const { createHash } = require('crypto');
const { template } = require('@babel/core');
const { defaults } = require('@istanbuljs/schema');
const { SourceCoverage } = require('./source-coverage');
const { SHA, MAGIC_KEY, MAGIC_VALUE } = require('./constants');
// pattern for istanbul to ignore a section
const COMMENT_RE = /^\s*istanbul\s+ignore\s+(if|else|next)(?=\W|$)/;
// pattern for istanbul to ignore the whole file
const COMMENT_FILE_RE = /^\s*istanbul\s+ignore\s+(file)(?=\W|$)/;
// source map URL pattern
const SOURCE_MAP_RE = /[#@]\s*sourceMappingURL=(.*)\s*$/m;
// generate a variable name from hashing the supplied file path
function genVar(filename) {
const hash = createHash(SHA);
hash.update(filename);
return 'cov_' + parseInt(hash.digest('hex').substr(0, 12), 16).toString(36);
}
// VisitState holds the state of the visitor, provides helper functions
// and is the `this` for the individual coverage visitors.
class VisitState {
constructor(
types,
sourceFilePath,
inputSourceMap,
ignoreClassMethods = [],
reportLogic = false
) {
this.varName = genVar(sourceFilePath);
this.attrs = {};
this.nextIgnore = null;
this.cov = new SourceCoverage(sourceFilePath);
if (typeof inputSourceMap !== 'undefined') {
this.cov.inputSourceMap(inputSourceMap);
}
this.ignoreClassMethods = ignoreClassMethods;
this.types = types;
this.sourceMappingURL = null;
this.reportLogic = reportLogic;
}
// should we ignore the node? Yes, if specifically ignoring
// or if the node is generated.
shouldIgnore(path) {
return this.nextIgnore || !path.node.loc;
}
// extract the ignore comment hint (next|if|else) or null
hintFor(node) {
let hint = null;
if (node.leadingComments) {
node.leadingComments.forEach(c => {
const v = (
c.value || /* istanbul ignore next: paranoid check */ ''
).trim();
const groups = v.match(COMMENT_RE);
if (groups) {
hint = groups[1];
}
});
}
return hint;
}
// extract a source map URL from comments and keep track of it
maybeAssignSourceMapURL(node) {
const extractURL = comments => {
if (!comments) {
return;
}
comments.forEach(c => {
const v = (
c.value || /* istanbul ignore next: paranoid check */ ''
).trim();
const groups = v.match(SOURCE_MAP_RE);
if (groups) {
this.sourceMappingURL = groups[1];
}
});
};
extractURL(node.leadingComments);
extractURL(node.trailingComments);
}
// for these expressions the statement counter needs to be hoisted, so
// function name inference can be preserved
counterNeedsHoisting(path) {
return (
path.isFunctionExpression() ||
path.isArrowFunctionExpression() ||
path.isClassExpression()
);
}
// all the generic stuff that needs to be done on enter for every node
onEnter(path) {
const n = path.node;
this.maybeAssignSourceMapURL(n);
// if already ignoring, nothing more to do
if (this.nextIgnore !== null) {
return;
}
// check hint to see if ignore should be turned on
const hint = this.hintFor(n);
if (hint === 'next') {
this.nextIgnore = n;
return;
}
// else check custom node attribute set by a prior visitor
if (this.getAttr(path.node, 'skip-all') !== null) {
this.nextIgnore = n;
}
// else check for ignored class methods
if (
path.isFunctionExpression() &&
this.ignoreClassMethods.some(
name => path.node.id && name === path.node.id.name
)
) {
this.nextIgnore = n;
return;
}
if (
path.isClassMethod() &&
this.ignoreClassMethods.some(name => name === path.node.key.name)
) {
this.nextIgnore = n;
return;
}
}
// all the generic stuff on exit of a node,
// including reseting ignores and custom node attrs
onExit(path) {
// restore ignore status, if needed
if (path.node === this.nextIgnore) {
this.nextIgnore = null;
}
// nuke all attributes for the node
delete path.node.__cov__;
}
// set a node attribute for the supplied node
setAttr(node, name, value) {
node.__cov__ = node.__cov__ || {};
node.__cov__[name] = value;
}
// retrieve a node attribute for the supplied node or null
getAttr(node, name) {
const c = node.__cov__;
if (!c) {
return null;
}
return c[name];
}
//
increase(type, id, index) {
const T = this.types;
const wrap =
index !== null
? // If `index` present, turn `x` into `x[index]`.
