qapi: Replace uncommon use of the error API by the common one

We commonly use the error API like this:

    err = NULL;
    foo(..., &err);
    if (err) {
        goto out;
    }
    bar(..., &err);

Every error source is checked separately.  The second function is only
called when the first one succeeds.  Both functions are free to pass
their argument to error_set().  Because error_set() asserts no error
has been set, this effectively means they must not be called with an
error set.

The qapi-generated code uses the error API differently:

    // *errp was initialized to NULL somewhere up the call chain
    frob(..., errp);
    gnat(..., errp);

Errors accumulate in *errp: first error wins, subsequent errors get
dropped.  To make this work, the second function does nothing when
called with an error set.  Requires non-null errp, or else the second
function can't see the first one fail.

This usage has also bled into visitor tests, and two device model
object property getters rtc_get_date() and balloon_stats_get_all().

With the "accumulate" technique, you need fewer error checks in
callers, and buy that with an error check in every callee.  Can be
nice.

However, mixing the two techniques is confusing.  You can't use the
"accumulate" technique with functions designed for the "check
separately" technique.  You can use the "check separately" technique
with functions designed for the "accumulate" technique, but then
error_set() can't catch you setting an error more than once.

Standardize on the "check separately" technique for now, because it's
overwhelmingly prevalent.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index 1a635e2572d250ac3ca51617b66db385781abec0..1948946c05642ecf56b03a92e692aae1a05c72ca 100644 (file)
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -275,7 +275,6 @@ Example:
         qapi_dealloc_visitor_cleanup(md);
     }
 
-
     void qapi_free_UserDefOne(UserDefOne * obj)
     {
         QapiDeallocVisitor *md;
@@ -352,49 +351,54 @@ Example:
     {
         Error *err = NULL;
         visit_type_int(m, &(*obj)->integer, "integer", &err);
+        if (err) {
+            goto out;
+        }
         visit_type_str(m, &(*obj)->string, "string", &err);
+        if (err) {
+            goto out;
+        }
 
+    out:
         error_propagate(errp, err);
     }
 
     void visit_type_UserDefOne(Visitor *m, UserDefOne ** obj, const char *name, Error **errp)
     {
-        if (!error_is_set(errp)) {
-            Error *err = NULL;
-            visit_start_struct(m, (void **)obj, "UserDefOne", name, sizeof(UserDefOne), &err);
-            if (!err) {
-                if (*obj) {
-                    visit_type_UserDefOne_fields(m, obj, &err);
-                    error_propagate(errp, err);
-                    err = NULL;
-                }
-                /* Always call end_struct if start_struct succeeded.  */
-                visit_end_struct(m, &err);
+        Error *err = NULL;
+
+        visit_start_struct(m, (void **)obj, "UserDefOne", name, sizeof(UserDefOne), &err);
+        if (!err) {
+            if (*obj) {
+                visit_type_UserDefOne_fields(m, obj, errp);
             }
-            error_propagate(errp, err);
+            visit_end_struct(m, &err);
         }
+        error_propagate(errp, err);
     }
 
     void visit_type_UserDefOneList(Visitor *m, UserDefOneList ** obj, const char *name, Error **errp)
     {
-        GenericList *i, **prev = (GenericList **)obj;
         Error *err = NULL;
+        GenericList *i, **prev;
 
-        if (!error_is_set(errp)) {
-            visit_start_list(m, name, &err);
-            if (!err) {
-                for (; (i = visit_next_list(m, prev, &err)) != NULL; prev = &i) {
-                    UserDefOneList *native_i = (UserDefOneList *)i;
-                    visit_type_UserDefOne(m, &native_i->value, NULL, &err);
-                }
-                error_propagate(errp, err);
-                err = NULL;
-
-                /* Always call end_list if start_list succeeded.  */
-                visit_end_list(m, &err);
-            }
-            error_propagate(errp, err);
+        visit_start_list(m, name, &err);
+        if (err) {
+            goto out;
+        }
+
+        for (prev = (GenericList **)obj;
+             !err && (i = visit_next_list(m, prev, &err)) != NULL;
+             prev = &i) {
+            UserDefOneList *native_i = (UserDefOneList *)i;
+            visit_type_UserDefOne(m, &native_i->value, NULL, &err);
         }
+
+        error_propagate(errp, err);
+        err = NULL;
+        visit_end_list(m, &err);
+    out:
+        error_propagate(errp, err);
     }
     mdroth@illuin:~/w/qemu2.git$ cat qapi-generated/example-qapi-visit.h
 [Uninteresting stuff omitted...]
@@ -434,15 +438,20 @@ Example:
 
