Tag all queued ops. (e_book_cancel_op): Added. Search for a pending op

2001-03-17  Jon Trowbridge  <trow@ximian.com>

	* backend/ebook/e-book.c (e_book_queue_op): Tag all queued ops.
	(e_book_cancel_op): Added.  Search for a pending op with a given
	tag, and mark it as inactive.
	(e_book_do_response_get_cursor): Don't execute callback if this
	operations has been cancelled.
	(e_book_do_response_get_view): Ditto.
	(e_book_do_response_get_changes): Ditto.
	(e_book_do_response_get_supported_fields): Ditto.
	(e_book_get_supported_fields): Return an operation tag (that can
	be used to cancel the operation) rather than just TRUE/FALSE.
	Zero is always an invalid tag and is returned in the case of an
	error, so this shouldn't break any code that looked at the return
	value (unless it did so in a particularly stupid way, of course).
	(e_book_get_cursor): Ditto.
	(e_book_get_book_view): Ditto.
	(e_book_get_changes): Ditto.
	(e_book_cancel): Added.  Cancel a pending operation.  (Basically
	a call to e_book_cancel_op with error checking, etc.)

	* backend/ebook/e-book-types.h: Added E_BOOK_STATUS_CANCELLED.

svn path=/trunk/; revision=8790

1 files changed, 95 insertions, 39 deletions

diff --git a/addressbook/backend/ebook/e-book.c b/addressbook/backend/ebook/e-book.c
index 25fb42a37b..c603f94743 100644
--- a/addressbook/backend/ebook/e-book.c
+++ b/addressbook/backend/ebook/e-book.c
@@ -44,8 +44,7 @@ struct _EBookPrivate {
 	 */
 	GList                 *pending_ops;
 
-	guint sq_tag;
-	GList *sq_pending;
+	guint op_tag;
 };
 
 enum {
@@ -58,6 +57,8 @@ enum {
 static guint e_book_signals [LAST_SIGNAL];
 
 typedef struct {
+	guint     tag;
+	gboolean  active;
 	gpointer  cb;
 	gpointer  closure;
 	EBookViewListener *listener;
@@ -66,7 +67,7 @@ typedef struct {
 /*
  * Local response queue management.
  */
-static void
+static guint
 e_book_queue_op (EBook    *book,
 		 gpointer  cb,
 		 gpointer  closure,
@@ -75,12 +76,16 @@ e_book_queue_op (EBook    *book,
 	EBookOp *op;
 
 	op           = g_new0 (EBookOp, 1);
+	op->tag      = book->priv->op_tag++;
+	op->active   = TRUE;
 	op->cb       = cb;
 	op->closure  = closure;
 	op->listener = listener;
 
 	book->priv->pending_ops =
 		g_list_append (book->priv->pending_ops, op);
+
+	return op->tag;
 }
 
 static EBookOp *
@@ -104,6 +109,23 @@ e_book_pop_op (EBook *book)
 	return op;
 }
 
+static gboolean
+e_book_cancel_op (EBook *book, guint tag)
+{
+	GList *iter;
+	gboolean cancelled = FALSE;
+
+	for (iter = book->priv->pending_ops; iter != NULL && !cancelled; iter = g_list_next (iter)) {
+		EBookOp *op = iter->data;
+		if (op->tag == tag) {
+			op->active = FALSE;
+			cancelled = TRUE;
+		}
+	}
+	
+	return cancelled;
+}
+
 static void
 e_book_do_response_create_card (EBook                 *book,
 				EBookListenerResponse *resp)
@@ -161,8 +183,12 @@ e_book_do_response_get_cursor (EBook                 *book,
 
 	cursor = e_card_cursor_new(resp->cursor);
 
-	if (op->cb)
-		((EBookCursorCallback) op->cb) (book, resp->status, cursor, op->closure);
+	if (op->cb) {
+		if (op->active)
+			((EBookCursorCallback) op->cb) (book, resp->status, cursor, op->closure);
+		else
+			((EBookCursorCallback) op->cb) (book, E_BOOK_STATUS_CANCELLED, NULL, op->closure);
+	}
 