x => T.memberExpression(x, T.numericLiteral(index), true)
: x => x;
return T.updateExpression(
'++',
wrap(
T.memberExpression(
T.memberExpression(
T.callExpression(T.identifier(this.varName), []),
T.identifier(type)
),
T.numericLiteral(id),
true
)
)
);
}
// Reads the logic expression conditions and conditionally increments truthy counter.
increaseTrue(type, id, index, node) {
const T = this.types;
const tempName = `${this.varName}_temp`;
return T.sequenceExpression([
T.assignmentExpression(
'=',
T.memberExpression(
T.callExpression(T.identifier(this.varName), []),
T.identifier(tempName)
),
node // Only evaluates once.
),
T.parenthesizedExpression(
T.conditionalExpression(
T.memberExpression(
T.callExpression(T.identifier(this.varName), []),
T.identifier(tempName)
),
this.increase(type, id, index),
T.nullLiteral()
)
),
T.memberExpression(
T.callExpression(T.identifier(this.varName), []),
T.identifier(tempName)
)
]);
}
insertCounter(path, increment) {
const T = this.types;
if (path.isBlockStatement()) {
path.node.body.unshift(T.expressionStatement(increment));
} else if (path.isStatement()) {
path.insertBefore(T.expressionStatement(increment));
} else if (
this.counterNeedsHoisting(path) &&
T.isVariableDeclarator(path.parentPath)
) {
// make an attempt to hoist the statement counter, so that
// function names are maintained.
const parent = path.parentPath.parentPath;
if (parent && T.isExportNamedDeclaration(parent.parentPath)) {
parent.parentPath.insertBefore(
T.expressionStatement(increment)
);
} else if (
parent &&
(T.isProgram(parent.parentPath) ||
T.isBlockStatement(parent.parentPath))
) {
parent.insertBefore(T.expressionStatement(increment));
} else {
path.replaceWith(T.sequenceExpression([increment, path.node]));
}
} /* istanbul ignore else: not expected */ else if (
path.isExpression()
) {
path.replaceWith(T.sequenceExpression([increment, path.node]));
} else {
console.error(
'Unable to insert counter for node type:',
path.node.type
);
}
}
insertStatementCounter(path) {
/* istanbul ignore if: paranoid check */
if (!(path.node && path.node.loc)) {
return;
}
const index = this.cov.newStatement(path.node.loc);
const increment = this.increase('s', index, null);
this.insertCounter(path, increment);
}
insertFunctionCounter(path) {
const T = this.types;
/* istanbul ignore if: paranoid check */
if (!(path.node && path.node.loc)) {
return;
}
const n = path.node;
let dloc = null;
// get location for declaration
switch (n.type) {
case 'FunctionDeclaration':
case 'FunctionExpression':
/* istanbul ignore else: paranoid check */
if (n.id) {
dloc = n.id.loc;
}
break;
}
if (!dloc) {
dloc = {
start: n.loc.start,
end: { line: n.loc.start.line, column: n.loc.start.column + 1 }
};
}
const name = path.node.id ? path.node.id.name : path.node.name;
const index = this.cov.newFunction(name, dloc, path.node.body.loc);
const increment = this.increase('f', index, null);
const body = path.get('body');
/* istanbul ignore else: not expected */
if (body.isBlockStatement()) {
body.node.body.unshift(T.expressionStatement(increment));
} else {
console.error(
'Unable to process function body node type:',
path.node.type
);
}
}
getBranchIncrement(branchName, loc) {
const index = this.cov.addBranchPath(branchName, loc);
return this.increase('b', branchName, index);
}
getBranchLogicIncrement(path, branchName, loc) {
const index = this.cov.addBranchPath(branchName, loc);
return [
this.increase('b', branchName, index),
this.increaseTrue('bT', branchName, index, path.node)
];
}
insertBranchCounter(path, branchName, loc) {
const increment = this.getBranchIncrement(
branchName,
loc || path.node.loc
);
this.insertCounter(path, increment);
}
findLeaves(node, accumulator, parent, property) {
if (!node) {
return;
}
if (node.type === 'LogicalExpression') {
const hint = this.hintFor(node);
if (hint !== 'next') {
this.findLeaves(node.left, accumulator, node, 'left');
this.findLeaves(node.right, accumulator, node, 'right');
}
} else {
accumulator.push({
node,
parent,
property
});
}
}
}
// generic function that takes a set of visitor methods and
// returns a visitor object with `enter` and `exit` properties,
// such that:
//
// * standard entry processing is done
// * the supplied visitors are called only when ignore is not in effect
// This relieves them from worrying about ignore states and generated nodes.
