[RFC,v2,3/9] errp: rename errp to errp_in where it is IN-argument

Commit Message

Vladimir Sementsov-Ogievskiy Sept. 23, 2019, 4:12 p.m. UTC

Error **errp is almost always OUT-argument: it's assumed to be NULL, or
pointer to NULL-initialized pointer, or pointer to error_abort or
error_fatal, for callee to report error.

But very few functions (most of the are error API) instead get Error
**errp as IN-argument: it's assumed to be set, and callee should clean
it. In such cases, rename errp to errp_in.

Signed-off-by: Vladimir Sementsov-Ogievskiy <[e-mail]>
---
 include/monitor/hmp.h |  2 +-
 include/qapi/error.h  |  8 ++++----
 ui/vnc.h              |  2 +-
 monitor/hmp-cmds.c    |  8 ++++----
 ui/vnc.c              | 10 +++++-----
 util/error.c          |  2 +-
 6 files changed, 16 insertions(+), 16 deletions(-)

Comments

Eric Blake Sept. 23, 2019, 6:35 p.m. UTC | #1

On 9/23/19 11:12 AM, Vladimir Sementsov-Ogievskiy wrote:
> Error **errp is almost always OUT-argument: it's assumed to be NULL, or
> pointer to NULL-initialized pointer, or pointer to error_abort or
> error_fatal, for callee to report error.
> 
> But very few functions (most of the are error API) instead get Error
> **errp as IN-argument: it's assumed to be set, and callee should clean
> it. In such cases, rename errp to errp_in.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <[e-mail]>
> ---
>  include/monitor/hmp.h |  2 +-
>  include/qapi/error.h  |  8 ++++----
>  ui/vnc.h              |  2 +-
>  monitor/hmp-cmds.c    |  8 ++++----
>  ui/vnc.c              | 10 +++++-----
>  util/error.c          |  2 +-
>  6 files changed, 16 insertions(+), 16 deletions(-)

This is worthwhile, regardless of the fate of the rest of the series.

Reviewed-by: Eric Blake <[e-mail]>

Patch

diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index a0e9511440..f929814f1a 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -16,7 +16,7 @@ 
 
 #include "qemu/readline.h"
 
-void hmp_handle_error(Monitor *mon, Error **errp);
+void hmp_handle_error(Monitor *mon, Error **errp_in);
 
 void hmp_info_name(Monitor *mon, const QDict *qdict);
 void hmp_info_version(Monitor *mon, const QDict *qdict);
diff --git a/include/qapi/error.h b/include/qapi/error.h
index 551385aa91..4264d22223 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -283,7 +283,7 @@  void error_free(Error *err);
 /*
  * Convenience function to assert that *@errp is set, then silently free it.
  */
-void error_free_or_abort(Error **errp);
+void error_free_or_abort(Error **errp_in);
 
 /*
  * Convenience function to warn_report() and free @err.
@@ -301,19 +301,19 @@  void error_report_err(Error *err);
  * Functions to clean Error **errp: call corresponding Error *err cleaning
  * function an set pointer to NULL
  */
-static inline void error_free_errp(Error **errp)
+static inline void error_free_errp(Error **errp_in)
 {
     error_free(*errp_in);
     *errp_in = NULL;
 }
 
-static inline void error_report_errp(Error **errp)
+static inline void error_report_errp(Error **errp_in)
 {
     error_report_err(*errp_in);
     *errp_in = NULL;
 }
 
-static inline void warn_report_errp(Error **errp)
+static inline void warn_report_errp(Error **errp_in)
 {
     warn_report_err(*errp_in);
     *errp_in = NULL;
diff --git a/ui/vnc.h b/ui/vnc.h
index fea79c2fc9..00e0b48f2f 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -547,7 +547,7 @@  uint32_t read_u32(uint8_t *data, size_t offset);
 
 /* Protocol stage functions */
 void vnc_client_error(VncState *vs);
-size_t vnc_client_io_error(VncState *vs, ssize_t ret, Error **errp);
+size_t vnc_client_io_error(VncState *vs, ssize_t ret, Error **errp_in);
 
 void start_client_init(VncState *vs);
 void start_auth_vnc(VncState *vs);
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index b2551c16d1..941d5d0a45 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -60,11 +60,11 @@ 
 #include <spice/enums.h>
 #endif
 
-void hmp_handle_error(Monitor *mon, Error **errp)
+void hmp_handle_error(Monitor *mon, Error **errp_in)
 {
-    assert(errp);
-    if (*errp) {
-        error_reportf_err(*errp, "Error: ");
+    assert(errp_in);
+    if (*errp_in) {
+        error_reportf_err(*errp_in, "Error: ");
     }
 }
 
diff --git a/ui/vnc.c b/ui/vnc.c
index 87b8045afe..9d6384d9b1 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -1312,7 +1312,7 @@  void vnc_disconnect_finish(VncState *vs)
     g_free(vs);
 }
 
-size_t vnc_client_io_error(VncState *vs, ssize_t ret, Error **errp)
+size_t vnc_client_io_error(VncState *vs, ssize_t ret, Error **errp_in)
 {
     if (ret <= 0) {
         if (ret == 0) {
@@ -1320,14 +1320,14 @@  size_t vnc_client_io_error(VncState *vs, ssize_t ret, Error **errp)
             vnc_disconnect_start(vs);
         } else if (ret != QIO_CHANNEL_ERR_BLOCK) {
             trace_vnc_client_io_error(vs, vs->ioc,
-                                      errp ? error_get_pretty(*errp) :
+                                      errp_in ? error_get_pretty(*errp_in) :
                                       "Unknown");
             vnc_disconnect_start(vs);
         }
 
-        if (errp) {
-            error_free(*errp);
-            *errp = NULL;
+        if (errp_in) {
+            error_free(*errp_in);
+            *errp_in = NULL;
         }
         return 0;
     }
diff --git a/util/error.c b/util/error.c
index dfba091757..b3ff3832d6 100644
--- a/util/error.c
+++ b/util/error.c
@@ -271,7 +271,7 @@  void error_free(Error *err)
     }
 }
 
-void error_free_or_abort(Error **errp)
+void error_free_or_abort(Error **errp_in)
 {
     assert(errp_in && *errp_in);
     error_free(*errp_in);