[gnome-builder] libide/gui: make ide_session_item_get_metadata() more convenient

[Christian Hergert <chergert src gnome org>]

commit f7cd407c6cf73c2155ec04597a567342c2875fdc
Author: Christian Hergert <chergert redhat com>
Date:   Fri Sep 16 13:39:14 2022 -0700

    libide/gui: make ide_session_item_get_metadata() more convenient
    
    We can use g_variant_check_format_string() to make this function much more
    convenient in addins. That way we don't have to check for the metadata
    upfront, and instead can do:
    
     if (ide_session_item_get_metadata (item, "size", "(ii)", &width, &height))
    
    which is a lot cleaner than open-coding all the checks.

 src/libide/gui/ide-session-item.c | 26 +++++++++++++++-----------
 src/libide/gui/ide-session-item.h |  2 +-
 2 files changed, 16 insertions(+), 12 deletions(-)
---
diff --git a/src/libide/gui/ide-session-item.c b/src/libide/gui/ide-session-item.c
index 8780a93d1..ac785378a 100644
--- a/src/libide/gui/ide-session-item.c
+++ b/src/libide/gui/ide-session-item.c
@@ -464,11 +464,12 @@ ide_session_item_has_metadata_with_type (IdeSessionItem    *self,
  *
  * Extract a metadata value matching @format.
  *
- * It is an error to use this function on untrusted data where you have not
- * checked the type of the value of @key using ide_session_item_has_metadata()
- * or ide_session_item_has_metadata_with_type().
+ * @format must not reference the #GVariant, which means you need to make
+ * copies of data, such as "s" instead of "&s".
+ *
+ * Returns: %TRUE if @key was found with @format and parameters were set.
  */
-void
+gboolean
 ide_session_item_get_metadata (IdeSessionItem *self,
                                const char      *key,
                                const char      *format,
@@ -477,21 +478,24 @@ ide_session_item_get_metadata (IdeSessionItem *self,
   GVariant *value;
   va_list args;
 
-  g_return_if_fail (IDE_IS_SESSION_ITEM (self));
-  g_return_if_fail (key != NULL);
-  g_return_if_fail (format != NULL);
-  g_return_if_fail (g_variant_type_string_is_valid (format));
-  g_return_if_fail (ide_session_item_has_metadata (self, key, NULL));
+  g_return_val_if_fail (IDE_IS_SESSION_ITEM (self), FALSE);
+  g_return_val_if_fail (key != NULL, FALSE);
+  g_return_val_if_fail (format != NULL, FALSE);
+  g_return_val_if_fail (g_variant_type_string_is_valid (format), FALSE);
 
-  value = ide_session_item_get_metadata_value (self, key, NULL);
+  if (!(value = ide_session_item_get_metadata_value (self, key, NULL)))
+    return FALSE;
 
-  g_return_if_fail (value != NULL);
+  if (!g_variant_check_format_string (value, format, TRUE))
+    return FALSE;
 
   va_start (args, format);
   g_variant_get_va (value, format, NULL, &args);
   va_end (args);
 
   g_variant_unref (value);
+
+  return TRUE;
 }
 
 /**
diff --git a/src/libide/gui/ide-session-item.h b/src/libide/gui/ide-session-item.h
index 5a76bd601..44b6b9d75 100644
--- a/src/libide/gui/ide-session-item.h
+++ b/src/libide/gui/ide-session-item.h
@@ -71,7 +71,7 @@ gboolean        ide_session_item_has_metadata_with_type (IdeSessionItem      *se
                                                          const char          *key,
                                                          const GVariantType  *expected_type);
 IDE_AVAILABLE_IN_ALL
-void            ide_session_item_get_metadata           (IdeSessionItem      *self,
+gboolean        ide_session_item_get_metadata           (IdeSessionItem      *self,
                                                          const char          *key,
                                                          const char          *format,
                                                          ...);