mu: better error handling for opening database read-only

Be a bit clearer for the user.

lib/mu-store.cc

@@ -479,23 +479,20 @@ mu_store_new_readable (const char* xpath, GError **err)
 		return reinterpret_cast<MuStore*>(new Store (xpath));
 
         } catch (const Mu::Error& me) {
-                if (me.code() == Mu::Error::Code::SchemaMismatch)
+                if (me.code() == Mu::Error::Code::SchemaMismatch) {
-                        g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR_XAPIAN_NEEDS_REINDEX,
+                        g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR_XAPIAN_SCHEMA_MISMATCH,
-                                     "read-only database @ %s needs (re)indexing", xpath);
+                                     "read-only database @ %s schema version does not match",
-                else
+                                     xpath);
-                        g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR_XAPIAN,
+                        return NULL;
-                                     "error opening database @ %s: %s", xpath, me.what());
+                }
-        // } catch (const Xapian::DatabaseNotFoundError& dbe) { // Xapian 1.4.10
+        } catch (const Xapian::Error& dbe) {
-        //         g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR_XAPIAN_NEEDS_REINDEX,
+                g_warning ("failed to open database @ %s: %s", xpath,
-        //                      "database @ %s not found", xpath);
+                           dbe.get_error_string() ? dbe.get_error_string() : "something went wrong");
-        } catch (const Xapian::DatabaseOpeningError& dbe) {
-                g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR_XAPIAN_NEEDS_REINDEX,
-                             "failed to open database @ %s", xpath);
-        } catch (...) {
-                g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR_XAPIAN,
-                             "error opening database @ %s", xpath);
         }
 
+        g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR_XAPIAN_CANNOT_OPEN,
+                     "failed to open database @ %s", xpath);
+
         return NULL;
 }
 

lib/utils/mu-util.h

@@ -344,7 +344,10 @@ enum _MuError {
 	MU_ERROR_XAPIAN_MODIFIED             = 23,
         /* database was modified; reload */
 	MU_ERROR_XAPIAN_NEEDS_REINDEX        = 24,
-
+        /* database schema version doesn't match */
+        MU_ERROR_XAPIAN_SCHEMA_MISMATCH      = 25,
+        /* failed to open the database */
+        MU_ERROR_XAPIAN_CANNOT_OPEN          = 26,
 
 	/* GMime related errors */
 

mu/mu-cmd.c

@@ -569,6 +569,33 @@ show_usage (void)
 typedef MuError (*store_func) (MuStore *, MuConfig *, GError **err);
 
 
+static MuError
+with_readonly_store (store_func func, MuConfig *opts, GError **err)
+{
+	MuError		 merr;
+	MuStore		*store;
+	const char	*path;
+
+	if (opts->rebuild) {
+		g_set_error (err, MU_ERROR_DOMAIN, MU_ERROR,
+			     "cannot rebuild a read-only database");
+		return MU_G_ERROR_CODE(err);
+	}
+
+	path  = mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB);
+	store = mu_store_new_readable (path, err);
+
+	if (!store)
+		return MU_G_ERROR_CODE(err);
+
+	merr = func (store, opts, err);
+	mu_store_unref (store);
+
+	return merr;
+}
+
+
+
 static MuStore*
 get_store (MuConfig *opts, gboolean read_only, GError **err)
 {
@@ -672,9 +699,10 @@ mu_cmd_execute (MuConfig *opts, GError **err)
 	case MU_CONFIG_CMD_EXTRACT: merr = mu_cmd_extract (opts, err); break;
 
 	case MU_CONFIG_CMD_CFIND:
-		merr = with_store (mu_cmd_cfind, opts, TRUE, err); break;
+		merr = with_readonly_store (mu_cmd_cfind, opts, err); break;
 	case MU_CONFIG_CMD_FIND:
-		merr = with_store (mu_cmd_find, opts, TRUE, err);      break;
+		merr = with_readonly_store (mu_cmd_find, opts, err);  break;
+
 	case MU_CONFIG_CMD_INDEX:
 		merr = with_store (mu_cmd_index, opts, FALSE, err);    break;
 	case MU_CONFIG_CMD_ADD:

mu/mu.cc

@@ -51,9 +51,13 @@ show_version (void)
 static void
 handle_error (MuConfig *conf, MuError merr, GError **err)
 {
+	const char *path;
+
 	if (!(err && *err))
 		return;
 
+	path  = mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB);
+
 	switch ((*err)->code) {
 	case MU_ERROR_XAPIAN_CANNOT_GET_WRITELOCK:
 		g_printerr ("maybe mu is already running?\n");
@@ -71,6 +75,17 @@ handle_error (MuConfig *conf, MuError merr, GError **err)
 		g_printerr ("see the mu manpage for commands, or "
 			    "'mu script' for the scripts\n");
 		break;
+	case MU_ERROR_XAPIAN_CANNOT_OPEN:
+		g_printerr("Failed to open database @ %s, \n"
+			   "Please (re)build the database, i.e., with\n"
+				   "\tmu index --rebuild\n", path);
+		return;
+	case MU_ERROR_XAPIAN_SCHEMA_MISMATCH:
+		g_printerr("Failed to open database @ %s, \n"
+			   "because the schema version does not match mu's.\n\n"
+			   "Please rebuild the database, i.e., with\n"
+				   "\tmu index --rebuild\n", path);
+		return;
 	default:
 		break; /* nothing to do */
 	}