++

* Add support for specifying dependency rules to filter for

* Lint files

* Add more supported C++ file types

Author: rockbruno

Example/HelloWorld/BUILD

@@ -3,6 +3,7 @@ load("@build_bazel_rules_apple//apple:ios.bzl", "ios_application", "ios_unit_tes
 load("@build_bazel_rules_apple//apple:macos.bzl", "macos_application", "macos_command_line_application", "macos_unit_test")
 load("@build_bazel_rules_apple//apple:watchos.bzl", "watchos_application", "watchos_extension", "watchos_unit_test")
 load("@build_bazel_rules_swift//swift:swift.bzl", "swift_interop_hint", "swift_library")
+load("@rules_cc//cc:defs.bzl", "cc_library")
 load("@sourcekit_bazel_bsp//rules:setup_sourcekit_bsp.bzl", "setup_sourcekit_bsp")
 load("//tools:apple.bzl", "IOS_MINIMUM_OS_VERSION", "WATCHOS_MINIMUM_OS_VERSION", "MACOS_MINIMUM_OS_VERSION")
 
@@ -33,12 +34,29 @@ objc_library(
     name = "TodoObjCSupport",
     srcs = glob(
         [
-            "TodoObjCSupport/Sources/*.h",
+            "TodoObjCSupport/Sources/*.mm",
             "TodoObjCSupport/Sources/*.m",
         ],
     ),
     hdrs = glob(["TodoObjCSupport/Sources/*.h"]),
     aspect_hints = [":TodoObjCSupport_hint"],
+    deps = [":TodoCSupport"],
+)
+
+cc_library(
+    name = "TodoCSupport",
+    srcs = glob(
+        [
+            "TodoCSupport/src/*.cpp",
+            "TodoCSupport/src/*.c",
+        ],
+    ),
+    hdrs = glob(
+        [
+            "TodoCSupport/include/*.hpp",
+            "TodoCSupport/include/*.h",
+        ],
+    ),
 )
 
 swift_library(

Example/HelloWorld/HelloWorldLib/Sources/TodoItemRow.swift

@@ -42,9 +42,13 @@ struct TodoItemRow: View {
                     .foregroundColor(item.isCompleted ? .gray : .primary)
                     .animation(.easeInOut(duration: 0.2), value: item.isCompleted)
 
-                Text(SKDateDistanceCalculator.humanReadableDistance(fromNow: item.createdAt))
+                Text(SKObjCppUtils.humanReadableDistance(fromNow: item.createdAt))
                     .font(.caption)
                     .foregroundColor(.gray)
+                    .onAppear {
+                        print(SKObjCUtils.greetingFromC() as Any)
+                        print(SKObjCUtils.multiply(withC: 2, b: 2))
+                    }
             }
 
             Spacer()

Example/HelloWorld/TodoCSupport/include/SKCUtils.h

@@ -0,0 +1,34 @@
+// Copyright (c) 2025 Spotify AB.
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+
+#ifndef SK_C_UTILS_H
+#define SK_C_UTILS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+const char* sk_c_get_greeting(void);
+int sk_c_multiply(int a, int b);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

Example/HelloWorld/TodoCSupport/include/SKCppUtils.hpp

@@ -0,0 +1,13 @@
+#ifndef SK_CPP_UTILS_HPP
+#define SK_CPP_UTILS_HPP
+
+#include <string>
+
+namespace SKCppUtils {
+
+std::string getGreeting();
+int add(int a, int b);
+
+} // namespace SKCppUtils
+
+#endif

Example/HelloWorld/TodoCSupport/src/SKCUtils.c

@@ -0,0 +1,28 @@
+// Copyright (c) 2025 Spotify AB.
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+
+#include "../include/SKCUtils.h"
+
+const char* sk_c_get_greeting(void) {
+    return "Hello from C!";
+}
+
+int sk_c_multiply(int a, int b) {
+    return a * b;
+}

Example/HelloWorld/TodoCSupport/src/SKCppUtils.cpp

@@ -0,0 +1,13 @@
+#include "../include/SKCppUtils.hpp"
+
+namespace SKCppUtils {
+
+std::string getGreeting() {
+    return "Hello from C++!";
+}
+
+int add(int a, int b) {
+    return a + b;
+}
+
+} // namespace SKCppUtils

Example/HelloWorld/TodoObjCSupport/Sources/SKObjCUtils.h

@@ -0,0 +1,27 @@
+// Copyright (c) 2025 Spotify AB.
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+
+#import <Foundation/Foundation.h>
+
+@interface SKObjCUtils : NSObject
+
++ (NSString *)greetingFromC;
++ (NSInteger)multiplyWithC:(NSInteger)a b:(NSInteger)b;
+
+@end

Example/HelloWorld/TodoObjCSupport/Sources/SKObjCUtils.m

@@ -0,0 +1,34 @@
+// Copyright (c) 2025 Spotify AB.
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+
+#import "HelloWorld/TodoObjCSupport/Sources/SKObjCUtils.h"
+#import "HelloWorld/TodoCSupport/include/SKCUtils.h"
+
+@implementation SKObjCUtils
+
++ (NSString *)greetingFromC {
+    const char *cGreeting = sk_c_get_greeting();
+    return [NSString stringWithUTF8String:cGreeting];
+}
+
++ (NSInteger)multiplyWithC:(NSInteger)a b:(NSInteger)b {
+    return sk_c_multiply((int)a, (int)b);
+}
+
+@end

…pport/Sources/SKDateDistanceCalculator.h …/TodoObjCSupport/Sources/SKObjCppUtils.hExample/HelloWorld/TodoObjCSupport/Sources/SKDateDistanceCalculator.h renamed to Example/HelloWorld/TodoObjCSupport/Sources/SKObjCppUtils.h Example/HelloWorld/TodoObjCSupport/Sources/SKDateDistanceCalculator.h renamed to Example/HelloWorld/TodoObjCSupport/Sources/SKObjCppUtils.h

@@ -19,7 +19,7 @@
 
 #import <Foundation/Foundation.h>
 
-@interface SKDateDistanceCalculator : NSObject
+@interface SKObjCppUtils : NSObject
 
 /**
  * Calculates the time interval between the given date and now

…pport/Sources/SKDateDistanceCalculator.m …TodoObjCSupport/Sources/SKObjCppUtils.mmExample/HelloWorld/TodoObjCSupport/Sources/SKDateDistanceCalculator.m renamed to Example/HelloWorld/TodoObjCSupport/Sources/SKObjCppUtils.mm Example/HelloWorld/TodoObjCSupport/Sources/SKDateDistanceCalculator.m renamed to Example/HelloWorld/TodoObjCSupport/Sources/SKObjCppUtils.mm

@@ -17,15 +17,19 @@
 // specific language governing permissions and limitations
 // under the License.
 
-#import "HelloWorld/TodoObjCSupport/Sources/SKDateDistanceCalculator.h"
+#import "HelloWorld/TodoObjCSupport/Sources/SKObjCppUtils.h"
+#import "HelloWorld/TodoCSupport/include/SKCppUtils.hpp"
 
-@implementation SKDateDistanceCalculator
+@implementation SKObjCppUtils
 
 + (NSTimeInterval)distanceFromNow:(NSDate *)date {
   if (!date) {
     return 0.0;
   }
 
+  NSLog(@"%s", SKCppUtils::getGreeting().c_str());
+  NSLog(@"%ld", (long)SKCppUtils::add(1, 2));
+
   NSDate *now = [NSDate date];
   return [now timeIntervalSinceDate:date];
 }