parse-email-address
Version:
Parse/validate email addresses with RFC-5321, and message header address lists with RFC-5322.
555 lines (552 loc) • 20.8 kB
JavaScript
/**
* This is modified from a copy of
* https://github.com/kach/nearley/blob/96f1da12acdb986e8279355d3d34cf5b139ab268/lib/nearley.js
* which has the following license:
*
* The MIT License (MIT)
*
* Copyright (c) 2014, 2015, 2016, 2017, 2018, 2019 Kartik Chandra, Tim Radvan
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* It has been modified to use proper ES6 classes and proper ESM exports.
*/
export class Rule {
static highestId = 0;
constructor(name, symbols, postprocess) {
this.id = ++Rule.highestId;
this.name = name;
this.symbols = symbols; // a list of literal | regex class | nonterminal
this.postprocess = postprocess;
return this;
}
toString(withCursorAt) {
const symbolSequence = typeof withCursorAt === 'undefined'
? this.symbols.map(getSymbolShortDisplay).join(' ')
: this.symbols.slice(0, withCursorAt).map(getSymbolShortDisplay).join(' ') +
' ● ' +
this.symbols.slice(withCursorAt).map(getSymbolShortDisplay).join(' ');
return this.name + ' → ' + symbolSequence;
}
}
// a State is a rule at a position from a given starting point in the input stream (reference)
class State {
constructor(rule, dot, reference, wantedBy) {
this.rule = rule;
this.dot = dot;
this.reference = reference;
this.data = [];
this.wantedBy = wantedBy;
this.isComplete = this.dot === rule.symbols.length;
}
toString() {
return '{' + this.rule.toString(this.dot) + '}, from: ' + (this.reference || 0);
}
nextState(child) {
const state = new State(this.rule, this.dot + 1, this.reference, this.wantedBy);
state.left = this;
state.right = child;
if (state.isComplete) {
state.data = state.build();
// Having right set here will prevent the right state and its children
// form being garbage collected
state.right = undefined;
}
return state;
}
build() {
const children = [];
let node = this;
do {
children.push(node.right.data);
node = node.left;
} while (node.left);
children.reverse();
return children;
}
finish() {
if (this.rule.postprocess) {
this.data = this.rule.postprocess(this.data, this.reference, Parser.fail);
}
}
}
class Column {
constructor(grammar, index) {
this.grammar = grammar;
this.index = index;
this.states = [];
this.wants = {}; // states indexed by the non-terminal they expect
this.scannable = []; // list of states that expect a token
this.completed = {}; // states that are nullable
}
process(nextColumn) {
const states = this.states;
const wants = this.wants;
const completed = this.completed;
for (const state of states) {
// nb. we push() during iteration
if (state.isComplete) {
state.finish();
if (state.data !== Parser.fail) {
// complete
const wantedBy = state.wantedBy;
for (var i = wantedBy.length; i--;) {
// this line is hot
const left = wantedBy[i];
this.complete(left, state);
}
// special-case nullables
if (state.reference === this.index) {
// make sure future predictors of this rule get completed.
var exp = state.rule.name;
(this.completed[exp] = this.completed[exp] || []).push(state);
}
}
}
else {
// queue scannable states
var exp = state.rule.symbols[state.dot];
if (typeof exp !== 'string') {
this.scannable.push(state);
continue;
}
// predict
if (wants[exp]) {
wants[exp].push(state);
if (completed.hasOwnProperty(exp)) {
const nulls = completed[exp];
for (var i = 0; i < nulls.length; i++) {
const right = nulls[i];
this.complete(state, right);
}
}
}
else {
wants[exp] = [state];
this.predict(exp);
}
}
}
}
predict(exp) {
const rules = this.grammar.byName[exp] || [];
for (const r of rules) {
const wantedBy = this.wants[exp];
const s = new State(r, 0, this.index, wantedBy);
this.states.push(s);
}
}
complete(left, right) {
const copy = left.nextState(right);
this.states.push(copy);
}
}
export class Grammar {
constructor(rules, start) {
this.rules = rules;
this.start = start || this.rules[0].name;
const byName = (this.byName = {});
this.rules.forEach(function (rule) {
if (!byName.hasOwnProperty(rule.name)) {
byName[rule.name] = [];
}
byName[rule.name].push(rule);
});
}
// So we can allow passing (rules, start) directly to Parser for backwards compatibility
static fromCompiled(rules, start) {
const lexer = rules.Lexer;
if (rules.ParserStart) {
start = rules.ParserStart;
rules = rules.ParserRules;
}
var rules = rules.map(function (r) {
return new Rule(r.name, r.symbols, r.postprocess);
});
const g = new Grammar(rules, start);
g.lexer = lexer; // nb. storing lexer on Grammar is iffy, but unavoidable
return g;
}
}
class StreamLexer {
constructor() {
this.reset('');
}
reset(data, state) {
this.buffer = data;
this.index = 0;
this.line = state ? state.line : 1;
this.lastLineBreak = state ? -state.col : 0;
}
next() {
if (this.index < this.buffer.length) {
const ch = this.buffer[this.index++];
if (ch === '\n') {
this.line += 1;
this.lastLineBreak = this.index;
}
return { value: ch };
}
}
save() {
return {
line: this.line,
col: this.index - this.lastLineBreak,
};
}
formatError(token, message) {
// nb. this gets called after consuming the offending token,
// so the culprit is index-1
const buffer = this.buffer;
if (typeof buffer === 'string') {
const lines = buffer.split('\n').slice(Math.max(0, this.line - 5), this.line);
