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/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*
* @format
*/
"use strict";
var _traverse = _interopRequireDefault(require("@babel/traverse"));
var _types = require("@babel/types");
function _interopRequireDefault(obj) {
return obj && obj.__esModule ? obj : { default: obj };
}
const B64Builder = require("./B64Builder");
const t = require("@babel/types");
const nullthrows = require("nullthrows");
const fsPath = require("path");
/**
* Generate a map of source positions to function names. The names are meant to
* describe the stack frame in an error trace and may contain more contextual
* information than just the actual name of the function.
*
* The output is encoded for use in a source map. For details about the format,
* see MappingEncoder below.
*/
function generateFunctionMap(ast, context) {
const encoder = new MappingEncoder();
forEachMapping(ast, context, (mapping) => encoder.push(mapping));
return encoder.getResult();
}
/**
* Same as generateFunctionMap, but returns the raw array of mappings instead
* of encoding it for use in a source map.
*
* Lines are 1-based and columns are 0-based.
*/
function generateFunctionMappingsArray(ast, context) {
const mappings = [];
forEachMapping(ast, context, (mapping) => {
mappings.push(mapping);
});
return mappings;
}
/**
* Traverses a Babel AST and calls the supplied callback with function name
* mappings, one at a time.
*/
function forEachMapping(ast, context, pushMapping) {
const nameStack = [];
let tailPos = {
line: 1,
column: 0,
};
let tailName = null;
function advanceToPos(pos) {
if (tailPos && positionGreater(pos, tailPos)) {
const name = nameStack[0].name; // We always have at least Program
if (name !== tailName) {
pushMapping({
name,
start: {
line: tailPos.line,
column: tailPos.column,
},
});
tailName = name;
}
}
tailPos = pos;
}
function pushFrame(name, loc) {
advanceToPos(loc.start);
nameStack.unshift({
name,
loc,
});
}
function popFrame() {
const top = nameStack[0];
if (top) {
const { loc } = top;
advanceToPos(loc.end);
nameStack.shift();
}
}
if (!context) {
context = {};
}
const basename = context.filename
? fsPath.basename(context.filename).replace(/\..+$/, "")
: null;
const visitor = {
enter(path) {
let name = getNameForPath(path);
if (basename) {
name = removeNamePrefix(name, basename);
}
pushFrame(name, nullthrows(path.node.loc));
},
exit(path) {
popFrame();
},
};
(0, _traverse.default)(ast, {
Function: visitor,
Program: visitor,
Class: visitor,
});
}
const ANONYMOUS_NAME = "<anonymous>";
/**
* Derive a contextual name for the given AST node (Function, Program, Class or
* ObjectExpression).
*/
function getNameForPath(path) {
const { node, parent, parentPath } = path;
if ((0, _types.isProgram)(node)) {
return "<global>";
}
let { id } = path; // has an `id` so we don't need to infer one
if (node.id) {
// $FlowFixMe Flow error uncovered by typing Babel more strictly
return node.id.name;
}
let propertyPath;
let kind; // Find or construct an AST node that names the current node.
if ((0, _types.isObjectMethod)(node) || (0, _types.isClassMethod)(node)) {
// ({ foo() {} });
id = node.key;
if (node.kind !== "method" && node.kind !== "constructor") {
// Store the method's kind so we can add it to the final name.
kind = node.kind;
} // Also store the path to the property so we can find its context
// (object/class) later and add _its_ name to the result.
propertyPath = path;
} else if (
(0, _types.isObjectProperty)(parent) ||
(0, _types.isClassProperty)(parent)
) {
// ({ foo: function() {} });
id = parent.key; // Also store the path to the property so we can find its context
// (object/class) later and add _its_ name to the result.