     static void qmp_marshal_output_my_command(UserDefOne * ret_in, QObject **ret_out, Error **errp)
     {
+        Error *local_err = NULL;
         QmpOutputVisitor *mo = qmp_output_visitor_new();
         QapiDeallocVisitor *md;
         Visitor *v;
 
         v = qmp_output_get_visitor(mo);
-        visit_type_UserDefOne(v, &ret_in, "unused", errp);
-        if (!error_is_set(errp)) {
-            *ret_out = qmp_output_get_qobject(mo);
+        visit_type_UserDefOne(v, &ret_in, "unused", &local_err);
+        if (local_err) {
+            goto out;
         }
+        *ret_out = qmp_output_get_qobject(mo);
+
+    out:
+        error_propagate(errp, local_err);
         qmp_output_visitor_cleanup(mo);
         md = qapi_dealloc_visitor_new();
         v = qapi_dealloc_get_visitor(md);
@@ -452,6 +461,7 @@ Example:
 
     static void qmp_marshal_input_my_command(QDict *args, QObject **ret, Error **errp)
     {
+        Error *local_err = NULL;
         UserDefOne * retval = NULL;
         QmpInputVisitor *mi = qmp_input_visitor_new_strict(QOBJECT(args));
         QapiDeallocVisitor *md;
@@ -459,17 +469,20 @@ Example:
         UserDefOne * arg1 = NULL;
 
         v = qmp_input_get_visitor(mi);
-        visit_type_UserDefOne(v, &arg1, "arg1", errp);
-
-        if (error_is_set(errp)) {
+        visit_type_UserDefOne(v, &arg1, "arg1", &local_err);
+        if (local_err) {
             goto out;
         }
-        retval = qmp_my_command(arg1, errp);
-        if (!error_is_set(errp)) {
-            qmp_marshal_output_my_command(retval, ret, errp);
+
+        retval = qmp_my_command(arg1, &local_err);
+        if (local_err) {
+            goto out;
         }
 
+        qmp_marshal_output_my_command(retval, ret, &local_err);
+
     out:
+        error_propagate(errp, local_err);
         qmp_input_visitor_cleanup(mi);
         md = qapi_dealloc_visitor_new();
         v = qapi_dealloc_get_visitor(md);

diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index 6c3e3b6d75a870d48be76d2b9b244c28c55423f3..df545465628b7acc48885b6d81176030a2160e29 100644 (file)
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -804,13 +804,33 @@ static void rtc_get_date(Object *obj, Visitor *v, void *opaque,
         goto out;
     }
     visit_type_int32(v, &current_tm.tm_year, "tm_year", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_int32(v, &current_tm.tm_mon, "tm_mon", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_int32(v, &current_tm.tm_mday, "tm_mday", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_int32(v, &current_tm.tm_hour, "tm_hour", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_int32(v, &current_tm.tm_min, "tm_min", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_int32(v, &current_tm.tm_sec, "tm_sec", &err);
-    visit_end_struct(v, &err);
-
+    if (err) {
+        goto out_end;
+    }
+out_end:
+    error_propagate(errp, err);
+    err = NULL;
+    visit_end_struct(v, errp);
 out:
     error_propagate(errp, err);
 }

diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index ca99bd5f97c3c6b359dcdef76ef8a6df0f5d285e..bf2b588b24bbc4cd2c296314110d175a39437ebc 100644 (file)
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -121,23 +121,27 @@ static void balloon_stats_get_all(Object *obj, struct Visitor *v,
     if (err) {
         goto out;
     }
-
     visit_type_int(v, &s->stats_last_update, "last-update", &err);
+    if (err) {
+        goto out_end;
+    }
 
     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
     if (err) {
         goto out_end;
     }
-        
-    for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
+    for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
                          &err);
     }
+    error_propagate(errp, err);
+    err = NULL;
     visit_end_struct(v, &err);
 
 out_end:
+    error_propagate(errp, err);
+    err = NULL;
     visit_end_struct(v, &err);
-
 out:
     error_propagate(errp, err);
 }

diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index ffd76372d1fd69855a1425b76e154a40ab75260c..55f8d4068cbb689a9b5740a9eaab8a715aa438b7 100644 (file)
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -20,28 +20,24 @@
 void visit_start_struct(Visitor *v, void **obj, const char *kind,
                         const char *name, size_t size, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        v->start_struct(v, obj, kind, name, size, errp);
-    }
+    v->start_struct(v, obj, kind, name, size, errp);
 }
 
 void visit_end_struct(Visitor *v, Error **errp)
 {
-    assert(!error_is_set(errp));
     v->end_struct(v, errp);
 }
 
 void visit_start_implicit_struct(Visitor *v, void **obj, size_t size,
                                  Error **errp)
 {
-    if (!error_is_set(errp) && v->start_implicit_struct) {
+    if (v->start_implicit_struct) {
         v->start_implicit_struct(v, obj, size, errp);
     }
 }
 
 void visit_end_implicit_struct(Visitor *v, Error **errp)
 {
-    assert(!error_is_set(errp));
     if (v->end_implicit_struct) {
         v->end_implicit_struct(v, errp);
     }
@@ -49,30 +45,23 @@ void visit_end_implicit_struct(Visitor *v, Error **errp)
 
 void visit_start_list(Visitor *v, const char *name, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        v->start_list(v, name, errp);
-    }
+    v->start_list(v, name, errp);
 }
 
