-
Notifications
You must be signed in to change notification settings - Fork 95
/
schema.rs
983 lines (881 loc) · 31.3 KB
/
schema.rs
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
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
//! Logic for parsing and interacting with schemas in Avro format.
use std::borrow::Cow;
use std::collections::HashMap;
use std::fmt;
use digest::Digest;
use failure::Error;
use serde::ser::{Serialize, SerializeMap, SerializeSeq, Serializer};
use serde_json::{self, Map, Value};
use crate::types;
use crate::util::MapHelper;
/// Describes errors happened while parsing Avro schemas.
#[derive(Fail, Debug)]
#[fail(display = "Failed to parse schema: {}", _0)]
pub struct ParseSchemaError(String);
impl ParseSchemaError {
pub fn new<S>(msg: S) -> ParseSchemaError
where
S: Into<String>,
{
ParseSchemaError(msg.into())
}
}
/// Represents an Avro schema fingerprint
/// More information about Avro schema fingerprints can be found in the
/// [Avro Schema Fingerprint documentation](https://avro.apache.org/docs/current/spec.html#schema_fingerprints)
pub struct SchemaFingerprint {
pub bytes: Vec<u8>,
}
impl fmt::Display for SchemaFingerprint {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"{}",
self.bytes
.iter()
.map(|byte| format!("{:02x}", byte))
.collect::<Vec<String>>()
.join("")
)
}
}
/// Represents any valid Avro schema
/// More information about Avro schemas can be found in the
/// [Avro Specification](https://avro.apache.org/docs/current/spec.html#schemas)
#[derive(Clone, Debug, PartialEq)]
pub enum Schema {
/// A `null` Avro schema.
Null,
/// A `boolean` Avro schema.
Boolean,
/// An `int` Avro schema.
Int,
/// A `long` Avro schema.
Long,
/// A `float` Avro schema.
Float,
/// A `double` Avro schema.
Double,
/// A `bytes` Avro schema.
/// `Bytes` represents a sequence of 8-bit unsigned bytes.
Bytes,
/// A `string` Avro schema.
/// `String` represents a unicode character sequence.
String,
/// A `array` Avro schema. Avro arrays are required to have the same type for each element.
/// This variant holds the `Schema` for the array element type.
Array(Box<Schema>),
/// A `map` Avro schema.
/// `Map` holds a pointer to the `Schema` of its values, which must all be the same schema.
/// `Map` keys are assumed to be `string`.
Map(Box<Schema>),
/// A `union` Avro schema.
Union(UnionSchema),
/// A `record` Avro schema.
///
/// The `lookup` table maps field names to their position in the `Vec`
/// of `fields`.
Record {
name: Name,
doc: Documentation,
fields: Vec<RecordField>,
lookup: HashMap<String, usize>,
},
/// An `enum` Avro schema.
Enum {
name: Name,
doc: Documentation,
symbols: Vec<String>,
},
/// A `fixed` Avro schema.
Fixed { name: Name, size: usize },
}
/// This type is used to simplify enum variant comparison between `Schema` and `types::Value`.
/// It may have utility as part of the public API, but defining as `pub(crate)` for now.
///
/// **NOTE** This type was introduced due to a limitation of `mem::discriminant` requiring a _value_
/// be constructed in order to get the discriminant, which makes it difficult to implement a
/// function that maps from `Discriminant<Schema> -> Discriminant<Value>`. Conversion into this
/// intermediate type should be especially fast, as the number of enum variants is small, which
/// _should_ compile into a jump-table for the conversion.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub(crate) enum SchemaKind {
Null,
Boolean,
Int,
Long,
Float,
Double,
Bytes,
String,
Array,
Map,
Union,
Record,
Enum,
Fixed,
}
impl<'a> From<&'a Schema> for SchemaKind {
#[inline(always)]
fn from(schema: &'a Schema) -> SchemaKind {
// NOTE: I _believe_ this will always be fast as it should convert into a jump table.
