mirror of https://github.com/ceph/go-ceph
113 lines
2.7 KiB
Go
113 lines
2.7 KiB
Go
package rados
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// #cgo LDFLAGS: -lrados
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// #include <rados/librados.h>
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// #include <stdlib.h>
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//
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import "C"
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import (
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"unsafe"
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"github.com/ceph/go-ceph/internal/cutil"
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)
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// ReadOpOmapGetValsByKeysStep holds the result of the
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// GetOmapValuesByKeys read operation.
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// Result is valid only after Operate() was called.
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type ReadOpOmapGetValsByKeysStep struct {
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// C arguments
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iter C.rados_omap_iter_t
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prval *C.int
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// Internal state
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// canIterate is only set after the operation is performed and is
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// intended to prevent premature fetching of data.
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canIterate bool
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}
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func newReadOpOmapGetValsByKeysStep() *ReadOpOmapGetValsByKeysStep {
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s := &ReadOpOmapGetValsByKeysStep{
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prval: (*C.int)(C.malloc(C.sizeof_int)),
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}
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return s
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}
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func (s *ReadOpOmapGetValsByKeysStep) free() {
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s.canIterate = false
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C.rados_omap_get_end(s.iter)
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C.free(unsafe.Pointer(s.prval))
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s.prval = nil
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}
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func (s *ReadOpOmapGetValsByKeysStep) update() error {
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err := getError(*s.prval)
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s.canIterate = (err == nil)
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return err
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}
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// Next gets the next omap key/value pair referenced by
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// ReadOpOmapGetValsByKeysStep's internal iterator.
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// If there are no more elements to retrieve, (nil, nil) is returned.
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// May be called only after Operate() finished.
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func (s *ReadOpOmapGetValsByKeysStep) Next() (*OmapKeyValue, error) {
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if !s.canIterate {
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return nil, ErrOperationIncomplete
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}
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var (
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cKey *C.char
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cVal *C.char
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cKeyLen C.size_t
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cValLen C.size_t
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)
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ret := C.rados_omap_get_next2(s.iter, &cKey, &cVal, &cKeyLen, &cValLen)
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if ret != 0 {
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return nil, getError(ret)
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}
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if cKey == nil {
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// Iterator has reached the end of the list.
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return nil, nil
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}
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return &OmapKeyValue{
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Key: string(C.GoBytes(unsafe.Pointer(cKey), C.int(cKeyLen))),
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Value: C.GoBytes(unsafe.Pointer(cVal), C.int(cValLen)),
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}, nil
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}
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// GetOmapValuesByKeys starts iterating over specific key/value pairs.
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//
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// Implements:
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// void rados_read_op_omap_get_vals_by_keys2(rados_read_op_t read_op,
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// char const * const * keys,
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// size_t num_keys,
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// const size_t * key_lens,
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// rados_omap_iter_t * iter,
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// int * prval)
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func (r *ReadOp) GetOmapValuesByKeys(keys []string) *ReadOpOmapGetValsByKeysStep {
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s := newReadOpOmapGetValsByKeysStep()
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r.steps = append(r.steps, s)
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cKeys := cutil.NewBufferGroupStrings(keys)
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defer cKeys.Free()
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C.rados_read_op_omap_get_vals_by_keys2(
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r.op,
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(**C.char)(cKeys.BuffersPtr()),
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C.size_t(len(keys)),
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(*C.size_t)(cKeys.LengthsPtr()),
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&s.iter,
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s.prval,
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)
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return s
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}
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