Revert "libngspice is linked at compile time"

This reverts commit 75f8b20493.
In case of problems, ngspice demands to be detached which is not
possible when it is linked at compile time.

eeschema/CMakeLists.txt

@@ -316,7 +316,6 @@ target_link_libraries( eeschema_kiface
     gal
     ${wxWidgets_LIBRARIES}
     ${GDI_PLUS_LIBRARIES}
-    ${NGSPICE_LIBRARY}
     )
 set_target_properties( eeschema_kiface PROPERTIES
     # Decorate OUTPUT_NAME with PREFIX and SUFFIX, creating something like

eeschema/sim/ngspice.cpp

@@ -29,24 +29,33 @@
 #include <common.h>     // LOCALE_IO
 #include <wx/stdpaths.h>
 #include <wx/dir.h>
+#include <wx/dynlib.h>
 
 #include <sstream>
+#include <stdexcept>
 
 using namespace std;
 
 NGSPICE::NGSPICE()
 {
-    init();
+    init_dll();
 }
 
 
 NGSPICE::~NGSPICE()
 {
+    delete m_dll;
 }
 
 
 void NGSPICE::Init()
 {
+    if( m_error )
+    {
+        delete m_dll;
+        init_dll();
+    }
+
     Command( "reset" );
 }
 
@@ -55,7 +64,7 @@ vector<COMPLEX> NGSPICE::GetPlot( const string& aName, int aMaxLen )
 {
     LOCALE_IO c_locale;       // ngspice works correctly only with C locale
     vector<COMPLEX> data;
-    vector_info* vi = ngGet_Vec_Info( (char*) aName.c_str() );
+    vector_info* vi = m_ngGet_Vec_Info( (char*) aName.c_str() );
 
     if( vi )
     {
@@ -82,7 +91,7 @@ vector<double> NGSPICE::GetRealPlot( const string& aName, int aMaxLen )
 {
     LOCALE_IO c_locale;       // ngspice works correctly only with C locale
     vector<double> data;
-    vector_info* vi = ngGet_Vec_Info( (char*) aName.c_str() );
+    vector_info* vi = m_ngGet_Vec_Info( (char*) aName.c_str() );
 
     if( vi )
     {
@@ -114,7 +123,7 @@ vector<double> NGSPICE::GetImagPlot( const string& aName, int aMaxLen )
 {
     LOCALE_IO c_locale;       // ngspice works correctly only with C locale
     vector<double> data;
-    vector_info* vi = ngGet_Vec_Info( (char*) aName.c_str() );
+    vector_info* vi = m_ngGet_Vec_Info( (char*) aName.c_str() );
 
     if( vi )
     {
@@ -138,7 +147,7 @@ vector<double> NGSPICE::GetMagPlot( const string& aName, int aMaxLen )
 {
     LOCALE_IO c_locale;       // ngspice works correctly only with C locale
     vector<double> data;
-    vector_info* vi = ngGet_Vec_Info( (char*) aName.c_str() );
+    vector_info* vi = m_ngGet_Vec_Info( (char*) aName.c_str() );
 
     if( vi )
     {
@@ -165,7 +174,7 @@ vector<double> NGSPICE::GetPhasePlot( const string& aName, int aMaxLen )
 {
     LOCALE_IO c_locale;       // ngspice works correctly only with C locale
     vector<double> data;
-    vector_info* vi = ngGet_Vec_Info( (char*) aName.c_str() );
+    vector_info* vi = m_ngGet_Vec_Info( (char*) aName.c_str() );
 
     if( vi )
     {
@@ -205,8 +214,7 @@ bool NGSPICE::LoadNetlist( const string& aNetlist )
     }
 
     lines.push_back( nullptr );
-
-    ngSpice_Circ( lines.data() );
+    m_ngSpice_Circ( lines.data() );
 
     for( auto line : lines )
         free( line );
@@ -232,15 +240,14 @@ bool NGSPICE::Stop()
 bool NGSPICE::IsRunning()
 {
     LOCALE_IO c_locale;               // ngspice works correctly only with C locale
-    return ngSpice_running();
+    return m_ngSpice_Running();
 }
 
 
 bool NGSPICE::Command( const string& aCmd )
 {
     LOCALE_IO c_locale;               // ngspice works correctly only with C locale
-    ngSpice_Command( (char*) aCmd.c_str() );
-
+    m_ngSpice_Command( (char*) aCmd.c_str() );
     return true;
 }
 