match schema {
Schema::Null => SchemaKind::Null,
Schema::Boolean => SchemaKind::Boolean,
Schema::Int => SchemaKind::Int,
Schema::Long => SchemaKind::Long,
Schema::Float => SchemaKind::Float,
Schema::Double => SchemaKind::Double,
Schema::Bytes => SchemaKind::Bytes,
Schema::String => SchemaKind::String,
Schema::Array(_) => SchemaKind::Array,
Schema::Map(_) => SchemaKind::Map,
Schema::Union(_) => SchemaKind::Union,
Schema::Record { .. } => SchemaKind::Record,
Schema::Enum { .. } => SchemaKind::Enum,
Schema::Fixed { .. } => SchemaKind::Fixed,
}
}
}
impl<'a> From<&'a types::Value> for SchemaKind {
#[inline(always)]
fn from(value: &'a types::Value) -> SchemaKind {
match value {
types::Value::Null => SchemaKind::Null,
types::Value::Boolean(_) => SchemaKind::Boolean,
types::Value::Int(_) => SchemaKind::Int,
types::Value::Long(_) => SchemaKind::Long,
types::Value::Float(_) => SchemaKind::Float,
types::Value::Double(_) => SchemaKind::Double,
types::Value::Bytes(_) => SchemaKind::Bytes,
types::Value::String(_) => SchemaKind::String,
types::Value::Array(_) => SchemaKind::Array,
types::Value::Map(_) => SchemaKind::Map,
types::Value::Union(_) => SchemaKind::Union,
types::Value::Record(_) => SchemaKind::Record,
types::Value::Enum(_, _) => SchemaKind::Enum,
types::Value::Fixed(_, _) => SchemaKind::Fixed,
}
}
}
/// Represents names for `record`, `enum` and `fixed` Avro schemas.
///
/// Each of these `Schema`s have a `fullname` composed of two parts:
/// * a name
/// * a namespace
///
/// `aliases` can also be defined, to facilitate schema evolution.
///
/// More information about schema names can be found in the
/// [Avro specification](https://avro.apache.org/docs/current/spec.html#names)
#[derive(Clone, Debug, PartialEq)]
pub struct Name {
pub name: String,
pub namespace: Option<String>,
pub aliases: Option<Vec<String>>,
}
/// Represents documentation for complex Avro schemas.
pub type Documentation = Option<String>;
impl Name {
/// Create a new `Name`.
/// No `namespace` nor `aliases` will be defined.
pub fn new(name: &str) -> Name {
Name {
name: name.to_owned(),
namespace: None,
aliases: None,
}
}
/// Parse a `serde_json::Value` into a `Name`.
fn parse(complex: &Map<String, Value>) -> Result<Self, Error> {
let name = complex
.name()
.ok_or_else(|| ParseSchemaError::new("No `name` field"))?;
let namespace = complex.string("namespace");
let aliases: Option<Vec<String>> = complex
.get("aliases")
.and_then(|aliases| aliases.as_array())
.and_then(|aliases| {
aliases
.iter()
.map(|alias| alias.as_str())
.map(|alias| alias.map(|a| a.to_string()))
.collect::<Option<_>>()
});
Ok(Name {
name,
namespace,
aliases,
})
}
/// Return the `fullname` of this `Name`
///
/// More information about fullnames can be found in the
/// [Avro specification](https://avro.apache.org/docs/current/spec.html#names)
pub fn fullname(&self, default_namespace: Option<&str>) -> String {
if self.name.contains('.') {
self.name.clone()
} else {
let namespace = self
.namespace
.as_ref()
.map(|s| s.as_ref())
.or(default_namespace);
match namespace {
Some(ref namespace) => format!("{}.{}", namespace, self.name),
None => self.name.clone(),
}
}
}
}
/// Represents a `field` in a `record` Avro schema.
#[derive(Clone, Debug, PartialEq)]
pub struct RecordField {
/// Name of the field.
pub name: String,
/// Documentation of the field.
pub doc: Documentation,
/// Default value of the field.
/// This value will be used when reading Avro datum if schema resolution
/// is enabled.
pub default: Option<Value>,
/// Schema of the field.
pub schema: Schema,
/// Order of the field.
///
/// **NOTE** This currently has no effect.
pub order: RecordFieldOrder,
/// Position of the field in the list of `field` of its parent `Schema`
pub position: usize,
}
/// Represents any valid order for a `field` in a `record` Avro schema.