 GenericList *visit_next_list(Visitor *v, GenericList **list, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        return v->next_list(v, list, errp);
-    }
-
-    return 0;
+    return v->next_list(v, list, errp);
 }
 
 void visit_end_list(Visitor *v, Error **errp)
 {
-    assert(!error_is_set(errp));
     v->end_list(v, errp);
 }
 
 void visit_optional(Visitor *v, bool *present, const char *name,
                     Error **errp)
 {
-    if (!error_is_set(errp) && v->optional) {
+    if (v->optional) {
         v->optional(v, present, name, errp);
     }
 }
@@ -80,7 +69,7 @@ void visit_optional(Visitor *v, bool *present, const char *name,
 void visit_get_next_type(Visitor *v, int *obj, const int *qtypes,
                          const char *name, Error **errp)
 {
-    if (!error_is_set(errp) && v->get_next_type) {
+    if (v->get_next_type) {
         v->get_next_type(v, obj, qtypes, name, errp);
     }
 }
@@ -88,192 +77,172 @@ void visit_get_next_type(Visitor *v, int *obj, const int *qtypes,
 void visit_type_enum(Visitor *v, int *obj, const char *strings[],
                      const char *kind, const char *name, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        v->type_enum(v, obj, strings, kind, name, errp);
-    }
+    v->type_enum(v, obj, strings, kind, name, errp);
 }
 
 void visit_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        v->type_int(v, obj, name, errp);
-    }
+    v->type_int(v, obj, name, errp);
 }
 
 void visit_type_uint8(Visitor *v, uint8_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_uint8) {
-            v->type_uint8(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            if (value < 0 || value > UINT8_MAX) {
-                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
-                          "uint8_t");
-                return;
-            }
-            *obj = value;
+
+    if (v->type_uint8) {
+        v->type_uint8(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        if (value < 0 || value > UINT8_MAX) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                      "uint8_t");
+            return;
         }
+        *obj = value;
     }
 }
 
 void visit_type_uint16(Visitor *v, uint16_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_uint16) {
-            v->type_uint16(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            if (value < 0 || value > UINT16_MAX) {
-                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
-                          "uint16_t");
-                return;
-            }
-            *obj = value;
+
+    if (v->type_uint16) {
+        v->type_uint16(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        if (value < 0 || value > UINT16_MAX) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                      "uint16_t");
+            return;
         }
+        *obj = value;
     }
 }
 
 void visit_type_uint32(Visitor *v, uint32_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_uint32) {
-            v->type_uint32(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            if (value < 0 || value > UINT32_MAX) {
-                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
-                          "uint32_t");
-                return;
-            }
-            *obj = value;
+
+    if (v->type_uint32) {
+        v->type_uint32(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        if (value < 0 || value > UINT32_MAX) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                      "uint32_t");
+            return;
         }
+        *obj = value;
     }
 }
 
 void visit_type_uint64(Visitor *v, uint64_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_uint64) {
-            v->type_uint64(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            *obj = value;
-        }
+
+    if (v->type_uint64) {
+        v->type_uint64(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        *obj = value;
     }
 }
 
 void visit_type_int8(Visitor *v, int8_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_int8) {
-            v->type_int8(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            if (value < INT8_MIN || value > INT8_MAX) {
-                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
-                          "int8_t");
-                return;
-            }
-            *obj = value;
+
+    if (v->type_int8) {
+        v->type_int8(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        if (value < INT8_MIN || value > INT8_MAX) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                      "int8_t");
+            return;
         }
+        *obj = value;
     }
 }
 
 void visit_type_int16(Visitor *v, int16_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_int16) {
-            v->type_int16(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            if (value < INT16_MIN || value > INT16_MAX) {
-                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
-                          "int16_t");
-                return;
-            }
-            *obj = value;
+
+    if (v->type_int16) {
+        v->type_int16(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        if (value < INT16_MIN || value > INT16_MAX) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                      "int16_t");
+            return;
         }
+        *obj = value;
     }
 }
 
 void visit_type_int32(Visitor *v, int32_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_int32) {
-            v->type_int32(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            if (value < INT32_MIN || value > INT32_MAX) {
-                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
-                          "int32_t");
-                return;
-            }
-            *obj = value;
+
+    if (v->type_int32) {
+        v->type_int32(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        if (value < INT32_MIN || value > INT32_MAX) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                      "int32_t");
+            return;
         }
+        *obj = value;
     }
 }
 
