Re: [Libguestfs] [libnbd PATCH v4 06/25] generator: Support Extent64 arg in Go code

See the earlier commit "Add Extent64 arg type" for rationale in supporting a new generator arg type. This patch adds the Go bindings for use of Extent64, which required adding a counterpart Go type and introducing a helper function for copying from the C array to an actual Go object, very similar to the existing copy_uint32_array helper for 32-bit extents. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- v4: split out of larger patch [Laszlo], avoid awkward slice since we can't use copy() anyway [Laszlo] --- generator/GoLang.ml | 23 +++++++++++++++++++++++ golang/handle.go | 6 ++++++ 2 files changed, 29 insertions(+) diff --git a/generator/GoLang.ml b/generator/GoLang.ml index cc7d78b6..7a516366 100644 --- a/generator/GoLang.ml +++ b/generator/GoLang.ml @@ -528,6 +528,21 @@ let } return ret } + +func copy_extent_array(entries *C.nbd_extent, count C.size_t) []LibnbdExtent { + if (uint64(count) > 64*1024*1024) { + panic(\"violation of state machine guarantee\") + }

+ ret := make([]LibnbdExtent, count) + addr := uintptr(unsafe.Pointer(entries)) + for i := 0; i < int(count); i++ { + ptr := (*C.nbd_extent)(unsafe.Pointer(addr)) + ret[i].Length = uint64((*ptr).length) + ret[i].Flags = uint64((*ptr).flags) + addr += unsafe.Sizeof(*ptr) + } + return ret +} "; List.iter ( @@ -542,6 +557,8 @@ let match cbarg with | CBArrayAndLen (UInt32 n, _) -> pr "%s []uint32" n; + | CBArrayAndLen (Extent64 n, _) -> + pr "%s []LibnbdExtent" n; | CBBytesIn (n, len) -> pr "%s []byte" n; | CBInt n -> @@ -568,6 +585,8 @@ let match cbarg with | CBArrayAndLen (UInt32 n, count) -> pr "%s *C.uint32_t, %s C.size_t" n count + | CBArrayAndLen (Extent64 n, count) -> + pr "%s *C.nbd_extent, %s C.size_t" n count | CBBytesIn (n, len) -> pr "%s unsafe.Pointer, %s C.size_t" n len | CBInt n -> @@ -610,6 +629,8 @@ let match cbarg with | CBArrayAndLen (UInt32 n, count) -> pr "copy_uint32_array(%s, %s)" n count + | CBArrayAndLen (Extent64 n, count) -> + pr "copy_extent_array(%s, %s)" n count | CBBytesIn (n, len) -> pr "C.GoBytes(%s, C.int(%s))" n len | CBInt n -> @@ -760,6 +781,8 @@ let match cbarg with | CBArrayAndLen (UInt32 n, count) -> pr "uint32_t *%s, size_t %s" n count + | CBArrayAndLen (Extent64 n, count) -> + pr "nbd_extent *%s, size_t %s" n count | CBBytesIn (n, len) -> pr "void *%s, size_t %s" n len | CBInt n -> diff --git a/golang/handle.go b/golang/handle.go index 5fe4ed4f..2b0ee6d5 100644 --- a/golang/handle.go +++ b/golang/handle.go @@ -58,6 +58,12 @@ func (h *Libnbd) String() string { return "&Libnbd{}" } +/* Used for block status callback. */ +type LibnbdExtent struct { + Length uint64 // length of the extent + Flags uint64 // flags describing properties of the extent +} + /* All functions (except Close) return ([result,] LibnbdError). */ type LibnbdError struct { Op string // operation which failed --