mcp_account_storage_get_flags: add

The initial flag is STORES_TYPES, which can be used to decide whether
to try to attach types to untyped parameters. Of our built-in plugins,
the default keyfile/variant-file storage and the D-Bus test plugin
have STORES_TYPES, but the "diversion" plugin does not.

Flags are account-specific in case they ever need to vary per-account
(e.g. a FROM_TELEPATHY_0 flag might be one way to deal with migration
from Telepathy 0.x to 1.0).

Also add some convenience API (has_all_flags, has_any_flag) to make
code that uses these flags easier to understand.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=71093
Reviewed-by: Guillaume Desmottes <guillaume.desmottes@collabora.co.uk>

2 files changed, 111 insertions, 0 deletions

diff --git a/mission-control-plugins/account-storage.c b/mission-control-plugins/account-storage.c
index d93d2c1b..f36ed25c 100644
--- a/mission-control-plugins/account-storage.c
+++ b/mission-control-plugins/account-storage.c
@@ -56,6 +56,7 @@
  *   iface->desc = "The FOO storage backend";
  *   iface->provider = "org.freedesktop.Telepathy.MissionControl5.FooStorage";
  *
+ *   iface->get_flags = foo_plugin_get_flags;
  *   iface->delete_async = foo_plugin_delete_async;
  *   iface->delete_finish = foo_plugin_delete_finish;
  *   iface->commit = foo_plugin_commit;
@@ -101,6 +102,15 @@
 
 #endif /* ENABLE_DEBUG */
 
+/**
+ * McpAccountStorageFlags:
+ * @MCP_ACCOUNT_STORAGE_FLAG_NONE: no particular flags
+ * @MCP_ACCOUNT_STORAGE_FLAG_STORES_TYPES: this backend can store parameter
+ *  values' types
+ *
+ * Flags describing the features and capabilities of a backend.
+ */
+
 enum
 {
   CREATED,
@@ -215,6 +225,13 @@ default_list_untyped_parameters (McpAccountStorage *storage,
   return NULL;
 }
 
+static McpAccountStorageFlags
+default_get_flags (McpAccountStorage *storage,
+    const gchar *account)
+{
+  return MCP_ACCOUNT_STORAGE_FLAG_NONE;
+}
+
 static void
 class_init (gpointer klass,
     gpointer data)
@@ -222,6 +239,7 @@ class_init (gpointer klass,
   GType type = G_TYPE_FROM_CLASS (klass);
   McpAccountStorageIface *iface = klass;
 
+  iface->get_flags = default_get_flags;
   iface->create = default_create;
   iface->delete_async = default_delete_async;
   iface->delete_finish = default_delete_finish;
@@ -1205,3 +1223,75 @@ mcp_account_storage_emit_reconnect (McpAccountStorage *storage,
   SDEBUG (storage, "%s", account);
   g_signal_emit (storage, signals[RECONNECT], 0, account);
 }
+
+/**
+ * mcp_account_storage_get_flags:
+ * @storage: an #McpAccountStorage instance
+ * @account: the unique name of the account to inspect
+ *
+ * Get the backend's features and capabilities. The default implementation
+ * returns %MCP_ACCOUNT_STORAGE_FLAG_NONE. Additionally providing
+ * %MCP_ACCOUNT_STORAGE_FLAG_STORES_TYPES is strongly recommended.
+ *
+ * Returns: a bitmask of API features that apply to @account
+ */
+McpAccountStorageFlags
+mcp_account_storage_get_flags (McpAccountStorage *storage,
+    const gchar *account)
+{
+  McpAccountStorageIface *iface = MCP_ACCOUNT_STORAGE_GET_IFACE (storage);
+
+  g_return_val_if_fail (iface != NULL, MCP_ACCOUNT_STORAGE_FLAG_NONE);
+  g_return_val_if_fail (iface->get_flags != NULL,
+      MCP_ACCOUNT_STORAGE_FLAG_NONE);
+
+  return iface->get_flags (storage, account);
+}
+
+/**
+ * mcp_account_storage_has_all_flags:
+ * @storage: an #McpAccountStorage instance
+ * @account: the unique name of the account to inspect
+ * @require_all: bitwise "or" of zero or more flags
+ *
+ * Return whether this account has all of the specified flags,
+ * according to mcp_account_storage_get_flags().
+ *
+ * If @require_all is 0, the result will always be %TRUE
+ * (the account has all of the flags in the empty set).
+ *
+ * Returns: %TRUE if @account has every flag in @require_all
+ */
+gboolean
+mcp_account_storage_has_all_flags (McpAccountStorage *storage,
+    const gchar *account,
+    McpAccountStorageFlags require_all)
+{
+  return ((mcp_account_storage_get_flags (storage, account) & require_all) ==
+    require_all);
+}
+
+
+/**
+ * mcp_account_storage_has_any_flag:
+ * @storage: an #McpAccountStorage instance
+ * @account: the unique name of the account to inspect
+ * @require_one: bitwise "or" of one or more flags
+ *
+ * Return whether this account has at least one of the required flags,
+ * according to mcp_account_storage_get_flags().
+ *
+ * If @require_one is 0, the result will always be %FALSE
+ * (it is not true that the account has at least one of the flags
+ * in the empty set).
+ *
+ * Returns: %TRUE if @account has every flag in @require_all
+ */
+gboolean
+mcp_account_storage_has_any_flag (McpAccountStorage *storage,
+    const gchar *account,
+    McpAccountStorageFlags require_one)
+{
+  return ((mcp_account_storage_get_flags (storage, account) & require_one)
+      != 0);
+}
diff --git a/mission-control-plugins/account-storage.h b/mission-control-plugins/account-storage.h
index c1a1ece6..95ffcc14 100644
--- a/mission-control-plugins/account-storage.h
+++ b/mission-control-plugins/account-storage.h
@@ -47,6 +47,12 @@ typedef enum {
     MCP_ACCOUNT_STORAGE_SET_RESULT_UNCHANGED
 } McpAccountStorageSetResult;
 
+typedef enum /*< flags >*/
+{
+    MCP_ACCOUNT_STORAGE_FLAG_NONE = 0,
+    MCP_ACCOUNT_STORAGE_FLAG_STORES_TYPES = (1 << 0)
+} McpAccountStorageFlags;
+
 /* API for plugins to implement */
 typedef struct _McpAccountStorage McpAccountStorage;
 typedef struct _McpAccountStorageIface McpAccountStorageIface;
@@ -162,6 +168,9 @@ struct _McpAccountStorageIface
   gchar **(*list_untyped_parameters) (McpAccountStorage *storage,
       McpAccountManager *am,
       const gchar *account);
+
+  McpAccountStorageFlags (*get_flags) (McpAccountStorage *storage,
+      const gchar *account);
 };
 
 /* virtual methods */
@@ -246,6 +255,18 @@ McpAccountStorageSetResult mcp_account_storage_set_parameter (
     GVariant *value,
     McpParameterFlags flags);
 
+McpAccountStorageFlags mcp_account_storage_get_flags (
+    McpAccountStorage *storage,
+    const gchar *account);
+gboolean mcp_account_storage_has_all_flags (
+    McpAccountStorage *storage,
+    const gchar *account,
+    McpAccountStorageFlags require_all);
+gboolean mcp_account_storage_has_any_flag (
+    McpAccountStorage *storage,
+    const gchar *account,
+    McpAccountStorageFlags require_one);
+
 void mcp_account_storage_emit_created (McpAccountStorage *storage,
     const gchar *account);
 void mcp_account_storage_emit_altered_one (McpAccountStorage *storage,