// * standard exit processing is done
//
function entries(...enter) {
// the enter function
const wrappedEntry = function(path, node) {
this.onEnter(path);
if (this.shouldIgnore(path)) {
return;
}
enter.forEach(e => {
e.call(this, path, node);
});
};
const exit = function(path, node) {
this.onExit(path, node);
};
return {
enter: wrappedEntry,
exit
};
}
function coverStatement(path) {
this.insertStatementCounter(path);
}
/* istanbul ignore next: no node.js support */
function coverAssignmentPattern(path) {
const n = path.node;
const b = this.cov.newBranch('default-arg', n.loc);
this.insertBranchCounter(path.get('right'), b);
}
function coverFunction(path) {
this.insertFunctionCounter(path);
}
function coverVariableDeclarator(path) {
this.insertStatementCounter(path.get('init'));
}
function coverClassPropDeclarator(path) {
this.insertStatementCounter(path.get('value'));
}
function makeBlock(path) {
const T = this.types;
if (!path.node) {
path.replaceWith(T.blockStatement([]));
}
if (!path.isBlockStatement()) {
path.replaceWith(T.blockStatement([path.node]));
path.node.loc = path.node.body[0].loc;
path.node.body[0].leadingComments = path.node.leadingComments;
path.node.leadingComments = undefined;
}
}
function blockProp(prop) {
return function(path) {
makeBlock.call(this, path.get(prop));
};
}
function makeParenthesizedExpressionForNonIdentifier(path) {
const T = this.types;
if (path.node && !path.isIdentifier()) {
path.replaceWith(T.parenthesizedExpression(path.node));
}
}
function parenthesizedExpressionProp(prop) {
return function(path) {
makeParenthesizedExpressionForNonIdentifier.call(this, path.get(prop));
};
}
function convertArrowExpression(path) {
const n = path.node;
const T = this.types;
if (!T.isBlockStatement(n.body)) {
const bloc = n.body.loc;
if (n.expression === true) {
n.expression = false;
}
n.body = T.blockStatement([T.returnStatement(n.body)]);
// restore body location
n.body.loc = bloc;
// set up the location for the return statement so it gets
// instrumented
n.body.body[0].loc = bloc;
}
}
function coverIfBranches(path) {
const n = path.node;
const hint = this.hintFor(n);
const ignoreIf = hint === 'if';
const ignoreElse = hint === 'else';
const branch = this.cov.newBranch('if', n.loc);
if (ignoreIf) {
this.setAttr(n.consequent, 'skip-all', true);
} else {
this.insertBranchCounter(path.get('consequent'), branch, n.loc);
}
if (ignoreElse) {
this.setAttr(n.alternate, 'skip-all', true);
} else {
this.insertBranchCounter(path.get('alternate'), branch);
}
}
function createSwitchBranch(path) {
const b = this.cov.newBranch('switch', path.node.loc);
this.setAttr(path.node, 'branchName', b);
}
function coverSwitchCase(path) {
const T = this.types;
const b = this.getAttr(path.parentPath.node, 'branchName');
/* istanbul ignore if: paranoid check */
if (b === null) {
throw new Error('Unable to get switch branch name');
}
const increment = this.getBranchIncrement(b, path.node.loc);
path.node.consequent.unshift(T.expressionStatement(increment));
}
function coverTernary(path) {
const n = path.node;
const branch = this.cov.newBranch('cond-expr', path.node.loc);
const cHint = this.hintFor(n.consequent);
const aHint = this.hintFor(n.alternate);
if (cHint !== 'next') {
this.insertBranchCounter(path.get('consequent'), branch);
}
if (aHint !== 'next') {
this.insertBranchCounter(path.get('alternate'), branch);
}
}
function coverLogicalExpression(path) {
const T = this.types;
if (path.parentPath.node.type === 'LogicalExpression') {
return; // already processed
}
const leaves = [];
this.findLeaves(path.node, leaves);
const b = this.cov.newBranch(
'binary-expr',
path.node.loc,
this.reportLogic
);
for (let i = 0; i < leaves.length; i += 1) {
const leaf = leaves[i];