#[derive(Clone, Debug, PartialEq)]
pub enum RecordFieldOrder {
Ascending,
Descending,
Ignore,
}
impl RecordField {
/// Parse a `serde_json::Value` into a `RecordField`.
fn parse(field: &Map<String, Value>, position: usize) -> Result<Self, Error> {
let name = field
.name()
.ok_or_else(|| ParseSchemaError::new("No `name` in record field"))?;
// TODO: "type" = "<record name>"
let schema = field
.get("type")
.ok_or_else(|| ParseSchemaError::new("No `type` in record field").into())
.and_then(|type_| Schema::parse(type_))?;
let default = field.get("default").cloned();
let order = field
.get("order")
.and_then(|order| order.as_str())
.and_then(|order| match order {
"ascending" => Some(RecordFieldOrder::Ascending),
"descending" => Some(RecordFieldOrder::Descending),
"ignore" => Some(RecordFieldOrder::Ignore),
_ => None,
}).unwrap_or_else(|| RecordFieldOrder::Ascending);
Ok(RecordField {
name,
doc: field.doc(),
default,
schema,
order,
position,
})
}
}
#[derive(Debug, Clone)]
pub struct UnionSchema {
schemas: Vec<Schema>,
// Used to ensure uniqueness of schema inputs, and provide constant time finding of the
// schema index given a value.
// **NOTE** that this approach does not work for named types, and will have to be modified
// to support that. A simple solution is to also keep a mapping of the names used.
variant_index: HashMap<SchemaKind, usize>,
}
impl UnionSchema {
pub(crate) fn new(schemas: Vec<Schema>) -> Result<Self, Error> {
let mut vindex = HashMap::new();
for (i, schema) in schemas.iter().enumerate() {
if let Schema::Union(_) = schema {
Err(ParseSchemaError::new(
"Unions may not directly contain a union",
))?;
}
let kind = SchemaKind::from(schema);
if vindex.insert(kind, i).is_some() {
Err(ParseSchemaError::new(
"Unions cannot contain duplicate types",
))?;
}
}
Ok(UnionSchema {
schemas,
variant_index: vindex,
})
}
/// Returns a slice to all variants of this schema.
pub fn variants(&self) -> &[Schema] {
&self.schemas
}
/// Returns true if the first variant of this `UnionSchema` is `Null`.
pub fn is_nullable(&self) -> bool {
!self.schemas.is_empty() && self.schemas[0] == Schema::Null
}
/// Optionally returns a reference to the schema matched by this value, as well as its position
/// within this enum.
pub fn find_schema(&self, value: &crate::types::Value) -> Option<(usize, &Schema)> {
let kind = SchemaKind::from(value);
self.variant_index
.get(&kind)
.cloned()
.map(|i| (i, &self.schemas[i]))
}
}
// No need to compare variant_index, it is derivative of schemas.
impl PartialEq for UnionSchema {
fn eq(&self, other: &UnionSchema) -> bool {
self.schemas.eq(&other.schemas)
}
}
impl Schema {
/// Create a `Schema` from a string representing a JSON Avro schema.
pub fn parse_str(input: &str) -> Result<Self, Error> {
let value = serde_json::from_str(input)?;
Self::parse(&value)
}
/// Create a `Schema` from a `serde_json::Value` representing a JSON Avro
/// schema.
pub fn parse(value: &Value) -> Result<Self, Error> {
match *value {
Value::String(ref t) => Schema::parse_primitive(t.as_str()),
Value::Object(ref data) => Schema::parse_complex(data),
Value::Array(ref data) => Schema::parse_union(data),
_ => Err(ParseSchemaError::new("Must be a JSON string, object or array").into()),
}
}
/// Converts `self` into its [Parsing Canonical Form].
///
/// [Parsing Canonical Form]:
/// https://avro.apache.org/docs/1.8.2/spec.html#Parsing+Canonical+Form+for+Schemas
pub fn canonical_form(&self) -> String {
let json = serde_json::to_value(self).unwrap();
parsing_canonical_form(&json)
}
/// Generate [fingerprint] of Schema's [Parsing Canonical Form].
