apple/ErrorRef: new library wrapping CFErrorRef

src/apple/ErrorRef.hxx

+/*
+ * Copyright 2020 Max Kellermann <max.kellermann@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef APPLE_ERROR_REF_HXX
+#define APPLE_ERROR_REF_HXX
+
+#include <CoreFoundation/CFError.h>
+
+#include <utility>
+
+namespace Apple {
+
+class ErrorRef {
+	CFErrorRef ref = nullptr;
+
+public:
+	explicit ErrorRef(CFErrorRef _ref) noexcept
+		:ref(_ref) {}
+
+	ErrorRef(CFAllocatorRef allocator, CFErrorDomain domain,
+		 CFIndex code, CFDictionaryRef userInfo) noexcept
+		:ref(CFErrorCreate(allocator, domain, code, userInfo)) {}
+
+	ErrorRef(ErrorRef &&src) noexcept
+		:ref(std::exchange(src.ref, nullptr)) {}
+
+	~ErrorRef() noexcept {
+		if (ref)
+			CFRelease(ref);
+	}
+
+	ErrorRef &operator=(ErrorRef &&src) noexcept {
+		using std::swap;
+		swap(ref, src.ref);
+		return *this;
+	}
+
+	operator bool() const noexcept {
+		return ref != nullptr;
+	}
+
+	CFStringRef CopyDescription() const noexcept {
+		return CFErrorCopyDescription(ref);
+	}
+};
+
+} // namespace Apple
+
+#endif

src/output/plugins/OSXOutputPlugin.cxx

@@ -17,9 +17,10 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "apple/StringRef.hxx"
 #include "config.h"
 #include "OSXOutputPlugin.hxx"
+#include "apple/ErrorRef.hxx"
+#include "apple/StringRef.hxx"
 #include "../OutputAPI.hxx"
 #include "mixer/MixerList.hxx"
 #include "util/RuntimeError.hxx"
@@ -111,14 +112,12 @@ static constexpr Domain osx_output_domain("osx_output");
 static void
 osx_os_status_to_cstring(OSStatus status, char *str, size_t size)
 {
-	CFErrorRef cferr = CFErrorCreate(nullptr, kCFErrorDomainOSStatus, status, nullptr);
-	const Apple::StringRef cfstr(CFErrorCopyDescription(cferr));
+	Apple::ErrorRef cferr(nullptr, kCFErrorDomainOSStatus, status, nullptr);
+	const Apple::StringRef cfstr(cferr.CopyDescription());
 	if (!cfstr.GetCString(str, size)) {
 		/* conversion failed, return empty string */
 		*str = '\0';
 	}
-	if (cferr)
-		CFRelease(cferr);
 }
 
 static bool