propertyPath = parentPath;
} else if ((0, _types.isVariableDeclarator)(parent)) {
// let foo = function () {};
id = parent.id;
} else if ((0, _types.isAssignmentExpression)(parent)) {
// foo = function () {};
id = parent.left;
} else if ((0, _types.isJSXExpressionContainer)(parent)) {
var _parentPath$parentPat;
const grandParentNode =
parentPath === null || parentPath === void 0
? void 0
: (_parentPath$parentPat = parentPath.parentPath) === null ||
_parentPath$parentPat === void 0
? void 0
: _parentPath$parentPat.node;
if ((0, _types.isJSXElement)(grandParentNode)) {
// <foo>{function () {}}</foo>
const openingElement = grandParentNode.openingElement;
id = t.jsxMemberExpression(
// $FlowFixMe Flow error uncovered by typing Babel more strictly
t.jsxMemberExpression(openingElement.name, t.jsxIdentifier("props")),
t.jsxIdentifier("children")
);
} else if ((0, _types.isJSXAttribute)(grandParentNode)) {
var _parentPath$parentPat2, _parentPath$parentPat3;
// <foo bar={function () {}} />
const openingElement =
parentPath === null || parentPath === void 0
? void 0
: (_parentPath$parentPat2 = parentPath.parentPath) === null ||
_parentPath$parentPat2 === void 0
? void 0
: (_parentPath$parentPat3 = _parentPath$parentPat2.parentPath) ===
null || _parentPath$parentPat3 === void 0
? void 0
: _parentPath$parentPat3.node;
const prop = grandParentNode;
id = t.jsxMemberExpression(
// $FlowFixMe Flow error uncovered by typing Babel more strictly
t.jsxMemberExpression(openingElement.name, t.jsxIdentifier("props")), // $FlowFixMe Flow error uncovered by typing Babel more strictly
prop.name
);
}
} // Collapse the name AST, if any, into a string.
let name = getNameFromId(id);
if (name == null) {
// We couldn't find a name directly. Try the parent in certain cases.
if (isAnyCallExpression(parent)) {
// foo(function () {})
const argIndex = parent.arguments.indexOf(node);
if (argIndex !== -1) {
const calleeName = getNameFromId(parent.callee); // var f = Object.freeze(function () {})
if (argIndex === 0 && calleeName === "Object.freeze") {
return getNameForPath(nullthrows(parentPath));
} // var f = useCallback(function () {})
if (
argIndex === 0 &&
(calleeName === "useCallback" || calleeName === "React.useCallback")
) {
return getNameForPath(nullthrows(parentPath));
}
if (calleeName) {
return `${calleeName}$argument_${argIndex}`;
}
}
}
if (
(0, _types.isTypeCastExpression)(parent) &&
parent.expression === node
) {
return getNameForPath(nullthrows(parentPath));
}
if ((0, _types.isExportDefaultDeclaration)(parent)) {
return "default";
} // We couldn't infer a name at all.
return ANONYMOUS_NAME;
} // Annotate getters and setters.
if (kind != null) {
name = kind + "__" + name;
} // Annotate members with the name of their containing object/class.
if (propertyPath) {
if ((0, _types.isClassBody)(propertyPath.parent)) {
// $FlowFixMe Discovered when typing babel-traverse
const className = getNameForPath(propertyPath.parentPath.parentPath);
if (className !== ANONYMOUS_NAME) {
const separator = propertyPath.node.static ? "." : "#";
name = className + separator + name;
}
} else if ((0, _types.isObjectExpression)(propertyPath.parent)) {
const objectName = getNameForPath(nullthrows(propertyPath.parentPath));
if (objectName !== ANONYMOUS_NAME) {
name = objectName + "." + name;
}
}
}
return name;
}
function isAnyCallExpression(node) {
return (
node.type === "CallExpression" ||
node.type === "NewExpression" ||
node.type === "OptionalCallExpression"
);
}
function isAnyMemberExpression(node) {
return (
node.type === "MemberExpression" ||
node.type === "JSXMemberExpression" ||
node.type === "OptionalMemberExpression"
);
}
function isAnyIdentifier(node) {
return (0, _types.isIdentifier)(node) || (0, _types.isJSXIdentifier)(node);
}
function getNameFromId(id) {
const parts = getNamePartsFromId(id);
if (!parts.length) {
return null;
}
if (parts.length > 5) {
return (
parts[0] +
"." +
parts[1] +
"..." +
parts[parts.length - 2] +
"." +
parts[parts.length - 1]
);
}
return parts.join(".");
}
function getNamePartsFromId(id) {
if (!id) {
return [];
}
if (isAnyCallExpression(id)) {
return getNamePartsFromId(id.callee);
}