///
/// [Parsing Canonical Form]:
/// https://avro.apache.org/docs/1.8.2/spec.html#Parsing+Canonical+Form+for+Schemas
/// [fingerprint]:
/// https://avro.apache.org/docs/current/spec.html#schema_fingerprints
pub fn fingerprint<D: Digest>(&self) -> SchemaFingerprint {
let mut d = D::new();
d.input(self.canonical_form());
SchemaFingerprint {
bytes: d.result().to_vec(),
}
}
/// Parse a `serde_json::Value` representing a primitive Avro type into a
/// `Schema`.
fn parse_primitive(primitive: &str) -> Result<Self, Error> {
match primitive {
"null" => Ok(Schema::Null),
"boolean" => Ok(Schema::Boolean),
"int" => Ok(Schema::Int),
"long" => Ok(Schema::Long),
"double" => Ok(Schema::Double),
"float" => Ok(Schema::Float),
"bytes" => Ok(Schema::Bytes),
"string" => Ok(Schema::String),
other => Err(ParseSchemaError::new(format!("Unknown type: {}", other)).into()),
}
}
/// Parse a `serde_json::Value` representing a complex Avro type into a
/// `Schema`.
///
/// Avro supports "recursive" definition of types.
/// e.g: {"type": {"type": "string"}}
fn parse_complex(complex: &Map<String, Value>) -> Result<Self, Error> {
match complex.get("type") {
Some(&Value::String(ref t)) => match t.as_str() {
"record" => Schema::parse_record(complex),
"enum" => Schema::parse_enum(complex),
"array" => Schema::parse_array(complex),
"map" => Schema::parse_map(complex),
"fixed" => Schema::parse_fixed(complex),
other => Schema::parse_primitive(other),
},
Some(&Value::Object(ref data)) => match data.get("type") {
Some(ref value) => Schema::parse(value),
None => Err(
ParseSchemaError::new(format!("Unknown complex type: {:?}", complex)).into(),
),
},
_ => Err(ParseSchemaError::new("No `type` in complex type").into()),
}
}
/// Parse a `serde_json::Value` representing a Avro record type into a
/// `Schema`.
fn parse_record(complex: &Map<String, Value>) -> Result<Self, Error> {
let name = Name::parse(complex)?;
let mut lookup = HashMap::new();
let fields: Vec<RecordField> = complex
.get("fields")
.and_then(|fields| fields.as_array())
.ok_or_else(|| ParseSchemaError::new("No `fields` in record").into())
.and_then(|fields| {
fields
.iter()
.filter_map(|field| field.as_object())
.enumerate()
.map(|(position, field)| RecordField::parse(field, position))
.collect::<Result<_, _>>()
})?;
for field in &fields {
lookup.insert(field.name.clone(), field.position);
}
Ok(Schema::Record {
name,
doc: complex.doc(),
fields,
lookup,
})
}
/// Parse a `serde_json::Value` representing a Avro enum type into a
/// `Schema`.
fn parse_enum(complex: &Map<String, Value>) -> Result<Self, Error> {
let name = Name::parse(complex)?;
let symbols = complex
.get("symbols")
.and_then(|v| v.as_array())
.ok_or_else(|| ParseSchemaError::new("No `symbols` field in enum"))
.and_then(|symbols| {
symbols
.iter()
.map(|symbol| symbol.as_str().map(|s| s.to_string()))
.collect::<Option<_>>()
.ok_or_else(|| ParseSchemaError::new("Unable to parse `symbols` in enum"))
})?;
Ok(Schema::Enum {
name,
doc: complex.doc(),
symbols,
})
}
/// Parse a `serde_json::Value` representing a Avro array type into a
/// `Schema`.
fn parse_array(complex: &Map<String, Value>) -> Result<Self, Error> {
complex
.get("items")
.ok_or_else(|| ParseSchemaError::new("No `items` in array").into())
.and_then(|items| Schema::parse(items))
.map(|schema| Schema::Array(Box::new(schema)))
}
/// Parse a `serde_json::Value` representing a Avro map type into a
/// `Schema`.
fn parse_map(complex: &Map<String, Value>) -> Result<Self, Error> {
complex
.get("values")
.ok_or_else(|| ParseSchemaError::new("No `values` in map").into())
.and_then(|items| Schema::parse(items))
.map(|schema| Schema::Map(Box::new(schema)))
}
/// Parse a `serde_json::Value` representing a Avro union type into a
/// `Schema`.
fn parse_union(items: &[Value]) -> Result<Self, Error> {
items
.iter()
.map(Schema::parse)
.collect::<Result<Vec<_>, _>>()
.and_then(|schemas| Ok(Schema::Union(UnionSchema::new(schemas)?)))