@@ -270,13 +277,34 @@ string NGSPICE::GetXAxis( SIM_TYPE aType ) const
 }
 
 
-void NGSPICE::init()
+void NGSPICE::init_dll()
 {
     if( m_initialized )
         return;
 
     LOCALE_IO c_locale;               // ngspice works correctly only with C locale
-    ngSpice_Init( &cbSendChar, &cbSendStat, &cbControlledExit, NULL, NULL, &cbBGThreadRunning, this );
+
+#ifdef __WINDOWS__
+    m_dll = new wxDynamicLibrary( "libngspice-0.dll" );
+#else
+    m_dll = new wxDynamicLibrary( wxDynamicLibrary::CanonicalizeName( "ngspice" ) );
+#endif
+
+    if( !m_dll || !m_dll->IsLoaded() )
+        throw std::runtime_error( "Missing ngspice shared library" );
+
+    m_error = false;
+
+    // Obtain function pointers
+    m_ngSpice_Init = (ngSpice_Init) m_dll->GetSymbol( "ngSpice_Init" );
+    m_ngSpice_Circ = (ngSpice_Circ) m_dll->GetSymbol( "ngSpice_Circ" );
+    m_ngSpice_Command = (ngSpice_Command) m_dll->GetSymbol( "ngSpice_Command" );
+    m_ngGet_Vec_Info = (ngGet_Vec_Info) m_dll->GetSymbol( "ngGet_Vec_Info" );
+    m_ngSpice_AllPlots = (ngSpice_AllPlots) m_dll->GetSymbol( "ngSpice_AllPlots" );
+    m_ngSpice_AllVecs = (ngSpice_AllVecs) m_dll->GetSymbol( "ngSpice_AllVecs" );
+    m_ngSpice_Running = (ngSpice_Running) m_dll->GetSymbol( "ngSpice_running" ); // it is not a typo
+
+    m_ngSpice_Init( &cbSendChar, &cbSendStat, &cbControlledExit, NULL, NULL, &cbBGThreadRunning, this );
 
     // Load a custom spinit file, to fix the problem with loading .cm files
     // Switch to the executable directory, so the relative paths are correct
@@ -321,8 +349,8 @@ void NGSPICE::init()
     // Restore the working directory
     wxSetWorkingDirectory( cwd );
 
-    // Workarounds to avoid hang ups on certain errors,
-    // they have to be called, no matter what is in the spinit file
+    // Workarounds to avoid hang ups on certain errors
+    // These commands have to be called, no matter what is in the spinit file
     Command( "unset interactive" );
     Command( "set noaskquit" );
     Command( "set nomoremode" );

eeschema/sim/ngspice.h

@@ -79,6 +79,30 @@ public:
 private:
     void init();
 
+    // Performs DLL initialization, obtains function pointers
+    void init_dll();
+
+    // ngspice library functions
+    typedef void (*ngSpice_Init)( SendChar*, SendStat*, ControlledExit*,
+                                    SendData*, SendInitData*, BGThreadRunning*, void* );
+    typedef int (*ngSpice_Circ)( char** circarray );
+    typedef int (*ngSpice_Command)( char* command );
+    typedef pvector_info (*ngGet_Vec_Info)( char* vecname );
+    typedef char** (*ngSpice_AllPlots)( void );
+    typedef char** (*ngSpice_AllVecs)( char* plotname );
+    typedef bool (*ngSpice_Running)( void );
+
+    ///> Handles to DLL functions
+    ngSpice_Init m_ngSpice_Init;
+    ngSpice_Circ m_ngSpice_Circ;
+    ngSpice_Command m_ngSpice_Command;
+    ngGet_Vec_Info m_ngGet_Vec_Info;
+    ngSpice_AllPlots m_ngSpice_AllPlots;
+    ngSpice_AllVecs m_ngSpice_AllVecs;
+    ngSpice_Running m_ngSpice_Running;
+
+    wxDynamicLibrary* m_dll;
+
     ///> Executes commands from a file
     bool loadSpinit( const std::string& aFileName );
 
@@ -97,6 +121,9 @@ private:
 
     void dump();
 
+    ///> Error flag, meaning ngspice needs to be reloaded
+    bool m_error;
+
     ///> NGspice should be initialized only once
     static bool m_initialized;