lib/yajl/Handle: libyajl C++ bindings

Makefile.am

@@ -242,6 +242,9 @@ CURL_SOURCES = \
 	src/lib/curl/Multi.hxx \
 	src/lib/curl/Slist.hxx
 
+YAJL_SOURCES = \
+	src/lib/yajl/Handle.hxx
+
 UPNP_SOURCES = \
 	src/lib/upnp/Compat.hxx \
 	src/lib/upnp/Init.cxx src/lib/upnp/Init.hxx \
@@ -1647,6 +1650,7 @@ endif
 
 if ENABLE_SOUNDCLOUD
 libplaylist_plugins_a_SOURCES += \
+	$(YAJL_SOURCES) \
 	src/playlist/plugins/SoundCloudPlaylistPlugin.cxx \
 	src/playlist/plugins/SoundCloudPlaylistPlugin.hxx
 PLAYLIST_LIBS += $(YAJL_LIBS)

src/lib/yajl/Handle.hxx

@@ -0,0 +1,93 @@
+/*
+ * 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_HANDLE_HXX
+#define YAJL_HANDLE_HXX
+
+#include "util/RuntimeError.hxx"
+#include "util/ScopeExit.hxx"
+
+#include <yajl/yajl_parse.h>
+
+#include <stdexcept>
+#include <algorithm>
+
+namespace Yajl {
+
+/**
+ * OO wrapper for "struct curl_slist *".
+ */
+class Handle {
+	yajl_handle handle = nullptr;
+
+public:
+	Handle() = default;
+
+	Handle(const yajl_callbacks *callbacks,
+	       yajl_alloc_funcs *afs,
+	       void *ctx) noexcept
+		:handle(yajl_alloc(callbacks, afs, ctx)) {}
+
+	Handle(Handle &&src) noexcept
+		:handle(std::exchange(src.handle, nullptr)) {}
+
+	~Handle() noexcept {
+		if (handle != nullptr)
+			yajl_free(handle);
+	}
+
+	Handle &operator=(Handle &&src) noexcept {
+		std::swap(handle, src.handle);
+		return *this;
+	}
+
+	void Parse(const unsigned char *jsonText, size_t jsonTextLength) {
+		HandleStatus(yajl_parse(handle, jsonText, jsonTextLength));
+	}
+
+	void CompleteParse() {
+		HandleStatus(yajl_complete_parse(handle));
+	}
+
+private:
+	void HandleStatus(yajl_status status) {
+		if (status == yajl_status_error) {
+			unsigned char *str = yajl_get_error(handle, false,
+							    nullptr, 0);
+			AtScopeExit(this, str) {
+				yajl_free_error(handle, str);
+			};
+			throw FormatRuntimeError("Failed to parse JSON: %s", str);
+		}
+	}
+};
+
+} // namespace Yajl
+
+#endif

src/playlist/plugins/SoundCloudPlaylistPlugin.cxx

@@ -21,6 +21,7 @@
 #include "SoundCloudPlaylistPlugin.hxx"
 #include "../PlaylistPlugin.hxx"
 #include "../MemorySongEnumerator.hxx"
+#include "lib/yajl/Handle.hxx"
 #include "config/Block.hxx"
 #include "input/InputStream.hxx"
 #include "tag/Builder.hxx"
@@ -30,8 +31,6 @@
 #include "util/ScopeExit.hxx"
 #include "Log.hxx"
 
-#include <yajl/yajl_parse.h>
-
 #include <string>
 
 #include <string.h>
@@ -221,18 +220,17 @@ static constexpr yajl_callbacks parse_callbacks = {
 /**
  * Read JSON data and parse it using the given YAJL parser.
  * @param url URL of the JSON data.
- * @param hand YAJL parser handle.
+ * @param handle YAJL parser handle.
  * @return -1 on error, 0 on success.
  */
 static int
-soundcloud_parse_json(const char *url, yajl_handle hand,
+soundcloud_parse_json(const char *url, Yajl::Handle &handle,
 		      Mutex &mutex, Cond &cond)
 try {
 	auto input_stream = InputStream::OpenReady(url, mutex, cond);
 
 	const std::lock_guard<Mutex> protect(mutex);
 
-	yajl_status stat;
 	bool done = false;
 
 	while (!done) {
@@ -243,16 +241,9 @@ try {
 			done = true;
 
 		if (done) {
-			stat = yajl_complete_parse(hand);
+			handle.CompleteParse();
 		} else
-			stat = yajl_parse(hand, buffer, nbytes);
-
-		if (stat != yajl_status_ok) {
-			unsigned char *str = yajl_get_error(hand, 1, buffer, nbytes);
-			LogError(soundcloud_domain, (const char *)str);
-			yajl_free_error(hand, str);
-			break;
-		}
+			handle.Parse(buffer, nbytes);
 	}
 
 	return 0;
@@ -310,10 +301,8 @@ soundcloud_open_uri(const char *uri, Mutex &mutex, Cond &cond)
 	}
 
 	SoundCloudJsonData data;
-	yajl_handle hand = yajl_alloc(&parse_callbacks, nullptr, &data);
-	AtScopeExit(hand, &data) { yajl_free(hand); };
-
-	int ret = soundcloud_parse_json(u, hand, mutex, cond);
+	Yajl::Handle handle(&parse_callbacks, nullptr, &data);
+	int ret = soundcloud_parse_json(u, handle, mutex, cond);
 
 	if (ret == -1)
 		return nullptr;