}
/// Parse a `serde_json::Value` representing a Avro fixed type into a
/// `Schema`.
fn parse_fixed(complex: &Map<String, Value>) -> Result<Self, Error> {
let name = Name::parse(complex)?;
let size = complex
.get("size")
.and_then(|v| v.as_i64())
.ok_or_else(|| ParseSchemaError::new("No `size` in fixed"))?;
Ok(Schema::Fixed {
name,
size: size as usize,
})
}
}
impl Serialize for Schema {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
match *self {
Schema::Null => serializer.serialize_str("null"),
Schema::Boolean => serializer.serialize_str("boolean"),
Schema::Int => serializer.serialize_str("int"),
Schema::Long => serializer.serialize_str("long"),
Schema::Float => serializer.serialize_str("float"),
Schema::Double => serializer.serialize_str("double"),
Schema::Bytes => serializer.serialize_str("bytes"),
Schema::String => serializer.serialize_str("string"),
Schema::Array(ref inner) => {
let mut map = serializer.serialize_map(Some(2))?;
map.serialize_entry("type", "array")?;
map.serialize_entry("items", &*inner.clone())?;
map.end()
},
Schema::Map(ref inner) => {
let mut map = serializer.serialize_map(Some(2))?;
map.serialize_entry("type", "map")?;
map.serialize_entry("values", &*inner.clone())?;
map.end()
},
Schema::Union(ref inner) => {
let variants = inner.variants();
let mut seq = serializer.serialize_seq(Some(variants.len()))?;
for v in variants {
seq.serialize_element(v)?;
}
seq.end()
},
Schema::Record {
ref name,
ref doc,
ref fields,
..
} => {
let mut map = serializer.serialize_map(None)?;
map.serialize_entry("type", "record")?;
if let Some(ref n) = name.namespace {
map.serialize_entry("namespace", n)?;
}
map.serialize_entry("name", &name.name)?;
if let Some(ref docstr) = doc {
map.serialize_entry("doc", docstr)?;
}
if let Some(ref aliases) = name.aliases {
map.serialize_entry("aliases", aliases)?;
}
map.serialize_entry("fields", fields)?;
map.end()
},
Schema::Enum {
ref name,
ref symbols,
..
} => {
let mut map = serializer.serialize_map(None)?;
map.serialize_entry("type", "enum")?;
map.serialize_entry("name", &name.name)?;
map.serialize_entry("symbols", symbols)?;
map.end()
},
Schema::Fixed { ref name, ref size } => {
let mut map = serializer.serialize_map(None)?;
map.serialize_entry("type", "fixed")?;
map.serialize_entry("name", &name.name)?;
map.serialize_entry("size", size)?;
map.end()
},
}
}
}
impl Serialize for RecordField {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
let mut map = serializer.serialize_map(None)?;
map.serialize_entry("name", &self.name)?;
map.serialize_entry("type", &self.schema)?;
if let Some(ref default) = self.default {
map.serialize_entry("default", default)?;
}
map.end()
}
}
/// Parses a **valid** avro schema into the Parsing Canonical Form.
