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, 16 insertions, 0 deletions

diff --git a/qemu-error.h b/qemu-error.h
index 5b05371fc..a1562aaa0 100644
--- a/qemu-error.h
+++ b/qemu-error.h
@@ -13,8 +13,24 @@
 #ifndef QEMU_ERROR_H
 #define QEMU_ERROR_H
 
+typedef struct Location {
+    /* all members are private to qemu-error.c */
+    enum { LOC_NONE } kind;
+    int num;
+    const void *ptr;
+    struct Location *prev;
+} Location;
+
+Location *loc_push_restore(Location *loc);
+Location *loc_push_none(Location *loc);
+Location *loc_pop(Location *loc);
+Location *loc_save(Location *loc);
+void loc_restore(Location *loc);
+void loc_set_none(void);
+
 void error_vprintf(const char *fmt, va_list ap);
 void error_printf(const char *fmt, ...) __attribute__ ((format(printf, 1, 2)));
+void error_print_loc(void);
 void error_report(const char *fmt, ...) __attribute__ ((format(printf, 1, 2)));
 void qerror_report_internal(const char *file, int linenr, const char *func,
                             const char *fmt, ...)