CSHARP-5779: Support Dictionary Keys and Values properties #1807
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rstam
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| return new AstComputedDocumentExpression(fields); | ||
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| public static AstExpression ComputedDocument(IEnumerable<(string Name, AstExpression Value)> fields) |
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A more convenient overload of ComputedDocument.
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| internal class DictionaryKeyCollectionSerializer<TKey, TValue> : EnumerableSerializerBase<Dictionary<TKey, TValue>.KeyCollection> |
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We need a serializer for Dictionary<TKey, TValue>.KeyCollection to be able to work with this type in LINQ queries or to deserialize them client-side.
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| internal class DictionaryValueCollectionSerializer<TKey, TValue> : SerializerBase<Dictionary<TKey, TValue>.ValueCollection>, IBsonArraySerializer |
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We need a serializer for Dictionary<TKey, TValue>.ValueCollection to be able to work with this type in LINQ queries or to deserialize them client-side.
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| internal class DictionarySerializer<TKey, TValue> : DictionarySerializerBase<Dictionary<TKey, TValue>, TKey, TValue> |
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This is just a more convenient way to create a serializer for Dictionary<TKey, TValue>.
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| internal class ICollectionSerializer<TItem> : EnumerableSerializerBase<ICollection<TItem>> |
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This is just a more convenient way to create a serializer for ICollection<TItem>.
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| internal class KeyValuePairWrappedValueSerializer<TKey, TValue> : SerializerBase<TValue>, IWrappedValueSerializer |
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This is a special serializer that deserializes a KeyValuePair but then extracts only the Value portion of it as the result.
It also represents values that are still coupled with the corresponding key as needed to work with a Dictionary<TKey, TValue>.ValueCollection.
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| public static TranslatedExpression Translate(TranslationContext context, Expression expression) | ||
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Whenever we want to use a value we go ahead and unwrap it if it is wrapped.
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| var ast = AstExpression.ObjectToArray(aggregateExpression.Ast); | ||
| var ienumerableSerializer = ArraySerializerHelper.CreateSerializer(keyValuePairSerializer); | ||
| var arrayOfDocumentsDictionarySerializer = DictionarySerializer.Create(DictionaryRepresentation.ArrayOfDocuments, keySerializer, valueSerializer); |
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We were creating the "wrong" serializer before.
| case "Values": | ||
| if (declaringTypeDefinition == typeof(Dictionary<,>)) | ||
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| var kvpPairsAst = dictionaryRepresentation switch |
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The tricky part about supporting Values is that we have to keep the keys that go with them, at least until some later time where the keys might no longer be needed.
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| else if (declaringTypeDefinition == typeof(IDictionary<,>)) | ||
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| var valuesAst = dictionaryRepresentation switch |
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Supporting Values for IDictionary<TKey, TValue> is MUCH more straightforward because the type is ICollection<TValue>.
| case "Keys": | ||
| var keysAst = dictionaryRepresentation switch | ||
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| DictionaryRepresentation.ArrayOfDocuments => AstExpression.Map(containerAst, kvpVar, AstExpression.GetField(kvpVar, "k")), |
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By the time we get here we will never encounter DictionaryRepresentation.Document, because the call to TranslateEnumerable on line 204 above will have already used $objectToArray to transform the representation from Document to ArrayOfDocuments.
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