go-ceph/rados/read_op_exec.go

112 lines
2.4 KiB
Go

//go:build ceph_preview
// +build ceph_preview
package rados
// #cgo LDFLAGS: -lrados
// #include <stdlib.h>
// #include <rados/librados.h>
//
import "C"
import (
"runtime"
"unsafe"
)
// ReadOpExecStep - step for exec operation code.
type ReadOpExecStep struct {
withoutFree
inBuffPtr *C.char
inBuffLen C.size_t
outBuffPtr *C.char
outBuffLen C.size_t
prval C.int
canReadOutput bool
}
// newExecStepOp - init new *execStepOp.
func newReadOpExecStep(in []byte) *ReadOpExecStep {
es := &ReadOpExecStep{
outBuffPtr: nil,
outBuffLen: 0,
prval: 0,
}
if len(in) > 0 {
es.inBuffPtr = (*C.char)(unsafe.Pointer(&in[0]))
es.inBuffLen = C.size_t(len(in))
}
runtime.SetFinalizer(es, func(es *ReadOpExecStep) {
if es != nil {
es.freeBuffer()
es = nil
}
})
return es
}
// freeBuffer - releases C allocated buffer. It is separated from es.free() because lifespan of C allocated buffer is
// longer than lifespan of read operation.
func (es *ReadOpExecStep) freeBuffer() {
if es.outBuffPtr != nil {
C.free(unsafe.Pointer(es.outBuffPtr))
es.outBuffPtr = nil
es.canReadOutput = false
}
}
// update - update state operation.
func (es *ReadOpExecStep) update() error {
err := getError(es.prval)
es.canReadOutput = err == nil
return err
}
// Bytes returns the result of the executed command as a byte slice.
func (es *ReadOpExecStep) Bytes() ([]byte, error) {
if !es.canReadOutput {
return nil, ErrOperationIncomplete
}
return C.GoBytes(unsafe.Pointer(es.outBuffPtr), C.int(es.outBuffLen)), nil
}
// Exec executes an OSD class method on an object.
// See rados_exec() in the RADOS C api documentation for a general description.
//
// Implements:
//
// void rados_read_op_exec(rados_read_op_t read_op,
// const char *cls,
// const char *method,
// const char *in_buf,
// size_t in_len,
// char **out_buf,
// size_t *out_len,
// int *prval);
func (r *ReadOp) Exec(clsName, method string, in []byte) *ReadOpExecStep {
cClsName := C.CString(clsName)
defer C.free(unsafe.Pointer(cClsName))
cMethod := C.CString(method)
defer C.free(unsafe.Pointer(cMethod))
es := newReadOpExecStep(in)
r.steps = append(r.steps, es)
C.rados_read_op_exec(
r.op,
cClsName,
cMethod,
es.inBuffPtr,
es.inBuffLen,
&es.outBuffPtr,
&es.outBuffLen,
&es.prval,
)
return es
}