let nextLineBreak = buffer.indexOf('\n', this.index);
if (nextLineBreak === -1) {
nextLineBreak = buffer.length;
}
const col = this.index - this.lastLineBreak;
const lastLineDigits = String(this.line).length;
message += ' at line ' + this.line + ' col ' + col + ':\n\n';
message += lines
.map(function (line, i) {
return pad(this.line - lines.length + i + 1, lastLineDigits) + ' ' + line;
}, this)
.join('\n');
message += '\n' + pad('', lastLineDigits + col) + '^\n';
return message;
}
else {
return message + ' at index ' + (this.index - 1);
}
function pad(n, length) {
const s = String(n);
return new Array(length - s.length + 1).join(' ') + s;
}
}
}
export class Parser {
// create a reserved token for indicating a parse fail
static fail = {};
constructor(rules, start, options) {
if (rules instanceof Grammar) {
var grammar = rules;
var options = start;
}
else {
var grammar = Grammar.fromCompiled(rules, start);
}
this.grammar = grammar;
// Read options
this.options = {
keepHistory: false,
lexer: grammar.lexer || new StreamLexer(),
};
for (const key in options || {}) {
this.options[key] = options[key];
}
// Setup lexer
this.lexer = this.options.lexer;
this.lexerState = undefined;
// Setup a table
const column = new Column(grammar, 0);
const table = (this.table = [column]);
// I could be expecting anything.
column.wants[grammar.start] = [];
column.predict(grammar.start);
// TODO what if start rule is nullable?
column.process();
this.current = 0; // token index
}
feed(chunk) {
const lexer = this.lexer;
lexer.reset(chunk, this.lexerState);
let token;
while (true) {
try {
token = lexer.next();
if (!token) {
break;
}
}
catch (e) {
// Create the next column so that the error reporter
// can display the correctly predicted states.
var nextColumn = new Column(this.grammar, this.current + 1);
this.table.push(nextColumn);
var err = new Error(this.reportLexerError(e));
err.offset = this.current;
err.token = e.token;
throw err;
}
// We add new states to table[current+1]
var column = this.table[this.current];
// GC unused states
if (!this.options.keepHistory) {
delete this.table[this.current - 1];
}
const n = this.current + 1;
var nextColumn = new Column(this.grammar, n);
this.table.push(nextColumn);
// Advance all tokens that expect the symbol
const literal = token.text === undefined ? token.value : token.text;
const value = lexer.constructor === StreamLexer ? token.value : token;
const scannable = column.scannable;
for (let w = scannable.length; w--;) {
const state = scannable[w];
const expect = state.rule.symbols[state.dot];
// Try to consume the token
// either regex or literal
if (expect.test
? expect.test(value)
: expect.type
? expect.type === token.type
: expect.literal === literal) {
// Add it
const next = state.nextState({
data: value,
token: token,
isToken: true,
reference: n - 1,
});
nextColumn.states.push(next);
}
}
// Next, for each of the rules, we either
// (a) complete it, and try to see if the reference row expected that
// rule
// (b) predict the next nonterminal it expects by adding that
// nonterminal's start state
// To prevent duplication, we also keep track of rules we have already
// added
nextColumn.process();
// If needed, throw an error:
if (nextColumn.states.length === 0) {
// No states at all! This is not good.
var err = new Error(this.reportError(token));
err.offset = this.current;
err.token = token;
throw err;
}
// maybe save lexer state
if (this.options.keepHistory) {
column.lexerState = lexer.save();
}
this.current++;
}
if (column) {
this.lexerState = lexer.save();
}
// Incrementally keep track of results
this.results = this.finish();
// Allow chaining, for whatever it's worth
return this;
}
reportLexerError(lexerError) {
let tokenDisplay, lexerMessage;
// Planning to add a token property to moo's thrown error
// even on erroring tokens to be used in error display below
const token = lexerError.token;
if (token) {
tokenDisplay = 'input ' + JSON.stringify(token.text[0]) + ' (lexer error)';
lexerMessage = this.lexer.formatError(token, 'Syntax error');
}
else {
tokenDisplay = 'input (lexer error)';
lexerMessage = lexerError.message;
}
return this.reportErrorCommon(lexerMessage, tokenDisplay);
}
reportError(token) {
const tokenDisplay = (token.type ? token.type + ' token: ' : '') +
JSON.stringify(token.value === undefined ? token : token.value);
const lexerMessage = this.lexer.formatError(token, 'Syntax error');
return this.reportErrorCommon(lexerMessage, tokenDisplay);
}
reportErrorCommon(lexerMessage, tokenDisplay) {
const lines = [];
lines.push(lexerMessage);
const lastColumnIndex = this.table.length - 2;
const lastColumn = this.table[lastColumnIndex];
const expectantStates = lastColumn.states.filter(function (state) {
const nextSymbol = state.rule.symbols[state.dot];
return nextSymbol && typeof nextSymbol !== 'string';
});
if (expectantStates.length === 0) {
lines.push('Unexpected ' +
tokenDisplay +
'. I did not expect any more input. Here is the state of my parse table:\n');
this.displayStateStack(lastColumn.states, lines);
}
else {
lines.push('Unexpected ' +
tokenDisplay +
'. Instead, I was expecting to see one of the following:\n');
// Display a "state stack" for each expectant state
// - which shows you how this state came to be, step by step.
