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

Makefile.am

@@ -236,6 +236,7 @@ endif
 
 CURL_SOURCES = \
 	src/lib/curl/Version.cxx src/lib/curl/Version.hxx \
+	src/lib/curl/Init.cxx src/lib/curl/Init.hxx \
 	src/lib/curl/Global.cxx src/lib/curl/Global.hxx \
 	src/lib/curl/Request.cxx src/lib/curl/Request.hxx \
 	src/lib/curl/Handler.hxx \

src/input/plugins/CurlInputPlugin.cxx

@@ -21,6 +21,7 @@
 #include "CurlInputPlugin.hxx"
 #include "lib/curl/Easy.hxx"
 #include "lib/curl/Global.hxx"
+#include "lib/curl/Init.hxx"
 #include "lib/curl/Request.hxx"
 #include "lib/curl/Handler.hxx"
 #include "lib/curl/Slist.hxx"
@@ -132,7 +133,7 @@ static unsigned proxy_port;
 
 static bool verify_peer, verify_host;
 
-static CurlGlobal *curl_global;
+static CurlInit *curl_init;
 
 static constexpr Domain curl_domain("curl");
 
@@ -165,7 +166,7 @@ CurlInputStream::FreeEasyIndirect()
 {
 	BlockingCall(GetEventLoop(), [this](){
 			FreeEasy();
-			curl_global->InvalidateSockets();
+			(*curl_init)->InvalidateSockets();
 		});
 }
 
@@ -286,9 +287,12 @@ CurlInputStream::OnError(std::exception_ptr e)
 static void
 input_curl_init(EventLoop &event_loop, const ConfigBlock &block)
 {
-	CURLcode code = curl_global_init(CURL_GLOBAL_ALL);
-	if (code != CURLE_OK)
-		throw PluginUnavailable(curl_easy_strerror(code));
+	try {
+		curl_init = new CurlInit(event_loop);
+	} catch (const std::runtime_error &e) {
+		LogError(e);
+		throw PluginUnavailable(e.what());
+	}
 
 	const auto version_info = curl_version_info(CURLVERSION_FIRST);
 	if (version_info != nullptr) {
@@ -316,28 +320,15 @@ input_curl_init(EventLoop &event_loop, const ConfigBlock &block)
 
 	verify_peer = block.GetBlockValue("verify_peer", true);
 	verify_host = block.GetBlockValue("verify_host", true);
-
-	try {
-		curl_global = new CurlGlobal(event_loop);
-	} catch (const std::runtime_error &e) {
-		LogError(e);
-		curl_slist_free_all(http_200_aliases);
-		curl_global_cleanup();
-		throw PluginUnavailable("curl_multi_init() failed");
-	}
 }
 
 static void
 input_curl_finish(void)
 {
-	BlockingCall(curl_global->GetEventLoop(), [](){
-			delete curl_global;
-		});
+	delete curl_init;
 
 	curl_slist_free_all(http_200_aliases);
 	http_200_aliases = nullptr;
-
-	curl_global_cleanup();
 }
 
 CurlInputStream::~CurlInputStream()
@@ -348,7 +339,7 @@ CurlInputStream::~CurlInputStream()
 void
 CurlInputStream::InitEasy()
 {
-	request = new CurlRequest(*curl_global, GetURI(), *this);
+	request = new CurlRequest(**curl_init, GetURI(), *this);
 
 	request->SetOption(CURLOPT_HTTP200ALIASES, http_200_aliases);
 	request->SetOption(CURLOPT_FOLLOWLOCATION, 1l);
@@ -425,7 +416,7 @@ CurlInputStream::DoSeek(offset_type new_offset)
 inline InputStream *
 CurlInputStream::Open(const char *url, Mutex &mutex, Cond &cond)
 {
-	CurlInputStream *c = new CurlInputStream(curl_global->GetEventLoop(),
+	CurlInputStream *c = new CurlInputStream((*curl_init)->GetEventLoop(),
 						 url, mutex, cond);
 
 	try {

src/lib/curl/Init.cxx

+/*
+ * 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

+/*
+ * 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

src/storage/plugins/CurlStorage.cxx

@@ -23,6 +23,7 @@
 #include "storage/StorageInterface.hxx"
 #include "storage/FileInfo.hxx"
 #include "storage/MemoryDirectoryReader.hxx"
+#include "lib/curl/Init.hxx"
 #include "lib/curl/Global.hxx"
 #include "lib/curl/Slist.hxx"
 #include "lib/curl/Request.hxx"
@@ -49,16 +50,12 @@
 class CurlStorage final : public Storage {
 	const std::string base;
 
-	CurlGlobal *const curl;
+	CurlInit curl;
 
 public:
 	CurlStorage(EventLoop &_loop, const char *_base)
 		:base(_base),
-		 curl(new CurlGlobal(_loop)) {}
-
-	~CurlStorage() {
-		BlockingCall(curl->GetEventLoop(), [this](){ delete curl; });
-	}
+		 curl(_loop) {}
 
 	/* virtual methods from class Storage */
 	StorageFileInfo GetInfo(const char *uri_utf8, bool follow) override;