if ((0, _types.isTypeCastExpression)(id)) {
return getNamePartsFromId(id.expression);
}
let name;
if (isAnyIdentifier(id)) {
name = id.name;
} else if ((0, _types.isNullLiteral)(id)) {
name = "null";
} else if ((0, _types.isRegExpLiteral)(id)) {
var _id$flags;
name = `_${id.pattern}_${
(_id$flags = id.flags) !== null && _id$flags !== void 0 ? _id$flags : ""
}`;
} else if ((0, _types.isTemplateLiteral)(id)) {
name = id.quasis.map((quasi) => quasi.value.raw).join("");
} else if ((0, _types.isLiteral)(id) && id.value != null) {
name = String(id.value);
}
if (name != null) {
return [t.toBindingIdentifierName(name)];
}
if ((0, _types.isImport)(id)) {
name = "import";
}
if (name != null) {
return [name];
}
if (isAnyMemberExpression(id)) {
if (
isAnyIdentifier(id.object) &&
id.object.name === "Symbol" &&
(isAnyIdentifier(id.property) || (0, _types.isLiteral)(id.property))
) {
const propertyName = getNameFromId(id.property);
if (propertyName) {
name = "@@" + propertyName;
}
} else {
const propertyName = getNamePartsFromId(id.property);
if (propertyName.length) {
const objectName = getNamePartsFromId(id.object);
if (objectName.length) {
return [...objectName, ...propertyName];
} else {
return propertyName;
}
}
}
}
return name ? [name] : [];
}
const DELIMITER_START_RE = /^[^A-Za-z0-9_$@]+/;
/**
* Strip the given prefix from `name`, if it occurs there, plus any delimiter
* characters that follow (of which at least one is required). If an empty
* string would be returned, return the original name instead.
*/
function removeNamePrefix(name, namePrefix) {
if (!namePrefix.length || !name.startsWith(namePrefix)) {
return name;
}
const shortenedName = name.substr(namePrefix.length);
const [delimiterMatch] = shortenedName.match(DELIMITER_START_RE) || [];
if (delimiterMatch) {
return shortenedName.substr(delimiterMatch.length) || name;
}
return name;
}
/**
* Encodes function name mappings as deltas in a Base64 VLQ format inspired by
* the standard source map format.
*
* Mappings on different lines are separated with a single `;` (even if there
* are multiple intervening lines).
* Mappings on the same line are separated with `,`.
*
* The first mapping of a line has the fields:
* [column delta, name delta, line delta]
*
* where the column delta is relative to the beginning of the line, the name
* delta is relative to the previously occurring name, and the line delta is
* relative to the previously occurring line.
*
* The 2...nth other mappings of a line have the fields:
* [column delta, name delta]
*
* where both fields are relative to their previous running values. The line
* delta is omitted since it is always 0 by definition.
*
* Lines and columns are both 0-based in the serialised format. In memory,
* lines are 1-based while columns are 0-based.
*/
class MappingEncoder {
constructor() {
this._namesMap = new Map();
this._names = [];
this._line = new RelativeValue(1);
this._column = new RelativeValue(0);
this._nameIndex = new RelativeValue(0);
this._mappings = new B64Builder();
}
getResult() {
return {
names: this._names,
mappings: this._mappings.toString(),
};
}
push({ name, start }) {
let nameIndex = this._namesMap.get(name);
if (typeof nameIndex !== "number") {
nameIndex = this._names.length;
this._names[nameIndex] = name;
this._namesMap.set(name, nameIndex);
}
const lineDelta = this._line.next(start.line);
const firstOfLine = this._mappings.pos === 0 || lineDelta > 0;
if (lineDelta > 0) {
// The next entry will have the line offset, so emit just one semicolon.
this._mappings.markLines(1);
this._column.reset(0);
}
this._mappings.startSegment(this._column.next(start.column));
this._mappings.append(this._nameIndex.next(nameIndex));
if (firstOfLine) {
this._mappings.append(lineDelta);
}
}
}
class RelativeValue {
constructor(value = 0) {
this.reset(value);
}
next(absoluteValue) {
const delta = absoluteValue - this._value;
this._value = absoluteValue;
return delta;
}
reset(value = 0) {
this._value = value;
}
}
function positionGreater(x, y) {
return x.line > y.line || (x.line === y.line && x.column > y.column);
}
module.exports = {
generateFunctionMap,
generateFunctionMappingsArray,
};