// If there is more than one derivation, we only display the first one.
const stateStacks = expectantStates.map(function (state) {
return this.buildFirstStateStack(state, []) || [state];
}, this);
// Display each state that is expecting a terminal symbol next.
stateStacks.forEach(function (stateStack) {
const state = stateStack[0];
const nextSymbol = state.rule.symbols[state.dot];
const symbolDisplay = this.getSymbolDisplay(nextSymbol);
lines.push('A ' + symbolDisplay + ' based on:');
this.displayStateStack(stateStack, lines);
}, this);
}
lines.push('');
return lines.join('\n');
}
displayStateStack(stateStack, lines) {
let lastDisplay;
let sameDisplayCount = 0;
for (const state of stateStack) {
const display = state.rule.toString(state.dot);
if (display === lastDisplay) {
sameDisplayCount++;
}
else {
if (sameDisplayCount > 0) {
lines.push(' ^ ' + sameDisplayCount + ' more lines identical to this');
}
sameDisplayCount = 0;
lines.push(' ' + display);
}
lastDisplay = display;
}
}
getSymbolDisplay(symbol) {
return getSymbolLongDisplay(symbol);
}
/*
Builds a the first state stack. You can think of a state stack as the call stack
of the recursive-descent parser which the Nearley parse algorithm simulates.
A state stack is represented as an array of state objects. Within a
state stack, the first item of the array will be the starting
state, with each successive item in the array going further back into history.
This function needs to be given a starting state and an empty array representing
the visited states, and it returns an single state stack.
*/
buildFirstStateStack(state, visited) {
if (visited.includes(state)) {
// Found cycle, return null
// to eliminate this path from the results, because
// we don't know how to display it meaningfully
return null;
}
if (state.wantedBy.length === 0) {
return [state];
}
const prevState = state.wantedBy[0];
const childVisited = [state].concat(visited);
const childResult = this.buildFirstStateStack(prevState, childVisited);
if (childResult === null) {
return null;
}
return [state].concat(childResult);
}
save() {
const column = this.table[this.current];
column.lexerState = this.lexerState;
return column;
}
restore(column) {
const index = column.index;
this.current = index;
this.table[index] = column;
this.table.splice(index + 1);
this.lexerState = column.lexerState;
// Incrementally keep track of results
this.results = this.finish();
}
// nb. deprecated: use save/restore instead!
rewind(index) {
if (!this.options.keepHistory) {
throw new Error('set option `keepHistory` to enable rewinding');
}
// nb. recall column (table) indices fall between token indices.
// col 0 -- token 0 -- col 1
this.restore(this.table[index]);
}
finish() {
// Return the possible parsings
const considerations = [];
const start = this.grammar.start;
const column = this.table[this.table.length - 1];
column.states.forEach(function (t) {
if (t.rule.name === start &&
t.dot === t.rule.symbols.length &&
t.reference === 0 &&
t.data !== Parser.fail) {
considerations.push(t);
}
});
return considerations.map(function (c) {
return c.data;
});
}
}
function getSymbolLongDisplay(symbol) {
const type = typeof symbol;
if (type === 'string') {
return symbol;
}
else if (type === 'object') {
if (symbol.literal) {
return JSON.stringify(symbol.literal);
}
else if (symbol instanceof RegExp) {
return 'character matching ' + symbol;
}
else if (symbol.type) {
return symbol.type + ' token';
}
else if (symbol.test) {
return 'token matching ' + String(symbol.test);
}
else {
throw new Error('Unknown symbol type: ' + symbol);
}
}
}
function getSymbolShortDisplay(symbol) {
const type = typeof symbol;
if (type === 'string') {
return symbol;
}
else if (type === 'object') {
if (symbol.literal) {
return JSON.stringify(symbol.literal);
}
else if (symbol instanceof RegExp) {
return symbol.toString();
}
else if (symbol.type) {
return '%' + symbol.type;
}
else if (symbol.test) {
return '<' + String(symbol.test) + '>';
}
else {
throw new Error('Unknown symbol type: ' + symbol);
}
}
}