error: make Error **errp const where it is appropriate

Mostly, Error ** is for returning error from the function, so the
callee sets it. However these three functions get already filled errp
parameter. They don't change the pointer itself, only change the
internal state of referenced Error object. So we can make it
Error *const * errp, to stress the behavior. It will also help
coccinelle script (in future) to distinguish such cases from common
errp usage.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20191205174635.18758-4-vsementsov@virtuozzo.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message typo fixed]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

diff --git a/include/qapi/error.h b/include/qapi/error.h
index 3f95141a01a847b8b03f673f70f9663d8f6dc5c9..ad5b6e896dedb28d26705c6a630b4303a358b1e9 100644 (file)
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -233,13 +233,13 @@ void error_propagate_prepend(Error **dst_errp, Error *local_err,
  * Prepend some text to @errp's human-readable error message.
  * The text is made by formatting @fmt, @ap like vprintf().
  */
-void error_vprepend(Error **errp, const char *fmt, va_list ap);
+void error_vprepend(Error *const *errp, const char *fmt, va_list ap);
 
 /*
  * Prepend some text to @errp's human-readable error message.
  * The text is made by formatting @fmt, ... like printf().
  */
-void error_prepend(Error **errp, const char *fmt, ...)
+void error_prepend(Error *const *errp, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
 
 /*
@@ -256,7 +256,7 @@ void error_prepend(Error **errp, const char *fmt, ...)
  * May be called multiple times.  The resulting hint should end with a
  * newline.
  */
-void error_append_hint(Error **errp, const char *fmt, ...)
+void error_append_hint(Error *const *errp, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
 
 /*

diff --git a/util/error.c b/util/error.c
index d4532ce31818307cd55b313ae4caddc17d86edb8..b6c89d141208cf9d7d683eeb6c309e960cd3722f 100644 (file)
--- a/util/error.c
+++ b/util/error.c
@@ -121,7 +121,7 @@ void error_setg_file_open_internal(Error **errp,
                               "Could not open '%s'", filename);
 }
 
-void error_vprepend(Error **errp, const char *fmt, va_list ap)
+void error_vprepend(Error *const *errp, const char *fmt, va_list ap)
 {
     GString *newmsg;
 
@@ -136,7 +136,7 @@ void error_vprepend(Error **errp, const char *fmt, va_list ap)
     (*errp)->msg = g_string_free(newmsg, 0);
 }
 
-void error_prepend(Error **errp, const char *fmt, ...)
+void error_prepend(Error *const *errp, const char *fmt, ...)
 {
     va_list ap;
 
@@ -145,7 +145,7 @@ void error_prepend(Error **errp, const char *fmt, ...)
     va_end(ap);
 }
 
-void error_append_hint(Error **errp, const char *fmt, ...)
+void error_append_hint(Error *const *errp, const char *fmt, ...)
 {
     va_list ap;
     int saved_errno = errno;