/// https://avro.apache.org/docs/1.8.2/spec.html#Parsing+Canonical+Form+for+Schemas
fn parsing_canonical_form(schema: &serde_json::Value) -> String {
match schema {
serde_json::Value::Object(map) => pcf_map(map),
serde_json::Value::String(s) => pcf_string(s),
serde_json::Value::Array(v) => pcf_array(v),
_ => unreachable!(),
}
}
fn pcf_map(schema: &Map<String, serde_json::Value>) -> String {
// Look for the namespace variant up front.
let ns = schema.get("namespace").and_then(|v| v.as_str());
let mut fields = Vec::new();
for (k, v) in schema {
// Reduce primitive types to their simple form. ([PRIMITIVE] rule)
if schema.len() == 1 && k == "type" {
// Invariant: function is only callable from a valid schema, so this is acceptable.
if let serde_json::Value::String(s) = v {
return pcf_string(s)
}
}
// Strip out unused fields ([STRIP] rule)
if field_ordering_position(k).is_none() {
continue
}
// Fully qualify the name, if it isn't already ([FULLNAMES] rule).
if k == "name" {
// Invariant: Only valid schemas. Must be a string.
let name = v.as_str().unwrap();
let n = match ns {
Some(namespace) if !name.contains('.') => {
Cow::Owned(format!("{}.{}", namespace, name))
},
_ => Cow::Borrowed(name),
};
fields.push((k, format!("{}:{}", pcf_string(k), pcf_string(&*n))));
continue
}
// Strip off quotes surrounding "size" type, if they exist ([INTEGERS] rule).
if k == "size" {
let i = match v.as_str() {
Some(s) => s.parse::<i64>().expect("Only valid schemas are accepted!"),
None => v.as_i64().unwrap(),
};
fields.push((k, format!("{}:{}", pcf_string(k), i)));
continue
}
// For anything else, recursively process the result.
fields.push((
k,
format!("{}:{}", pcf_string(k), parsing_canonical_form(v)),
));
}
// Sort the fields by their canonical ordering ([ORDER] rule).
fields.sort_unstable_by_key(|(k, _)| field_ordering_position(k).unwrap());
let inter = fields
.into_iter()
.map(|(_, v)| v)
.collect::<Vec<_>>()
.join(",");
format!("{{{}}}", inter)
}
fn pcf_array(arr: &[serde_json::Value]) -> String {
let inter = arr
.iter()
.map(parsing_canonical_form)
.collect::<Vec<String>>()
.join(",");
format!("[{}]", inter)
}
fn pcf_string(s: &str) -> String {
format!("\"{}\"", s)
}
// Used to define the ordering and inclusion of fields.
fn field_ordering_position(field: &str) -> Option<usize> {
let v = match field {
"name" => 1,
"type" => 2,
"fields" => 3,
"symbols" => 4,
"items" => 5,
"values" => 6,
"size" => 7,
_ => return None,
};
Some(v)
}
#[cfg(test)]
mod tests {
extern crate md5;
extern crate sha2;
use super::*;
#[test]
fn test_invalid_schema() {
assert!(Schema::parse_str("invalid").is_err());
}
#[test]
fn test_primitive_schema() {
assert_eq!(Schema::Null, Schema::parse_str("\"null\"").unwrap());
assert_eq!(Schema::Int, Schema::parse_str("\"int\"").unwrap());
assert_eq!(Schema::Double, Schema::parse_str("\"double\"").unwrap());
}
#[test]
fn test_array_schema() {
let schema = Schema::parse_str(r#"{"type": "array", "items": "string"}"#).unwrap();
assert_eq!(Schema::Array(Box::new(Schema::String)), schema);
}
#[test]
fn test_map_schema() {
let schema = Schema::parse_str(r#"{"type": "map", "values": "double"}"#).unwrap();
assert_eq!(Schema::Map(Box::new(Schema::Double)), schema);
}
#[test]
fn test_union_schema() {
let schema = Schema::parse_str(r#"["null", "int"]"#).unwrap();
assert_eq!(
Schema::Union(UnionSchema::new(vec![Schema::Null, Schema::Int]).unwrap()),
schema
);
}
#[test]
fn test_union_unsupported_schema() {
let schema = Schema::parse_str(r#"["null", ["null", "int"], "string"]"#);
assert!(schema.is_err());
}
#[test]
fn test_multi_union_schema() {
