zeroshade commented on a change in pull request #10106: URL: https://github.com/apache/arrow/pull/10106#discussion_r619890319
########## File path: go/arrow/array/map.go ########## @@ -0,0 +1,231 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package array // import "github.com/apache/arrow/go/arrow/array" + +import ( + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" +) + +// Map represents an immutable sequence of Key/Value structs. It is a +// logical type that is implemented as a List<Struct: key, value>. +type Map struct { + *List + keys, items Interface +} + +// NewMapData returns a new Map array value, from data +func NewMapData(data *Data) *Map { + a := &Map{List: &List{}} + a.refCount = 1 + a.setData(data) + return a +} + +// KeysSorted checks the datatype that was used to construct this array and +// returns the KeysSorted boolean value used to denote if the key array is +// sorted for each list element. +func (a *Map) KeysSorted() bool { return a.DataType().(*arrow.MapType).KeysSorted } + +func (a *Map) validateData(data *Data) { + if len(data.childData) != 1 || data.childData[0] == nil { + panic("arrow/array: expected one child array for map array") + } + + if data.childData[0].dtype.ID() != arrow.STRUCT { + panic("arrow/array: map array child should be struct type") + } + + if data.childData[0].NullN() != 0 { + panic("arrow/array: map array child array should have no nulls") + } + + if len(data.childData[0].childData) != 2 { + panic("arrow/array: map array child array should have two fields") + } + + if data.childData[0].childData[0].NullN() != 0 { + panic("arrow/array: map array keys array should have no nulls") + } +} + +func (a *Map) setData(data *Data) { + a.validateData(data) + + a.List.setData(data) + a.keys = MakeFromData(data.childData[0].childData[0]) + a.items = MakeFromData(data.childData[0].childData[1]) +} + +// Keys returns the full Array of Key values, equivalent to grabbing +// the key field of the child struct. +func (a *Map) Keys() Interface { return a.keys } + +// Items returns the full Array of Item values, equivalent to grabbing +// the Value field (the second field) of the child struct. +func (a *Map) Items() Interface { return a.items } + +func (a *Map) Retain() { + a.List.Retain() + a.keys.Retain() + a.items.Retain() +} + +func (a *Map) Release() { + a.List.Release() + a.keys.Release() + a.items.Release() +} + +func arrayEqualMap(left, right *Map) bool { + // since Map is implemented using a list, we can just use arrayEqualList + return arrayEqualList(left.List, right.List) +} + +type MapBuilder struct { + listBuilder *ListBuilder + + etype arrow.DataType + keytype, itemtype arrow.DataType + keyBuilder, itemBuilder Builder + keysSorted bool +} + +// NewMapBuilder returns a builder, using the provided memory allocator. Review comment: I used the example_test file to provide a simple usage example which would show up in the generated docs on pkg.go.dev, I figured that was more directly useful than putting one here, but i can also add one here too. ########## File path: go/arrow/datatype_nested.go ########## @@ -148,6 +148,40 @@ func (t *StructType) FieldByName(name string) (Field, bool) { return t.fields[i], true } +type MapType struct { + value *ListType + KeysSorted bool +} + +func MapOf(key, item DataType) *MapType { + if key == nil || item == nil { + panic("arrow: nil key or item type for MapType") + } + + return &MapType{value: ListOf(StructOf(Field{Name: "key", Type: key}, Field{Name: "value", Type: item, Nullable: true}))} Review comment: the current implementation of `StructOf` does not provide a name for the resulting struct, it only creates a datatype, rather than a Field. The DataType can then be used to create a Field and thus Name the struct. The same is true for the current implementation of `ListOf` here. The result is a `DataType` not a field and thus doesn't have a name. ########## File path: go/arrow/datatype_nested.go ########## @@ -148,6 +148,40 @@ func (t *StructType) FieldByName(name string) (Field, bool) { return t.fields[i], true } +type MapType struct { + value *ListType + KeysSorted bool +} + +func MapOf(key, item DataType) *MapType { + if key == nil || item == nil { + panic("arrow: nil key or item type for MapType") + } + + return &MapType{value: ListOf(StructOf(Field{Name: "key", Type: key}, Field{Name: "value", Type: item, Nullable: true}))} Review comment: I'll double check but I don't believe I enforce these names having to be named this way during reading. That said, naming them this way is how the spec describes it should be done. ########## File path: go/arrow/example_test.go ########## @@ -593,3 +593,66 @@ func Example_table() { // rec[3]["f1-i32"]: [16 17 18 19 20] // rec[3]["f2-f64"]: [16 17 18 19 20] } + +// This example demonstrates how to create a Map Array. +// The resulting array should be: Review comment: By putting the comment at the end of the method here in that format this example actually gets run as a test when running tests and confirms that the output of running this method matches the output comment at the end of the method. moving the comment at the end of the method would disable that benefit. ########## File path: go/arrow/internal/arrjson/arrjson.go ########## @@ -52,15 +52,16 @@ type Field struct { } type dataType struct { - Name string `json:"name"` - Signed bool `json:"isSigned,omitempty"` - BitWidth int `json:"bitWidth,omitempty"` - Precision string `json:"precision,omitempty"` - ByteWidth int `json:"byteWidth,omitempty"` - ListSize int32 `json:"listSize,omitempty"` - Unit string `json:"unit,omitempty"` - TimeZone string `json:"timezone,omitempty"` - Scale int `json:"scale,omitempty"` // for Decimal128 + Name string `json:"name"` Review comment: `KeysSorted` was added to the struct which is why the whitespace got adjusted ########## File path: go/arrow/internal/arrjson/arrjson_test.go ########## @@ -3101,4 +3102,640 @@ func makeDurationsWantJSONs() string { func makeDecimal128sWantJSONs() string { return `` // FIXME(fredgan): implement full decimal128 JSON support -} \ No newline at end of file +} + +func makeMapsWantJSONs() string { + return `{ Review comment: because these tests are generated from the `arrdata` record batches that's why this ends up this large. The reason why those records are the size they are is to ensure that we're properly testing handling multiple chunks with a map and multiple records. ########## File path: go/arrow/datatype_nested.go ########## @@ -148,6 +148,40 @@ func (t *StructType) FieldByName(name string) (Field, bool) { return t.fields[i], true } +type MapType struct { + value *ListType + KeysSorted bool +} + +func MapOf(key, item DataType) *MapType { + if key == nil || item == nil { + panic("arrow: nil key or item type for MapType") + } + + return &MapType{value: ListOf(StructOf(Field{Name: "key", Type: key}, Field{Name: "value", Type: item, Nullable: true}))} Review comment: Ok, I confirmed that the names hardcoded here do not affect reading maps that name it differently. The assumption, as per the spec, is always that the first field is the keys and the second field is the values. ########## File path: go/arrow/array/array_test.go ########## @@ -85,10 +85,16 @@ func TestMakeFromData(t *testing.T) { }}, {name: "duration", d: &testDataType{arrow.DURATION}}, + {name: "map", d: &testDataType{arrow.MAP}, child: []*array.Data{ + array.NewData(&testDataType{arrow.STRUCT}, 0, make([]*memory.Buffer, 4), []*array.Data{ Review comment: added comments for literals ########## File path: go/arrow/array/map.go ########## @@ -0,0 +1,231 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package array // import "github.com/apache/arrow/go/arrow/array" + +import ( + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" +) + +// Map represents an immutable sequence of Key/Value structs. It is a +// logical type that is implemented as a List<Struct: key, value>. +type Map struct { + *List + keys, items Interface +} + +// NewMapData returns a new Map array value, from data +func NewMapData(data *Data) *Map { + a := &Map{List: &List{}} + a.refCount = 1 + a.setData(data) + return a +} + +// KeysSorted checks the datatype that was used to construct this array and +// returns the KeysSorted boolean value used to denote if the key array is +// sorted for each list element. Review comment: added comments expanding on the keysorted lack of semantics ########## File path: go/arrow/array/map.go ########## @@ -0,0 +1,231 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package array // import "github.com/apache/arrow/go/arrow/array" + +import ( + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" +) + +// Map represents an immutable sequence of Key/Value structs. It is a +// logical type that is implemented as a List<Struct: key, value>. +type Map struct { + *List + keys, items Interface +} + +// NewMapData returns a new Map array value, from data +func NewMapData(data *Data) *Map { + a := &Map{List: &List{}} + a.refCount = 1 + a.setData(data) + return a +} + +// KeysSorted checks the datatype that was used to construct this array and +// returns the KeysSorted boolean value used to denote if the key array is +// sorted for each list element. +func (a *Map) KeysSorted() bool { return a.DataType().