On Wed, Jul 19, 2023 at 09:09:48AM +0000, Tage Johansson wrote:
> Add a new field `cbkind` to the `closure` type in generator/API.ml*.
> It tells how many times the closure may be invoked and for how long time
> it might be used. More specifically, it can take any of these values:
> - `CBOnceCommand`: The closure may only be called once and shall not
> be called after the command is retired.
> - `CBManyCommand`: The closure may be called any number of times but
> not after the command is retired.
> - `CBManyHandle`: The closure may be called any number of times before
> the handle is destructed.
> This information is needed in the Rust bindings for:
> a) Knowing if the closure trait should be `FnMut` or `FnOnce`
> (see <https://doc.rust-lang.org/std/ops/trait.FnOnce.html>).
> b) Knowing for what lifetime the closure should be valid. A closure that
> may be called after the function invokation has returned must live
> for the `'static` lifetime. But static closures are inconveniant for
> the user since they can't effectively borrow any local data. So it is
> good if this restriction is relaxed when it is not needed.
> ---
> generator/API.ml | 11 +++++++++++
> generator/API.mli | 13 +++++++++++++
> 2 files changed, 24 insertions(+)
>
> diff --git a/generator/API.ml b/generator/API.ml
> index f90a6fa..086b2f9 100644
> --- a/generator/API.ml
> +++ b/generator/API.ml
> @@ -77,6 +77,7 @@ and ret =
> and closure = {
> cbname : string;
> cbargs : cbarg list;
> + cbkind : cbkind;
I'm dubious about the premise of this patch, but let's at least call
it "cblifetime" since that's what it is expressing.
> }
> and cbarg =
> | CBArrayAndLen of arg * string
> @@ -87,6 +88,10 @@ and cbarg =
> | CBString of string
> | CBUInt of string
> | CBUInt64 of string
> +and cbkind =
> +| CBOnceCommand
> +| CBManyCommand
> +| CBManyHandle
> and enum = {
> enum_prefix : string;
> enums : (string * int) list
> @@ -141,20 +146,24 @@ the handle from the NBD protocol handshake."
> (* Closures. *)
> let chunk_closure = {
> cbname = "chunk";
> + cbkind = CBManyCommand;
> cbargs = [ CBBytesIn ("subbuf", "count");
> CBUInt64 "offset"; CBUInt "status";
> CBMutable (Int "error") ]
> }
> let completion_closure = {
> cbname = "completion";
> + cbkind = CBOnceCommand;
> cbargs = [ CBMutable (Int "error") ]
> }
> let debug_closure = {
> cbname = "debug";
> + cbkind = CBManyHandle;
> cbargs = [ CBString "context"; CBString "msg" ]
> }
> let extent_closure = {
> cbname = "extent";
> + cbkind = CBManyCommand;
> cbargs = [ CBString "metacontext";
> CBUInt64 "offset";
> CBArrayAndLen (UInt32 "entries",
> @@ -163,10 +172,12 @@ let extent_closure = {
> }
> let list_closure = {
> cbname = "list";
> + cbkind = CBManyCommand;
> cbargs = [ CBString "name"; CBString "description" ]
> }
> let context_closure = {
> cbname = "context";
> + cbkind = CBManyCommand;
> cbargs = [ CBString "name" ]
> }
> let all_closures = [ chunk_closure; completion_closure;
> diff --git a/generator/API.mli b/generator/API.mli
> index 361132d..73dc40a 100644
> --- a/generator/API.mli
> +++ b/generator/API.mli
> @@ -94,6 +94,10 @@ and ret =
> and closure = {
> cbname : string; (** name of callback function *)
> cbargs : cbarg list; (** all closures return int for now *)
> + (** Wether the closure should be used once or many times and wether it
> might
wether -> whether
Rich.
> + be used only until the command is completed or until the handle is
> + destructed. *)
> + cbkind : cbkind;
> }
> and cbarg =
> | CBArrayAndLen of arg * string (** array + number of entries *)
> @@ -104,6 +108,15 @@ and cbarg =
> | CBString of string (** like String *)
> | CBUInt of string (** like UInt *)
> | CBUInt64 of string (** like UInt64 *)
> +and cbkind =
> +| CBOnceCommand (** The closure will be used 0 or 1 time if the aio_* call
> + returned a error and exactly once if the call succeeded.
> + The closure may only be called before the command
> + is retired. (E.g., completion callback.) *)
> +| CBManyCommand (** The closure may be used any number of times but only
> + before the command is retired. (E.g., list callback.) *)
> +| CBManyHandle (** The closure may be used any number of times for as long
> + as the handle exists. (E.g., debug callback.) *)
> and enum = {
> enum_prefix : string; (** prefix of each enum variant *)
> enums : (string * int) list (** enum names and their values in C *)
> --
> 2.41.0
>
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--
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