From 681f41527280e56b97e0632c79e07350db2f5690 Mon Sep 17 00:00:00 2001
From: Sebastian Messmer <messmer@cryfs.org>
Date: Wed, 26 Oct 2016 13:50:20 -0700
Subject: [PATCH] Use curl_global_init/curl_global_cleanup for cleaner shutdown
 of executable

---
 src/cpp-utils/CMakeLists.txt                  |  1 +
 src/cpp-utils/network/CurlHttpClient.cpp      |  2 +-
 src/cpp-utils/network/CurlHttpClient.h        |  3 ++-
 src/cpp-utils/network/CurlInitializerRAII.cpp | 27 +++++++++++++++++++
 src/cpp-utils/network/CurlInitializerRAII.h   | 27 +++++++++++++++++++
 5 files changed, 58 insertions(+), 2 deletions(-)
 create mode 100644 src/cpp-utils/network/CurlInitializerRAII.cpp
 create mode 100644 src/cpp-utils/network/CurlInitializerRAII.h

diff --git a/src/cpp-utils/CMakeLists.txt b/src/cpp-utils/CMakeLists.txt
index 072600cf..a934bfed 100644
--- a/src/cpp-utils/CMakeLists.txt
+++ b/src/cpp-utils/CMakeLists.txt
@@ -12,6 +12,7 @@ set(SOURCES
         tempfile/TempDir.cpp
         network/HttpClient.cpp
         network/CurlHttpClient.cpp
+        network/CurlInitializerRAII.cpp
         network/FakeHttpClient.cpp
         io/Console.cpp
         io/DontEchoStdinToStdoutRAII.cpp
diff --git a/src/cpp-utils/network/CurlHttpClient.cpp b/src/cpp-utils/network/CurlHttpClient.cpp
index 317a3560..dcfd85f8 100644
--- a/src/cpp-utils/network/CurlHttpClient.cpp
+++ b/src/cpp-utils/network/CurlHttpClient.cpp
@@ -17,7 +17,7 @@ namespace cpputils {
         return size * nmemb;
     }
 
-    CurlHttpClient::CurlHttpClient() {
+    CurlHttpClient::CurlHttpClient(): curlInitializer(), curl() {
         curl = curl_easy_init();
     }
 
diff --git a/src/cpp-utils/network/CurlHttpClient.h b/src/cpp-utils/network/CurlHttpClient.h
index 439335b8..49f859a8 100644
--- a/src/cpp-utils/network/CurlHttpClient.h
+++ b/src/cpp-utils/network/CurlHttpClient.h
@@ -4,7 +4,7 @@
 
 #include "HttpClient.h"
 #include "../macros.h"
-#include <curl/curl.h>
+#include "CurlInitializerRAII.h"
 
 namespace cpputils {
 
@@ -17,6 +17,7 @@ namespace cpputils {
         boost::optional <std::string> get(const std::string &url, boost::optional<long> timeoutMsec = boost::none) override;
 
     private:
+        CurlInitializerRAII curlInitializer;
         CURL *curl;
 
         static size_t write_data(void *ptr, size_t size, size_t nmemb, std::ostringstream *stream);
diff --git a/src/cpp-utils/network/CurlInitializerRAII.cpp b/src/cpp-utils/network/CurlInitializerRAII.cpp
new file mode 100644
index 00000000..c9172852
--- /dev/null
+++ b/src/cpp-utils/network/CurlInitializerRAII.cpp
@@ -0,0 +1,27 @@
+#include "CurlInitializerRAII.h"
+
+using std::mutex;
+using std::unique_lock;
+
+namespace cpputils {
+
+mutex CurlInitializerRAII::_mutex;
+uint32_t CurlInitializerRAII::_refcount = 0;
+
+CurlInitializerRAII::CurlInitializerRAII() {
+    unique_lock<mutex> lock(_mutex);
+    if (0 == _refcount) {
+        curl_global_init(CURL_GLOBAL_ALL);
+    }
+    _refcount += 1;
+}
+
+CurlInitializerRAII::~CurlInitializerRAII() {
+    unique_lock<mutex> lock(_mutex);
+    _refcount -= 1;
+    if (0 == _refcount) {
+        curl_global_cleanup();
+    }
+}
+
+}
diff --git a/src/cpp-utils/network/CurlInitializerRAII.h b/src/cpp-utils/network/CurlInitializerRAII.h
new file mode 100644
index 00000000..a95d7dc5
--- /dev/null
+++ b/src/cpp-utils/network/CurlInitializerRAII.h
@@ -0,0 +1,27 @@
+#pragma once
+#ifndef MESSMER_CPPUTILS_NETWORK_CURLINITIALIZERRAII_HPP
+#define MESSMER_CPPUTILS_NETWORK_CURLINITIALIZERRAII_HPP
+
+#include <cpp-utils/macros.h>
+#include <mutex>
+#include <curl/curl.h>
+
+namespace cpputils {
+    // TODO Test
+
+    // When the first object of this class is created, it will initialize curl using curl_global_init().
+    // When the last object is destroyed, it will deinitialize curl using curl_global_cleanup().
+    class CurlInitializerRAII final {
+    public:
+        CurlInitializerRAII();
+        ~CurlInitializerRAII();
+    private:
+        static std::mutex _mutex;
+        static uint32_t _refcount;
+
+        DISALLOW_COPY_AND_ASSIGN(CurlInitializerRAII);
+    };
+
+}
+
+#endif