similar to: [PATCH libnbd] generator: Define new Closure type

As before, but this one has working Python bindings. OCaml still TBD. Rich.

v1 was here: https://www.redhat.com/archives/libguestfs/2019-July/thread.html#00231 The changes address everything that Eric picked up in his review of the first two patches. I have also added two more patches (4 and 5) which respectively fix docs and change int status -> unsigned status, as discussed. Passes make, check, check-valgrind. Rich.

This implements most of what I wrote here: https://www.redhat.com/archives/libguestfs/2019-July/msg00213.html

I think I've addressed everything that was raised in review. Some of the highlights: - Callbacks should be freed reliably along all exit paths. - There's a simple test of closure lifetimes. - I've tried to use VALID|FREE in all the places where I'm confident that it's safe and correct to do. There may be more places. Note this is an optimization and shouldn't

On 7/16/19 6:04 AM, Richard W.M. Jones wrote: > A Closure is a list of (usually one, but can be more) closures. In C > there is also a singe ‘void *user_data’ parameter which is passed by > the caller into the function and through as the first parameter of > each callback invocation. > > By grouping the previously separate Opaque and Callback* parameters > together we can

These are some simplifications to the generator. They don't probably make much sense on their own, but they are preparatory to better handling of enums, and or'd lists of flags. Rich.

Posting now that I got something to compile (at the expense of breaking OCaml bindings), but I'm open to ideas on how to improve it. Eric Blake (2): generator: Tweak print_c_arg_list to take alternate first arg RFC: generator: Handle shared callbacks in Python generator/generator | 556 ++++++++++++++++++++++---------------------- 1 file changed, 280 insertions(+), 276 deletions(-) --

Patches 1 & 2 are rather complex, but the end result is that we pass closures + user_data + free function in single struct parameters as I described previously in this email: https://www.redhat.com/archives/libguestfs/2019-August/msg00210.html Patch 3 adds a convenient FREE_CALLBACK macro which seems a worthwhile simplification if you buy into 1 & 2. Patch 4 adds another macro which is

In v2: - now based on my proposal to add LIBNBD_SHUTDOWN_IMMEDIATE - four flags instead of two: STRICT_FLAGS is new (patch 4), and STRICT_BOUNDS is separate from STRICT_ZERO_SIZE (patch 5) - various refactorings for more shared code and less duplication Eric Blake (5): api: Add xxx_MASK constant for each Flags type generator: Refactor filtering of accepted OFlags api: Add

As promised in my earlier thread on libnbd completion callback question. Eric Blake (2): generator: Refactor handling of closures in unlocked functions generator: Free closures on failure docs/libnbd.pod | 2 +- generator/C.ml | 48 +++++++++++------ generator/C.mli | 1 + lib/debug.c | 7 +-- lib/opt.c | 31 ++++++-----

Patches 1-4 are basically uncontroversial, straightforward refactoring and IMHO we should just push them. Possibly 1-3 should be squashed together, but I posted them separately so they are easier to review. Patches 5 and 6 together implement OClosure. Patch 5 adds the feature and is simple to understand. Patch 6 changes the Closure completion callbacks into OClosure, but because it doesn't

A Closure is a list of (usually one, but can be more) closures. In C there is also a singe ‘void *user_data’ parameter which is passed by the caller into the function and through as the first parameter of each callback invocation. By grouping the previously separate Opaque and Callback* parameters together we can avoid the awkward situation where we have to scan through the argument list to try

I still need to wire in the use of *_notify functions into nbdkit to prove whether it makes the code any faster or easier to maintain, but at least the added example shows one good use case for the new API. Eric Blake (6): api: Add nbd_aio_in_flight generator: Allow DEAD state actions to run generator: Allow Int64 in callbacks states: Prepare for aio notify callback api: Add new

On 7/24/19 7:17 AM, Richard W.M. Jones wrote: > In preparation for closure lifetimes, split up the Closure so it no > longer describes a list of closures, but a single callback. > > This changes the API because functions which take 2 or more closures > now pass a separate user_data for each one. > --- > docs/libnbd.pod | 3 +- >

As discussed in this thread, the parameter is an invitation to write code with race conditions: https://www.redhat.com/archives/libguestfs/2019-July/thread.html#00309 --- docs/libnbd.pod | 6 +- examples/glib-main-loop.c | 10 ++-- examples/strict-structured-reads.c | 2 +- generator/generator | 57

For example nbd_set_debug takes a callback function. Previously this was defined explicitly inside the function parameters. This commit defines a new public typedef: typedef int (*nbd_debug_callback) (unsigned valid_flag, void *user_data, const char *context, const char *msg); and then uses the typedef like this: extern int nbd_set_debug_callback

I've mentioned this topic before (in fact, the idea of adding NBD_CMD_FLAG_DF was first mentioned at [1]), but finally finished enough of an implementation to feel confident in posting it. I'd still like to add something under examples/ that uses the new API to implement strict checking of a server's structured replies read implementation (ensure that a server never sends data after

Now runs a complete set of tests, notably including the AIO test. File descriptors are passed in and out as plain ints (instead of *os.File) for a couple of reasons: (1) We have to pass the plain int to syscall.Select. (2) Turning an fd into an os.File causes golang to set the blocking flag which is deeply unhelpful. Rich.

This feature is roughly finished now, although it needs a few more tests and some examples. It's pretty much up to par with all the other bindings, but it lacks a completely safe AIO buffer. It won't stop you from freeing the buffer too early) because golang's GC inexplicably lacks a way to declare a root from C. I can probably do it with a global variable and ref counting on the

v1 was here: https://www.redhat.com/archives/libguestfs/2019-August/msg00168.html I pushed uncontroversial patches 1-4 v2: - The implementation of OClosure (new patch 1) in Python is fixed. - Patch 2 (old patch 5) is unchanged. - I added a new API for removing debug callbacks. I think this approach has some advantages over using OClosure. - I didn't yet do any work on changing the