 void visit_type_int64(Visitor *v, int64_t *obj, const char *name, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        if (v->type_int64) {
-            v->type_int64(v, obj, name, errp);
-        } else {
-            v->type_int(v, obj, name, errp);
-        }
+    if (v->type_int64) {
+        v->type_int64(v, obj, name, errp);
+    } else {
+        v->type_int(v, obj, name, errp);
     }
 }
 
 void visit_type_size(Visitor *v, uint64_t *obj, const char *name, Error **errp)
 {
     int64_t value;
-    if (!error_is_set(errp)) {
-        if (v->type_size) {
-            v->type_size(v, obj, name, errp);
-        } else if (v->type_uint64) {
-            v->type_uint64(v, obj, name, errp);
-        } else {
-            value = *obj;
-            v->type_int(v, &value, name, errp);
-            *obj = value;
-        }
+
+    if (v->type_size) {
+        v->type_size(v, obj, name, errp);
+    } else if (v->type_uint64) {
+        v->type_uint64(v, obj, name, errp);
+    } else {
+        value = *obj;
+        v->type_int(v, &value, name, errp);
+        *obj = value;
     }
 }
 
 void visit_type_bool(Visitor *v, bool *obj, const char *name, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        v->type_bool(v, obj, name, errp);
-    }
+    v->type_bool(v, obj, name, errp);
 }
 
 void visit_type_str(Visitor *v, char **obj, const char *name, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        v->type_str(v, obj, name, errp);
-    }
+    v->type_str(v, obj, name, errp);
 }
 
 void visit_type_number(Visitor *v, double *obj, const char *name, Error **errp)
 {
-    if (!error_is_set(errp)) {
-        v->type_number(v, obj, name, errp);
-    }
+    v->type_number(v, obj, name, errp);
 }
 
 void output_type_enum(Visitor *v, int *obj, const char *strings[],
@@ -299,13 +268,15 @@ void input_type_enum(Visitor *v, int *obj, const char *strings[],
                      const char *kind, const char *name,
                      Error **errp)
 {
+    Error *local_err = NULL;
     int64_t value = 0;
     char *enum_str;
 
     assert(strings);
 
-    visit_type_str(v, &enum_str, name, errp);
-    if (error_is_set(errp)) {
+    visit_type_str(v, &enum_str, name, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
         return;
     }
 

diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index 341dba27a8e0e090f81f11c3831b9a13a39f50dd..386f17ef44b35773cbe2d42196d96e84715421ba 100644 (file)
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -2,16 +2,19 @@
 # QAPI command marshaller generator
 #
 # Copyright IBM, Corp. 2011
+# Copyright (C) 2014 Red Hat, Inc.
 #
 # Authors:
 #  Anthony Liguori <aliguori@us.ibm.com>
 #  Michael Roth    <mdroth@linux.vnet.ibm.com>
+#  Markus Armbruster <armbru@redhat.com>
 #
 # This work is licensed under the terms of the GNU GPL, version 2.
 # See the COPYING file in the top-level directory.
 
 from ordereddict import OrderedDict
 from qapi import *
+import re
 import sys
 import os
 import getopt
@@ -37,6 +40,15 @@ def generate_command_decl(name, args, ret_type):
 ''',
                  ret_type=c_type(ret_type), name=c_fun(name), args=arglist).strip()
 
+def gen_err_check(errvar):
+    if errvar:
+        return mcgen('''
+if (local_err) {
+    goto out;
+}
+''')
+    return ''
+
 def gen_sync_call(name, args, ret_type, indent=0):
     ret = ""
     arglist=""
@@ -49,15 +61,14 @@ def gen_sync_call(name, args, ret_type, indent=0):
         arglist += "%s, " % (c_var(argname))
     push_indent(indent)
     ret = mcgen('''
-%(retval)sqmp_%(name)s(%(args)serrp);
+%(retval)sqmp_%(name)s(%(args)s&local_err);
 
