On Tue, Nov 17, 2020 at 2:43 AM Eduardo Habkost <ehabkost@redhat.com> wrote:

> Provide a separate QNumValue type that can be used for QNum value
> literals without the referencing counting and memory allocation
> features provided by QObject.
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v1 -> v2:
> * Fix "make check" failure, by updating check-qnum unit test to
>   use the new struct fields
> ---
>  include/qapi/qmp/qnum.h | 40 +++++++++++++++++++--
>  qobject/qnum.c          | 78 ++++++++++++++++++++---------------------
>  tests/check-qnum.c      | 14 ++++----
>  3 files changed, 84 insertions(+), 48 deletions(-)
>
> diff --git a/include/qapi/qmp/qnum.h b/include/qapi/qmp/qnum.h
> index 55c27b1c24..62fbdfda68 100644
> --- a/include/qapi/qmp/qnum.h
> +++ b/include/qapi/qmp/qnum.h
> @@ -46,20 +46,56 @@ typedef enum {
>   * in range: qnum_get_try_int() / qnum_get_try_uint() check range and
>   * convert under the hood.
>   */
> -struct QNum {
> -    struct QObjectBase_ base;
> +
> +/**
> + * struct QNumValue: the value of a QNum
> + *
> + * QNumValue literals can be constructed using the `QNUM_VAL_INT`,
> + * `QNUM_VAL_UINT`, and `QNUM_VAL_DOUBLE` macros.
> + */
> +typedef struct QNumValue {
> +    /* private: */
>      QNumKind kind;
>      union {
>          int64_t i64;
>          uint64_t u64;
>          double dbl;
>      } u;
> +} QNumValue;
> +
> +#define QNUM_VAL_INT(value) \
> +    { .kind = QNUM_I64, .u.i64 = value }
> +#define QNUM_VAL_UINT(value) \
> +    { .kind = QNUM_U64, .u.u64 = value }
> +#define QNUM_VAL_DOUBLE(value) \
> +    { .kind = QNUM_DOUBLE, .u.dbl = value }
> +
> +struct QNum {
> +    struct QObjectBase_ base;
> +    QNumValue value;
>  };
>
> +/**
> + * qnum_from_int(): Create a new QNum from a QNumValue
>

Copy-pasta qnum_from_int() -> qnum_from_value()

I wonder if there is a check for that kind of mistake, as it may be common.

+ * @value: QNumValue
> + *
> + * Return strong reference.
> + */
> +QNum *qnum_from_value(QNumValue value);
>
+
>  QNum *qnum_from_int(int64_t value);
>  QNum *qnum_from_uint(uint64_t value);
>  QNum *qnum_from_double(double value);
>
> +/**
> + * qnum_get_value(): Get QNumValue from QNum
> + * @qn: QNum object
> + */
> +static inline const QNumValue *qnum_get_value(const QNum *qn)
> +{
> +    return &qn->value;
> +}
> +
>

Nothing uses that function in this patch. Should be put into use.

 bool qnum_get_try_int(const QNum *qn, int64_t *val);
>  int64_t qnum_get_int(const QNum *qn);
>
> diff --git a/qobject/qnum.c b/qobject/qnum.c
> index 69fd9a82d9..f80d4efd76 100644
> --- a/qobject/qnum.c
> +++ b/qobject/qnum.c
> @@ -15,6 +15,15 @@
>  #include "qemu/osdep.h"
>  #include "qapi/qmp/qnum.h"
>
> +QNum *qnum_from_value(QNumValue value)
>

I wonder if it shouldn't be made "inline" in header too (if that can help
avoid argument copy).

