go-ceph/internal/cutil/command_input.go
John Mulligan e40744fdf6 cutil: add a new internal package for c+go utility functions
Now we have sufficient boilerplate in our code for interacting with
various types and ceph calls with similar needs we establish a new
internal package, "cutil" (C utilities).

Note that many of the return types are wrapped. This is due to the
limits placed on us by cgo.  Despite the irritating limitations Go
places on "exporting" C types it still ought to help in the long run for
patterns that are very common or patterns that are subtle and we want to
write specific tests for.

Signed-off-by: John Mulligan <jmulligan@redhat.com>
2020-05-12 17:18:08 -04:00

63 lines
1.3 KiB
Go

package cutil
/*
#include <stdlib.h>
*/
import "C"
import (
"unsafe"
)
// CommandInput can be used to manage the input to ceph's *_command functions.
type CommandInput struct {
cmd []*C.char
inbuf []byte
}
// NewCommandInput creates C-level pointers from go byte buffers suitable
// for passing off to ceph's *_command functions.
func NewCommandInput(cmd [][]byte, inputBuffer []byte) *CommandInput {
ci := &CommandInput{
cmd: make([]*C.char, len(cmd)),
inbuf: inputBuffer,
}
for i := range cmd {
ci.cmd[i] = C.CString(string(cmd[i]))
}
return ci
}
// Free any C memory managed by this CommandInput.
func (ci *CommandInput) Free() {
for i := range ci.cmd {
C.free(unsafe.Pointer(ci.cmd[i]))
}
ci.cmd = nil
}
// Cmd returns an unsafe wrapper around an array of C-strings.
func (ci *CommandInput) Cmd() CharPtrPtr {
ptr := &ci.cmd[0]
return CharPtrPtr(ptr)
}
// CmdLen returns the length of the array of C-strings returned by
// Cmd.
func (ci *CommandInput) CmdLen() SizeT {
return SizeT(len(ci.cmd))
}
// InBuf returns an unsafe wrapper to a C char*.
func (ci *CommandInput) InBuf() CharPtr {
if len(ci.inbuf) == 0 {
return nil
}
return CharPtr(&ci.inbuf[0])
}
// InBufLen returns the length of the buffer returned by InBuf.
func (ci *CommandInput) InBufLen() SizeT {
return SizeT(len(ci.inbuf))
}