const hint = this.hintFor(leaf.node);
if (hint === 'next') {
continue;
}
if (this.reportLogic) {
const increment = this.getBranchLogicIncrement(
leaf,
b,
leaf.node.loc
);
if (!increment[0]) {
continue;
}
leaf.parent[leaf.property] = T.sequenceExpression([
increment[0],
increment[1]
]);
continue;
}
const increment = this.getBranchIncrement(b, leaf.node.loc);
if (!increment) {
continue;
}
leaf.parent[leaf.property] = T.sequenceExpression([
increment,
leaf.node
]);
}
}
const codeVisitor = {
ArrowFunctionExpression: entries(convertArrowExpression, coverFunction),
AssignmentPattern: entries(coverAssignmentPattern),
BlockStatement: entries(), // ignore processing only
ExportDefaultDeclaration: entries(), // ignore processing only
ExportNamedDeclaration: entries(), // ignore processing only
ClassMethod: entries(coverFunction),
ClassDeclaration: entries(parenthesizedExpressionProp('superClass')),
ClassProperty: entries(coverClassPropDeclarator),
ClassPrivateProperty: entries(coverClassPropDeclarator),
ObjectMethod: entries(coverFunction),
ExpressionStatement: entries(coverStatement),
BreakStatement: entries(coverStatement),
ContinueStatement: entries(coverStatement),
DebuggerStatement: entries(coverStatement),
ReturnStatement: entries(coverStatement),
ThrowStatement: entries(coverStatement),
TryStatement: entries(coverStatement),
VariableDeclaration: entries(), // ignore processing only
VariableDeclarator: entries(coverVariableDeclarator),
IfStatement: entries(
blockProp('consequent'),
blockProp('alternate'),
coverStatement,
coverIfBranches
),
ForStatement: entries(blockProp('body'), coverStatement),
ForInStatement: entries(blockProp('body'), coverStatement),
ForOfStatement: entries(blockProp('body'), coverStatement),
WhileStatement: entries(blockProp('body'), coverStatement),
DoWhileStatement: entries(blockProp('body'), coverStatement),
SwitchStatement: entries(createSwitchBranch, coverStatement),
SwitchCase: entries(coverSwitchCase),
WithStatement: entries(blockProp('body'), coverStatement),
FunctionDeclaration: entries(coverFunction),
FunctionExpression: entries(coverFunction),
LabeledStatement: entries(coverStatement),
ConditionalExpression: entries(coverTernary),
LogicalExpression: entries(coverLogicalExpression)
};
const globalTemplateAlteredFunction = template(`
var Function = (function(){}).constructor;
var global = (new Function(GLOBAL_COVERAGE_SCOPE))();
`);
const globalTemplateFunction = template(`
var global = (new Function(GLOBAL_COVERAGE_SCOPE))();
`);
const globalTemplateVariable = template(`
var global = GLOBAL_COVERAGE_SCOPE;
`);
// the template to insert at the top of the program.
const coverageTemplate = template(
`
function COVERAGE_FUNCTION () {
var path = PATH;
var hash = HASH;
GLOBAL_COVERAGE_TEMPLATE
var gcv = GLOBAL_COVERAGE_VAR;
var coverageData = INITIAL;
var coverage = global[gcv] || (global[gcv] = {});
if (!coverage[path] || coverage[path].hash !== hash) {
coverage[path] = coverageData;
}
var actualCoverage = coverage[path];
{
// @ts-ignore
COVERAGE_FUNCTION = function () {
return actualCoverage;
}
}
return actualCoverage;
}
`,
{ preserveComments: true }
);
// the rewire plugin (and potentially other babel middleware)
// may cause files to be instrumented twice, see:
// https://github.com/istanbuljs/babel-plugin-istanbul/issues/94
// we should only instrument code for coverage the first time
// it's run through istanbul-lib-instrument.
function alreadyInstrumented(path, visitState) {
return path.scope.hasBinding(visitState.varName);
}
function shouldIgnoreFile(programNode) {
return (
programNode.parent &&
programNode.parent.comments.some(c => COMMENT_FILE_RE.test(c.value))
);
}
/**
* programVisitor is a `babel` adaptor for instrumentation.
