1 files changed, 436 insertions, 0 deletions
diff --git a/src/plugins/Plugins.vala b/src/plugins/Plugins.vala
new file mode 100644
index 0000000..d0f9185
--- /dev/null
+++ b/src/plugins/Plugins.vala
@@ -0,0 +1,436 @@
+/* Copyright 2011-2014 Yorba Foundation
+ *
+ * This software is licensed under the GNU Lesser General Public License
+ * (version 2.1 or later).  See the COPYING file in this distribution.
+ */
+
+namespace Plugins {
+
+// GModule doesn't have a truly generic way to determine if a file is a shared library by extension,
+// so these are hard-coded
+private const string[] SHARED_LIB_EXTS = { "so", "la" };
+
+// Although not expecting this system to last very long, these ranges declare what versions of this
+// interface are supported by the current implementation.
+private const int MIN_SPIT_INTERFACE = 0;
+private const int MAX_SPIT_INTERFACE = 0;
+
+public class ExtensionPoint {
+    public GLib.Type pluggable_type { get; private set; }
+    // name is user-visible
+    public string name { get; private set; }
+    public string? icon_name { get; private set; }
+    public string[]? core_ids { get; private set; }
+    
+    public ExtensionPoint(Type pluggable_type, string name, string? icon_name, string[]? core_ids) {
+        this.pluggable_type = pluggable_type;
+        this.name = name;
+        this.icon_name = icon_name;
+        this.core_ids = core_ids;
+    }
+}
+
+private class ModuleRep {
+    public File file;
+    public Module? module;
+    public Spit.Module? spit_module = null;
+    public int spit_interface = Spit.UNSUPPORTED_INTERFACE;
+    public string? id = null;
+    
+    private ModuleRep(File file) {
+        this.file = file;
+        
+        module = Module.open(file.get_path(), ModuleFlags.BIND_LAZY);
+    }
+    
+    ~ModuleRep() {
+        // ensure that the Spit.Module is destroyed before the GLib.Module
+        spit_module = null;
+    }
+    
+    // Have to use this funky static factory because GModule is a compact class and has no copy
+    // constructor.  The handle must be kept open for the lifetime of the application (or until
+    // the module is ready to be discarded), as dropping the reference will unload the binary.
+    public static ModuleRep? open(File file) {
+        ModuleRep module_rep = new ModuleRep(file);
+        
+        return (module_rep.module != null) ? module_rep : null;
+    }
+}
+
+private class PluggableRep {
+    public Spit.Pluggable pluggable { get; private set; }
+    public string id { get; private set; }
+    public bool is_core { get; private set; default = false; }
+    public bool activated { get; private set; default = false; }
+    
+    private bool enabled = false;
+    
+    // Note that creating a PluggableRep does not activate it.
+    public PluggableRep(Spit.Pluggable pluggable) {
+        this.pluggable = pluggable;
+        id = pluggable.get_id();
+    }
+    
+    public void activate() {
+        // determine if a core pluggable (which is only known after all the extension points
+        // register themselves)
+        is_core = is_core_pluggable(pluggable);
+        
+       FuzzyPropertyState saved_state = Config.Facade.get_instance().is_plugin_enabled(id);
+        enabled = ((is_core && (saved_state != FuzzyPropertyState.DISABLED)) ||
+            (!is_core && (saved_state == FuzzyPropertyState.ENABLED)));
+        
+        // inform the plugin of its activation state
+        pluggable.activation(enabled);
+        
+        activated = true;
+    }
+    
+    public bool is_enabled() {
+        return enabled;
+    }
+    
+    // Returns true if value changed, false otherwise
+    public bool set_enabled(bool enabled) {
+        if (enabled == this.enabled)
+            return false;
+        
+        this.enabled = enabled;
+        Config.Facade.get_instance().set_plugin_enabled(id, enabled);
+        pluggable.activation(enabled);
+        
