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| 1 | +import { CodecAndValueVisitors, containsBytes, ReadonlyUint8Array } from '@codama/dynamic-codecs'; |
| 2 | +import { |
| 3 | + CODAMA_ERROR__DISCRIMINATOR_FIELD_HAS_NO_DEFAULT_VALUE, |
| 4 | + CODAMA_ERROR__DISCRIMINATOR_FIELD_NOT_FOUND, |
| 5 | + CodamaError, |
| 6 | +} from '@codama/errors'; |
| 7 | +import { |
| 8 | + assertIsNode, |
| 9 | + ConstantDiscriminatorNode, |
| 10 | + constantDiscriminatorNode, |
| 11 | + constantValueNode, |
| 12 | + DiscriminatorNode, |
| 13 | + FieldDiscriminatorNode, |
| 14 | + isNode, |
| 15 | + SizeDiscriminatorNode, |
| 16 | + StructTypeNode, |
| 17 | +} from '@codama/nodes'; |
| 18 | +import { visit } from '@codama/visitors-core'; |
| 19 | + |
| 20 | +export function matchDiscriminators( |
| 21 | + bytes: ReadonlyUint8Array, |
| 22 | + discriminators: DiscriminatorNode[], |
| 23 | + struct: StructTypeNode, |
| 24 | + visitors: CodecAndValueVisitors, |
| 25 | +): boolean { |
| 26 | + return ( |
| 27 | + discriminators.length > 0 && |
| 28 | + discriminators.every(discriminator => matchDiscriminator(bytes, discriminator, struct, visitors)) |
| 29 | + ); |
| 30 | +} |
| 31 | + |
| 32 | +function matchDiscriminator( |
| 33 | + bytes: ReadonlyUint8Array, |
| 34 | + discriminator: DiscriminatorNode, |
| 35 | + struct: StructTypeNode, |
| 36 | + visitors: CodecAndValueVisitors, |
| 37 | +): boolean { |
| 38 | + if (isNode(discriminator, 'constantDiscriminatorNode')) { |
| 39 | + return matchConstantDiscriminator(bytes, discriminator, visitors); |
| 40 | + } |
| 41 | + if (isNode(discriminator, 'fieldDiscriminatorNode')) { |
| 42 | + return matchFieldDiscriminator(bytes, discriminator, struct, visitors); |
| 43 | + } |
| 44 | + assertIsNode(discriminator, 'sizeDiscriminatorNode'); |
| 45 | + return matchSizeDiscriminator(bytes, discriminator); |
| 46 | +} |
| 47 | + |
| 48 | +function matchConstantDiscriminator( |
| 49 | + bytes: ReadonlyUint8Array, |
| 50 | + discriminator: ConstantDiscriminatorNode, |
| 51 | + { codecVisitor, valueVisitor }: CodecAndValueVisitors, |
| 52 | +): boolean { |
| 53 | + const codec = visit(discriminator.constant.type, codecVisitor); |
| 54 | + const value = visit(discriminator.constant.value, valueVisitor); |
| 55 | + const bytesToMatch = codec.encode(value); |
| 56 | + return containsBytes(bytes, bytesToMatch, discriminator.offset); |
| 57 | +} |
| 58 | + |
| 59 | +function matchFieldDiscriminator( |
| 60 | + bytes: ReadonlyUint8Array, |
| 61 | + discriminator: FieldDiscriminatorNode, |
| 62 | + struct: StructTypeNode, |
| 63 | + visitors: CodecAndValueVisitors, |
| 64 | +): boolean { |
| 65 | + const field = struct.fields.find(field => field.name === discriminator.name); |
| 66 | + if (!field) { |
| 67 | + throw new CodamaError(CODAMA_ERROR__DISCRIMINATOR_FIELD_NOT_FOUND, { |
| 68 | + field: discriminator.name, |
| 69 | + }); |
| 70 | + } |
| 71 | + if (!field.defaultValue) { |
| 72 | + throw new CodamaError(CODAMA_ERROR__DISCRIMINATOR_FIELD_HAS_NO_DEFAULT_VALUE, { |
| 73 | + field: discriminator.name, |
| 74 | + }); |
| 75 | + } |
| 76 | + const constantNode = constantValueNode(field.type, field.defaultValue); |
| 77 | + const constantDiscriminator = constantDiscriminatorNode(constantNode, discriminator.offset); |
| 78 | + return matchConstantDiscriminator(bytes, constantDiscriminator, visitors); |
| 79 | +} |
| 80 | + |
| 81 | +function matchSizeDiscriminator(bytes: ReadonlyUint8Array, discriminator: SizeDiscriminatorNode): boolean { |
| 82 | + return bytes.length === discriminator.size; |
| 83 | +} |
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