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Maven plugin for generating graphql clients
/* @flow /
/**
* Copyright (c) 2015, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
import type { Token } from './ast';
import type { Source } from './source';
import { syntaxError } from '../error';
/**
* Given a Source object, this returns a Lexer for that source.
* A Lexer is a stateful stream generator in that every time
* it is advanced, it returns the next token in the Source. Assuming the
* source lexes, the final Token emitted by the lexer will be of kind
* EOF, after which the lexer will repeatedly return the same EOF token
* whenever called.
*/
export function createLexer(
source: Source,
options: TOptions
): Lexer {
const startOfFileToken = new Tok(SOF, 0, 0, 0, 0, null);
const lexer: Lexer = {
source,
options,
lastToken: startOfFileToken,
token: startOfFileToken,
line: 1,
lineStart: 0,
advance: advanceLexer
};
return lexer;
}
function advanceLexer() {
let token = this.lastToken = this.token;
if (token.kind !== EOF) {
do {
token = token.next = readToken(this, token);
} while (token.kind === COMMENT);
this.token = token;
}
return token;
}
/**
* The return type of createLexer.
*/
export type Lexer = {
source: Source;
options: TOptions;
/**
* The previously focused non-ignored token.
*/
lastToken: Token;
/**
* The currently focused non-ignored token.
*/
token: Token;
/**
* The (1-indexed) line containing the current token.
*/
line: number;
/**
* The character offset at which the current line begins.
*/
lineStart: number;
/**
* Advances the token stream to the next non-ignored token.
*/
advance(): Token;
};
// Each kind of token.
const SOF = '';
const EOF = '';
const BANG = '!';
const DOLLAR = '$';
const PAREN_L = '(';
const PAREN_R = ')';
const SPREAD = '...';
const COLON = ':';
const EQUALS = '=';
const AT = '@';
const BRACKET_L = '[';
const BRACKET_R = ']';
const BRACE_L = '{';
const PIPE = '|';
const BRACE_R = '}';
const NAME = 'Name';
const INT = 'Int';
const FLOAT = 'Float';
const STRING = 'String';
const COMMENT = 'Comment';
/**
* An exported enum describing the different kinds of tokens that the
* lexer emits.
*/
export const TokenKind = {
SOF,
EOF,
BANG,
DOLLAR,
PAREN_L,
PAREN_R,
SPREAD,
COLON,
EQUALS,
AT,
BRACKET_L,
BRACKET_R,
BRACE_L,
PIPE,
BRACE_R,
NAME,
INT,
FLOAT,
STRING,
COMMENT
};
/**
* A helper function to describe a token as a string for debugging
*/
export function getTokenDesc(token: Token): string {
const value = token.value;
return value ? `${token.kind} "${value}"` : token.kind;
}
const charCodeAt = String.prototype.charCodeAt;
const slice = String.prototype.slice;
/**
* Helper function for constructing the Token object.
*/
function Tok(
kind,
start: number,
end: number,
line: number,
column: number,
prev: Token | null,
value?: string
) {
this.kind = kind;
this.start = start;
this.end = end;
this.line = line;
this.column = column;
this.value = value;
this.prev = prev;
this.next = null;
}
// Print a simplified form when appearing in JSON/util.inspect.
Tok.prototype.toJSON = Tok.prototype.inspect = function toJSON() {
return {
kind: this.kind,
value: this.value,
line: this.line,
column: this.column
};
};
function printCharCode(code) {
return (
// NaN/undefined represents access beyond the end of the file.
isNaN(code) ? EOF :
// Trust JSON for ASCII.
code < 0x007F ? JSON.stringify(String.fromCharCode(code)) :
// Otherwise print the escaped form.
`"\\u${('00' + code.toString(16).toUpperCase()).slice(-4)}"`
);
}
/**
* Gets the next token from the source starting at the given position.
*
* This skips over whitespace and comments until it finds the next lexable
* token, then lexes punctuators immediately or calls the appropriate helper
* function for more complicated tokens.
*/
function readToken(lexer: Lexer<*>, prev: Token): Token {
const source = lexer.source;
const body = source.body;
const bodyLength = body.length;
const position = positionAfterWhitespace(body, prev.end, lexer);
const line = lexer.line;
const col = 1 + position - lexer.lineStart;
if (position >= bodyLength) {
return new Tok(EOF, bodyLength, bodyLength, line, col, prev);
}
const code = charCodeAt.call(body, position);
// SourceCharacter
if (code < 0x0020 && code !== 0x0009 && code !== 0x000A && code !== 0x000D) {
throw syntaxError(
source,
position,
`Cannot contain the invalid character ${printCharCode(code)}.`
);
}
switch (code) {
// !