+        return true;
+    }
+}
+
+private File[] search_dirs;
+private Gee.HashMap<string, ModuleRep> module_table;
+private Gee.HashMap<string, PluggableRep> pluggable_table;
+private Gee.HashMap<Type, ExtensionPoint> extension_points;
+private Gee.HashSet<string> core_ids;
+
+public void init() throws Error {
+    search_dirs = new File[0];
+    search_dirs += AppDirs.get_user_plugins_dir();
+    search_dirs += AppDirs.get_system_plugins_dir();
+    
+    module_table = new Gee.HashMap<string, ModuleRep>();
+    pluggable_table = new Gee.HashMap<string, PluggableRep>();
+    extension_points = new Gee.HashMap<Type, ExtensionPoint>();
+    core_ids = new Gee.HashSet<string>();
+    
+    // do this after constructing member variables so accessors don't blow up if GModule isn't
+    // supported
+    if (!Module.supported()) {
+        warning("Plugins not support: GModule not supported on this platform.");
+        
+        return;
+    }
+    
+    foreach (File dir in search_dirs) {
+        try {
+            search_for_plugins(dir);
+        } catch (Error err) {
+            debug("Unable to search directory %s for plugins: %s", dir.get_path(), err.message);
+        }
+    }
+}
+
+public void terminate() {
+    search_dirs = null;
+    pluggable_table = null;
+    module_table = null;
+    extension_points = null;
+    core_ids = null;
+}
+
+public class Notifier {
+    private static Notifier? instance = null;
+    
+    public signal void pluggable_activation(Spit.Pluggable pluggable, bool enabled);
+    
+    private Notifier() {
+    }
+    
+    public static Notifier get_instance() {
+        if (instance == null)
+            instance = new Notifier();
+        
+        return instance;
+    }
+}
+
+public void register_extension_point(Type type, string name, string? icon_name, string[]? core_ids) {
+    // if this assertion triggers, it means this extension point has already registered
+    assert(!extension_points.has_key(type));
+    
+    extension_points.set(type, new ExtensionPoint(type, name, icon_name, core_ids));
+    
+    // add core IDs to master list
+    if (core_ids != null) {
+        foreach (string core_id in core_ids)
+            Plugins.core_ids.add(core_id);
+    }
+    
+    // activate all the pluggables for this extension point
+    foreach (PluggableRep pluggable_rep in pluggable_table.values) {
+        if (!pluggable_rep.pluggable.get_type().is_a(type))
+            continue;
+        
+        pluggable_rep.activate();
+        Notifier.get_instance().pluggable_activation(pluggable_rep.pluggable, pluggable_rep.is_enabled());
+    }
+}
+
+public Gee.Collection<Spit.Pluggable> get_pluggables(bool include_disabled = false) {
+    Gee.Collection<Spit.Pluggable> all = new Gee.HashSet<Spit.Pluggable>();
+    foreach (PluggableRep pluggable_rep in pluggable_table.values) {
+        if (pluggable_rep.activated && (include_disabled || pluggable_rep.is_enabled()))
+            all.add(pluggable_rep.pluggable);
+    }
+    
+    return all;
+}
+
+public bool is_core_pluggable(Spit.Pluggable pluggable) {
+    return core_ids.contains(pluggable.get_id());
+}
+
+private ModuleRep? get_module_for_pluggable(Spit.Pluggable needle) {
+    foreach (ModuleRep module_rep in module_table.values) {
+        Spit.Pluggable[]? pluggables = module_rep.spit_module.get_pluggables();
+        if (pluggables != null) {
+            foreach (Spit.Pluggable pluggable in pluggables) {
+                if (pluggable == needle)
+                    return module_rep;
+            }
+        }
+    }
+    
+    return null;
+}
+
+public string? get_pluggable_module_id(Spit.Pluggable needle) {
+    ModuleRep? module_rep = get_module_for_pluggable(needle);
+    
+    return (module_rep != null) ? module_rep.spit_module.get_id() : null;
+}
+
+public Gee.Collection<ExtensionPoint> get_extension_points(owned CompareDataFunc? compare_func = null) {
