[Qemu-devel] [PATCH v10 15/25] qapi: Consolidate visitor small integer callbacks

[Eric Blake <eblake@redhat.com>]

Commit 4e27e819 introduced optional visitor callbacks for all
sorts of int types, but no visitor has supplied any of the
callbacks for sizes less than 64 bits.  In other words, the
generic implementation based on using type_[u]int64() followed
by bounds-checking works just fine. In the interest of
simplicity, it's easier to make the visitor callback interface
not have to worry about the other sizes.

Adding some helper functions minimizes the boilerplate required
to correct FIXMEs added earlier with regards to questionable
reuse of errp, particularly now that we can guarantee from a
single file audit that value is unchanged if an error is set.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

---
v10: tweak copyright line, rebase to earlier changes
v9: hoist some of visitor-impl.h changes into 9/35 and 10/35
v8: no change
v7: further factor out helper functions that eliminate the
questionable errp reuse
v6: split off from v5 23/46
original version also appeared in v6-v9 of subset D
---
 include/qapi/visitor-impl.h |   8 +--
 qapi/qapi-visit-core.c      | 158 +++++++++++++++++---------------------------
 2 files changed, 60 insertions(+), 106 deletions(-)

diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index 92c4bcb..29e2c08 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -1,7 +1,7 @@
 /*
  * Core Definitions for QAPI Visitor implementations
  *
- * Copyright (C) 2012 Red Hat, Inc.
+ * Copyright (C) 2012-2016 Red Hat, Inc.
  *
  * Author: Paolo Bonizni <pbonzini@redhat.com>
  *
@@ -56,12 +56,6 @@ struct Visitor
     /* May be NULL; most useful for input visitors. */
     void (*optional)(Visitor *v, bool *present, const char *name);

-    void (*type_uint8)(Visitor *v, uint8_t *obj, const char *name, Error **errp);
-    void (*type_uint16)(Visitor *v, uint16_t *obj, const char *name, Error **errp);
-    void (*type_uint32)(Visitor *v, uint32_t *obj, const char *name, Error **errp);
-    void (*type_int8)(Visitor *v, int8_t *obj, const char *name, Error **errp);
-    void (*type_int16)(Visitor *v, int16_t *obj, const char *name, Error **errp);
-    void (*type_int32)(Visitor *v, int32_t *obj, const char *name, Error **errp);
     bool (*start_union)(Visitor *v, bool data_present, Error **errp);
 };

diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index ac5a861..d65521f 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -94,129 +94,89 @@ void visit_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp)
     v->type_int64(v, obj, name, errp);
 }

+static void visit_type_uintN(Visitor *v, uint64_t *obj, const char *name,
+                             uint64_t max, const char *type, Error **errp)
+{
+    Error *err = NULL;
+    uint64_t value = *obj;
+
+    v->type_uint64(v, &value, name, &err);
+    if (err) {
+        error_propagate(errp, err);
+    } else if (value > max) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   name ? name : "null", type);
+    } else {
+        *obj = value;
+    }
+}
+
 void visit_type_uint8(Visitor *v, uint8_t *obj, const char *name, Error **errp)
 {
-    uint64_t value;
-
-    if (v->type_uint8) {
-        v->type_uint8(v, obj, name, errp);
-    } else {
-        value = *obj;
-        v->type_uint64(v, &value, name, errp);
-        if (value > UINT8_MAX) {
-            /* FIXME questionable reuse of errp if callback changed
-               value on error */
-            error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
-                       name ? name : "null", "uint8_t");
-            return;
-        }
-        *obj = value;
-    }
+    uint64_t value = *obj;
+    visit_type_uintN(v, &value, name, UINT8_MAX, "uint8_t", errp);
+    *obj = value;
 }

-void visit_type_uint16(Visitor *v, uint16_t *obj, const char *name, Error **errp)
+void visit_type_uint16(Visitor *v, uint16_t *obj, const char *name,
+                       Error **errp)
 {
-    uint64_t value;
-
-    if (v->type_uint16) {
-        v->type_uint16(v, obj, name, errp);
-    } else {
-        value = *obj;
-        v->type_uint64(v, &value, name, errp);
-        if (value > UINT16_MAX) {
-            /* FIXME questionable reuse of errp if callback changed
-               value on error */
-            error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
-                       name ? name : "null", "uint16_t");
-            return;
-        }
-        *obj = value;
-    }
+    uint64_t value = *obj;
+    visit_type_uintN(v, &value, name, UINT16_MAX, "uint16_t", errp);
+    *obj = value;
 }