case 33: return new Tok(BANG, position, position + 1, line, col, prev);
// #
case 35: return readComment(source, position, line, col, prev);
// $
case 36: return new Tok(DOLLAR, position, position + 1, line, col, prev);
// (
case 40: return new Tok(PAREN_L, position, position + 1, line, col, prev);
// )
case 41: return new Tok(PAREN_R, position, position + 1, line, col, prev);
// .
case 46:
if (charCodeAt.call(body, position + 1) === 46 &&
charCodeAt.call(body, position + 2) === 46) {
return new Tok(SPREAD, position, position + 3, line, col, prev);
}
break;
// :
case 58: return new Tok(COLON, position, position + 1, line, col, prev);
// =
case 61: return new Tok(EQUALS, position, position + 1, line, col, prev);
// @
case 64: return new Tok(AT, position, position + 1, line, col, prev);
// [
case 91:
return new Tok(BRACKET_L, position, position + 1, line, col, prev);
// ]
case 93:
return new Tok(BRACKET_R, position, position + 1, line, col, prev);
// {
case 123:
return new Tok(BRACE_L, position, position + 1, line, col, prev);
// |
case 124: return new Tok(PIPE, position, position + 1, line, col, prev);
// }
case 125:
return new Tok(BRACE_R, position, position + 1, line, col, prev);
// A-Z _ a-z
case 65: case 66: case 67: case 68: case 69: case 70: case 71: case 72:
case 73: case 74: case 75: case 76: case 77: case 78: case 79: case 80:
case 81: case 82: case 83: case 84: case 85: case 86: case 87: case 88:
case 89: case 90:
case 95:
case 97: case 98: case 99: case 100: case 101: case 102: case 103: case 104:
case 105: case 106: case 107: case 108: case 109: case 110: case 111:
case 112: case 113: case 114: case 115: case 116: case 117: case 118:
case 119: case 120: case 121: case 122:
return readName(source, position, line, col, prev);
// - 0-9
case 45:
case 48: case 49: case 50: case 51: case 52:
case 53: case 54: case 55: case 56: case 57:
return readNumber(source, position, code, line, col, prev);
// "
case 34: return readString(source, position, line, col, prev);
}
throw syntaxError(
source,
position,
unexpectedCharacterMessage(code)
);
}
/**
* Report a message that an unexpected character was encountered.
*/
function unexpectedCharacterMessage(code) {
if (code === 39) { // '
return 'Unexpected single quote character (\'), did you mean to use ' +
'a double quote (")?';
}
return 'Cannot parse the unexpected character ' + printCharCode(code) + '.';
}
/**
* Reads from body starting at startPosition until it finds a non-whitespace
* or commented character, then returns the position of that character for
* lexing.
*/
function positionAfterWhitespace(
body: string,
startPosition: number,
lexer: Lexer<*>
): number {
const bodyLength = body.length;
let position = startPosition;
while (position < bodyLength) {
const code = charCodeAt.call(body, position);
// tab | space | comma | BOM
if (code === 9 || code === 32 || code === 44 || code === 0xFEFF) {
++position;
} else if (code === 10) { // new line
++position;
++lexer.line;
lexer.lineStart = position;
} else if (code === 13) { // carriage return
if (charCodeAt.call(body, position + 1) === 10) {
position += 2;
} else {
++position;
}
++lexer.line;
lexer.lineStart = position;
} else {
break;
}
}
return position;
}
/**
* Reads a comment token from the source file.
*
* #[\u0009\u0020-\uFFFF]*
*/
function readComment(source, start, line, col, prev): Token {
const body = source.body;
let code;
let position = start;
do {
code = charCodeAt.call(body, ++position);
} while (
code !== null &&
// SourceCharacter but not LineTerminator
(code > 0x001F || code === 0x0009)
);
return new Tok(
COMMENT,
start,
position,
line,
col,
prev,
slice.call(body, start + 1, position)
);
}
/**
* Reads a number token from the source file, either a float
* or an int depending on whether a decimal point appears.
*
* Int: -?(0|[1-9][0-9]*)
* Float: -?(0|[1-9][0-9]*)(\.[0-9]+)?((E|e)(+|-)?[0-9]+)?