+    Gee.Collection<ExtensionPoint> sorted = new Gee.TreeSet<ExtensionPoint>((owned) compare_func);
+    sorted.add_all(extension_points.values);
+    
+    return sorted;
+}
+
+public Gee.Collection<Spit.Pluggable> get_pluggables_for_type(Type type,
+    owned CompareDataFunc? compare_func = null, bool include_disabled = false) {
+    // if this triggers it means the extension point didn't register itself at init() time
+    assert(extension_points.has_key(type));
+    
+    Gee.Collection<Spit.Pluggable> for_type = new Gee.TreeSet<Spit.Pluggable>((owned) compare_func);
+    foreach (PluggableRep pluggable_rep in pluggable_table.values) {
+        if (pluggable_rep.activated 
+            && pluggable_rep.pluggable.get_type().is_a(type) 
+            && (include_disabled || pluggable_rep.is_enabled())) {
+            for_type.add(pluggable_rep.pluggable);
+        }
+    }
+    
+    return for_type;
+}
+
+public string? get_pluggable_name(string id) {
+    PluggableRep? pluggable_rep = pluggable_table.get(id);
+    
+    return (pluggable_rep != null && pluggable_rep.activated) 
+        ? pluggable_rep.pluggable.get_pluggable_name() : null;
+}
+
+public bool get_pluggable_info(string id, ref Spit.PluggableInfo info) {
+    PluggableRep? pluggable_rep = pluggable_table.get(id);
+    if (pluggable_rep == null || !pluggable_rep.activated)
+        return false;
+    
+    pluggable_rep.pluggable.get_info(ref info);
+    
+    return true;
+}
+
+public bool get_pluggable_enabled(string id, out bool enabled) {
+    PluggableRep? pluggable_rep = pluggable_table.get(id);
+    if (pluggable_rep == null || !pluggable_rep.activated) {
+        enabled = false;
+        
+        return false;
+    }
+    
+    enabled = pluggable_rep.is_enabled();
+    
+    return true;
+}
+
+public void set_pluggable_enabled(string id, bool enabled) {
+    PluggableRep? pluggable_rep = pluggable_table.get(id);
+    if (pluggable_rep == null || !pluggable_rep.activated)
+        return;
+    
+    if (pluggable_rep.set_enabled(enabled))
+        Notifier.get_instance().pluggable_activation(pluggable_rep.pluggable, enabled);
+}
+
+public File get_pluggable_module_file(Spit.Pluggable pluggable) {
+    ModuleRep? module_rep = get_module_for_pluggable(pluggable);
+    
+    return (module_rep != null) ? module_rep.file : null;
+}
+
+public int compare_pluggable_names(void *a, void *b) {
+    Spit.Pluggable *apluggable = (Spit.Pluggable *) a;
+    Spit.Pluggable *bpluggable = (Spit.Pluggable *) b;
+    
+    return apluggable->get_pluggable_name().collate(bpluggable->get_pluggable_name());
+}
+
+public int compare_extension_point_names(void *a, void *b) {
+    ExtensionPoint *apoint = (ExtensionPoint *) a;
+    ExtensionPoint *bpoint = (ExtensionPoint *) b;
+    
+    return apoint->name.collate(bpoint->name);
+}
+
+private bool is_shared_library(File file) {
+    string name, ext;
+    disassemble_filename(file.get_basename(), out name, out ext);
+    
+    foreach (string shared_ext in SHARED_LIB_EXTS) {
+        if (ext == shared_ext)
+            return true;
+    }
+    
+    return false;
+}
+
+private void search_for_plugins(File dir) throws Error {
+    debug("Searching %s for plugins ...", dir.get_path());
+    
+    // build a set of module names sans file extension ... this is to deal with the question of
+    // .so vs. .la existing in the same directory (and letting GModule deal with the problem)
+    FileEnumerator enumerator = dir.enumerate_children(Util.FILE_ATTRIBUTES,
+        FileQueryInfoFlags.NOFOLLOW_SYMLINKS, null);
+    for (;;) {
+        FileInfo? info = enumerator.next_file(null);
+        if (info == null)
+            break;
+        
+        if (info.get_is_hidden())
+            continue;
+        
+        File file = dir.get_child(info.get_name());
+        
+        switch (info.get_file_type()) {
+            case FileType.DIRECTORY:
+                try {
