config: add NMConfigGetValueFlags argument to nm_config_data_get_value()

In some cases we want the returned value to be stripped. In some cases,
we want to read the raw value instead of the string parsed by GKeyFile.
Add an flags argument to nm_config_data_get_value(). It is up to the caller
to determine the exact meaning (and whether to strip).

By adding the flags argument, the caller can get the desired behavior easier
without having to workaround it afterwards. But more importantly, it becomes
apparent that there are different ways to retrieve the value and the caller
should decide on the details.

src/nm-config-data.h

@@ -45,6 +45,23 @@ G_BEGIN_DECLS
 #define NM_CONFIG_DATA_NO_AUTO_DEFAULT       "no-auto-default"
 #define NM_CONFIG_DATA_DNS_MODE              "dns"
 
+typedef enum { /*<flags >*/
+	NM_CONFIG_GET_VALUE_NONE                   = 0,
+
+	/* use g_key_file_get_value() instead of g_key_file_get_string(). */
+	NM_CONFIG_GET_VALUE_RAW                    = (1LL << 0),
+
+	/* strip whitespaces */
+	NM_CONFIG_GET_VALUE_STRIP                  = (1LL << 1),
+
+	/* if the returned string would be the empty word, return NULL. */
+	NM_CONFIG_GET_VALUE_NO_EMPTY               = (1LL << 2),
+
+	/* special flag to read device spec. You want to use this before passing the
+	 * value to nm_match_spec_split(). */
+	NM_CONFIG_GET_VALUE_TYPE_SPEC              = NM_CONFIG_GET_VALUE_RAW,
+} NMConfigGetValueFlags;
+
 typedef enum { /*< flags >*/
 	NM_CONFIG_CHANGE_NONE                      = 0,
 
@@ -87,8 +104,8 @@ const char *nm_config_data_get_config_main_file (const NMConfigData *config_data
 const char *nm_config_data_get_config_description (const NMConfigData *config_data);
 
 gboolean nm_config_data_has_group (const NMConfigData *self, const char *group);
-gboolean nm_config_data_has_value (const NMConfigData *self, const char *group, const char *key);
-char *nm_config_data_get_value (const NMConfigData *config_data, const char *group, const char *key);
+gboolean nm_config_data_has_value (const NMConfigData *self, const char *group, const char *key, NMConfigGetValueFlags flags);
+char *nm_config_data_get_value (const NMConfigData *config_data, const char *group, const char *key, NMConfigGetValueFlags flags);
 gint nm_config_data_get_value_boolean (const NMConfigData *self, const char *group, const char *key, gint default_value);
 
 const char *nm_config_data_get_connectivity_uri (const NMConfigData *config_data);