[ease] [editor] Improved save dialog handling.

[Nate Stedman <natesm src gnome org>]

commit f1fcff8471618ac7097a469f3e4c2aad577bb5ef
Author: Nate Stedman <natesm gmail com>
Date:   Mon Oct 11 15:05:53 2010 -0400

    [editor] Improved save dialog handling.
    
    - Added function allowing "verification" of save dialogs via a
      delegate function.
    
    - Use this function to add functionality to the document save
      dialog. Ease will ask if the user would like to append ".ease"
      if the filename does not end with it already, and will check
      for filename collisions and force verification before anything
      if overwritten.

 ease-core/ease-dialogs.vala |  245 +++++++++++++++++++++++++++++++++++++------
 1 files changed, 213 insertions(+), 32 deletions(-)
---
diff --git a/ease-core/ease-dialogs.vala b/ease-core/ease-dialogs.vala
index d5b09de..476e5e7 100644
--- a/ease-core/ease-dialogs.vala
+++ b/ease-core/ease-dialogs.vala
@@ -20,6 +20,42 @@
  */
 namespace Ease.Dialog
 {
+	private const string VERIFY_EASE_SECONDARY =
+		_("The specified filename does not end with a \".ease\" extension. Would you like to append one?");
+	private const string VERIFY_EASE_PRIMARY = _("Append .ease?");
+	
+	private const string VERIFY_OVERWRITE_FMT = _("Overwrite %s?");
+	private const string VERIFY_OVERWRITE_SECONDARY_FMT =
+		_("The file \"%s\" already exists. Would you like to overwrite it?");
+	
+	/**
+	 * Displays a question (Yes/No/Cancel) dialog.
+	 */
+	public Gtk.ResponseType question(string title, string main_text,
+	                                 string secondary_text, Gtk.Window? modal,
+	                                 bool with_cancel)
+	{
+		var dialog = new Gtk.MessageDialog.with_markup(modal,
+		                                               Gtk.DialogFlags.MODAL,
+		                                               Gtk.MessageType.QUESTION,
+		                                               0, null);
+		// set text
+		dialog.use_markup = dialog.secondary_use_markup = true;
+		dialog.text = main_text;
+		dialog.secondary_text = secondary_text;
+		
+		// add buttons
+		dialog.add_buttons("gtk-yes", Gtk.ResponseType.YES,
+		                   "gtk-no", Gtk.ResponseType.NO, null);
+		if (with_cancel) dialog.add_button("gtk-cancel",
+		                                   Gtk.ResponseType.CANCEL);
+		
+		// run the dialog
+		var ret = (Gtk.ResponseType)dialog.run();
+		dialog.destroy();
+		return ret;
+	}
+	
 	/**
 	 * Displays an "Open" dialog with the specified title. Returns null if
 	 * cancelled, otherwise returns the selected path.
@@ -96,7 +132,7 @@ namespace Ease.Dialog
 	 */
 	public string? save(string title, Gtk.Window? modal)
 	{
-		return save_ext(title, modal, null);
+		return save_real(title, modal, null, null);
 	}
 
 	/**
@@ -110,29 +146,32 @@ namespace Ease.Dialog
 	 * @param ext A function to modify the dialog before it is displayed.
 	 */
 	public string? save_ext(string title, Gtk.Window? modal,
-	                        FileChooserDialogExtension? ext)
+	                        FileChooserDialogExtension ext)
 	{
-		var dialog = new Gtk.FileChooserDialog(title,
-			                                   modal,
-			                                   Gtk.FileChooserAction.SAVE,
-			                                   "gtk-save",
-			                                   Gtk.ResponseType.ACCEPT,
-			                                   "gtk-cancel",
-			                                   Gtk.ResponseType.CANCEL,
-			                                   null);
-		if (ext != null) ext(dialog);
-		
-		if (dialog.run() == Gtk.ResponseType.ACCEPT)
-		{
-			// clean up the file dialog
-			string path = dialog.get_filename();
-			dialog.destroy();
-			return path;
-		}
-		dialog.destroy();
-		return null;
+		return save_real(title, modal, ext, null);
+	}
+	
+	/**
+	 * Displays an "Save" dialog with the specified title. The
+	 * { link FileChooserDialogExtension} can be used to modify the
+	 * dialog before it is displayed. Upon completion, a
+	 * { link FileChooserDialogVerify} can be used to modify the return value
+	 * of the dialog. Returns null if cancelled, otherwise returns the selected
+	 * path (with any modifications).
+	 *
+	 * @param title The dialog's title.
+	 * @param modal The window that the dialog should be modal for.
+	 * @param ext A function to modify the dialog before it is displayed.
+	 * @param verify A function to verify the dialog's return path.
+	 */
+	public string? save_verified(string title, Gtk.Window? modal,
+	                             FileChooserDialogExtension ext,
+	                             FileChooserDialogVerify verify)
+	{
+		return save_real(title, modal, ext, verify);
 	}
 	