(*arrow.MapType).KeysSorted } + +func (a *Map) validateData(data *Data) { + if len(data.childData) != 1 || data.childData[0] == nil { + panic("arrow/array: expected one child array for map array") + } + + if data.childData[0].dtype.ID() != arrow.STRUCT { + panic("arrow/array: map array child should be struct type") + } + + if data.childData[0].NullN() != 0 { + panic("arrow/array: map array child array should have no nulls") + } + + if len(data.childData[0].childData) != 2 { + panic("arrow/array: map array child array should have two fields") + } + + if data.childData[0].childData[0].NullN() != 0 { + panic("arrow/array: map array keys array should have no nulls") + } +} + +func (a *Map) setData(data *Data) { + a.validateData(data) + + a.List.setData(data) + a.keys = MakeFromData(data.childData[0].childData[0]) + a.items = MakeFromData(data.childData[0].childData[1]) +} + +// Keys returns the full Array of Key values, equivalent to grabbing +// the key field of the child struct. +func (a *Map) Keys() Interface { return a.keys } + +// Items returns the full Array of Item values, equivalent to grabbing +// the Value field (the second field) of the child struct. +func (a *Map) Items() Interface { return a.items } + +func (a *Map) Retain() { Review comment: added ########## File path: go/arrow/array/map.go ########## @@ -0,0 +1,231 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package array // import "github.com/apache/arrow/go/arrow/array" + +import ( + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" +) + +// Map represents an immutable sequence of Key/Value structs. It is a +// logical type that is implemented as a List<Struct: key, value>. +type Map struct { + *List + keys, items Interface +} + +// NewMapData returns a new Map array value, from data +func NewMapData(data *Data) *Map { + a := &Map{List: &List{}} + a.refCount = 1 + a.setData(data) + return a +} + +// KeysSorted checks the datatype that was used to construct this array and +// returns the KeysSorted boolean value used to denote if the key array is +// sorted for each list element. +func (a *Map) KeysSorted() bool { return a.DataType().(*arrow.MapType).KeysSorted } + +func (a *Map) validateData(data *Data) { + if len(data.childData) != 1 || data.childData[0] == nil { + panic("arrow/array: expected one child array for map array") + } + + if data.childData[0].dtype.ID() != arrow.STRUCT { + panic("arrow/array: map array child should be struct type") + } + + if data.childData[0].NullN() != 0 { + panic("arrow/array: map array child array should have no nulls") + } + + if len(data.childData[0].childData) != 2 { + panic("arrow/array: map array child array should have two fields") + } + + if data.childData[0].childData[0].NullN() != 0 { + panic("arrow/array: map array keys array should have no nulls") + } +} + +func (a *Map) setData(data *Data) { + a.validateData(data) + + a.List.setData(data) + a.keys = MakeFromData(data.childData[0].childData[0]) + a.items = MakeFromData(data.childData[0].childData[1]) +} + +// Keys returns the full Array of Key values, equivalent to grabbing +// the key field of the child struct. +func (a *Map) Keys() Interface { return a.keys } + +// Items returns the full Array of Item values, equivalent to grabbing +// the Value field (the second field) of the child struct. +func (a *Map) Items() Interface { return a.items } + +func (a *Map) Retain() { + a.List.Retain() + a.keys.Retain() + a.items.Retain() +} + +func (a *Map) Release() { + a.List.Release() + a.keys.Release() + a.items.Release() +} + +func arrayEqualMap(left, right *Map) bool { + // since Map is implemented using a list, we can just use arrayEqualList + return arrayEqualList(left.List, right.List) +} + +type MapBuilder struct { + listBuilder *ListBuilder + + etype arrow.DataType + keytype, itemtype arrow.DataType + keyBuilder, itemBuilder Builder + keysSorted bool +} + +// NewMapBuilder returns a builder, using the provided memory allocator. +// The created Map builder will create a map array whose keys will be a non-nullable +// array of type `keytype` and whose mapped items will be a nullable array of itemtype. +func NewMapBuilder(mem memory.Allocator, keytype, itemtype arrow.DataType, keysSorted bool) *MapBuilder { Review comment: done. ########## File path: go/arrow/array/map.go ########## @@ -0,0 +1,231 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package array // import "github.com/apache/arrow/go/arrow/array" + +import ( + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" +) + +// Map represents an immutable sequence of Key/Value structs. It is a +// logical type that is implemented as a List<Struct: key, value>. +type Map struct { + *List + keys, items Interface +} + +// NewMapData returns a new Map array value, from data +func NewMapData(data *Data) *Map { + a := &Map{List: &List{}} + a.refCount = 1 + a.setData(data) + return a +} + +// KeysSorted checks the datatype that was used to construct this array and +// returns the KeysSorted boolean value used to denote if the key array is +// sorted for each list element. +func (a *Map) KeysSorted() bool { return a.DataType().