 ''',
                 name=c_fun(name), args=arglist, retval=retval).rstrip()
     if ret_type:
+        ret += "\n" + gen_err_check('local_err')
         ret += "\n" + mcgen(''''
-if (!error_is_set(errp)) {
-    %(marshal_output_call)s
-}
+%(marshal_output_call)s
 ''',
                             marshal_output_call=gen_marshal_output_call(name, ret_type)).rstrip()
     pop_indent(indent)
@@ -67,7 +78,7 @@ if (!error_is_set(errp)) {
 def gen_marshal_output_call(name, ret_type):
     if not ret_type:
         return ""
-    return "qmp_marshal_output_%s(retval, ret, errp);" % c_fun(name)
+    return "qmp_marshal_output_%s(retval, ret, &local_err);" % c_fun(name)
 
 def gen_visitor_input_containers_decl(args, obj):
     ret = ""
@@ -109,7 +120,8 @@ bool has_%(argname)s = false;
 
 def gen_visitor_input_block(args, dealloc=False):
     ret = ""
-    errparg = 'errp'
+    errparg = '&local_err'
+    errarg = 'local_err'
 
     if len(args) == 0:
         return ret
@@ -118,6 +130,7 @@ def gen_visitor_input_block(args, dealloc=False):
 
     if dealloc:
         errparg = 'NULL'
+        errarg = None;
         ret += mcgen('''
 qmp_input_visitor_cleanup(mi);
 md = qapi_dealloc_visitor_new();
@@ -132,15 +145,20 @@ v = qmp_input_get_visitor(mi);
         if optional:
             ret += mcgen('''
 visit_optional(v, &has_%(c_name)s, "%(name)s", %(errp)s);
-if (has_%(c_name)s) {
 ''',
                          c_name=c_var(argname), name=argname, errp=errparg)
+            ret += gen_err_check(errarg)
+            ret += mcgen('''
+if (has_%(c_name)s) {
+''',
+                         c_name=c_var(argname))
             push_indent()
         ret += mcgen('''
 %(visitor)s(v, &%(c_name)s, "%(name)s", %(errp)s);
 ''',
                      c_name=c_var(argname), name=argname, argtype=argtype,
                      visitor=type_visitor(argtype), errp=errparg)
+        ret += gen_err_check(errarg)
         if optional:
             pop_indent()
             ret += mcgen('''
@@ -161,15 +179,20 @@ def gen_marshal_output(name, args, ret_type, middle_mode):
     ret = mcgen('''
 static void qmp_marshal_output_%(c_name)s(%(c_ret_type)s ret_in, QObject **ret_out, Error **errp)
 {
+    Error *local_err = NULL;
     QmpOutputVisitor *mo = qmp_output_visitor_new();
     QapiDeallocVisitor *md;
     Visitor *v;
 
     v = qmp_output_get_visitor(mo);
-    %(visitor)s(v, &ret_in, "unused", errp);
-    if (!error_is_set(errp)) {
-        *ret_out = qmp_output_get_qobject(mo);
+    %(visitor)s(v, &ret_in, "unused", &local_err);
+    if (local_err) {
+        goto out;
     }
+    *ret_out = qmp_output_get_qobject(mo);
+
+out:
+    error_propagate(errp, local_err);
     qmp_output_visitor_cleanup(mo);
     md = qapi_dealloc_visitor_new();
     v = qapi_dealloc_get_visitor(md);
@@ -196,13 +219,12 @@ def gen_marshal_input(name, args, ret_type, middle_mode):
     ret = mcgen('''
 %(header)s
 {
+    Error *local_err = NULL;
 ''',
                 header=hdr)
 
     if middle_mode:
         ret += mcgen('''
-    Error *local_err = NULL;
-    Error **errp = &local_err;
     QDict *args = (QDict *)qdict;
 ''')
 
@@ -229,19 +251,22 @@ def gen_marshal_input(name, args, ret_type, middle_mode):
                      visitor_input_block=gen_visitor_input_block(args))
     else:
         ret += mcgen('''
+
     (void)args;
 ''')
 
     ret += mcgen('''
-    if (error_is_set(errp)) {
-        goto out;
-    }
 %(sync_call)s
 ''',
                  sync_call=gen_sync_call(name, args, ret_type, indent=4))
-    ret += mcgen('''
+    if re.search('^ *goto out\\;', ret, re.MULTILINE):
+        ret += mcgen('''
 
 out:
+''')
+    if not middle_mode:
+        ret += mcgen('''
+    error_propagate(errp, local_err);
 ''')
     ret += mcgen('''
 %(visitor_input_block_cleanup)s

diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 1ef753a9b92a55020dbe635852fca93d919e1984..06a79f1631369b3a56ca2b24181f1e76bacae882 100644 (file)
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -2,16 +2,19 @@
 # QAPI visitor generator
 #
 # Copyright IBM, Corp. 2011
+# Copyright (C) 2014 Red Hat, Inc.
 #
 # Authors:
 #  Anthony Liguori <aliguori@us.ibm.com>
 #  Michael Roth    <mdroth@linux.vnet.ibm.com>
+#  Markus Armbruster <armbru@redhat.com>
 #
 # This work is licensed under the terms of the GNU GPL, version 2.
 # See the COPYING file in the top-level directory.
 