+	
 	/**
 	 * Displays an "Save" dialog for an Ease { link Document}. Returns null if
 	 * cancelled, otherwise returns the selected path. The title parameter
@@ -143,24 +182,166 @@ namespace Ease.Dialog
 	 */
 	public string? save_document(string title, Gtk.Window? modal)
 	{
-		return save_ext(title, modal, (dialog) => {
-			// add a filter for ease documents
-			var filter = new Gtk.FileFilter();
-			filter.add_pattern("*.ease");
-			filter.set_name(_("Ease Presentations"));
-			dialog.add_filter(filter);
+		return save_verified(title, modal,
+			// extension function
+			(dialog) => {
+				// add a filter for ease documents
+				var filter = new Gtk.FileFilter();
+				filter.add_pattern("*.ease");
+				filter.set_name(_("Ease Presentations"));
+				dialog.add_filter(filter);
 			
-			// add a filter for all files
-			filter = new Gtk.FileFilter();
-			filter.set_name(_("All Files"));
-			filter.add_pattern("*");
-			dialog.add_filter(filter);
+				// add a filter for all files
+				filter = new Gtk.FileFilter();
+				filter.set_name(_("All Files"));
+				filter.add_pattern("*");
+				dialog.add_filter(filter);
+			},
+		
+			// verification function
+			(dialog) => {
+				// get the current filename
+				var filename = Path.get_basename(dialog.get_filename());
+				
+				// let's see if it already has .ease
+				bool has_suffix = filename.has_suffix(".ease");
+				
+				// if there's no .ease suffix
+				if (!has_suffix)
+				{
+					// ask the user if they'd like to append .ease
+					var code = question(VERIFY_EASE_PRIMARY,
+					                    VERIFY_EASE_PRIMARY,
+						                VERIFY_EASE_SECONDARY,
+							            modal, true);
+			
+					// react to the response, nothing needs to be done for "no"
+					switch (code)
+					{
+						case Gtk.ResponseType.CANCEL:
+							return DialogCode.REJECT;
+					
+						case Gtk.ResponseType.YES:
+							// append .ease to the filename
+							dialog.set_current_name(filename + ".ease");
+							break;
+					}
+				}
+				
+				// now let's check for filename collisions
+				if (FileUtils.test(dialog.get_filename(), FileTest.EXISTS))
+				{
+					// ask the user if they'd like to overwrite
+					var code = question(
+						VERIFY_OVERWRITE_FMT.printf(
+							Path.get_basename(dialog.get_filename())),
+						VERIFY_OVERWRITE_FMT.printf(
+							Path.get_basename(dialog.get_filename())),
+						VERIFY_OVERWRITE_SECONDARY_FMT.printf(
+							Path.get_basename(dialog.get_filename())),
+						modal, true);
+					
+					// react to the response
+					switch (code)
+					{
+						case Gtk.ResponseType.CANCEL:
+							return DialogCode.REJECT;
+					
+						case Gtk.ResponseType.YES:
+							return DialogCode.ACCEPT;
+						
+						default: // NO
+							return DialogCode.REINVOKE;
+					}
+				}
+				
+				// if no collisons, we're good to save
+				return DialogCode.ACCEPT;
 		});
 	}
 	
+	private string save_real(string title, Gtk.Window? modal,
+	                         FileChooserDialogExtension? ext,
+	                         FileChooserDialogVerify? verify)
+	{
+		var dialog = new Gtk.FileChooserDialog(title,
+			                                   modal,
+			                                   Gtk.FileChooserAction.SAVE,
+			                                   "gtk-save",
+			                                   Gtk.ResponseType.ACCEPT,
+			                                   "gtk-cancel",
+			                                   Gtk.ResponseType.CANCEL,
+			                                   null);
+		// run the extension function if applicable
+		if (ext != null) ext(dialog);
+		
+		// default to ACCEPT (so we leave the loop if there is no verify func)
+		DialogCode code = DialogCode.ACCEPT;
+		do
+		{
+			// return if the user cancels in the save dialog
+			if (dialog.run() != Gtk.ResponseType.ACCEPT)
+			{
+				dialog.destroy();
+				return null;
+			}
+			
+			// (potentially temporarily) hide the dialog
+			dialog.hide();
+			
+			// run the verification function
+			if (verify != null) code = verify(dialog);
+			
+			// return if the user cancels in the verification function
+			if (code == DialogCode.REJECT)
+			{
+				dialog.destroy();
+				return null;
+			}
+			
+			// if the dialog is coming back, present it
+			if (code == DialogCode.REINVOKE) dialog.present();
+		}
+		while (code != DialogCode.ACCEPT); // otherwise, continue until accept
+		
+		// clean up the file dialog and return the path
+		string path = dialog.get_filename();
+		dialog.destroy();
+		return path;
+	}
+	
 	/**
 	 * Allows a caller to manipulate a dialog before is is displayed.
 	 */
 	public delegate void FileChooserDialogExtension(Gtk.FileChooserDialog d);
+	
+	/**
+	 * Allows a caller to manipulate the return value of a dialog, and
+	 * potentially reinvoke it.
+	 */
+	public delegate DialogCode FileChooserDialogVerify(Gtk.FileChooserDialog d);
+	
+	/**
+	 * Enumerates the possible behaviors a { link FileChooserDialogVerify} can
+	 * request.
+	 */
+	public enum DialogCode
+	{
+		/**
+		 * Causes the dialog to return its (potentially modified) path
+		 */
+		ACCEPT,
+		
+		/**
+		 * Causes the dialog to return null, as if no path was selected.
+		 */
+		REJECT,
+		
+		/**
+		 * Causes the dialog to run again. This will rerun any associated
+		 * { link FileChooserDialogExtension} and recreate the dialog.
+		 */
+		REINVOKE;
+	}
 }