plugin: new plugin library

[ncmpc.git] / src / plugin.h

diff --git a/src/plugin.h b/src/plugin.h
new file mode 100644 (file)
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--- /dev/null
+++ b/src/plugin.h
@@ -0,0 +1,92 @@
+/*
+ * (c) 2004-2008 The Music Player Daemon Project
+ * http://www.musicpd.org/
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef PLUGIN_H
+#define PLUGIN_H
+
+#include <glib.h>
+#include <stdbool.h>
+
+/**
+ * A list of registered plugins.
+ */
+struct plugin_list {
+       GPtrArray *plugins;
+};
+
+/**
+ * When a plugin cycle is finished, this function is called.  In any
+ * case, plugin_stop() has to be called to free all memory.
+ *
+ * @param result the plugin's output (stdout) on success; NULL on failure
+ * @param data the caller defined pointer passed to plugin_run()
+ */
+typedef void (*plugin_callback_t)(const GString *result, void *data);
+
+/**
+ * This object represents a cycle through all available plugins, until
+ * a plugin returns a positive result.
+ */
+struct plugin_cycle;
+
+/**
+ * Initialize an empty plugin_list structure.
+ */
+static inline void
+plugin_list_init(struct plugin_list *list)
+{
+       list->plugins = g_ptr_array_new();
+}
+
+/**
+ * Load all plugins (executables) in a directory.
+ */
+bool
+plugin_list_load_directory(struct plugin_list *list, const char *path);
+
+/**
+ * Frees all memory held by the plugin_list object (but not the
+ * pointer itself).
+ */
+void plugin_list_deinit(struct plugin_list *list);
+
+/**
+ * Run plugins in this list, until one returns success (or until the
+ * plugin list is exhausted).
+ *
+ * @param list the plugin list
+ * @param args NULL terminated command line arguments passed to the
+ * plugin programs
+ * @param callback the callback function which will be called when a
+ * result is available
+ * @param callback_data caller defined pointer which is passed to the
+ * callback function
+ */
+struct plugin_cycle *
+plugin_run(struct plugin_list *list, const char *const*args,
+          plugin_callback_t callback, void *callback_data);
+
+/**
+ * Stops the plugin cycle and frees resources.  This can be called to
+ * abort the current cycle, or after the plugin_callback_t has been
+ * invoked.
+ */
+void
+plugin_stop(struct plugin_cycle *invocation);
+
+#endif