lib: catch exceptions in n_m_get_flag, provide n_m_get_flag_st

It's not very nice to return FALSE for an error, so provide
notmuch_message_get_flag_st as a migration path.

Bump LIBNOTMUCH_MINOR_VERSION because the API is extended.

2 files changed, 55 insertions, 5 deletions

diff --git a/lib/message.cc b/lib/message.cc
index 5ea5aa22..4e1be986 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -1166,15 +1166,40 @@ notmuch_message_count_files (notmuch_message_t *message)
     return _notmuch_string_list_length (message->filename_list);
 }
 
+notmuch_status_t
+notmuch_message_get_flag_st (notmuch_message_t *message,
+			     notmuch_message_flag_t flag,
+			     notmuch_bool_t *is_set)
+{
+    if (! is_set)
+	return NOTMUCH_STATUS_NULL_POINTER;
+
+    try {
+	if (flag == NOTMUCH_MESSAGE_FLAG_GHOST &&
+	    ! NOTMUCH_TEST_BIT (message->lazy_flags, flag))
+	    _notmuch_message_ensure_metadata (message, NULL);
+    } catch (Xapian::Error &error) {
+	LOG_XAPIAN_EXCEPTION (message, error);
+	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+    }
+
+    *is_set = NOTMUCH_TEST_BIT (message->flags, flag);
+    return NOTMUCH_STATUS_SUCCESS;
+}
+
 notmuch_bool_t
 notmuch_message_get_flag (notmuch_message_t *message,
 			  notmuch_message_flag_t flag)
 {
-    if (flag == NOTMUCH_MESSAGE_FLAG_GHOST &&
-	! NOTMUCH_TEST_BIT (message->lazy_flags, flag))
-	_notmuch_message_ensure_metadata (message, NULL);
+    notmuch_bool_t is_set;
+    notmuch_status_t status;
+
+    status = notmuch_message_get_flag_st (message, flag, &is_set);
 
-    return NOTMUCH_TEST_BIT (message->flags, flag);
+    if (status)
+	return FALSE;
+    else
+	return is_set;
 }
 
 void
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 693e5076..0491e8f8 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -58,7 +58,7 @@ NOTMUCH_BEGIN_DECLS
  * version in Makefile.local.
  */
 #define LIBNOTMUCH_MAJOR_VERSION        5
-#define LIBNOTMUCH_MINOR_VERSION        2
+#define LIBNOTMUCH_MINOR_VERSION        3
 #define LIBNOTMUCH_MICRO_VERSION        0
 
 
@@ -1486,12 +1486,37 @@ typedef enum _notmuch_message_flag {
 
 /**
  * Get a value of a flag for the email corresponding to 'message'.
+ *
+ * returns FALSE in case of errors.
+ *
+ * @deprecated Deprecated as of libnotmuch 5.3 (notmuch 0.31). Please
+ * use notmuch_message_get_flag_st instead.
  */
+NOTMUCH_DEPRECATED(5,3)
 notmuch_bool_t
 notmuch_message_get_flag (notmuch_message_t *message,
 			  notmuch_message_flag_t flag);
 
 /**
+ * Get a value of a flag for the email corresponding to 'message'.
+ *
+ * @param message a message object
+ * @param flag flag to check
+ * @param is_set pointer to boolean to store flag value.
+ *
+ * @retval #NOTMUCH_STATUS_SUCCESS
+ * @retval #NOTMUCH_STATUS_NULL_POINTER is_set is NULL
+ * @retval #NOTMUCH_STATUS_XAPIAN_EXCEPTION Accessing the database
+ * triggered an exception.
+ *
+ * @since libnotmuch 5.3 (notmuch 0.31)
+ */
+notmuch_status_t
+notmuch_message_get_flag_st (notmuch_message_t *message,
+			     notmuch_message_flag_t flag,
+			     notmuch_bool_t *is_set);
+
+/**
  * Set a value of a flag for the email corresponding to 'message'.
  */
 void