error: Infrastructure to track locations for error reporting

New struct Location holds a location.  So far, the only location is
LOC_NONE, so this doesn't do anything useful yet.

Passing the current location all over the place would be too
cumbersome.  Hide it away in static cur_loc instead, and provide
accessors.  Print it in error_report().

Store it in QError, and print it in qerror_print().

Store it in QemuOpt, for use by qemu_opts_foreach().  This makes
error_report() do the right thing when it runs within
qemu_opts_foreach().

We may still have to store it in other data structures holding user
input for better error messages.  Left for another day.

1 files changed, 4 insertions, 1 deletions

diff --git a/qerror.c b/qerror.c
index a6f021395..b40048061 100644
--- a/qerror.c
+++ b/qerror.c
@@ -224,6 +224,7 @@ QError *qerror_from_info(const char *file, int linenr, const char *func,
     QError *qerr;
 
     qerr = qerror_new();
+    loc_save(&qerr->loc);
     qerr->linenr = linenr;
     qerr->file = file;
     qerr->func = func;
@@ -321,10 +322,12 @@ QString *qerror_human(const QError *qerror)
  * it uses error_report() for this, so that the output is routed to the right
  * place (ie. stderr or Monitor's device).
  */
-void qerror_print(const QError *qerror)
+void qerror_print(QError *qerror)
 {
     QString *qstring = qerror_human(qerror);
+    loc_push_restore(&qerror->loc);
     error_report("%s", qstring_get_str(qstring));
+    loc_pop(&qerror->loc);
     QDECREF(qstring);
 }