Init curl in InitPgm for thread safety

curl itself highly recommends not initializing curl from within a thread.
Due to the PCM, this can happen in a thread these days.

Pointed out by Érico Rolim in https://gitlab.com/kicad/code/kicad/-/merge_requests/855

common/kicad_curl/kicad_curl.cpp

@@ -27,109 +27,21 @@
 // conflicts for some defines, at least on Windows
 #include <kicad_curl/kicad_curl.h>
 
-#include <mutex>
 #include <ki_exception.h>   // THROW_IO_ERROR
 
 
-
-// These are even more private than class members, and since there is only
-// one instance of KICAD_CURL ever, these statics are hidden here to simplify the
-// client (API) header file.
-static volatile bool s_initialized;
-
-static std::mutex s_lock;        // for s_initialized
-
-/// At process termination, using atexit() keeps the CURL stuff out of the
-/// singletops and PGM_BASE.
-static void at_terminate()
-{
-    KICAD_CURL::Cleanup();
-}
-
-
 void KICAD_CURL::Init()
 {
-    // We test s_initialized twice in an effort to avoid
-    // unnecessarily locking s_lock.  This understands that the common case
-    // will not need to lock.
-    if( !s_initialized )
+    if( curl_global_init( CURL_GLOBAL_ALL ) != CURLE_OK )
     {
-        std::lock_guard<std::mutex> lock( s_lock );
-
-        if( !s_initialized )
-        {
-            if( curl_global_init( CURL_GLOBAL_ALL ) != CURLE_OK )
-            {
-                THROW_IO_ERROR( "curl_global_init() failed." );
-            }
-
-            s_initialized = true;
-        }
+        THROW_IO_ERROR( "curl_global_init() failed." );
     }
 }
 
 
 void KICAD_CURL::Cleanup()
 {
-    /*
-
-    Calling lock_guard() from a static destructor will typically be bad, since the
-    s_lock may already have been statically destroyed itself leading to a boost
-    exception. (Remember C++ does not provide certain sequencing of static
-    destructor invocation.)
-
-    To prevent this we test s_initialized twice, which ensures that the lock_guard
-    is only instantiated on the first call, which should be from
-    PGM_BASE::destroy() which is first called earlier than static destruction.
-    Then when called again from the actual PGM_BASE::~PGM_BASE() function,
-    lock_guard will not be instantiated because s_initialized will be false.
-
-    */
-
-    if( s_initialized )
-    {
-        std::lock_guard<std::mutex> lock( s_lock );
-
-        if( s_initialized )
-        {
-            curl_global_cleanup();
-
-            atexit( &at_terminate );
-
-            s_initialized = false;
-        }
-    }
-}
-
-
-std::string KICAD_CURL::GetSimpleVersion()
-{
-    if( !s_initialized )
-        Init();
-
-    curl_version_info_data* info = curl_version_info( CURLVERSION_NOW );
-
-    std::string res;
-
-    if( info->version )
-    {
-        res += "libcurl version: " + std::string( info->version );
-    }
-
-    res += " (";
-
-    if( info->features & CURL_VERSION_SSL )
-    {
-        res += "with SSL - ";
-        res += std::string( info->ssl_version );
-    }
-    else
-    {
-        res += "without SSL";
-    }
-    res += ")";
-
-    return res;
+    curl_global_cleanup();
 }
 
 

common/kicad_curl/kicad_curl_easy.cpp

@@ -115,12 +115,6 @@ static int progressinfo( void* aProgress, double aDLtotal, double aDLnow, double
 KICAD_CURL_EASY::KICAD_CURL_EASY() :
         m_headers( nullptr )
 {
-    // Call KICAD_CURL::Init() from in here every time, but only the first time
-    // will incur any overhead.  This strategy ensures that libcurl is never loaded
-    // unless it is needed.
-
-    KICAD_CURL::Init();
-
     m_CURL = curl_easy_init();
 
     if( !m_CURL )

common/pgm_base.cpp

@@ -52,6 +52,7 @@
 #include <eda_draw_frame.h>
 #include <gestfich.h>
 #include <id.h>
+#include <kicad_curl/kicad_curl.h>
 #include <kiplatform/policy.h>
 #include <lockfile.h>
 #include <menus_helpers.h>
@@ -151,6 +152,8 @@ PGM_BASE::~PGM_BASE()
 
 void PGM_BASE::Destroy()
 {
+    KICAD_CURL::Cleanup();
+
 #ifdef KICAD_USE_SENTRY
     sentry_close();
 #endif
@@ -409,6 +412,8 @@ bool PGM_BASE::InitPgm( bool aHeadless, bool aSkipPyInit, bool aIsUnitTest )
     // In particular, the user cache path is the most likely to be hit by startup code
     PATHS::EnsureUserPathsExist();
 
+    KICAD_CURL::Init();
+
 #ifdef KICAD_USE_SENTRY
     sentryInit();
 #endif

include/kicad_curl/kicad_curl.h

@@ -53,10 +53,6 @@
 #  endif
 #endif
 
-
-struct DYN_LOOKUP;
-
-
 /**
  * Simple wrapper class to call curl_global_init and curl_global_cleanup for KiCad.
  */
@@ -88,17 +84,6 @@ public:
     {
         return curl_version();
     }
-
-
-    /**
-     * Report back curl version only and SSL library support.
-     *
-     * @return  Generated version string.
-     */
-    static std::string GetSimpleVersion();
-
-private:
-    friend class KICAD_CURL_EASY;
 };
 
 #endif // KICAD_CURL_H_