Ported the AboutDialog to C++, thanks @alexrj for the work.

New "configuration" menu over the snapshots, user preferences etc.

xs/src/slic3r/Config/Snapshot.cpp

@@ -205,6 +205,22 @@ size_t SnapshotDB::load_db()
     return m_snapshots.size();
 }
 
+void SnapshotDB::update_slic3r_versions(std::vector<Index> &index_db)
+{
+	for (Snapshot &snapshot : m_snapshots) {
+		for (Snapshot::VendorConfig &vendor_config : snapshot.vendor_configs) {
+			auto it = std::find_if(index_db.begin(), index_db.end(), [&vendor_config](const Index &idx) { return idx.vendor() == vendor_config.name; });
+			if (it != index_db.end()) {
+				Index::const_iterator it_version = it->find(vendor_config.version);
+				if (it_version != it->end()) {
+					vendor_config.min_slic3r_version = it_version->min_slic3r_version;
+					vendor_config.max_slic3r_version = it_version->max_slic3r_version;
+				}
+			}
+		}
+	}
+}
+
 static void copy_config_dir_single_level(const boost::filesystem::path &path_src, const boost::filesystem::path &path_dst)
 {
     if (! boost::filesystem::is_directory(path_dst) && 
@@ -303,6 +319,26 @@ boost::filesystem::path SnapshotDB::create_db_dir()
     return snapshots_dir;
 }
 
+SnapshotDB& SnapshotDB::singleton()
+{
+	static SnapshotDB instance;
+	bool       loaded = false;
+	if (! loaded) {
+		try {
+			loaded = true;
+			// Load the snapshot database.
+			instance.load_db();
+			// Load the vendor specific configuration indices.
+			std::vector<Index> index_db = Index::load_db();
+			// Update the min / max slic3r versions compatible with the configurations stored inside the snapshots
+			// based on the min / max slic3r versions defined by the vendor specific config indices.
+			instance.update_slic3r_versions(index_db);
+		} catch (std::exception &ex) {
+		}
+	}
+	return instance;
+}
+
 } // namespace Config
 } // namespace GUI
 } // namespace Slic3r

xs/src/slic3r/Config/Snapshot.hpp

@@ -6,6 +6,7 @@
 
 #include <boost/filesystem.hpp>
 
+#include "Version.hpp"
 #include "../Utils/Semver.hpp"
 
 namespace Slic3r { 
@@ -15,6 +16,8 @@ class AppConfig;
 namespace GUI {
 namespace Config {
 
+class Version;
+
 // A snapshot contains:
 // 		Slic3r.ini
 // 		vendor/
@@ -75,12 +78,16 @@ public:
 class SnapshotDB
 {
 public:
+	// Initialize the SnapshotDB singleton instance. Load the database if it has not been loaded yet.
+	static SnapshotDB&				singleton();
+
 	typedef std::vector<Snapshot>::const_iterator const_iterator;
 
 	// Load the snapshot database from the snapshots directory.
 	// If the snapshot directory or its parent does not exist yet, it will be created.
 	// Returns a number of snapshots loaded.
 	size_t 							load_db();
+	void 							update_slic3r_versions(std::vector<Index> &index_db);
 
 	// Create a snapshot directory, copy the vendor config bundles, user print/filament/printer profiles,
 	// create an index.

xs/src/slic3r/Config/Version.cpp

@@ -6,6 +6,8 @@
 
 #include "../../libslic3r/libslic3r.h"
 #include "../../libslic3r/Config.hpp"
+#include "../../libslic3r/FileParserError.hpp"
+#include "../../libslic3r/Utils.hpp"
 
 namespace Slic3r { 
 namespace GUI {
@@ -62,11 +64,12 @@ inline std::string unquote_version_comment(char *value, char *end, const std::st
 	return svalue;
 }
 
-size_t Index::load(const std::string &path)
+size_t Index::load(const boost::filesystem::path &path)
 {
 	m_configs.clear();
+	m_vendor = path.stem().string();
 
