github.com/cayleygraph/cayley@v0.7.7/writer/single.go (about)

     1  // Copyright 2014 The Cayley Authors. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package writer
    16  
    17  import (
    18  	"github.com/cayleygraph/cayley/graph"
    19  	"github.com/cayleygraph/quad"
    20  )
    21  
    22  func init() {
    23  	graph.RegisterWriter("single", NewSingleReplication)
    24  }
    25  
    26  type Single struct {
    27  	qs         graph.QuadStore
    28  	ignoreOpts graph.IgnoreOpts
    29  }
    30  
    31  func NewSingle(qs graph.QuadStore, opts graph.IgnoreOpts) (graph.QuadWriter, error) {
    32  	return &Single{
    33  		qs:         qs,
    34  		ignoreOpts: opts,
    35  	}, nil
    36  }
    37  
    38  func NewSingleReplication(qs graph.QuadStore, opts graph.Options) (graph.QuadWriter, error) {
    39  	ignoreMissing, err := opts.BoolKey("ignore_missing", graph.IgnoreMissing)
    40  	if err != nil {
    41  		return nil, err
    42  	}
    43  
    44  	ignoreDuplicate, err := opts.BoolKey("ignore_duplicate", graph.IgnoreDuplicates)
    45  	if err != nil {
    46  		return nil, err
    47  	}
    48  
    49  	return NewSingle(qs, graph.IgnoreOpts{
    50  		IgnoreMissing: ignoreMissing,
    51  		IgnoreDup:     ignoreDuplicate,
    52  	})
    53  }
    54  
    55  func (s *Single) AddQuad(q quad.Quad) error {
    56  	deltas := make([]graph.Delta, 1)
    57  	deltas[0] = graph.Delta{
    58  		Quad:   q,
    59  		Action: graph.Add,
    60  	}
    61  	return s.qs.ApplyDeltas(deltas, s.ignoreOpts)
    62  }
    63  
    64  func (s *Single) AddQuadSet(set []quad.Quad) error {
    65  	tx := graph.NewTransactionN(len(set))
    66  	for _, q := range set {
    67  		tx.AddQuad(q)
    68  	}
    69  	return s.qs.ApplyDeltas(tx.Deltas, s.ignoreOpts)
    70  }
    71  
    72  func (s *Single) RemoveQuad(q quad.Quad) error {
    73  	deltas := make([]graph.Delta, 1)
    74  	deltas[0] = graph.Delta{
    75  		Quad:   q,
    76  		Action: graph.Delete,
    77  	}
    78  	return s.qs.ApplyDeltas(deltas, s.ignoreOpts)
    79  }
    80  
    81  // RemoveNode removes all quads with the given value.
    82  //
    83  // It returns ErrNodeNotExists if node is missing.
    84  func (s *Single) RemoveNode(v quad.Value) error {
    85  	gv := s.qs.ValueOf(v)
    86  	if gv == nil {
    87  		return graph.ErrNodeNotExists
    88  	}
    89  	del := graph.NewRemover(s)
    90  	defer del.Close()
    91  
    92  	total := 0
    93  	// TODO(dennwc): QuadStore may remove node without iterations. Consider optional interface for this.
    94  	for _, d := range []quad.Direction{quad.Subject, quad.Predicate, quad.Object, quad.Label} {
    95  		r := graph.NewResultReader(s.qs, s.qs.QuadIterator(d, gv))
    96  		n, err := quad.Copy(del, r)
    97  		r.Close()
    98  		if err != nil {
    99  			return err
   100  		}
   101  		total += n
   102  	}
   103  	if err := del.Flush(); err != nil {
   104  		return err
   105  	}
   106  	if total == 0 {
   107  		return graph.ErrNodeNotExists
   108  	}
   109  	return nil
   110  }
   111  
   112  func (s *Single) Close() error {
   113  	// Nothing to clean up locally.
   114  	return nil
   115  }
   116  
   117  func (s *Single) ApplyTransaction(t *graph.Transaction) error {
   118  	return s.qs.ApplyDeltas(t.Deltas, s.ignoreOpts)
   119  }