 from ordereddict import OrderedDict
 from qapi import *
+import re
 import sys
 import os
 import getopt
@@ -32,9 +35,7 @@ static void visit_type_implicit_%(c_type)s(Visitor *m, %(c_type)s **obj, Error *
 
     visit_start_implicit_struct(m, (void **)obj, sizeof(%(c_type)s), &err);
     if (!err) {
-        visit_type_%(c_type)s_fields(m, obj, &err);
-        error_propagate(errp, err);
-        err = NULL;
+        visit_type_%(c_type)s_fields(m, obj, errp);
         visit_end_implicit_struct(m, &err);
     }
     error_propagate(errp, err);
@@ -64,12 +65,9 @@ def generate_visit_struct_fields(name, field_prefix, fn_prefix, members, base =
 
 static void visit_type_%(full_name)s_field_%(c_name)s(Visitor *m, %(name)s **obj, Error **errp)
 {
-    Error *err = NULL;
 ''',
                          name=name, full_name=full_name, c_name=c_var(argname))
-            push_indent()
             ret += generate_visit_struct_body(full_name, argname, argentry)
-            pop_indent()
             ret += mcgen('''
 }
 ''')
@@ -89,6 +87,9 @@ static void visit_type_%(full_name)s_fields(Visitor *m, %(name)s ** obj, Error *
     if base:
         ret += mcgen('''
 visit_type_implicit_%(type)s(m, &(*obj)->%(c_prefix)s%(c_name)s, &err);
+if (err) {
+    goto out;
+}
 ''',
                      c_prefix=c_var(field_prefix),
                      type=type_name(base), c_name=c_var('base'))
@@ -97,7 +98,7 @@ visit_type_implicit_%(type)s(m, &(*obj)->%(c_prefix)s%(c_name)s, &err);
         if optional:
             ret += mcgen('''
 visit_optional(m, &(*obj)->%(c_prefix)shas_%(c_name)s, "%(name)s", &err);
-if ((*obj)->%(prefix)shas_%(c_name)s) {
+if (!err && (*obj)->%(prefix)shas_%(c_name)s) {
 ''',
                          c_prefix=c_var(field_prefix), prefix=field_prefix,
                          c_name=c_var(argname), name=argname)
@@ -120,11 +121,20 @@ visit_type_%(type)s(m, &(*obj)->%(c_prefix)s%(c_name)s, "%(name)s", &err);
             pop_indent()
             ret += mcgen('''
 }
+''')
+        ret += mcgen('''
+if (err) {
+    goto out;
+}
 ''')
 
     pop_indent()
-    ret += mcgen('''
+    if re.search('^ *goto out\\;', ret, re.MULTILINE):
+        ret += mcgen('''
 
+out:
+''')
+    ret += mcgen('''
     error_propagate(errp, err);
 }
 ''')
@@ -133,9 +143,9 @@ visit_type_%(type)s(m, &(*obj)->%(c_prefix)s%(c_name)s, "%(name)s", &err);
 
 def generate_visit_struct_body(field_prefix, name, members):
     ret = mcgen('''
-if (!error_is_set(errp)) {
+    Error *err = NULL;
+
 ''')
-    push_indent()
 
     if not field_prefix:
         full_name = name
@@ -144,36 +154,26 @@ if (!error_is_set(errp)) {
 
     if len(field_prefix):
         ret += mcgen('''
-visit_start_struct(m, NULL, "", "%(name)s", 0, &err);
+    visit_start_struct(m, NULL, "", "%(name)s", 0, &err);
 ''',
                 name=name)
     else:
         ret += mcgen('''
-Error *err = NULL;
-visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s), &err);
+    visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s), &err);
 ''',
                 name=name)
 
     ret += mcgen('''
-if (!err) {
-    if (*obj) {
-        visit_type_%(name)s_fields(m, obj, &err);
-        error_propagate(errp, err);
-        err = NULL;
+    if (!err) {
+        if (*obj) {
+            visit_type_%(name)s_fields(m, obj, errp);
+        }
+        visit_end_struct(m, &err);
     }
+    error_propagate(errp, err);
 ''',
         name=full_name)
 
-    ret += mcgen('''
-    /* Always call end_struct if start_struct succeeded.  */
-    visit_end_struct(m, &err);
-}
-error_propagate(errp, err);
-''')
-    pop_indent()
-    ret += mcgen('''
-}
-''')
     return ret
 
 def generate_visit_struct(expr):
@@ -191,9 +191,7 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
 ''',
                 name=name)
 
-    push_indent()
     ret += generate_visit_struct_body("", name, members)
-    pop_indent()
 
     ret += mcgen('''
 }
@@ -205,24 +203,26 @@ def generate_visit_list(name, members):
 
 void visit_type_%(name)sList(Visitor *m, %(name)sList ** obj, const char *name, Error **errp)
 {
-    GenericList *i, **prev = (GenericList **)obj;
     Error *err = NULL;
+    GenericList *i, **prev;
 
