101 lines
2.0 KiB
JavaScript
101 lines
2.0 KiB
JavaScript
import type NodePath from "../path";
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/**
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* This class is responsible for a binding inside of a scope.
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*
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* It tracks the following:
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*
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* * Node path.
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* * Amount of times referenced by other nodes.
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* * Paths to nodes that reassign or modify this binding.
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* * The kind of binding. (Is it a parameter, declaration etc)
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*/
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export default class Binding {
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constructor({ existing, identifier, scope, path, kind }) {
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this.identifier = identifier;
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this.scope = scope;
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this.path = path;
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this.kind = kind;
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this.constantViolations = [];
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this.constant = true;
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this.referencePaths = [];
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this.referenced = false;
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this.references = 0;
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this.clearValue();
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if (existing) {
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this.constantViolations = [].concat(
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existing.path,
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existing.constantViolations,
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this.constantViolations,
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);
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}
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}
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constantViolations: Array<NodePath>;
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constant: boolean;
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referencePaths: Array<NodePath>;
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referenced: boolean;
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references: number;
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hasDeoptedValue: boolean;
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hasValue: boolean;
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value: any;
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deoptValue() {
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this.clearValue();
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this.hasDeoptedValue = true;
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}
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setValue(value: any) {
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if (this.hasDeoptedValue) return;
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this.hasValue = true;
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this.value = value;
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}
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clearValue() {
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this.hasDeoptedValue = false;
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this.hasValue = false;
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this.value = null;
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}
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/**
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* Register a constant violation with the provided `path`.
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*/
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reassign(path: Object) {
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this.constant = false;
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if (this.constantViolations.indexOf(path) !== -1) {
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return;
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}
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this.constantViolations.push(path);
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}
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/**
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* Increment the amount of references to this binding.
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*/
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reference(path: NodePath) {
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if (this.referencePaths.indexOf(path) !== -1) {
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return;
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}
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this.referenced = true;
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this.references++;
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this.referencePaths.push(path);
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}
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/**
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* Decrement the amount of references to this binding.
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*/
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dereference() {
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this.references--;
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this.referenced = !!this.references;
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}
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}
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