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54 lines
1.8 KiB
TypeScript
54 lines
1.8 KiB
TypeScript
// Copyright 2018 the Deno authors. All rights reserved. MIT license.
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import { flatbuffers } from "flatbuffers";
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import * as util from "./util";
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// Re-export some types.
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export type Offset = flatbuffers.Offset;
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export class ByteBuffer extends flatbuffers.ByteBuffer {}
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export interface Builder extends flatbuffers.Builder {
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inUse: boolean;
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}
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const globalBuilder = new flatbuffers.Builder() as Builder;
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globalBuilder.inUse = false;
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// This is a wrapper around the real Builder .
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// The purpose is to reuse a single ArrayBuffer for every message.
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// We can do this because the "control" messages sent to the privileged
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// side are guarenteed to be used during the call to libdeno.send().
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export function createBuilder(): Builder {
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// tslint:disable-next-line:no-any
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const gb = globalBuilder as any;
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util.assert(!gb.inUse);
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let bb = globalBuilder.dataBuffer();
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// Only create a new backing ArrayBuffer if the previous one had grown very
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// large in capacity. This should only happen rarely.
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if (bb.capacity() > 1024) {
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util.log(`realloc flatbuffer ArrayBuffer because it was ${bb.capacity()}`);
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bb = ByteBuffer.allocate(1024);
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}
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gb.bb = bb;
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// Remaining space in the ByteBuffer.
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gb.space = globalBuilder.dataBuffer().capacity();
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// Minimum alignment encountered so far.
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gb.minalign = 1;
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// The vtable for the current table.
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gb.vtable = null;
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// The amount of fields we're actually using.
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gb.vtable_in_use = 0;
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// Whether we are currently serializing a table.
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gb.isNested = false;
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// Starting offset of the current struct/table.
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gb.object_start = 0;
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// List of offsets of all vtables.
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gb.vtables = [];
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// For the current vector being built.
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gb.vector_num_elems = 0;
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// False omits default values from the serialized data
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gb.force_defaults = false;
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gb.inUse = true;
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return gb as Builder;
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}
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