 	/*
 	 * Release the remote GNOME_Evolution_Addressbook_Book in the PAS.
@@ -209,12 +235,19 @@ e_book_do_response_get_view (EBook                 *book,
 			   "in local op queue!\n");
 		return;
 	}
-
+	
 	book_view = e_book_view_new(resp->book_view, op->listener);
 	
-	if (op->cb)
-		((EBookBookViewCallback) op->cb) (book, resp->status, book_view, op->closure);
-
+	/* Only execute the callback if the operation is still flagged as active (i.e. hasn't
+	   been cancelled.  This is mildly wasteful since we unnecessaryily create the
+	   book_view, etc... but I'm leery of tinkering with the CORBA magic. */
+	if (op->cb) {
+		if (op->active)
+			((EBookBookViewCallback) op->cb) (book, resp->status, book_view, op->closure);
+		else
+			((EBookBookViewCallback) op->cb) (book, E_BOOK_STATUS_CANCELLED, NULL, op->closure);
+	}
+	
 	/*
 	 * Release the remote GNOME_Evolution_Addressbook_Book in the PAS.
 	 */
@@ -262,8 +295,12 @@ e_book_do_response_get_changes (EBook                 *book,
 
 	book_view = e_book_view_new (resp->book_view, op->listener);
 	
-	if (op->cb)
-		((EBookBookViewCallback) op->cb) (book, resp->status, book_view, op->closure);
+	if (op->cb) {
+		if (op->active)
+			((EBookBookViewCallback) op->cb) (book, resp->status, book_view, op->closure);
+		else
+			((EBookBookViewCallback) op->cb) (book, E_BOOK_STATUS_CANCELLED, NULL, op->closure);
+	}
 
 	/*
 	 * Release the remote GNOME_Evolution_Addressbook_BookView in the PAS.
@@ -358,8 +395,13 @@ e_book_do_response_get_supported_fields (EBook                 *book,
 		return;
 	}
 
-	if (op->cb)
-		((EBookFieldsCallback) op->cb) (book, resp->status, resp->fields, op->closure);
+	if (op->cb) {
+		if (op->active)
+			((EBookFieldsCallback) op->cb) (book, resp->status, resp->fields, op->closure);
+		else
+			((EBookFieldsCallback) op->cb) (book, E_BOOK_STATUS_CANCELLED, NULL, op->closure);
+	}
+
 	g_free (op);
 }
 
@@ -559,7 +601,7 @@ e_book_get_static_capabilities (EBook *book)
 	return ret_val;
 }
 
-gboolean
+guint
 e_book_get_supported_fields (EBook              *book,
 			     EBookFieldsCallback cb,
 			     gpointer            closure)
@@ -570,7 +612,7 @@ e_book_get_supported_fields (EBook              *book,
 
 	if (book->priv->load_state != URILoaded) {
 		g_warning ("e_book_unload_uri: No URI is loaded!\n");
-		return FALSE;
+		return 0;
 	}
 
 	GNOME_Evolution_Addressbook_Book_getSupportedFields(book->priv->corba_book, &ev);
@@ -579,14 +621,12 @@ e_book_get_supported_fields (EBook              *book,
 		g_warning ("e_book_get_supported_fields: Exception "
 			   "during get_supported_fields!\n");
 		CORBA_exception_free (&ev);
-		return FALSE;
+		return 0;
 	}
 
 	CORBA_exception_free (&ev);
 
-	e_book_queue_op (book, cb, closure, NULL);
-
-	return TRUE;
+	return e_book_queue_op (book, cb, closure, NULL);
 }
 
 static gboolean
@@ -1000,7 +1040,7 @@ e_book_check_connection (EBook *book)
 	return TRUE;
 }
 
-gboolean
+guint
 e_book_get_cursor       (EBook               *book,
 			 gchar               *query,
 			 EBookCursorCallback  cb,
@@ -1008,12 +1048,12 @@ e_book_get_cursor       (EBook               *book,
 {
 	CORBA_Environment ev;
   
-	g_return_val_if_fail (book != NULL,     FALSE);
-	g_return_val_if_fail (E_IS_BOOK (book), FALSE);
+	g_return_val_if_fail (book != NULL,     0);
+	g_return_val_if_fail (E_IS_BOOK (book), 0);
 
 	if (book->priv->load_state != URILoaded) {
 		g_warning ("e_book_check_connection: No URI loaded!\n");
-		return FALSE;
+		return 0;
 	}
 	