+{
> +    QNum *qn = g_new(QNum, 1);
> +
> +    qobject_init(QOBJECT(qn), QTYPE_QNUM);
> +    qn->value = value;
> +    return qn;
> +}
> +
>  /**
>   * qnum_from_int(): Create a new QNum from an int64_t
>   * @value: int64_t value
> @@ -23,13 +32,7 @@
>   */
>  QNum *qnum_from_int(int64_t value)
>  {
> -    QNum *qn = g_new(QNum, 1);
> -
> -    qobject_init(QOBJECT(qn), QTYPE_QNUM);
> -    qn->kind = QNUM_I64;
> -    qn->u.i64 = value;
> -
> -    return qn;
> +    return qnum_from_value((QNumValue) QNUM_VAL_INT(value));
>  }
>
>  /**
> @@ -40,13 +43,7 @@ QNum *qnum_from_int(int64_t value)
>   */
>  QNum *qnum_from_uint(uint64_t value)
>  {
> -    QNum *qn = g_new(QNum, 1);
> -
> -    qobject_init(QOBJECT(qn), QTYPE_QNUM);
> -    qn->kind = QNUM_U64;
> -    qn->u.u64 = value;
> -
> -    return qn;
> +    return qnum_from_value((QNumValue) QNUM_VAL_UINT(value));
>  }
>
>  /**
> @@ -57,13 +54,7 @@ QNum *qnum_from_uint(uint64_t value)
>   */
>  QNum *qnum_from_double(double value)
>  {
> -    QNum *qn = g_new(QNum, 1);
> -
> -    qobject_init(QOBJECT(qn), QTYPE_QNUM);
> -    qn->kind = QNUM_DOUBLE;
> -    qn->u.dbl = value;
> -
> -    return qn;
> +    return qnum_from_value((QNumValue) QNUM_VAL_DOUBLE(value));
>  }
>
>  /**
> @@ -75,15 +66,17 @@ QNum *qnum_from_double(double value)
>   */
>  bool qnum_get_try_int(const QNum *qn, int64_t *val)
>  {
> -    switch (qn->kind) {
> +    const QNumValue *qv = &qn->value;
> +
> +    switch (qv->kind) {
>      case QNUM_I64:
> -        *val = qn->u.i64;
> +        *val = qv->u.i64;
>          return true;
>      case QNUM_U64:
> -        if (qn->u.u64 > INT64_MAX) {
> +        if (qv->u.u64 > INT64_MAX) {
>              return false;
>          }
> -        *val = qn->u.u64;
> +        *val = qv->u.u64;
>          return true;
>      case QNUM_DOUBLE:
>          return false;
> @@ -116,15 +109,17 @@ int64_t qnum_get_int(const QNum *qn)
>   */
>  bool qnum_get_try_uint(const QNum *qn, uint64_t *val)
>  {
> -    switch (qn->kind) {
> +    const QNumValue *qv = &qn->value;
> +
> +    switch (qv->kind) {
>      case QNUM_I64:
> -        if (qn->u.i64 < 0) {
> +        if (qv->u.i64 < 0) {
>              return false;
>          }
> -        *val = qn->u.i64;
> +        *val = qv->u.i64;
>          return true;
>      case QNUM_U64:
> -        *val = qn->u.u64;
> +        *val = qv->u.u64;
>          return true;
>      case QNUM_DOUBLE:
>          return false;
> @@ -156,13 +151,15 @@ uint64_t qnum_get_uint(const QNum *qn)
>   */
>  double qnum_get_double(const QNum *qn)
>  {
> -    switch (qn->kind) {
> +    const QNumValue *qv = &qn->value;
> +
> +    switch (qv->kind) {
>      case QNUM_I64:
> -        return qn->u.i64;
> +        return qv->u.i64;
>      case QNUM_U64:
> -        return qn->u.u64;
> +        return qv->u.u64;
>      case QNUM_DOUBLE:
> -        return qn->u.dbl;
> +        return qv->u.dbl;
>      }
>
>      assert(0);
> @@ -171,14 +168,15 @@ double qnum_get_double(const QNum *qn)
>
>  char *qnum_to_string(QNum *qn)
>  {
> +    const QNumValue *qv = &qn->value;
>

qnum_get_value() ?

