47 lines
1.5 KiB
TypeScript
47 lines
1.5 KiB
TypeScript
import { Buffer } from "buffer";
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import { Layout } from "buffer-layout";
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import { sha256 } from "js-sha256";
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import { Idl } from "../../idl.js";
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import { IdlCoder } from "./idl.js";
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import * as features from "../../utils/features";
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import { BorshAccountHeader } from "./accounts";
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export class BorshStateCoder {
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private layout: Layout;
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readonly header: BorshAccountHeader;
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public constructor(idl: Idl) {
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if (idl.state === undefined) {
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throw new Error("Idl state not defined.");
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}
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this.layout = IdlCoder.typeDefLayout(idl.state.struct, idl.types);
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this.header = new BorshAccountHeader(idl);
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}
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public async encode<T = any>(name: string, account: T): Promise<Buffer> {
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const buffer = Buffer.alloc(1000); // TODO: use a tighter buffer.
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const len = this.layout.encode(account, buffer);
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let ns = features.isSet("anchor-deprecated-state") ? "account" : "state";
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const header = this.header.encode(name, ns);
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const accData = buffer.slice(0, len);
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return Buffer.concat([header, accData]);
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}
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public decode<T = any>(data: Buffer): T {
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// Chop off header.
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data = data.slice(BorshAccountHeader.size());
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return this.layout.decode(data);
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}
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// Calculates unique 8 byte discriminator prepended to all anchor state accounts.
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async discriminator(name: string): Promise<Buffer> {
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let ns = features.isSet("anchor-deprecated-state") ? "account" : "state";
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return Buffer.from(sha256.digest(`${ns}:${name}`)).slice(
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0,
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this.header.discriminatorSize()
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);
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}
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}
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