Added a mechanism to load c++ extensions dynamically.

(bzr r14761.1.1)

1 files changed, 103 insertions, 0 deletions

diff --git a/src/extension/loader.cpp b/src/extension/loader.cpp
new file mode 100644
index 000000000..df193a051
--- /dev/null
+++ b/src/extension/loader.cpp
@@ -0,0 +1,103 @@
+/*
+ * Loader for external plug-ins.
+ *
+ * Authors:
+ *   Moritz Eberl <moritz@semiodesk.com>
+ *
+ * Copyright (C) 2016 Authors
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include "loader.h"
+#include "system.h"
+#include <exception>
+#include <string.h>
+#include "dependency.h"
+
+namespace Inkscape {
+namespace Extension {
+
+typedef Implementation::Implementation *(*_getImplementation)(void);
+
+bool Loader::LoadDependency(Dependency *dep)
+{
+    GModule *module = NULL;
+    module = g_module_open(dep->getName(), (GModuleFlags)0);
+    if (module == NULL) {
+        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::LoadImplementation(Inkscape::XML::Document *doc)
+{
+    try {
+        Inkscape::XML::Node *repr = doc->root();
+        Inkscape::XML::Node *child_repr = repr->firstChild();
+        while (child_repr != NULL) {
+            char const *chname = child_repr->name();
+            if (!strncmp(chname, INKSCAPE_EXTENSION_NS_NC, strlen(INKSCAPE_EXTENSION_NS_NC))) {
+                chname += strlen(INKSCAPE_EXTENSION_NS);
+            }
+
+            if (!strcmp(chname, "dependency")) {
+                Dependency dep = Dependency(child_repr);
+                bool success = LoadDependency(&dep);
+                if( !success ){
+                    const char *res = g_module_error();
+                    g_warning("Unable to load dependency %s of plugin %s.\nDetails: %s\n", dep.getName(), res);
+                    return NULL;
+                }
+            } 
+
+            if (!strcmp(chname, "plugin")) {
+                if (const gchar *name = child_repr->attribute("name")) {
+                    GModule *module = NULL;
+                    _getImplementation GetImplementation = NULL;
+                    gchar *path = g_build_filename(_baseDirectory, name, (char *) NULL);
+                    module = g_module_open(path, G_MODULE_BIND_LOCAL);
+                    g_free(path);
+                    if (module == NULL) {
+                        const char *res = g_module_error();
+                        g_warning("Unable to load extension %s.\nDetails: %s\n", name, res);
+                        return NULL;
+                    }
+
+                    if (g_module_symbol(module, "GetImplementation", (gpointer *) &GetImplementation) == FALSE) {
+                        const char *res = g_module_error();
+                        g_warning("Unable to load extension %s.\nDetails: %s\n", name, res);
+                        return NULL;
+                    }
+
+                    Implementation::Implementation *i = GetImplementation();
+                    return i;
+                }
+            } 
+
+            child_repr = child_repr->next();
+        }
+    } catch (std::exception &e) {
+        g_warning("Unable to load extension.");
+    }
+    return NULL;
+}
+
+} // 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:
\ No newline at end of file