lib/curl/Init: share a CurlGlobal instance between input and storage

src/lib/curl/Init.cxx

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2008-2017 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.
+ */
+
+#include "config.h"
+#include "Init.hxx"
+#include "Global.hxx"
+#include "event/Call.hxx"
+#include "thread/Mutex.hxx"
+
+#include <atomic>
+
+#include <assert.h>
+
+Mutex CurlInit::mutex;
+unsigned CurlInit::ref;
+CurlGlobal *CurlInit::instance;
+
+CurlInit::CurlInit(EventLoop &event_loop)
+{
+	const std::lock_guard<Mutex> protect(mutex);
+	if (++ref > 1) {
+		assert(&event_loop == &instance->GetEventLoop());
+		return;
+	}
+
+	CURLcode code = curl_global_init(CURL_GLOBAL_ALL);
+	if (code != CURLE_OK)
+		throw std::runtime_error(curl_easy_strerror(code));
+
+	assert(instance == nullptr);
+	instance = new CurlGlobal(event_loop);
+}
+
+CurlInit::~CurlInit()
+{
+	const std::lock_guard<Mutex> protect(mutex);
+	if (--ref > 0)
+		return;
+
+	BlockingCall(instance->GetEventLoop(), [](){
+			delete instance;
+			instance = nullptr;
+		});
+
+	curl_global_cleanup();
+}

src/lib/curl/Init.hxx

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2008-2017 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 CURL_INIT_HXX
+#define CURL_INIT_HXX
+
+#include "check.h"
+
+class Mutex;
+class EventLoop;
+class CurlGlobal;
+
+/**
+ * This class performs one-time initialization of libCURL and creates
+ * one #CurlGlobal instance, shared across all #CurlInit instances.
+ */
+class CurlInit {
+	static Mutex mutex;
+	static unsigned ref;
+	static CurlGlobal *instance;
+
+public:
+	explicit CurlInit(EventLoop &event_loop);
+	~CurlInit();
+
+	CurlInit(const CurlInit &) = delete;
+	CurlInit &operator=(const CurlInit &) = delete;
+
+	CurlGlobal &operator*() {
+		return *instance;
+	}
+
+	CurlGlobal *operator->() {
+		return instance;
+	}
+};
+
+#endif