Run-time config for advanced options

This can be used for "advanced" options which are for developers
to use for feature-flags and other configuration. Run time config
has some advantages over preprocessor defines:

* Can be changed without recompilation
   * Sensitive to XDG_CONFIG_DIR, so flipping configs is easy
* Better compiler coverage (less conditionally compiled code means
  less chance to break a different configuration). Also better
  analysis coverage.
* Type safe config params
* Centralised documentation: it's in doxygen, in one place

No advanced config should be required by a general users. If a general
user does use one of these configs, it's probably because:

* There is a bug and one of these configs is a workaround
* A config in here is generally useful and should be moved into the
  relevant application config and given UI.

For now, the config is read-only, and is read from the
"kicad_advanced" config file in the normal config dir.

Documentation/development/testing.md

@@ -259,9 +259,20 @@ Some available masks:
     * `KICAD_GEDA_PLUGIN`
     * `KICAD_PCB_PLUGIN`
 
+# Advanced configuration
+
+There are some advance configuration options, which are mostly used for
+development or testing purposes.
+
+To set these options, you can create the file `kicad_advanced` and set the keys
+as desired (the [advanced config documentation][] for a current list. You should
+never need to set these keys for normal usage - if you do, that's a bug.
+
 
 [CTest]: https://cmake.org/cmake/help/latest/module/CTest.html
 [Boost Unit Test framework]: https://www.boost.org/doc/libs/1_68_0/libs/test/doc/html/index.html
 [boost-test-functions]: https://www.boost.org/doc/libs/1_68_0/libs/test/doc/html/boost_test/utf_reference/testing_tool_ref.html
 [AFL fuzzing tool]: http://lcamtuf.coredump.cx/afl/
-[trace mask documentation]: http://docs.kicad-pcb.org/doxygen/group__trace__env__vars.html
+[trace mask documentation]: http://docs.kicad-pcb.org/doxygen/group__trace__env__vars.html
+[trace mask documentation]: http://docs.kicad-pcb.org/doxygen/group__trace__env__vars.html
+[advanced config documentation]: http://docs.kicad-pcb.org/doxygen/namespaceAC__KEYS.html

common/CMakeLists.txt

@@ -269,6 +269,7 @@ set( COMMON_SRCS
     ${COMMON_PAGE_LAYOUT_SRCS}
     ${COMMON_PREVIEW_ITEMS_SRCS}
     ${PLOTTERS_CONTROL_SRCS}
+    advanced_config.cpp
     base_struct.cpp
     bezier_curves.cpp
     bin_mod.cpp

