[feat] FFI: add FileChooser Gtk3 backend (#631)

ffi/filechooser.lua

@@ -0,0 +1,14 @@
+local ffi = require("ffi")
+local util = require("ffi/util")
+
+if util.isSDL() then
+    if util.haveSDL2() then
+        local ok, gtk = pcall(ffi.load, "gtk-3")
+        if not ok then
+            ok, gtk = pcall(ffi.load, "gtk-3.so.0")
+        end
+        if ok then
+            return require("ffi/filechooser_gtk-3")
+        end
+    end
+end

ffi/filechooser_gtk-3.lua

@@ -0,0 +1,56 @@
+local ffi = require "ffi"
+
+local dummy = require("ffi/gtk-3_h")
+
+local ok, gtk = pcall(ffi.load, "gtk-3")
+if not ok then
+    ok, gtk = pcall(ffi.load, "gtk-3.so.0")
+end
+if not ok then return end
+
+local FileChooser = {
+    type = "gtk-3",
+}
+
+--[[
+Mostly taken from https://love2d.org/forums/viewtopic.php?f=4&t=82442
+
+Proof of concept, https://github.com/Alloyed/nativefiledialog might be better.
+--]]
+
+function FileChooser:show(action, button, title)
+    gtk.gtk_init(nil, nil)
+
+    local d = gtk.gtk_file_chooser_dialog_new(
+        title,
+        nil,
+        action,
+        "_Cancel", ffi.cast("const gchar *", gtk.GTK_RESPONSE_CANCEL),
+        button, ffi.cast("const gchar *", gtk.GTK_RESPONSE_OK),
+        nil)
+
+    local response = gtk.gtk_dialog_run(d)
+    local filename = gtk.gtk_file_chooser_get_filename(d)
+
+    gtk.gtk_widget_destroy(d)
+
+    while gtk.gtk_events_pending() do
+        gtk.gtk_main_iteration()
+    end
+
+    if response == gtk.GTK_RESPONSE_OK then
+        return filename ~= nil and ffi.string(filename) or nil
+    end
+end
+
+function FileChooser:save(title)
+    return self:show(gtk.GTK_FILE_CHOOSER_ACTION_SAVE,
+        "_Save", title or "Save As")
+end
+
+function FileChooser:open(title)
+    return self:show(gtk.GTK_FILE_CHOOSER_ACTION_OPEN,
+        "_Open", title or "Open")
+end
+
+return FileChooser

ffi/gtk-3_h.lua

@@ -0,0 +1,70 @@
+local ffi = require "ffi"
+
+ffi.cdef [[
+
+typedef void GtkDialog;
+typedef void GtkWidget;
+typedef void GtkWindow;
+typedef void GtkFileChooser;
+
+typedef int gint;
+typedef char gchar;
+typedef bool gboolean;
+
+typedef enum
+{
+  GTK_FILE_CHOOSER_ACTION_OPEN,
+  GTK_FILE_CHOOSER_ACTION_SAVE,
+  GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER,
+  GTK_FILE_CHOOSER_ACTION_CREATE_FOLDER
+} GtkFileChooserAction;
+
+typedef enum
+{
+  GTK_RESPONSE_NONE         = -1,
+  GTK_RESPONSE_REJECT       = -2,
+  GTK_RESPONSE_ACCEPT       = -3,
+  GTK_RESPONSE_DELETE_EVENT = -4,
+  GTK_RESPONSE_OK           = -5,
+  GTK_RESPONSE_CANCEL       = -6,
+  GTK_RESPONSE_CLOSE        = -7,
+  GTK_RESPONSE_YES          = -8,
+  GTK_RESPONSE_NO           = -9,
+  GTK_RESPONSE_APPLY        = -10,
+  GTK_RESPONSE_HELP         = -11
+} GtkResponseType;
+
+void gtk_init (
+    int *argc,
+    char ***argv
+);
+
+gboolean gtk_events_pending (
+    void
+);
+
+gboolean gtk_main_iteration (
+    void
+);
+
+GtkWidget * gtk_file_chooser_dialog_new (
+    const gchar *title,
+    GtkWindow *parent,
+    GtkFileChooserAction action,
+    const gchar *first_button_text,
+    ...
+);
+
+gint gtk_dialog_run (
+    GtkDialog *dialog
+);
+
+void gtk_widget_destroy (
+    GtkWidget *widget
+);
+
+gchar * gtk_file_chooser_get_filename (
+    GtkFileChooser *chooser
+);
+
+]]

ffi/input_SDL2_0.lua

@@ -1,3 +1,4 @@
+local FileChooser = require("ffi/filechooser")
 -- load common SDL input/video library
 local SDL = require("ffi/SDL2_0")
 
@@ -11,4 +12,5 @@ return {
     hasClipboardText = SDL.hasClipboardText,
     getClipboardText = SDL.getClipboardText,
     setClipboardText = SDL.setClipboardText,
+    file_chooser = FileChooser,
 }