[vlc-devel] [PATCH 1/9] vlc_list: add a typedef vlc_list_node to clarify which is the list and which is the node
Steve Lhomme
robux4 at ycbcr.xyz
Mon Aug 20 09:24:51 CEST 2018
An example of the confusion we want to avoid and what led me to dig into
this code:
vlc_list siblings
Is is a list or a list item/node ? The plural led me to think it it's a
list of siblings but I was wrong. Having "vlc_list_node siblings" would
clear that confusion.
On 20/08/2018 09:21, Steve Lhomme wrote:
> On 17/08/2018 19:06, Rémi Denis-Courmont wrote:
>> You cannot have a different typedef here. This is by design. And we
>> already use different member names for heads and nodes.
>
> It's possible, it's even desirable. "vlc_list node" is the part that
> doesn't make sense here. A node is not a list, the fact it shares the
> same internals is because of the current design. It may change in the
> future, but what is 100% is that a node must not be used as a vlc_list
> despite its type. And so it should not imply it can be from its type
> (maybe the mnemonic is wrong, who knows).
>
>>
>> Le 17 août 2018 16:04:33 GMT+03:00, Steve Lhomme <robux4 at ycbcr.xyz> a
>> écrit :
>>
>> ---
>> include/vlc_list.h | 23 +++++++++++++----------
>> 1 file changed, 13 insertions(+), 10 deletions(-)
>>
>> diff --git a/include/vlc_list.h b/include/vlc_list.h
>> index 45263cc789..002119db6b 100644
>> --- a/include/vlc_list.h
>> +++ b/include/vlc_list.h
>> @@ -45,6 +45,9 @@ struct vlc_list
>> struct vlc_list *next;
>> };
>> +/* type to use in list items to differentiate with the
>> list itself */
>> +typedef struct vlc_list vlc_list_node;
>> +
>> /**
>> * Static initializer for a list head.
>> */
>> @@ -66,7 +69,7 @@ static inline void vlc_list_init(struct
>> vlc_list *restrict head)
>> * \param prev Node pointer of the previous element.
>> * \param next Node pointer of the next element.
>> */
>> -static inline void vlc_list_add_between(struct vlc_list
>> *restrict node,
>> +static inline void vlc_list_add_between(vlc_list_node *restrict
>> node,
>> struct vlc_list *prev,
>> struct vlc_list *next)
>> {
>> @@ -82,7 +85,7 @@ static inline void vlc_list_add_between(struct
>> vlc_list *restrict node,
>> * \param node Node pointer of the element to insert [OUT].
>> * \param prev Node pointer of the previous element.
>> */
>> -static inline void vlc_list_add_after(struct vlc_list *restrict
>> node,
>> +static inline void vlc_list_add_after(vlc_list_node *restrict node,
>> struct vlc_list *prev)
>> {
>> vlc_list_add_between(node, prev, prev->next);
>> @@ -94,7 +97,7 @@ static inline void vlc_list_add_after(struct
>> vlc_list *restrict node,
>> * \param node Node pointer of the element to insert [OUT].
>> * \param prev Node pointer of the next element.
>> */
>> -static inline void vlc_list_add_before(struct vlc_list *restrict
>> node,
>> +static inline void vlc_list_add_before(vlc_list_node *restrict
>> node,
>> struct vlc_list *next)
>> {
>> vlc_list_add_between(node, next->prev, next);
>> @@ -106,7 +109,7 @@ static inline void vlc_list_add_before(struct
>> vlc_list *restrict node,
>> * \param node Node pointer of the element to append to the
>> list [OUT].
>> * \param head Head pointer of the list to append the element to.
>> */
>> -static inline void vlc_list_append(struct vlc_list *restrict node,
>> +static inline void vlc_list_append(vlc_list_node *restrict node,
>> struct vlc_list *head)
>> {
>> vlc_list_add_before(node, head);
>> @@ -118,7 +121,7 @@ static inline void vlc_list_append(struct
>> vlc_list *restrict node,
>> * \param node Node pointer of the element to prepend to the
>> list [OUT].
>> * \param head Head pointer of the list to prepend the element to.
>> */
>> -static inline void vlc_list_prepend(struct vlc_list *restrict node,
>> +static inline void vlc_list_prepend(vlc_list_node *restrict node,
>> struct vlc_list *head)
>> {
>> vlc_list_add_after(node, head);
>> @@ -131,7 +134,7 @@ static inline void vlc_list_prepend(struct
>> vlc_list *restrict node,
>> * \warning The element must be inside a list.
>> * Otherwise the behaviour is undefined.
>> */
>> -static inline void vlc_list_remove(struct vlc_list *restrict node)
>> +static inline void vlc_list_remove(vlc_list_node *restrict node)
>> {
>> struct vlc_list *prev = node->prev;
>> struct vlc_list *next = node->next;
>> @@ -177,7 +180,7 @@ static inline bool vlc_list_is_empty(const
>> struct vlc_list *head)
>> * \retval false The element is not first (or is in another list).
>> * \retval true The element is first.
>> */
>> -static inline bool vlc_list_is_first(const struct vlc_list *node,
>> +static inline bool vlc_list_is_first(const vlc_list_node *node,
>> const struct vlc_list *head)
>> {
>> return node->prev == head;
>> @@ -192,7 +195,7 @@ static inline bool vlc_list_is_first(const
>> struct vlc_list *node,
>> * \retval false The element is not last (or is in another list).
>> * \retval true The element is last.
>> */
>> -static inline bool vlc_list_is_last(const struct vlc_list *node,
>> +static inline bool vlc_list_is_last(const vlc_list_node *node,
>> const struct vlc_list *head)
>> {
>> return node->next == head;
>> @@ -289,7 +292,7 @@ static inline void
>> *vlc_list_last_or_null(const struct vlc_list *head,
>> }
>> static inline void *vlc_list_prev_or_null(const struct
>> vlc_list *head,
>> - struct vlc_list *node,
>> + vlc_list_node *node,
>> size_t offset)
>> {
>> if (vlc_list_is_first(node, head))
>> @@ -298,7 +301,7 @@ static inline void
>> *vlc_list_prev_or_null(const struct vlc_list *head,
>> }
>> static inline void *vlc_list_next_or_null(const struct
>> vlc_list *head,
>> - struct vlc_list *node,
>> + vlc_list_node *node,
>> size_t offset)
>> {
>> if (vlc_list_is_last(node, head))
>>
>>
>> --
>> Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez
>> excuser ma brièveté.
>>
>>
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