Added a mechanism to load c++ extensions dynamically.

(bzr r14761.1.1)

7 files changed, 202 insertions, 8 deletions

diff --git a/src/extension/CMakeLists.txt b/src/extension/CMakeLists.txt
index 21e652563..238e8d3df 100644
--- a/src/extension/CMakeLists.txt
+++ b/src/extension/CMakeLists.txt
@@ -14,6 +14,7 @@ set(extension_SRC
 	print.cpp
 	system.cpp
 	timer.cpp
+    loader.cpp
 
 	implementation/implementation.cpp
 	implementation/xslt.cpp
@@ -90,6 +91,7 @@ set(extension_SRC
 	print.h
 	system.h
 	timer.h
+    loader.h
 
 	implementation/implementation.h
 	implementation/script.h
diff --git a/src/extension/Makefile_insert b/src/extension/Makefile_insert
index 4e75de13a..fb9713904 100644
--- a/src/extension/Makefile_insert
+++ b/src/extension/Makefile_insert
@@ -13,6 +13,8 @@ ink_common_sources +=	\
     extension/execution-env.h \
     extension/init.cpp	\
     extension/init.h	\
+	extension/loader.h \
+	extension/loader.cpp \
     extension/param/parameter.h \
     extension/param/parameter.cpp \
     extension/param/notebook.h \
diff --git a/src/extension/dependency.cpp b/src/extension/dependency.cpp
index e46b6fbd2..712a9068d 100644
--- a/src/extension/dependency.cpp
+++ b/src/extension/dependency.cpp
@@ -235,6 +235,18 @@ bool Dependency::check (void) const
 }
 
 /**
+    \brief   Accessor to the name attribute.
+    \return  A string containing the name of the dependency.
+
+    Returns the name of the dependency as found in the configuration file.
+ 
+*/
+const gchar* Dependency::getName()
+{
+    return _string;
+}
+
+/**
     \brief   Print out a dependency to a string.
 */
 std::ostream &
diff --git a/src/extension/dependency.h b/src/extension/dependency.h
index 829912dc3..5d0a4844e 100644
--- a/src/extension/dependency.h
+++ b/src/extension/dependency.h
@@ -58,6 +58,7 @@ public:
     Dependency  (Inkscape::XML::Node * in_repr);
     virtual ~Dependency (void);
     bool check  (void) const;
+    const gchar* getName();
     Glib::ustring &get_help (void) const;
     Glib::ustring &get_link (void) const;
 
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
diff --git a/src/extension/loader.h b/src/extension/loader.h
new file mode 100644
index 000000000..c09260f72
--- /dev/null
+++ b/src/extension/loader.h
@@ -0,0 +1,73 @@
+/** @file
+ * 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
+ */
+
+#ifndef INKSCAPE_EXTENSION_LOADER_H_
+#define INKSCAPE_EXTENSION_LOADER_H_
+
+#include "extension.h"
+#include "implementation/implementation.h"
+#include <gmodule.h>
+
+
+namespace Inkscape {
+namespace Extension {
+
+/** This class contains the mechanism to load c++ plugins dynamically.
+*/
+class Loader {
+
+public:
+    /**
+     * Sets a base directory where to look for the actual plugin to load.
+     * 
+     * @param dir is the path where the plugin should be loaded from.
+     */
+    void setBaseDirectory(const gchar *dir) {
+        _baseDirectory = dir;
+    }
+
+    /**
+     * Loads plugin dependencies which are needed for the plugin to load.
+     * 
+     * @param dep
+     */
+    bool LoadDependency(Dependency *dep);
+
+    /**
+     * 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 *LoadImplementation(Inkscape::XML::Document *doc);
+
+private:
+    const gchar *_baseDirectory; /**< The base directory to load a plugin from */
+
+
+};
+
+} // namespace Extension
+} // namespace Inkscape */
+
+#endif // _LOADER_H_
+
+/*
+  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
diff --git a/src/extension/system.cpp b/src/extension/system.cpp
index 6a95717f2..5a77ac28e 100644
--- a/src/extension/system.cpp
+++ b/src/extension/system.cpp
@@ -39,6 +39,7 @@
 #include "io/sys.h"
 #include "inkscape.h"
 #include "document-undo.h"
+#include "loader.h"
 
 
 namespace Inkscape {
@@ -426,7 +427,7 @@ build_from_reprdoc(Inkscape::XML::Document *doc, Implementation::Implementation
     enum {
         MODULE_EXTENSION,
         MODULE_XSLT,
-        /* MODULE_PLUGIN, */
+        MODULE_PLUGIN,
         MODULE_UNKNOWN_IMP
     } module_implementation_type = MODULE_UNKNOWN_IMP;
     enum {
@@ -465,10 +466,8 @@ build_from_reprdoc(Inkscape::XML::Document *doc, Implementation::Implementation
             module_implementation_type = MODULE_EXTENSION;
         } else if (!strcmp(element_name, INKSCAPE_EXTENSION_NS "xslt")) {
             module_implementation_type = MODULE_XSLT;
-#if 0
-        } else if (!strcmp(element_name, "plugin")) {
+        } else if (!strcmp(element_name,  INKSCAPE_EXTENSION_NS "plugin")) {
             module_implementation_type = MODULE_PLUGIN;
-#endif
         }
 
         //Inkscape::XML::Node *old_repr = child_repr;
@@ -489,13 +488,15 @@ build_from_reprdoc(Inkscape::XML::Document *doc, Implementation::Implementation
                 imp = static_cast<Implementation::Implementation *>(xslt);
                 break;
             }
-#if 0
             case MODULE_PLUGIN: {
-                Implementation::Plugin *plugin = new Implementation::Plugin();
-                imp = static_cast<Implementation::Implementation *>(plugin);
+                Inkscape::Extension::Loader loader = Inkscape::Extension::Loader();
+                loader.setBaseDirectory ( Inkscape::Application::profile_path("extensions"));
+                imp = loader.LoadImplementation(doc);
+                if( imp != NULL) {
+                    return new Extension(repr, imp);
+                }
                 break;
             }
-#endif
             default: {
                 imp = NULL;
                 break;