     char *buffer;
>      int len;
>
> -    switch (qn->kind) {
> +    switch (qv->kind) {
>      case QNUM_I64:
> -        return g_strdup_printf("%" PRId64, qn->u.i64);
> +        return g_strdup_printf("%" PRId64, qv->u.i64);
>      case QNUM_U64:
> -        return g_strdup_printf("%" PRIu64, qn->u.u64);
> +        return g_strdup_printf("%" PRIu64, qv->u.u64);
>      case QNUM_DOUBLE:
>          /* FIXME: snprintf() is locale dependent; but JSON requires
>           * numbers to be formatted as if in the C locale. Dependence
> @@ -189,7 +187,7 @@ char *qnum_to_string(QNum *qn)
>           * rounding errors; we should be using DBL_DECIMAL_DIG (17),
>           * and only rounding to a shorter number if the result would
>           * still produce the same floating point value.  */
> -        buffer = g_strdup_printf("%f" , qn->u.dbl);
> +        buffer = g_strdup_printf("%f" , qv->u.dbl);
>          len = strlen(buffer);
>          while (len > 0 && buffer[len - 1] == '0') {
>              len--;
> @@ -221,8 +219,10 @@ char *qnum_to_string(QNum *qn)
>   */
>  bool qnum_is_equal(const QObject *x, const QObject *y)
>  {
> -    QNum *num_x = qobject_to(QNum, x);
> -    QNum *num_y = qobject_to(QNum, y);
> +    const QNum *qnum_x = qobject_to(QNum, x);
> +    const QNum *qnum_y = qobject_to(QNum, y);
> +    const QNumValue *num_x = &qnum_x->value;
> +    const QNumValue *num_y = &qnum_y->value;
>
>      switch (num_x->kind) {
>      case QNUM_I64:
> diff --git a/tests/check-qnum.c b/tests/check-qnum.c
> index 4105015872..9499b0d845 100644
> --- a/tests/check-qnum.c
> +++ b/tests/check-qnum.c
> @@ -30,8 +30,8 @@ static void qnum_from_int_test(void)
>
>      qn = qnum_from_int(value);
>      g_assert(qn != NULL);
> -    g_assert_cmpint(qn->kind, ==, QNUM_I64);
> -    g_assert_cmpint(qn->u.i64, ==, value);
> +    g_assert_cmpint(qn->value.kind, ==, QNUM_I64);
> +    g_assert_cmpint(qn->value.u.i64, ==, value);
>      g_assert_cmpint(qn->base.refcnt, ==, 1);
>      g_assert_cmpint(qobject_type(QOBJECT(qn)), ==, QTYPE_QNUM);
>
> @@ -45,8 +45,8 @@ static void qnum_from_uint_test(void)
>
>      qn = qnum_from_uint(value);
>      g_assert(qn != NULL);
> -    g_assert_cmpint(qn->kind, ==, QNUM_U64);
> -    g_assert(qn->u.u64 == value);
> +    g_assert_cmpint(qn->value.kind, ==, QNUM_U64);
> +    g_assert(qn->value.u.u64 == value);
>      g_assert(qn->base.refcnt == 1);
>      g_assert(qobject_type(QOBJECT(qn)) == QTYPE_QNUM);
>
> @@ -60,8 +60,8 @@ static void qnum_from_double_test(void)
>
>      qn = qnum_from_double(value);
>      g_assert(qn != NULL);
> -    g_assert_cmpint(qn->kind, ==, QNUM_DOUBLE);
> -    g_assert_cmpfloat(qn->u.dbl, ==, value);
> +    g_assert_cmpint(qn->value.kind, ==, QNUM_DOUBLE);
> +    g_assert_cmpfloat(qn->value.u.dbl, ==, value);
>      g_assert_cmpint(qn->base.refcnt, ==, 1);
>      g_assert_cmpint(qobject_type(QOBJECT(qn)), ==, QTYPE_QNUM);
>
> @@ -74,7 +74,7 @@ static void qnum_from_int64_test(void)
>      const int64_t value = 0x1234567890abcdefLL;
>
>      qn = qnum_from_int(value);
> -    g_assert_cmpint((int64_t) qn->u.i64, ==, value);
> +    g_assert_cmpint((int64_t) qn->value.u.i64, ==, value);
>
>      qobject_unref(qn);
>  }
> --
> 2.28.0
>
>
>
lgtm otherwise

-- 
Marc-André Lureau