(*arrow.MapType).KeysSorted } + +func (a *Map) validateData(data *Data) { + if len(data.childData) != 1 || data.childData[0] == nil { + panic("arrow/array: expected one child array for map array") + } + + if data.childData[0].dtype.ID() != arrow.STRUCT { + panic("arrow/array: map array child should be struct type") + } + + if data.childData[0].NullN() != 0 { + panic("arrow/array: map array child array should have no nulls") + } + + if len(data.childData[0].childData) != 2 { + panic("arrow/array: map array child array should have two fields") + } + + if data.childData[0].childData[0].NullN() != 0 { + panic("arrow/array: map array keys array should have no nulls") + } +} + +func (a *Map) setData(data *Data) { + a.validateData(data) + + a.List.setData(data) + a.keys = MakeFromData(data.childData[0].childData[0]) + a.items = MakeFromData(data.childData[0].childData[1]) +} + +// Keys returns the full Array of Key values, equivalent to grabbing +// the key field of the child struct. +func (a *Map) Keys() Interface { return a.keys } + +// Items returns the full Array of Item values, equivalent to grabbing +// the Value field (the second field) of the child struct. +func (a *Map) Items() Interface { return a.items } + +func (a *Map) Retain() { + a.List.Retain() + a.keys.Retain() + a.items.Retain() +} + +func (a *Map) Release() { + a.List.Release() + a.keys.Release() + a.items.Release() +} + +func arrayEqualMap(left, right *Map) bool { + // since Map is implemented using a list, we can just use arrayEqualList + return arrayEqualList(left.List, right.List) +} + +type MapBuilder struct { + listBuilder *ListBuilder + + etype arrow.DataType + keytype, itemtype arrow.DataType + keyBuilder, itemBuilder Builder + keysSorted bool +} + +// NewMapBuilder returns a builder, using the provided memory allocator. +// The created Map builder will create a map array whose keys will be a non-nullable +// array of type `keytype` and whose mapped items will be a nullable array of itemtype. +func NewMapBuilder(mem memory.Allocator, keytype, itemtype arrow.DataType, keysSorted bool) *MapBuilder { + etype := arrow.MapOf(keytype, itemtype) + etype.KeysSorted = keysSorted + listBldr := NewListBuilder(mem, etype.ValueType()) + keyBldr := listBldr.ValueBuilder().(*StructBuilder).FieldBuilder(0) + keyBldr.Retain() + itemBldr := listBldr.ValueBuilder().(*StructBuilder).FieldBuilder(1) + itemBldr.Retain() + return &MapBuilder{ + listBuilder: listBldr, + keyBuilder: keyBldr, + itemBuilder: itemBldr, + etype: etype, + keytype: keytype, + itemtype: itemtype, + keysSorted: keysSorted, + } +} + +func (b *MapBuilder) Retain() { Review comment: added ########## File path: go/arrow/array/map.go ########## @@ -0,0 +1,231 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package array // import "github.com/apache/arrow/go/arrow/array" + +import ( + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" +) + +// Map represents an immutable sequence of Key/Value structs. It is a +// logical type that is implemented as a List<Struct: key, value>. +type Map struct { + *List + keys, items Interface +} + +// NewMapData returns a new Map array value, from data +func NewMapData(data *Data) *Map { + a := &Map{List: &List{}} + a.refCount = 1 + a.setData(data) + return a +} + +// KeysSorted checks the datatype that was used to construct this array and +// returns the KeysSorted boolean value used to denote if the key array is +// sorted for each list element. +func (a *Map) KeysSorted() bool { return a.DataType().(*arrow.MapType).KeysSorted } + +func (a *Map) validateData(data *Data) { + if len(data.childData) != 1 || data.childData[0] == nil { + panic("arrow/array: expected one child array for map array") + } + + if data.childData[0].dtype.ID() != arrow.STRUCT { + panic("arrow/array: map array child should be struct type") + } + + if data.childData[0].NullN() != 0 { + panic("arrow/array: map array child array should have no nulls") + } + + if len(data.childData[0].childData) != 2 { + panic("arrow/array: map array child array should have two fields") + } + + if data.childData[0].childData[0].NullN() != 0 { + panic("arrow/array: map array keys array should have no nulls") + } +} + +func (a *Map) setData(data *Data) { + a.validateData(data) + + a.List.setData(data) + a.keys = MakeFromData(data.childData[0].childData[0]) + a.items = MakeFromData(data.childData[0].childData[1]) +} + +// Keys returns the full Array of Key values, equivalent to grabbing +// the key field of the child struct. +func (a *Map) Keys() Interface { return a.keys } + +// Items returns the