lib/yajl/Callbacks: OO wrapper for yajl_callbacks

src/lib/yajl/Callbacks.hxx

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2018 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 YAJL_CALLBACKS_HXX
+#define YAJL_CALLBACKS_HXX
+
+#include "util/Cast.hxx"
+#include "util/StringView.hxx"
+
+#include <yajl/yajl_parse.h>
+
+namespace Yajl {
+
+/**
+ * Helper template which allows implementing callbacks as regular
+ * methods.  The "ctx" parameter is casted to the enclosing class.
+ */
+template<class T>
+struct CallbacksWrapper {
+	static T &Cast(void *ctx) {
+		return *(T *)ctx;
+	}
+
+	static int Integer(void *ctx, long long integerVal) noexcept {
+		return Cast(ctx).Integer(integerVal);
+	}
+
+	static int String(void *ctx, const unsigned char *stringVal,
+			  size_t stringLen) noexcept {
+		return Cast(ctx).String(StringView((const char *)stringVal,
+						   stringLen));
+	}
+
+	static int StartMap(void *ctx) noexcept {
+		return Cast(ctx).StartMap();
+	}
+
+	static int MapKey(void *ctx, const unsigned char *key,
+			  size_t stringLen) noexcept {
+		return Cast(ctx).MapKey(StringView((const char *)key,
+						   stringLen));
+	}
+
+	static int EndMap(void *ctx) noexcept {
+		return Cast(ctx).EndMap();
+	}
+};
+
+} // namespace Yajl
+
+#endif