-void visit_type_uint32(Visitor *v, uint32_t *obj, const char *name, Error **errp)
+void visit_type_uint32(Visitor *v, uint32_t *obj, const char *name,
+                       Error **errp)
 {
-    uint64_t value;
-
-    if (v->type_uint32) {
-        v->type_uint32(v, obj, name, errp);
-    } else {
-        value = *obj;
-        v->type_uint64(v, &value, name, errp);
-        if (value > UINT32_MAX) {
-            /* FIXME questionable reuse of errp if callback changed
-               value on error */
-            error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
-                       name ? name : "null", "uint32_t");
-            return;
-        }
-        *obj = value;
-    }
+    uint64_t value = *obj;
+    visit_type_uintN(v, &value, name, UINT32_MAX, "uint32_t", errp);
+    *obj = value;
 }

-void visit_type_uint64(Visitor *v, uint64_t *obj, const char *name, Error **errp)
+void visit_type_uint64(Visitor *v, uint64_t *obj, const char *name,
+                       Error **errp)
 {
     v->type_uint64(v, obj, name, errp);
 }

+static void visit_type_intN(Visitor *v, int64_t *obj, const char *name,
+                            int64_t min, int64_t max, const char *type,
+                            Error **errp)
+{
+    Error *err = NULL;
+    int64_t value = *obj;
+
+    v->type_int64(v, &value, name, &err);
+    if (err) {
+        error_propagate(errp, err);
+    } else if (value < min || value > max) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   name ? name : "null", type);
+    } else {
+        *obj = value;
+    }
+}
+
 void visit_type_int8(Visitor *v, int8_t *obj, const char *name, Error **errp)
 {
-    int64_t value;
-
-    if (v->type_int8) {
-        v->type_int8(v, obj, name, errp);
-    } else {
-        value = *obj;
-        v->type_int64(v, &value, name, errp);
-        if (value < INT8_MIN || value > INT8_MAX) {
-            /* FIXME questionable reuse of errp if callback changed
-               value on error */
-            error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
-                       name ? name : "null", "int8_t");
-            return;
-        }
-        *obj = value;
-    }
+    int64_t value = *obj;
+    visit_type_intN(v, &value, name, INT8_MIN, INT8_MAX, "int8_t", errp);
+    *obj = value;
 }

 void visit_type_int16(Visitor *v, int16_t *obj, const char *name, Error **errp)
 {
-    int64_t value;
-
-    if (v->type_int16) {
-        v->type_int16(v, obj, name, errp);
-    } else {
-        value = *obj;
-        v->type_int64(v, &value, name, errp);
-        if (value < INT16_MIN || value > INT16_MAX) {
-            /* FIXME questionable reuse of errp if callback changed
-               value on error */
-            error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
-                       name ? name : "null", "int16_t");
-            return;
-        }
-        *obj = value;
-    }
+    int64_t value = *obj;
+    visit_type_intN(v, &value, name, INT16_MIN, INT16_MAX, "int16_t", errp);
+    *obj = value;
 }

 void visit_type_int32(Visitor *v, int32_t *obj, const char *name, Error **errp)
 {
-    int64_t value;
-
-    if (v->type_int32) {
-        v->type_int32(v, obj, name, errp);
-    } else {
-        value = *obj;
-        v->type_int64(v, &value, name, errp);
-        if (value < INT32_MIN || value > INT32_MAX) {
-            /* FIXME questionable reuse of errp if callback changed
-               value on error */
-            error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
-                       name ? name : "null", "int32_t");
-            return;
-        }
-        *obj = value;
-    }
+    int64_t value = *obj;
+    visit_type_intN(v, &value, name, INT32_MIN, INT32_MAX, "int32_t", errp);
+    *obj = value;
 }

 void visit_type_int64(Visitor *v, int64_t *obj, const char *name, Error **errp)
-- 
2.5.0