1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
package transformers
import (
"container/list"
"fmt"
"os"
"strings"
"github.com/johnkerl/miller/v6/pkg/cli"
"github.com/johnkerl/miller/v6/pkg/mlrval"
"github.com/johnkerl/miller/v6/pkg/types"
)
// ----------------------------------------------------------------
const verbNameGap = "gap"
var GapSetup = TransformerSetup{
Verb: verbNameGap,
UsageFunc: transformerGapUsage,
ParseCLIFunc: transformerGapParseCLI,
IgnoresInput: false,
}
func transformerGapUsage(
o *os.File,
) {
fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameGap)
fmt.Fprint(o, "Emits an empty record every n records, or when certain values change.\n")
fmt.Fprintf(o, "Options:\n")
fmt.Fprintf(o, "Emits an empty record every n records, or when certain values change.\n")
fmt.Fprintf(o, "-g {a,b,c} Print a gap whenever values of these fields (e.g. a,b,c) changes.\n")
fmt.Fprintf(o, "-n {n} Print a gap every n records.\n")
fmt.Fprintf(o, "One of -f or -g is required.\n")
fmt.Fprintf(o, "-n is ignored if -g is present.\n")
fmt.Fprintf(o, "-h|--help Show this message.\n")
}
func transformerGapParseCLI(
pargi *int,
argc int,
args []string,
_ *cli.TOptions,
doConstruct bool, // false for first pass of CLI-parse, true for second pass
) IRecordTransformer {
// Skip the verb name from the current spot in the mlr command line
argi := *pargi
verb := args[argi]
argi++
gapCount := int64(-1)
var groupByFieldNames []string = nil
for argi < argc /* variable increment: 1 or 2 depending on flag */ {
opt := args[argi]
if !strings.HasPrefix(opt, "-") {
break // No more flag options to process
}
if args[argi] == "--" {
break // All transformers must do this so main-flags can follow verb-flags
}
argi++
if opt == "-h" || opt == "--help" {
transformerGapUsage(os.Stdout)
os.Exit(0)
} else if opt == "-n" {
gapCount = cli.VerbGetIntArgOrDie(verb, opt, args, &argi, argc)
} else if opt == "-g" {
groupByFieldNames = cli.VerbGetStringArrayArgOrDie(verb, opt, args, &argi, argc)
} else {
transformerGapUsage(os.Stderr)
os.Exit(1)
}
}
if gapCount == -1 && groupByFieldNames == nil {
transformerGapUsage(os.Stderr)
os.Exit(1)
}
*pargi = argi
if !doConstruct { // All transformers must do this for main command-line parsing
return nil
}
transformer, err := NewTransformerGap(
gapCount,
groupByFieldNames,
)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
return transformer
}
// ----------------------------------------------------------------
type TransformerGap struct {
// input
gapCount int64
groupByFieldNames []string
// state
recordTransformerFunc RecordTransformerFunc
recordCount int64
previousGroupingKey string
}
func NewTransformerGap(
gapCount int64,
groupByFieldNames []string,
) (*TransformerGap, error) {
tr := &TransformerGap{
gapCount: gapCount,
groupByFieldNames: groupByFieldNames,
recordCount: 0,
previousGroupingKey: "",
}
if groupByFieldNames == nil {
tr.recordTransformerFunc = tr.transformUnkeyed
} else {
tr.recordTransformerFunc = tr.transformKeyed
}
return tr, nil
}
// ----------------------------------------------------------------
func (tr *TransformerGap) Transform(
inrecAndContext *types.RecordAndContext,
outputRecordsAndContexts *list.List, // list of *types.RecordAndContext
inputDownstreamDoneChannel <-chan bool,
outputDownstreamDoneChannel chan<- bool,
) {
HandleDefaultDownstreamDone(inputDownstreamDoneChannel, outputDownstreamDoneChannel)
tr.recordTransformerFunc(inrecAndContext, outputRecordsAndContexts, inputDownstreamDoneChannel, outputDownstreamDoneChannel)
}
func (tr *TransformerGap) transformUnkeyed(
inrecAndContext *types.RecordAndContext,
outputRecordsAndContexts *list.List, // list of *types.RecordAndContext
inputDownstreamDoneChannel <-chan bool,
outputDownstreamDoneChannel chan<- bool,
) {
if !inrecAndContext.EndOfStream {
if tr.recordCount > 0 && tr.recordCount%tr.gapCount == 0 {
newrec := mlrval.NewMlrmapAsRecord()
outputRecordsAndContexts.PushBack(types.NewRecordAndContext(newrec, &inrecAndContext.Context))
}
outputRecordsAndContexts.PushBack(inrecAndContext)
tr.recordCount++
} else {
outputRecordsAndContexts.PushBack(inrecAndContext)
}
}
func (tr *TransformerGap) transformKeyed(
inrecAndContext *types.RecordAndContext,
outputRecordsAndContexts *list.List, // list of *types.RecordAndContext
inputDownstreamDoneChannel <-chan bool,
outputDownstreamDoneChannel chan<- bool,
) {
if !inrecAndContext.EndOfStream {
inrec := inrecAndContext.Record
groupingKey, ok := inrec.GetSelectedValuesJoined(tr.groupByFieldNames)
if !ok {
groupingKey = ""
}
if groupingKey != tr.previousGroupingKey && tr.recordCount > 0 {
newrec := mlrval.NewMlrmapAsRecord()
outputRecordsAndContexts.PushBack(types.NewRecordAndContext(newrec, &inrecAndContext.Context))
}
outputRecordsAndContexts.PushBack(inrecAndContext)
tr.previousGroupingKey = groupingKey
tr.recordCount++
} else {
outputRecordsAndContexts.PushBack(inrecAndContext)
}
}
|