let schema = Schema::parse_str(r#"["null", "int", "float", "string", "bytes"]"#);
assert!(schema.is_ok());
let schema = schema.unwrap();
assert_eq!(SchemaKind::from(&schema), SchemaKind::Union);
let union_schema = match schema {
Schema::Union(u) => u,
_ => unreachable!(),
};
assert_eq!(union_schema.variants().len(), 5);
let mut variants = union_schema.variants().iter();
assert_eq!(SchemaKind::from(variants.next().unwrap()), SchemaKind::Null);
assert_eq!(SchemaKind::from(variants.next().unwrap()), SchemaKind::Int);
assert_eq!(
SchemaKind::from(variants.next().unwrap()),
SchemaKind::Float
);
assert_eq!(
SchemaKind::from(variants.next().unwrap()),
SchemaKind::String
);
assert_eq!(
SchemaKind::from(variants.next().unwrap()),
SchemaKind::Bytes
);
assert_eq!(variants.next(), None);
}
#[test]
fn test_record_schema() {
let schema = Schema::parse_str(
r#"
{
"type": "record",
"name": "test",
"fields": [
{"name": "a", "type": "long", "default": 42},
{"name": "b", "type": "string"}
]
}
"#,
).unwrap();
let mut lookup = HashMap::new();
lookup.insert("a".to_owned(), 0);
lookup.insert("b".to_owned(), 1);
let expected = Schema::Record {
name: Name::new("test"),
doc: None,
fields: vec![
RecordField {
name: "a".to_string(),
doc: None,
default: Some(Value::Number(42i64.into())),
schema: Schema::Long,
order: RecordFieldOrder::Ascending,
position: 0,
},
RecordField {
name: "b".to_string(),
doc: None,
default: None,
schema: Schema::String,
order: RecordFieldOrder::Ascending,
position: 1,
},
],
lookup,
};
assert_eq!(expected, schema);
}
#[test]
fn test_enum_schema() {
let schema = Schema::parse_str(
r#"{"type": "enum", "name": "Suit", "symbols": ["diamonds", "spades", "clubs", "hearts"]}"#,
).unwrap();
let expected = Schema::Enum {
name: Name::new("Suit"),
doc: None,
symbols: vec![
"diamonds".to_owned(),
"spades".to_owned(),
"clubs".to_owned(),
"hearts".to_owned(),
],
};
assert_eq!(expected, schema);
}
#[test]
fn test_fixed_schema() {
let schema = Schema::parse_str(r#"{"type": "fixed", "name": "test", "size": 16}"#).unwrap();
let expected = Schema::Fixed {
name: Name::new("test"),
size: 16usize,
};
assert_eq!(expected, schema);
}
#[test]
fn test_no_documentation() {
let schema =
Schema::parse_str(r#"{"type": "enum", "name": "Coin", "symbols": ["heads", "tails"]}"#)
.unwrap();
let doc = match schema {
Schema::Enum { doc, .. } => doc,
_ => return assert!(false),
};
assert!(doc.is_none());
}
#[test]
fn test_documentation() {
let schema = Schema::parse_str(
r#"{"type": "enum", "name": "Coin", "doc": "Some documentation", "symbols": ["heads", "tails"]}"#
).unwrap();
let doc = match schema {
Schema::Enum { doc, .. } => doc,
_ => None,
};
assert_eq!("Some documentation".to_owned(), doc.unwrap());
}
// Tests to ensure Schema is Send + Sync. These tests don't need to _do_ anything, if they can
// compile, they pass.
#[test]
fn test_schema_is_send() {
fn send<S: Send>(_s: S) {}
let schema = Schema::Null;
send(schema);
}
#[test]
fn test_schema_is_sync() {
fn sync<S: Sync>(_s: S) {}
let schema = Schema::Null;
sync(&schema);
sync(schema);
}
#[test]
fn test_schema_fingerprint() {
use self::md5::Md5;
use self::sha2::Sha256;
let raw_schema = r#"
{
"type": "record",
"name": "test",
"fields": [
{"name": "a", "type": "long", "default": 42},
{"name": "b", "type": "string"}
]
}
"#;
let schema = Schema::parse_str(raw_schema).unwrap();
assert_eq!(
"c4d97949770866dec733ae7afa3046757e901d0cfea32eb92a8faeadcc4de153",
format!("{}", schema.fingerprint::<Sha256>())
);
assert_eq!(
"7bce8188f28e66480a45ffbdc3615b7d",
format!("{}", schema.fingerprint::<Md5>())
);
}
}