common/advanced_config.cpp

@@ -0,0 +1,161 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2018 KiCad Developers, see AUTHORS.txt for contributors.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#include <advanced_config.h>
+
+#include <common.h>
+#include <config_params.h>
+
+#include <wx/config.h>
+#include <wx/filename.h>
+#include <wx/log.h>
+
+/*
+ * Flag to enable advanced config debugging
+ *
+ * Use "KICAD_ADVANCED_CONFIG" to enable.
+ *
+ * @ingroup trace_env_vars
+ */
+static const wxChar AdvancedConfigMask[] = wxT( "KICAD_ADVANCED_CONFIG" );
+
+/**
+ * List of known keys for advanced configuration options.
+ *
+ * Set these options in the file `kicad_advanced` in the
+ * KiCad config directory.
+ */
+namespace AC_KEYS
+{
+} // namespace KEYS
+
+
+/*
+ * Get a simple string for common parameters.
+ *
+ * This isn't exhaustive, but it covers most common types that might be
+ * used in the advance config
+ */
+wxString dumpParamCfg( const PARAM_CFG_BASE& aParam )
+{
+    wxString s = aParam.m_Ident + ": ";
+
+    /*
+     * This implementation is rather simplistic, but it is
+     * effective enough for simple uses. A better implementation would be
+     * some kind of visitor, but that's somewhat more work.
+     */
+    switch( aParam.m_Type )
+    {
+    case paramcfg_id::PARAM_INT:
+    case paramcfg_id::PARAM_INT_WITH_SCALE:
+        s << *static_cast<const PARAM_CFG_INT&>( aParam ).m_Pt_param;
+        break;
+    case paramcfg_id::PARAM_DOUBLE:
+        s << *static_cast<const PARAM_CFG_DOUBLE&>( aParam ).m_Pt_param;
+        break;
+    case paramcfg_id::PARAM_WXSTRING:
+        s << *static_cast<const PARAM_CFG_WXSTRING&>( aParam ).m_Pt_param;
+        break;
+    case paramcfg_id::PARAM_FILENAME:
+        s << *static_cast<const PARAM_CFG_FILENAME&>( aParam ).m_Pt_param;
+        break;
+    case paramcfg_id::PARAM_BOOL:
+        s << ( *static_cast<const PARAM_CFG_BOOL&>( aParam ).m_Pt_param ? "true" : "false" );
+        break;
+    default: s << "Unsupported PARAM_CFG variant: " << aParam.m_Type;
+    }
+
+    return s;
+}
+
+
+/**
+ * Dump the configs in the given array to trace.
+ */
+static void dumpCfg( const PARAM_CFG_ARRAY& aArray )
+{
+    // only dump if we need to
+    if( !wxLog::IsAllowedTraceMask( AdvancedConfigMask ) )
+        return;
+
+    for( const auto& param : aArray )
+    {
+        wxLogTrace( AdvancedConfigMask, dumpParamCfg( param ) );
+    }
+}
+
+
+/**
+ * Get the filename for the advanced config file
+ *
+ * The user must check the file exists if they care.
+ */
+static wxFileName getAdvancedCfgFilename()
+{
+    const static wxString cfg_filename{ "kicad_advanced" };
+    return wxFileName( GetKicadConfigPath(), cfg_filename );
+}
+
+
+ADVANCED_CFG::ADVANCED_CFG()
+{
+    wxLogTrace( AdvancedConfigMask, "Init advanced config" );
+    loadFromConfigFile();
+}
+
+
+const ADVANCED_CFG& ADVANCED_CFG::GetCfg()
+{
+    static ADVANCED_CFG instance;
+    return instance;
+}
+
+
+void ADVANCED_CFG::loadFromConfigFile()
+{
+    const auto k_advanced = getAdvancedCfgFilename();
+
+    if( !k_advanced.FileExists() )
+    {
+        wxLogTrace( AdvancedConfigMask, "File does not exist %s", k_advanced.GetFullPath() );
+        return;
+    }
+
+    wxLogTrace( AdvancedConfigMask, "Loading advanced config from: %s", k_advanced.GetFullPath() );
+
+    wxFileConfig file_cfg( "", "", k_advanced.GetFullPath() );
+    loadSettings( file_cfg );
+}
+
+
+void ADVANCED_CFG::loadSettings( wxConfigBase& aCfg )
+{
+    PARAM_CFG_ARRAY configParams;
+
+    // Add configs here
+
+    wxConfigLoadSetups( &aCfg, configParams );
+
+    dumpCfg( configParams );
+}

include/advanced_config.h

@@ -0,0 +1,85 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2018 KiCad Developers, see AUTHORS.txt for contributors.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#ifndef ADVANCED_CFG__H
+#define ADVANCED_CFG__H
+
+class wxConfigBase;
+
+/**
+ * Class containing "advanced" configuration options.
+ *
+ * Options set here are for developer or advanced users only. If a general user
+ * needs to set one of these for normal KiCad use, either:
+ * * They are working around some bug that should be fixed, or
+ * * The parameter they are setting is of general interest and should be in the
+ *   main application config, with UI provided.
+ *
+ * Options in this class are, in general, preferable to #defines, as they
+ * allow more flexible configuration by developers, and don't hide code from
+ * the compiler on other configurations, which can result in broken builds.
+ *
+ * Never use advanced configs in an untestable way. If a function depends on
+ * advanced config such that you cannot test it without changing the config,
+ * "lift" the config to a higher level and make pass it as parameter of the code
+ * under test. The tests can pass their own values as needed.
+ *
+ * This also applies to code that does not depend on "common" - it cannot
+ * use this class, so you must pass configuration in as proper parameters.
+ *
+ * Sometimes you can just use values directly, and sometimes helper functions
+ * might be provided to allow extra logic (for example when a advanced config
+ * applies only on certain platforms).
+ *
+ * For more information on what config keys set these parameters in the
+ * config files, and why you might want to set them, see #AC_KEYS
+ *
+ */
+class ADVANCED_CFG
+{
+public:
+    /**
+     * Get the singleton instance's config, which is shared by all
+     * consumers of advanced config.
+     *
+     * This configuration is read-only - to set options, users should
+     * add the parameters to their config files at ~/.config/kicad/advanced, or the
+     * platform equivalent.
+     */
+    static const ADVANCED_CFG& GetCfg();
+
+private:
+    ADVANCED_CFG();
+
+    /**
+     * Load the config from the normal config file
+     */
+    void loadFromConfigFile();
+
+    /*
+     * Load config from the given config base
+     */
+    void loadSettings( wxConfigBase& aCfg );
+};
+
+#endif // ADVANCED_CFG__H