1 files changed, 140 insertions, 0 deletions
diff --git a/src/extension/loader.cpp b/src/extension/loader.cpp
new file mode 100644
index 0000000..d409d09
--- /dev/null
+++ b/src/extension/loader.cpp
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Loader for external plug-ins.
+ *
+ * Authors:
+ *   Moritz Eberl <moritz@semiodesk.com>
+ *
+ * Copyright (C) 2016 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "loader.h"
+
+#include <gmodule.h>
+
+#include "system.h"
+#include <cstring>
+#include "dependency.h"
+#include "inkscape-version.h"
+
+namespace Inkscape {
+namespace Extension {
+
+typedef Implementation::Implementation *(*_getImplementation)();
+typedef const gchar *(*_getInkscapeVersion)();
+
+bool Loader::load_dependency(Dependency *dep)
+{
+    GModule *module = nullptr;
+    module = g_module_open(dep->get_name(), (GModuleFlags)0);
+    if (module == nullptr) {
+        return false;
+    }
+    return true;
+}
+
+/**
+ * @brief Load the actual implementation of a plugin supplied by the plugin.
+ * @param doc The xml representation of the INX extension configuration.
+ * @return The implementation of the extension loaded from the plugin.
+ */
+Implementation::Implementation *Loader::load_implementation(Inkscape::XML::Document *doc)
+{
+    try {
+        
+        Inkscape::XML::Node *repr = doc->root();
+        Inkscape::XML::Node *child_repr = repr->firstChild();
+        
+        // Iterate over the xml content
+        while (child_repr != nullptr) {
+            char const *chname = child_repr->name();
+            if (!strncmp(chname, INKSCAPE_EXTENSION_NS_NC, strlen(INKSCAPE_EXTENSION_NS_NC))) {
+                chname += strlen(INKSCAPE_EXTENSION_NS);
+            }
+            
+            // Deal with dependencies if we have them
+            if (!strcmp(chname, "dependency")) {
+                Dependency dep = Dependency(child_repr, nullptr); // TODO: Why is "this" not an extension?
+                // try to load it
+                bool success = load_dependency(&dep);
+                if( !success ){
+                    // Could not load dependency, we abort
+                    const char *res = g_module_error();
+                    g_warning("Unable to load dependency %s of plugin %s.\nDetails: %s\n", dep.get_name(), "<todo>", res);
+                    return nullptr;
+                }
+            } 
+
+            // Found a plugin to load
+            if (!strcmp(chname, "plugin")) {
+                
+                // The name of the plugin is actually the library file we want to load
+                if (const gchar *name = child_repr->attribute("name")) {
+                    GModule *module = nullptr;
+                    _getImplementation GetImplementation = nullptr;
+                    _getInkscapeVersion GetInkscapeVersion = nullptr;
+                    
+                    // build the path where to look for the plugin
+                    gchar *path = g_build_filename(_baseDirectory.c_str(), name, (char *) nullptr);
+                    module = g_module_open(path, G_MODULE_BIND_LOCAL);
+                    g_free(path);
+                    
+                    if (module == nullptr) {
+                        // we were not able to load the plugin, write warning and abort
+                        const char *res = g_module_error();
+                        g_warning("Unable to load extension %s.\nDetails: %s\n", name, res);
+                        return nullptr;
+                    }
+
+                    // Get a handle to the version function of the module
+                    if (g_module_symbol(module, "GetInkscapeVersion", (gpointer *) &GetInkscapeVersion) == FALSE) {
+                        // This didn't work, write warning and abort
+                        const char *res = g_module_error();
+                        g_warning("Unable to load extension %s.\nDetails: %s\n", name, res);
+                        return nullptr;
+                    }
+                    
+                    // Get a handle to the function that delivers the implementation
+                    if (g_module_symbol(module, "GetImplementation", (gpointer *) &GetImplementation) == FALSE) {
+                        // This didn't work, write warning and abort
+                        const char *res = g_module_error();
+                        g_warning("Unable to load extension %s.\nDetails: %s\n", name, res);
+                        return nullptr;
+                    }
+                    
+                    // Get version and test against this version
+                    const gchar* version = GetInkscapeVersion();
+                    if( strcmp(version, version_string) != 0) {
+                        // The versions are different, display warning.
+                        g_warning("Plugin was built against Inkscape version %s, this is %s. The plugin might not be compatible.", version, version_string);
+                    }
+                    
+                    
+                    Implementation::Implementation *i = GetImplementation();
+                    return i;
+                }
+            } 
+
+            child_repr = child_repr->next();
+        }
+    } catch (std::exception &e) {
+        g_warning("Unable to load extension.");
+    }
+    return nullptr;
+}
+
+} // namespace Extension
+} // namespace Inkscape
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace .0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim:filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99: