Re: [Qemu-devel] [PATCH v8 11/35] qapi: Consolidate visitor small integer callbacks

[Marc-André Lureau]

Hi

On Mon, Dec 21, 2015 at 6:08 PM, Eric Blake <address@hidden> wrote:
> 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 <address@hidden>
>
> ---
> 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 |  22 +++---
>  qapi/qapi-visit-core.c      | 158 
> +++++++++++++++++---------------------------
>  2 files changed, 70 insertions(+), 110 deletions(-)
>
> diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
> index 70326e0..5ee2974 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, 2015 Red Hat, Inc.
>   *
>   * Author: Paolo Bonizni <address@hidden>
>   *
> @@ -36,6 +36,16 @@ struct Visitor
>      void (*get_next_type)(Visitor *v, QType *type, bool promote_int,
>                            const char *name, Error **errp);
>
> +    /* Must be set. */
> +    void (*type_int64)(Visitor *v, int64_t *obj, const char *name,
> +                       Error **errp);
> +    /* Must be set. */
> +    void (*type_uint64)(Visitor *v, uint64_t *obj, const char *name,
> +                        Error **errp);
> +    /* Optional; fallback is type_uint64().  */
> +    void (*type_size)(Visitor *v, uint64_t *obj, const char *name,
> +                      Error **errp);
> +    /* Must be set. */
>      void (*type_bool)(Visitor *v, bool *obj, const char *name, Error **errp);
>      void (*type_str)(Visitor *v, char **obj, const char *name, Error **errp);
>      void (*type_number)(Visitor *v, double *obj, const char *name,
> @@ -46,16 +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_uint64)(Visitor *v, uint64_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);
> -    void (*type_int64)(Visitor *v, int64_t *obj, const char *name, Error 
> **errp);
> -    /* visit_type_size() falls back to (*type_uint64)() if type_size is 
> unset */
> -    void (*type_size)(Visitor *v, uint64_t *obj, const char *name, Error 
> **errp);
>      bool (*start_union)(Visitor *v, bool data_present, Error **errp);
>      void (*end_union)(Visitor *v, bool data_present, Error **errp);
>  };

I think it would be a good idea to move this chunk in the previous patch.

> diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
> index 4a8ad43..a48fd4e 100644
> --- a/qapi/qapi-visit-core.c
> +++ b/qapi/qapi-visit-core.c
> @@ -100,129 +100,89 @@ 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 type_uint64() changes
> -               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 type_uint64() changes
> -               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 type_uint64() changes
> -               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 type_int64() changes
> -               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 type_int64() changes
> -               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 type_int64() changes
> -               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)
> --
> 2.4.3
>
>

Looks good otherwise.
Reviewed-by: Marc-André Lureau <address@hidden>

-- 
Marc-André Lureau