-    boost::nowide::ifstream ifs(path);
+    boost::nowide::ifstream ifs(path.string());
     std::string line;
     size_t idx_line = 0;
     Version ver;
@@ -96,7 +99,7 @@ size_t Index::load(const std::string &path)
     		if (semver)
     			throw file_parser_error("Key cannot be a semantic version", path, idx_line);
     		// Verify validity of the key / value pair.
-			std::string svalue = unquote_value(left_trim(++ value), end, path, idx_line);
+			std::string svalue = unquote_value(left_trim(++ value), end, path.string(), idx_line);
     		if (key == "min_sic3r_version" || key == "max_slic3r_version") {
     			if (! svalue.empty())
 		    		semver = Semver::parse(key);
@@ -113,13 +116,24 @@ size_t Index::load(const std::string &path)
 		if (! semver)
 			throw file_parser_error("Invalid semantic version", path, idx_line);
 		ver.config_version = *semver;
-		ver.comment = (end <= key_end) ? "" : unquote_version_comment(value, end, path, idx_line);
+		ver.comment = (end <= key_end) ? "" : unquote_version_comment(value, end, path.string(), idx_line);
 		m_configs.emplace_back(ver);
     }
 
+    // Sort the configs by their version.
+    std::sort(m_configs.begin(), m_configs.end(), [](const Version &v1, const Version &v2) { return v1.config_version < v2.config_version; });
     return m_configs.size();
 }
 
+Index::const_iterator Index::find(const Semver &ver)
+{ 
+	Version key;
+	key.config_version = ver;
+	auto it = std::lower_bound(m_configs.begin(), m_configs.end(), key, 
+		[](const Version &v1, const Version &v2) { return v1.config_version < v2.config_version; });
+	return (it == m_configs.end() || it->config_version == ver) ? it : m_configs.end();
+}
+
 Index::const_iterator Index::recommended() const
 {
 	int idx = -1;
@@ -131,6 +145,31 @@ Index::const_iterator Index::recommended() const
 	return highest;
 }
 
+std::vector<Index> Index::load_db()
+{
+    boost::filesystem::path data_dir   = boost::filesystem::path(Slic3r::data_dir());
+    boost::filesystem::path vendor_dir = data_dir / "vendor";
+
+    std::vector<Index> index_db;
+    std::string errors_cummulative;
+	for (auto &dir_entry : boost::filesystem::directory_iterator(vendor_dir))
+        if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".idx")) {
+        	Index idx;
+            try {
+            	idx.load(dir_entry.path());
+            } catch (const std::runtime_error &err) {
+                errors_cummulative += err.what();
+                errors_cummulative += "\n";
+                continue;
+			}
+            index_db.emplace_back(std::move(idx));
+        }
+
+    if (! errors_cummulative.empty())
+        throw std::runtime_error(errors_cummulative);
+    return index_db;
+}
+
 } // namespace Config
 } // namespace GUI
 } // namespace Slic3r

xs/src/slic3r/Config/Version.hpp

@@ -4,6 +4,8 @@
 #include <string>
 #include <vector>
 
+#include <boost/filesystem.hpp>
+
 #include "../../libslic3r/FileParserError.hpp"
 #include "../Utils/Semver.hpp"
 
@@ -54,17 +56,25 @@ public:
 	typedef std::vector<Version>::const_iterator const_iterator;
 	// Read a config index file in the simple format described in the Index class comment.
 	// Throws Slic3r::file_parser_error and the standard std file access exceptions.
-	size_t						load(const std::string &path);
+	size_t						load(const boost::filesystem::path &path);
+
+	const std::string&			vendor() const { return m_vendor; }
 
 	const_iterator				begin()   const { return m_configs.begin(); }
 	const_iterator				end()     const { return m_configs.end(); }
+	const_iterator 				find(const Semver &ver);
 	const std::vector<Version>& configs() const { return m_configs; }
 	// Finds a recommended config to be installed for the current Slic3r version.
 	// Returns configs().end() if such version does not exist in the index. This shall never happen
 	// if the index is valid.
 	const_iterator				recommended() const;
 
+	// Load all vendor specific indices.
+	// Throws Slic3r::file_parser_error and the standard std file access exceptions.
+	static std::vector<Index>	load_db();
+
 private:
+	std::string 				m_vendor;
 	std::vector<Version>		m_configs;
 };