-    if (!error_is_set(errp)) {
-        visit_start_list(m, name, &err);
-        if (!err) {
-            for (; (i = visit_next_list(m, prev, &err)) != NULL; prev = &i) {
-                %(name)sList *native_i = (%(name)sList *)i;
-                visit_type_%(name)s(m, &native_i->value, NULL, &err);
-            }
-            error_propagate(errp, err);
-            err = NULL;
-
-            /* Always call end_list if start_list succeeded.  */
-            visit_end_list(m, &err);
-        }
-        error_propagate(errp, err);
+    visit_start_list(m, name, &err);
+    if (err) {
+        goto out;
+    }
+
+    for (prev = (GenericList **)obj;
+         !err && (i = visit_next_list(m, prev, &err)) != NULL;
+         prev = &i) {
+        %(name)sList *native_i = (%(name)sList *)i;
+        visit_type_%(name)s(m, &native_i->value, NULL, &err);
     }
+
+    error_propagate(errp, err);
+    err = NULL;
+    visit_end_list(m, &err);
+out:
+    error_propagate(errp, err);
 }
 ''',
                 name=name)
@@ -244,10 +244,15 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
 {
     Error *err = NULL;
 
-    if (!error_is_set(errp)) {
-        visit_start_implicit_struct(m, (void**) obj, sizeof(%(name)s), &err);
-        visit_get_next_type(m, (int*) &(*obj)->kind, %(name)s_qtypes, name, &err);
-        switch ((*obj)->kind) {
+    visit_start_implicit_struct(m, (void**) obj, sizeof(%(name)s), &err);
+    if (err) {
+        goto out;
+    }
+    visit_get_next_type(m, (int*) &(*obj)->kind, %(name)s_qtypes, name, &err);
+    if (err) {
+        goto out_end;
+    }
+    switch ((*obj)->kind) {
 ''',
     name=name)
 
@@ -262,22 +267,24 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
 
         enum_full_value = generate_enum_full_value(disc_type, key)
         ret += mcgen('''
-        case %(enum_full_value)s:
-            visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, name, &err);
-            break;
+    case %(enum_full_value)s:
+        visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, name, &err);
+        break;
 ''',
                 enum_full_value = enum_full_value,
                 c_type = type_name(members[key]),
                 c_name = c_fun(key))
 
     ret += mcgen('''
-        default:
-            abort();
-        }
-        error_propagate(errp, err);
-        err = NULL;
-        visit_end_implicit_struct(m, &err);
+    default:
+        abort();
     }
+out_end:
+    error_propagate(errp, err);
+    err = NULL;
+    visit_end_implicit_struct(m, &err);
+out:
+    error_propagate(errp, err);
 }
 ''')
 
@@ -324,19 +331,20 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
 {
     Error *err = NULL;
 
-    if (!error_is_set(errp)) {
-        visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s), &err);
-        if (!err) {
-            if (*obj) {
+    visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s), &err);
+    if (err) {
+        goto out;
+    }
+    if (*obj) {
 ''',
                  name=name)
 
-    push_indent()
-    push_indent()
-
     if base:
         ret += mcgen('''
         visit_type_%(name)s_fields(m, obj, &err);
+        if (err) {
+            goto out_obj;
+        }
 ''',
             name=name)
 
@@ -346,8 +354,10 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
         disc_key = discriminator
     ret += mcgen('''
         visit_type_%(disc_type)s(m, &(*obj)->kind, "%(disc_key)s", &err);
-        if (!err) {
-            switch ((*obj)->kind) {
+        if (err) {
+            goto out_obj;
+        }
+        switch ((*obj)->kind) {
 ''',
                  disc_type = disc_type,
                  disc_key = disc_key)
@@ -360,32 +370,25 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
 
         enum_full_value = generate_enum_full_value(disc_type, key)
         ret += mcgen('''
-            case %(enum_full_value)s:
-                ''' + fmt + '''
-                break;
+        case %(enum_full_value)s:
+            ''' + fmt + '''
+            break;
 ''',
                 enum_full_value = enum_full_value,
                 c_type=type_name(members[key]),
                 c_name=c_fun(key))
 
     ret += mcgen('''
-            default:
-                abort();
-            }
+        default:
+            abort();
         }
+out_obj:
         error_propagate(errp, err);
         err = NULL;
-''')
-    pop_indent()
-    pop_indent()
-
-    ret += mcgen('''
-            }
-            /* Always call end_struct if start_struct succeeded.  */
-            visit_end_struct(m, &err);
-        }
-        error_propagate(errp, err);
     }
+    visit_end_struct(m, &err);
+out:
+    error_propagate(errp, err);
 }
 ''')
 
