[Xen-devel] [PATCH 05/24] golang/xenlight: define KeyValueList builtin type

[Nick Rosbrook <rosbrookn@xxxxxxxxx>]

From: Nick Rosbrook <rosbrookn@xxxxxxxxxxxx>

Define KeyValueList builtin type, analagous to libxl_key_value_list as
map[string]string, and implement its fromC and toC functions.

Signed-off-by: Nick Rosbrook <rosbrookn@xxxxxxxxxxxx>
---
Cc: George Dunlap <george.dunlap@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>

 tools/golang/xenlight/xenlight.go | 33 ++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/tools/golang/xenlight/xenlight.go 
b/tools/golang/xenlight/xenlight.go
index 4d4fad2a9d..8196a42855 100644
--- a/tools/golang/xenlight/xenlight.go
+++ b/tools/golang/xenlight/xenlight.go
@@ -202,11 +202,42 @@ func (chwcap C.libxl_hwcap) toGo() (ghwcap Hwcap) {
        return
 }
 
+// KeyValueList represents a libxl_key_value_list.
+type KeyValueList map[string]string
+
+func (kvl KeyValueList) fromC(ckvl *C.libxl_key_value_list) error {
+       size := int(C.libxl_key_value_list_length(ckvl))
+       list := (*[1 << 30]*C.char)(unsafe.Pointer(ckvl))[:size:size]
+
+       for i := 0; i < size*2; i += 2 {
+               kvl[C.GoString(list[i])] = C.GoString(list[i+1])
+       }
+
+       return nil
+}
+
+func (kvl KeyValueList) toC() (C.libxl_key_value_list, error) {
+       // Add extra slot for sentinel
+       var char *C.char
+       csize := 2*len(kvl) + 1
+       ckvl := (C.libxl_key_value_list)(C.malloc(C.ulong(csize) * 
C.ulong(unsafe.Sizeof(char))))
+       clist := (*[1 << 31]*C.char)(unsafe.Pointer(ckvl))[:csize:csize]
+
+       i := 0
+       for k, v := range kvl {
+               clist[i] = C.CString(k)
+               clist[i+1] = C.CString(v)
+               i += 2
+       }
+       clist[len(clist)-1] = nil
+
+       return ckvl, nil
+}
+
 // typedef struct {
 //     uint32_t size;          /* number of bytes in map */
 //     uint8_t *map;
 // } libxl_bitmap;
-
 // Implement the Go bitmap type such that the underlying data can
 // easily be copied in and out.  NB that we still have to do copies
 // both directions, because cgo runtime restrictions forbid passing to
-- 
2.19.1


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