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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import * as util from "./util.ts";
import { core } from "./core.ts";
import { TextDecoder } from "./text_encoding.ts";
import { ErrorKind, errors, getErrorClass } from "./errors.ts";
const promiseTableMin = new Map<number, util.Resolvable<RecordMinimal>>();
// Note it's important that promiseId starts at 1 instead of 0, because sync
// messages are indicated with promiseId 0. If we ever add wrap around logic for
// overflows, this should be taken into account.
let _nextPromiseId = 1;
const decoder = new TextDecoder();
function nextPromiseId(): number {
return _nextPromiseId++;
}
export interface RecordMinimal {
promiseId: number;
arg: number;
result: number;
err?: {
kind: ErrorKind;
message: string;
};
}
export function recordFromBufMinimal(ui8: Uint8Array): RecordMinimal {
const header = ui8.slice(0, 12);
const buf32 = new Int32Array(
header.buffer,
header.byteOffset,
header.byteLength / 4
);
const promiseId = buf32[0];
const arg = buf32[1];
const result = buf32[2];
let err;
if (arg < 0) {
const kind = result as ErrorKind;
const message = decoder.decode(ui8.slice(12));
err = { kind, message };
} else if (ui8.length != 12) {
throw new errors.InvalidData("BadMessage");
}
return {
promiseId,
arg,
result,
err
};
}
function unwrapResponse(res: RecordMinimal): number {
if (res.err != null) {
throw new (getErrorClass(res.err.kind))(res.err.message);
}
return res.result;
}
const scratch32 = new Int32Array(3);
const scratchBytes = new Uint8Array(
scratch32.buffer,
scratch32.byteOffset,
scratch32.byteLength
);
util.assert(scratchBytes.byteLength === scratch32.length * 4);
export function asyncMsgFromRust(ui8: Uint8Array): void {
const record = recordFromBufMinimal(ui8);
const { promiseId } = record;
const promise = promiseTableMin.get(promiseId);
promiseTableMin.delete(promiseId);
util.assert(promise);
promise.resolve(record);
}
export async function sendAsyncMinimal(
opId: number,
arg: number,
zeroCopy: Uint8Array
): Promise<number> {
const promiseId = nextPromiseId(); // AKA cmdId
scratch32[0] = promiseId;
scratch32[1] = arg;
scratch32[2] = 0; // result
const promise = util.createResolvable<RecordMinimal>();
const buf = core.dispatch(opId, scratchBytes, zeroCopy);
if (buf) {
const record = recordFromBufMinimal(buf);
// Sync result.
promise.resolve(record);
} else {
// Async result.
promiseTableMin.set(promiseId, promise);
}
const res = await promise;
return unwrapResponse(res);
}
export function sendSyncMinimal(
opId: number,
arg: number,
zeroCopy: Uint8Array
): number {
scratch32[0] = 0; // promiseId 0 indicates sync
scratch32[1] = arg;
const res = core.dispatch(opId, scratchBytes, zeroCopy)!;
const resRecord = recordFromBufMinimal(res);
return unwrapResponse(resRecord);
}
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