full Array of Item values, equivalent to grabbing +// the Value field (the second field) of the child struct. +func (a *Map) Items() Interface { return a.items } + +func (a *Map) Retain() { + a.List.Retain() + a.keys.Retain() + a.items.Retain() +} + +func (a *Map) Release() { + a.List.Release() + a.keys.Release() + a.items.Release() +} + +func arrayEqualMap(left, right *Map) bool { + // since Map is implemented using a list, we can just use arrayEqualList + return arrayEqualList(left.List, right.List) +} + +type MapBuilder struct { + listBuilder *ListBuilder + + etype arrow.DataType + keytype, itemtype arrow.DataType + keyBuilder, itemBuilder Builder + keysSorted bool +} + +// NewMapBuilder returns a builder, using the provided memory allocator. +// The created Map builder will create a map array whose keys will be a non-nullable +// array of type `keytype` and whose mapped items will be a nullable array of itemtype. +func NewMapBuilder(mem memory.Allocator, keytype, itemtype arrow.DataType, keysSorted bool) *MapBuilder { + etype := arrow.MapOf(keytype, itemtype) + etype.KeysSorted = keysSorted + listBldr := NewListBuilder(mem, etype.ValueType()) + keyBldr := listBldr.ValueBuilder().(*StructBuilder).FieldBuilder(0) + keyBldr.Retain() + itemBldr := listBldr.ValueBuilder().(*StructBuilder).FieldBuilder(1) + itemBldr.Retain() + return &MapBuilder{ + listBuilder: listBldr, + keyBuilder: keyBldr, + itemBuilder: itemBldr, + etype: etype, + keytype: keytype, + itemtype: itemtype, + keysSorted: keysSorted, + } +} + +func (b *MapBuilder) Retain() { + b.listBuilder.Retain() + b.keyBuilder.Retain() + b.itemBuilder.Retain() +} + +func (b *MapBuilder) Release() { + b.listBuilder.Release() + b.keyBuilder.Release() + b.itemBuilder.Release() +} + +// Len returns the current number of Maps that are in the builder +func (b *MapBuilder) Len() int { return b.listBuilder.Len() } + +func (b *MapBuilder) Cap() int { return b.listBuilder.Cap() } Review comment: added ########## File path: go/arrow/array/map.go ########## @@ -0,0 +1,231 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package array // import "github.com/apache/arrow/go/arrow/array" + +import ( + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" +) + +// Map represents an immutable sequence of Key/Value structs. It is a +// logical type that is implemented as a List<Struct: key, value>. +type Map struct { + *List + keys, items Interface +} + +// NewMapData returns a new Map array value, from data +func NewMapData(data *Data) *Map { + a := &Map{List: &List{}} + a.refCount = 1 + a.setData(data) + return a +} + +// KeysSorted checks the datatype that was used to construct this array and +// returns the KeysSorted boolean value used to denote if the key array is +// sorted for each list element. +func (a *Map) KeysSorted() bool { return a.DataType().(*arrow.MapType).KeysSorted } + +func (a *Map) validateData(data *Data) { + if len(data.childData) != 1 || data.childData[0] == nil { + panic("arrow/array: expected one child array for map array") + } + + if data.childData[0].dtype.ID() != arrow.STRUCT { + panic("arrow/array: map array child should be struct type") + } + + if data.childData[0].NullN() != 0 { + panic("arrow/array: map array child array should have no nulls") + } + + if len(data.childData[0].childData) != 2 { + panic("arrow/array: map array child array should have two fields") + } + + if data.childData[0].childData[0].NullN() != 0 { + panic("arrow/array: map array keys array should have no nulls") + } +} + +func (a *Map) setData(data *Data) { + a.validateData(data) + + a.List.setData(data) + a.keys = MakeFromData(data.childData[0].childData[0]) + a.items = MakeFromData(data.childData[0].childData[1]) +} + +// Keys returns the full Array of Key values, equivalent to grabbing +// the key field of the child struct. +func (a *Map) Keys() Interface { return a.keys } + +// Items returns the full Array of Item values, equivalent to grabbing +// the Value field (the second field) of the child struct. +func (a *Map) Items() Interface { return a.items } + +func (a *Map) Retain() { + a.List.Retain() + a.keys.Retain() + a.items.Retain() +} + +func (a *Map) Release() { + a.List.Release() + a.keys.Release() + a.items.Release() +} + +func arrayEqualMap(left, right *Map) bool { + // since Map is implemented using a list, we can just use arrayEqualList + return arrayEqualList(left.List, right.List) +} + +type MapBuilder struct { + listBuilder *ListBuilder + + etype arrow.DataType + keytype, itemtype arrow.DataType + keyBuilder, itemBuilder Builder + keysSorted bool +} + +// NewMapBuilder returns a builder, using the provided memory allocator. Review comment: added an example. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
