Re: [PATCH v2 1/5] qemu/qarray.h: introduce QArray

[Markus Armbruster]

Christian Schoenebeck <qemu_oss@crudebyte.com> writes:

> On Sonntag, 22. August 2021 15:16:46 CEST Christian Schoenebeck wrote:
>> Implements deep auto free of arrays while retaining common C-style
>> squared bracket access.
>> 
>> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
>> ---
>>  include/qemu/qarray.h | 150 ++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 150 insertions(+)
>>  create mode 100644 include/qemu/qarray.h
>> 
>> diff --git a/include/qemu/qarray.h b/include/qemu/qarray.h
>> new file mode 100644
>> index 0000000000..9885e5e9ed
>> --- /dev/null
>> +++ b/include/qemu/qarray.h
>> @@ -0,0 +1,150 @@

[...]

>> + * Consider the following user struct @c Foo which shall be used as scalar
>> + * (element) type of an array:
>> + * @code
>> + * typedef struct Foo {
>> + *     int i;
>> + *     char *s;
>> + * } Foo;
>> + * @endcode
>> + * and assume it has the following function to free memory allocated by @c 
>> Foo
>> + * instances:
>> + * @code
>> + * void free_foo(Foo *foo) {
>> + *     free(foo->s);
>> + * }
>> + * @endcode
>> + * Add the following to a shared header file:
>> + * @code
>> + * DECLARE_QARRAY_TYPE(Foo);
>> + * @endcode
>> + * and the following to a C unit file:
>> + * @code
>> + * DEFINE_QARRAY_TYPE(Foo, free_foo);
>> + * @endcode
>> + * Finally the array may then be used like this:
>> + * @code
>> + * void doSomething(int n) {
>> + *     QArrayRef(Foo) foos = NULL;
>> + *     QARRAY_CREATE(Foo, foos, n);
>> + *     for (size_t i = 0; i < n; ++i) {
>> + *         foos[i].i = i;
>> + *         foos[i].s = calloc(4096, 1);
>> + *         snprintf(foos[i].s, 4096, "foo %d", i);
>> + *     }
>> + * }
>> + * @endcode
>
> Or should that probably be changed to upper case QArrayRef() -> QARRAY_REF(), 
> because ...
>
>> + */

[...]

>> +/**
>> + * Used to declare a reference variable (unique pointer) for an array. After
>> + * leaving the scope of the reference variable, the associated array is
>> + * automatically freed.
>> + *
>> + * @param scalar_type - type of the individual array elements
>> + */
>> +#define QArrayRef(scalar_type) \
>> +    __attribute((__cleanup__(qarray_auto_free_##scalar_type))) scalar_type*
>> +
>
> ... it is actually a macro?

I'd change it.

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