* It returns an object with two methods `enter` and `exit`.
* These should be assigned to or called from `Program` entry and exit functions
* in a babel visitor.
* These functions do not make assumptions about the state set by Babel and thus
* can be used in a context other than a Babel plugin.
*
* The exit function returns an object that currently has the following keys:
*
* `fileCoverage` - the file coverage object created for the source file.
* `sourceMappingURL` - any source mapping URL found when processing the file.
*
* @param {Object} types - an instance of babel-types.
* @param {string} sourceFilePath - the path to source file.
* @param {Object} opts - additional options.
* @param {string} [opts.coverageVariable=__coverage__] the global coverage variable name.
* @param {boolean} [opts.reportLogic=false] report boolean value of logical expressions.
* @param {string} [opts.coverageGlobalScope=this] the global coverage variable scope.
* @param {boolean} [opts.coverageGlobalScopeFunc=true] use an evaluated function to find coverageGlobalScope.
* @param {Array} [opts.ignoreClassMethods=[]] names of methods to ignore by default on classes.
* @param {object} [opts.inputSourceMap=undefined] the input source map, that maps the uninstrumented code back to the
* original code.
*/
function programVisitor(types, sourceFilePath = 'unknown.js', opts = {}) {
const T = types;
opts = {
...defaults.instrumentVisitor,
...opts
};
const visitState = new VisitState(
types,
sourceFilePath,
opts.inputSourceMap,
opts.ignoreClassMethods,
opts.reportLogic
);
return {
enter(path) {
if (shouldIgnoreFile(path.find(p => p.isProgram()))) {
return;
}
if (alreadyInstrumented(path, visitState)) {
return;
}
path.traverse(codeVisitor, visitState);
},
exit(path) {
if (alreadyInstrumented(path, visitState)) {
return;
}
visitState.cov.freeze();
const coverageData = visitState.cov.toJSON();
if (shouldIgnoreFile(path.find(p => p.isProgram()))) {
return {
fileCoverage: coverageData,
sourceMappingURL: visitState.sourceMappingURL
};
}
coverageData[MAGIC_KEY] = MAGIC_VALUE;
const hash = createHash(SHA)
.update(JSON.stringify(coverageData))
.digest('hex');
coverageData.hash = hash;
const coverageNode = T.valueToNode(coverageData);
delete coverageData[MAGIC_KEY];
delete coverageData.hash;
let gvTemplate;
if (opts.coverageGlobalScopeFunc) {
if (path.scope.getBinding('Function')) {
gvTemplate = globalTemplateAlteredFunction({
GLOBAL_COVERAGE_SCOPE: T.stringLiteral(
'return ' + opts.coverageGlobalScope
)
});
} else {
gvTemplate = globalTemplateFunction({
GLOBAL_COVERAGE_SCOPE: T.stringLiteral(
'return ' + opts.coverageGlobalScope
)
});
}
} else {
gvTemplate = globalTemplateVariable({
GLOBAL_COVERAGE_SCOPE: opts.coverageGlobalScope
});
}
const cv = coverageTemplate({
GLOBAL_COVERAGE_VAR: T.stringLiteral(opts.coverageVariable),
GLOBAL_COVERAGE_TEMPLATE: gvTemplate,
COVERAGE_FUNCTION: T.identifier(visitState.varName),
PATH: T.stringLiteral(sourceFilePath),
INITIAL: coverageNode,
HASH: T.stringLiteral(hash)
});
// explicitly call this.varName to ensure coverage is always initialized
path.node.body.unshift(
T.expressionStatement(
T.callExpression(T.identifier(visitState.varName), [])
)
);
path.node.body.unshift(cv);
return {
fileCoverage: coverageData,
sourceMappingURL: visitState.sourceMappingURL
};
}
};
}
module.exports = programVisitor;
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