*/
function readNumber(source, start, firstCode, line, col, prev): Token {
const body = source.body;
let code = firstCode;
let position = start;
let isFloat = false;
if (code === 45) { // -
code = charCodeAt.call(body, ++position);
}
if (code === 48) { // 0
code = charCodeAt.call(body, ++position);
if (code >= 48 && code <= 57) {
throw syntaxError(
source,
position,
`Invalid number, unexpected digit after 0: ${printCharCode(code)}.`
);
}
} else {
position = readDigits(source, position, code);
code = charCodeAt.call(body, position);
}
if (code === 46) { // .
isFloat = true;
code = charCodeAt.call(body, ++position);
position = readDigits(source, position, code);
code = charCodeAt.call(body, position);
}
if (code === 69 || code === 101) { // E e
isFloat = true;
code = charCodeAt.call(body, ++position);
if (code === 43 || code === 45) { // + -
code = charCodeAt.call(body, ++position);
}
position = readDigits(source, position, code);
}
return new Tok(
isFloat ? FLOAT : INT,
start,
position,
line,
col,
prev,
slice.call(body, start, position)
);
}
/**
* Returns the new position in the source after reading digits.
*/
function readDigits(source, start, firstCode) {
const body = source.body;
let position = start;
let code = firstCode;
if (code >= 48 && code <= 57) { // 0 - 9
do {
code = charCodeAt.call(body, ++position);
} while (code >= 48 && code <= 57); // 0 - 9
return position;
}
throw syntaxError(
source,
position,
`Invalid number, expected digit but got: ${printCharCode(code)}.`
);
}
/**
* Reads a string token from the source file.
*
* "([^"\\\u000A\u000D]|(\\(u[0-9a-fA-F]{4}|["\\/bfnrt])))*"
*/
function readString(source, start, line, col, prev): Token {
const body = source.body;
let position = start + 1;
let chunkStart = position;
let code = 0;
let value = '';
while (
position < body.length &&
(code = charCodeAt.call(body, position)) !== null &&
// not LineTerminator
code !== 0x000A && code !== 0x000D &&
// not Quote (")
code !== 34
) {
// SourceCharacter
if (code < 0x0020 && code !== 0x0009) {
throw syntaxError(
source,
position,
`Invalid character within String: ${printCharCode(code)}.`
);
}
++position;
if (code === 92) { // \
value += slice.call(body, chunkStart, position - 1);
code = charCodeAt.call(body, position);
switch (code) {
case 34: value += '"'; break;
case 47: value += '/'; break;
case 92: value += '\\'; break;
case 98: value += '\b'; break;
case 102: value += '\f'; break;
case 110: value += '\n'; break;
case 114: value += '\r'; break;
case 116: value += '\t'; break;
case 117: // u
const charCode = uniCharCode(
charCodeAt.call(body, position + 1),
charCodeAt.call(body, position + 2),
charCodeAt.call(body, position + 3),
charCodeAt.call(body, position + 4)
);
if (charCode < 0) {
throw syntaxError(
source,
position,
'Invalid character escape sequence: ' +
`\\u${body.slice(position + 1, position + 5)}.`
);
}
value += String.fromCharCode(charCode);
position += 4;
break;
default:
throw syntaxError(
source,
position,
`Invalid character escape sequence: \\${String.fromCharCode(code)}.`
);
}
++position;
chunkStart = position;
}
}
if (code !== 34) { // quote (")
throw syntaxError(source, position, 'Unterminated string.');
}
value += slice.call(body, chunkStart, position);
return new Tok(STRING, start, position + 1, line, col, prev, value);
}
/**
* Converts four hexidecimal chars to the integer that the
* string represents. For example, uniCharCode('0','0','0','f')
* will return 15, and uniCharCode('0','0','f','f') returns 255.
*
* Returns a negative number on error, if a char was invalid.
*
* This is implemented by noting that char2hex() returns -1 on error,
* which means the result of ORing the char2hex() will also be negative.
*/
function uniCharCode(a, b, c, d) {
return char2hex(a) << 12 | char2hex(b) << 8 | char2hex(c) << 4 | char2hex(d);
}
/**
* Converts a hex character to its integer value.
* '0' becomes 0, '9' becomes 9
* 'A' becomes 10, 'F' becomes 15
* 'a' becomes 10, 'f' becomes 15
*
* Returns -1 on error.
*/
function char2hex(a) {
return (
a >= 48 && a <= 57 ? a - 48 : // 0-9
a >= 65 && a <= 70 ? a - 55 : // A-F
a >= 97 && a <= 102 ? a - 87 : // a-f
-1
);
}
/**
* Reads an alphanumeric + underscore name from the source.
*
* [_A-Za-z][_0-9A-Za-z]*
*/
function readName(source, position, line, col, prev): Token {
const body = source.body;
const bodyLength = body.length;
let end = position + 1;
let code = 0;
while (
end !== bodyLength &&
(code = charCodeAt.call(body, end)) !== null &&
(
code === 95 || // _
code >= 48 && code <= 57 || // 0-9
code >= 65 && code <= 90 || // A-Z
code >= 97 && code <= 122 // a-z
)
) {
++end;
}
return new Tok(
NAME,
position,
end,
line,
col,
prev,
slice.call(body, position, end)
);
}