+                    search_for_plugins(file);
+                } catch (Error err) {
+                    warning("Unable to search directory %s for plugins: %s", file.get_path(), err.message);
+                }
+            break;
+            
+            case FileType.REGULAR:
+                if (is_shared_library(file))
+                    load_module(file);
+            break;
+            
+            default:
+                // ignored
+            break;
+        }
+    }
+}
+
+private void load_module(File file) {
+    ModuleRep? module_rep = ModuleRep.open(file);
+    if (module_rep == null) {
+        critical("Unable to load module %s: %s", file.get_path(), Module.error());
+        
+        return;
+    }
+    
+    // look for the well-known entry point
+    void *entry;
+    if (!module_rep.module.symbol(Spit.ENTRY_POINT_NAME, out entry)) {
+        critical("Unable to load module %s: well-known entry point %s not found", file.get_path(),
+            Spit.ENTRY_POINT_NAME);
+        
+        return;
+    }
+    
+    Spit.EntryPoint spit_entry_point = (Spit.EntryPoint) entry;
+    
+    assert(MIN_SPIT_INTERFACE <= Spit.CURRENT_INTERFACE && Spit.CURRENT_INTERFACE <= MAX_SPIT_INTERFACE);
+    Spit.EntryPointParams params = Spit.EntryPointParams();
+    params.host_min_spit_interface = MIN_SPIT_INTERFACE;
+    params.host_max_spit_interface = MAX_SPIT_INTERFACE;
+    params.module_spit_interface = Spit.UNSUPPORTED_INTERFACE;
+    params.module_file = file;
+    
+    module_rep.spit_module = spit_entry_point(&params);
+    if (params.module_spit_interface == Spit.UNSUPPORTED_INTERFACE) {
+        critical("Unable to load module %s: module reports no support for SPIT interfaces %d to %d",
+            file.get_path(), MIN_SPIT_INTERFACE, MAX_SPIT_INTERFACE);
+        
+        return;
+    }
+    
+    if (params.module_spit_interface < MIN_SPIT_INTERFACE || params.module_spit_interface > MAX_SPIT_INTERFACE) {
+        critical("Unable to load module %s: module reports unsupported SPIT version %d (out of range %d to %d)",
+            file.get_path(), module_rep.spit_interface, MIN_SPIT_INTERFACE, MAX_SPIT_INTERFACE);
+        
+        return;
+    }
+    
+    module_rep.spit_interface = params.module_spit_interface;
+    
+    // verify type (as best as possible; still potential to segfault inside GType here)
+    if (!(module_rep.spit_module is Spit.Module))
+        module_rep.spit_module = null;
+    
+    if (module_rep.spit_module == null) {
+        critical("Unable to load module %s (SPIT %d): no spit module returned", file.get_path(),
+            module_rep.spit_interface);
+        
+        return;
+    }
+    
+    // if module has already been loaded, drop this one (search path is set up to load user-installed
+    // binaries prior to system binaries)
+    module_rep.id = prepare_input_text(module_rep.spit_module.get_id(), PrepareInputTextOptions.DEFAULT, -1);
+    if (module_rep.id == null) {
+        critical("Unable to load module %s (SPIT %d): invalid or empty module name",
+            file.get_path(), module_rep.spit_interface);
+        
+        return;
+    }
+    
+    if (module_table.has_key(module_rep.id)) {
+        critical("Not loading module %s (SPIT %d): module with name \"%s\" already loaded",
+            file.get_path(), module_rep.spit_interface, module_rep.id);
+        
+        return;
+    }
+    
+    debug("Loaded SPIT module \"%s %s\" (%s) [%s]", module_rep.spit_module.get_module_name(),
+        module_rep.spit_module.get_version(), module_rep.id, file.get_path());
+    
+    // stash in module table by their ID
+    module_table.set(module_rep.id, module_rep);
+    
+    // stash pluggables in pluggable table by their ID
+    foreach (Spit.Pluggable pluggable in module_rep.spit_module.get_pluggables())
+        pluggable_table.set(pluggable.get_id(), new PluggableRep(pluggable));
+}
+
+}
+