 	CORBA_exception_init (&ev);
@@ -1024,17 +1064,17 @@ e_book_get_cursor       (EBook               *book,
 		g_warning ("e_book_get_all_cards: Exception "
 			   "querying list of cards!\n");
 		CORBA_exception_free (&ev);
-		return FALSE;
+		return 0;
 	}
 	
 	CORBA_exception_free (&ev);
 
-	e_book_queue_op (book, cb, closure, NULL);
+	return e_book_queue_op (book, cb, closure, NULL);
 
 	return TRUE;
 }
 
-gboolean
+guint
 e_book_get_book_view       (EBook                 *book,
 			    gchar                 *query,
 			    EBookBookViewCallback  cb,
@@ -1043,12 +1083,12 @@ e_book_get_book_view       (EBook                 *book,
 	CORBA_Environment ev;
 	EBookViewListener *listener;
   
-	g_return_val_if_fail (book != NULL,     FALSE);
-	g_return_val_if_fail (E_IS_BOOK (book), FALSE);
+	g_return_val_if_fail (book != NULL,     0);
+	g_return_val_if_fail (E_IS_BOOK (book), 0);
 
 	if (book->priv->load_state != URILoaded) {
 		g_warning ("e_book_get_book_view: No URI loaded!\n");
-		return FALSE;
+		return 0;
 	}
 
 	listener = e_book_view_listener_new();
@@ -1061,17 +1101,15 @@ e_book_get_book_view       (EBook                 *book,
 		g_warning ("e_book_get_book_view: Exception "
 			   "getting book_view!\n");
 		CORBA_exception_free (&ev);
-		return FALSE;
+		return 0;
 	}
 	
 	CORBA_exception_free (&ev);
 
-	e_book_queue_op (book, cb, closure, listener);
-
-	return TRUE;
+	return e_book_queue_op (book, cb, closure, listener);
 }
 
-gboolean
+guint
 e_book_get_changes         (EBook                 *book,
 			    gchar                 *changeid,
 			    EBookBookViewCallback  cb,
@@ -1080,8 +1118,8 @@ e_book_get_changes         (EBook                 *book,
 	CORBA_Environment ev;
 	EBookViewListener *listener;
   
-	g_return_val_if_fail (book != NULL,     FALSE);
-	g_return_val_if_fail (E_IS_BOOK (book), FALSE);
+	g_return_val_if_fail (book != NULL,     0);
+	g_return_val_if_fail (E_IS_BOOK (book), 0);
 
 	if (book->priv->load_state != URILoaded) {
 		g_warning ("e_book_get_changes: No URI loaded!\n");
@@ -1098,14 +1136,31 @@ e_book_get_changes         (EBook                 *book,
 		g_warning ("e_book_changes: Exception "
 			   "getting changes!\n");
 		CORBA_exception_free (&ev);
-		return FALSE;
+		return 0;
 	}
 	
 	CORBA_exception_free (&ev);
 
-	e_book_queue_op (book, cb, closure, listener);
+	return e_book_queue_op (book, cb, closure, listener);
+}
 
-	return TRUE;
+/**
+ * e_book_cancel
+ */
+
+void
+e_book_cancel (EBook *book, guint tag)
+{
+	g_return_if_fail (book != NULL);
+	g_return_if_fail (E_IS_BOOK (book));
+	g_return_if_fail (tag != 0);
+
+	/* In an attempt to be useful, we take a bit of extra care in reporting
+	   errors.  This might come in handy someday. */
+	if (tag >= book->priv->op_tag)
+		g_warning ("Attempt to cancel unassigned operation (%u)", tag);
+	else if (! e_book_cancel_op (book, tag))
+		g_warning ("Attempt to cancel unknown operation (%u)", tag); 
 }
 
 /**
@@ -1154,6 +1209,7 @@ e_book_init (EBook *book)
 {
 	book->priv             = g_new0 (EBookPrivate, 1);
 	book->priv->load_state = URINotLoaded;
+	book->priv->op_tag = 1;
 }
 
 static void