add more error types to backend

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@3544 57a11ea4-9604-0410-9ed3-97b8803252fd

src/engine/Backend.c

@@ -31,6 +31,29 @@
 
 /* static short module = MOD_ENGINE; */
 
+/********************************************************************\
+ * error handling                                                   *
+\********************************************************************/
+
+void 
+xaccBackendSetError (Backend *be, GNCBackendError err)
+{
+   if (!be) return;
+   be->last_err = err;
+}
+
+GNCBackendError 
+xaccBackendGetError (Backend *be)
+{
+   GNCBackendError err;
+   if (!be) return ERR_BACKEND_NO_BACKEND;
+
+   /* use 'stack-pop' semantics */
+   err = be->last_err;
+   be->last_err = ERR_BACKEND_NO_ERR;
+   return err;
+}
+
 
 /********************************************************************\
  * Fetch the backend                                                *

src/engine/BackendP.h

@@ -27,7 +27,8 @@
 
 typedef enum {
   ERR_BACKEND_NO_ERR = 0,
-  ERR_BACKEND_MISC,
+  ERR_BACKEND_NO_BACKEND,   /* Backend * pointer was null the err routine */
+  ERR_BACKEND_MISC,         /* undetermined error */
 
   /* fileio errors */
   ERR_BFILEIO_FILE_BAD_READ,
@@ -38,10 +39,19 @@ typedef enum {
   ERR_BFILEIO_ALLOC,
 
   /* network errors */
-  ERR_NETIO_NO_CONNECTION,
-  ERR_NETIO_SHORT_READ,
-  ERR_NETIO_WRONG_CONTENT_TYPE,
-  ERR_NETIO_NOT_GNCXML
+  ERR_NETIO_NO_CONNECTION,      /* network failure */
+  ERR_NETIO_SHORT_READ,         /* not enough bytes received */
+  ERR_NETIO_WRONG_CONTENT_TYPE, /* wrong kind of server, wrong data served */
+  ERR_NETIO_NOT_GNCXML,
+
+  /* database errors */
+  ERR_SQL_BUSY,              /* single-mode access doesn't allow other users */
+  ERR_SQL_CANT_CONNECT,      /* network failure */
+  ERR_SQL_SEND_QUERY_FAILED,
+  ERR_SQL_FINISH_QUERY_FAILED,
+  ERR_SQL_GET_RESULT_FAILED,
+  ERR_SQL_CORRUPT_DB,
+  ERR_SQL_MISSING_DATA,     /* database doesn't contain expected data */
 } GNCBackendError;
 
 
@@ -128,6 +138,17 @@ struct _backend
   GNCBackendError last_err;
 };
 
+/*
+ * The xaccBackendSetError() routine pushes an error code onto the error
+ *   stack. (FIXME: the stack is 1 deep in current implementation).
+ *
+ * The xaccBackendGetError() routine pops an error code off the error
+ *   stack.
+ */
+
+void xaccBackendSetError (Backend *, GNCBackendError err);
+GNCBackendError xaccBackendGetError (Backend *);
+
 /*
  * The xaccGetAccountBackend() subroutine will find the
  *    persistent-data storage backend associated with this account.