@@ -505,7 +508,7 @@ fdecl.write(mcgen('''
 /* THIS FILE IS AUTOMATICALLY GENERATED, DO NOT MODIFY */
 
 /*
- * schema-defined QAPI visitor function
+ * schema-defined QAPI visitor functions
  *
  * Copyright IBM, Corp. 2011
  *

diff --git a/tests/test-qmp-input-strict.c b/tests/test-qmp-input-strict.c
index ec798c2acfc14cdf632a101d0ba22726b744cb99..0f770034b16b69e6952f66bec0c5c10cde47bf57 100644 (file)
--- a/tests/test-qmp-input-strict.c
+++ b/tests/test-qmp-input-strict.c
@@ -81,11 +81,19 @@ static void visit_type_TestStruct(Visitor *v, TestStruct **obj,
     }
 
     visit_type_int(v, &(*obj)->integer, "integer", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_bool(v, &(*obj)->boolean, "boolean", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_str(v, &(*obj)->string, "string", &err);
 
+out_end:
+    error_propagate(errp, err);
+    err = NULL;
     visit_end_struct(v, &err);
-
 out:
     error_propagate(errp, err);
 }

diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c
index a58a3e6fdb257c089f493c2e29ae0b6b60803196..1c8e87295ceaf76fffab9819132c5bc35e5e3456 100644 (file)
--- a/tests/test-qmp-input-visitor.c
+++ b/tests/test-qmp-input-visitor.c
@@ -199,16 +199,24 @@ static void visit_type_TestStruct(Visitor *v, TestStruct **obj,
 
     visit_start_struct(v, (void **)obj, "TestStruct", name, sizeof(TestStruct),
                        &err);
-    if (!err) {
-        visit_type_int(v, &(*obj)->integer, "integer", &err);
-        visit_type_bool(v, &(*obj)->boolean, "boolean", &err);
-        visit_type_str(v, &(*obj)->string, "string", &err);
-
-        /* Always call end_struct if start_struct succeeded.  */
-        error_propagate(errp, err);
-        err = NULL;
-        visit_end_struct(v, &err);
+    if (err) {
+        goto out;
     }
+    visit_type_int(v, &(*obj)->integer, "integer", &err);
+    if (err) {
+        goto out_end;
+    }
+    visit_type_bool(v, &(*obj)->boolean, "boolean", &err);
+    if (err) {
+        goto out_end;
+    }
+    visit_type_str(v, &(*obj)->string, "string", &err);
+
+out_end:
+    error_propagate(errp, err);
+    err = NULL;
+    visit_end_struct(v, &err);
+out:
     error_propagate(errp, err);
 }
 

diff --git a/tests/test-qmp-output-visitor.c b/tests/test-qmp-output-visitor.c
index dfd597cee1bb4cb5cae7be4438b6e1b374bdef64..9c154581d75e07988aed794b0c1cfc54c4ae672d 100644 (file)
--- a/tests/test-qmp-output-visitor.c
+++ b/tests/test-qmp-output-visitor.c
@@ -185,11 +185,19 @@ static void visit_type_TestStruct(Visitor *v, TestStruct **obj,
     }
 
     visit_type_int(v, &(*obj)->integer, "integer", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_bool(v, &(*obj)->boolean, "boolean", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_str(v, &(*obj)->string, "string", &err);
 
+out_end:
+    error_propagate(errp, err);
+    err = NULL;
     visit_end_struct(v, &err);
-
 out:
     error_propagate(errp, err);
 }

diff --git a/tests/test-visitor-serialization.c b/tests/test-visitor-serialization.c
index 85170e5c490a023666df9428482124bf3a19ba12..74d6481992f1ec86e5a3effab72416a2c5cad351 100644 (file)
--- a/tests/test-visitor-serialization.c
+++ b/tests/test-visitor-serialization.c
@@ -195,7 +195,7 @@ typedef struct TestStruct
 static void visit_type_TestStruct(Visitor *v, TestStruct **obj,
                                   const char *name, Error **errp)
 {
-    Error *err= NULL;
+    Error *err = NULL;
 
     visit_start_struct(v, (void **)obj, NULL, name, sizeof(TestStruct), &err);
     if (err) {
@@ -203,11 +203,19 @@ static void visit_type_TestStruct(Visitor *v, TestStruct **obj,
     }
 
     visit_type_int(v, &(*obj)->integer, "integer", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_bool(v, &(*obj)->boolean, "boolean", &err);
+    if (err) {
+        goto out_end;
+    }
     visit_type_str(v, &(*obj)->string, "string", &err);
 
+out_end:
+    error_propagate(errp, err);
+    err = NULL;
     visit_end_struct(v, &err);
-
 out:
     error_propagate(errp, err);
 }