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"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.callExpressionAffectsControlFlow = exports.SignatureEffect = exports.getControlFlowEnd = exports.endsControlFlow = void 0;
const ts = require("typescript");
const node_1 = require("../typeguard/node");
const util_1 = require("./util");
function endsControlFlow(statement, checker) {
return getControlFlowEnd(statement, checker).end;
}
exports.endsControlFlow = endsControlFlow;
const defaultControlFlowEnd = { statements: [], end: false };
function getControlFlowEnd(statement, checker) {
return node_1.isBlockLike(statement) ? handleBlock(statement, checker) : getControlFlowEndWorker(statement, checker);
}
exports.getControlFlowEnd = getControlFlowEnd;
function getControlFlowEndWorker(statement, checker) {
switch (statement.kind) {
case ts.SyntaxKind.ReturnStatement:
case ts.SyntaxKind.ThrowStatement:
case ts.SyntaxKind.ContinueStatement:
case ts.SyntaxKind.BreakStatement:
return { statements: [statement], end: true };
case ts.SyntaxKind.Block:
return handleBlock(statement, checker);
case ts.SyntaxKind.ForStatement:
case ts.SyntaxKind.WhileStatement:
return handleForAndWhileStatement(statement, checker);
case ts.SyntaxKind.ForOfStatement:
case ts.SyntaxKind.ForInStatement:
return handleForInOrOfStatement(statement, checker);
case ts.SyntaxKind.DoStatement:
return matchBreakOrContinue(getControlFlowEndWorker(statement.statement, checker), node_1.isBreakOrContinueStatement);
case ts.SyntaxKind.IfStatement:
return handleIfStatement(statement, checker);
case ts.SyntaxKind.SwitchStatement:
return matchBreakOrContinue(handleSwitchStatement(statement, checker), node_1.isBreakStatement);
case ts.SyntaxKind.TryStatement:
return handleTryStatement(statement, checker);
case ts.SyntaxKind.LabeledStatement:
return matchLabel(getControlFlowEndWorker(statement.statement, checker), statement.label);
case ts.SyntaxKind.WithStatement:
return getControlFlowEndWorker(statement.statement, checker);
case ts.SyntaxKind.ExpressionStatement:
if (checker === undefined)
return defaultControlFlowEnd;
return handleExpressionStatement(statement, checker);
default:
return defaultControlFlowEnd;
}
}
function handleBlock(statement, checker) {
const result = { statements: [], end: false };
for (const s of statement.statements) {
const current = getControlFlowEndWorker(s, checker);
result.statements.push(...current.statements);
if (current.end) {
result.end = true;
break;
}
}
return result;
}
function handleForInOrOfStatement(statement, checker) {
const end = matchBreakOrContinue(getControlFlowEndWorker(statement.statement, checker), node_1.isBreakOrContinueStatement);
end.end = false; // loop body is guaranteed to be executed
return end;
}
function handleForAndWhileStatement(statement, checker) {
const constantCondition = statement.kind === ts.SyntaxKind.WhileStatement
? getConstantCondition(statement.expression)
: statement.condition === undefined || getConstantCondition(statement.condition);
if (constantCondition === false)
return defaultControlFlowEnd; // loop body is never executed
const end = matchBreakOrContinue(getControlFlowEndWorker(statement.statement, checker), node_1.isBreakOrContinueStatement);
if (constantCondition === undefined)
end.end = false; // can't be sure that loop body is executed at all
return end;
}
/** Simply detects `true` and `false` in conditions. That matches TypeScript's behavior. */
function getConstantCondition(node) {
switch (node.kind) {
case ts.SyntaxKind.TrueKeyword:
return true;
case ts.SyntaxKind.FalseKeyword:
return false;
default:
return;
}
}
function handleIfStatement(node, checker) {
switch (getConstantCondition(node.expression)) {
case true:
// else branch is never executed
return getControlFlowEndWorker(node.thenStatement, checker);
case false:
// then branch is never executed
return node.elseStatement === undefined
? defaultControlFlowEnd
: getControlFlowEndWorker(node.elseStatement, checker);
}
const then = getControlFlowEndWorker(node.thenStatement, checker);
if (node.elseStatement === undefined)
return {
statements: then.statements,
end: false,
};
const elze = getControlFlowEndWorker(node.elseStatement, checker);
return {
statements: [...then.statements, ...elze.statements],
end: then.end && elze.end,
};
}
function handleSwitchStatement(node, checker) {
let hasDefault = false;
const result = {
statements: [],
end: false,
};
for (const clause of node.caseBlock.clauses) {
if (clause.kind === ts.SyntaxKind.DefaultClause)
hasDefault = true;
const current = handleBlock(clause, checker);
result.end = current.end;
result.statements.push(...current.statements);
}
result.end && (result.end = hasDefault || checker !== undefined && util_1.hasExhaustiveCaseClauses(node, checker));
return result;
}
function handleTryStatement(node, checker) {
let finallyResult;
if (node.finallyBlock !== undefined) {
finallyResult = handleBlock(node.finallyBlock, checker);
// if 'finally' always ends control flow, we are not interested in any jump statements from 'try' or 'catch'
if (finallyResult.end)
return finallyResult;
}
const tryResult = handleBlock(node.tryBlock, checker);
if (node.catchClause === undefined)
return { statements: finallyResult.statements.concat(tryResult.statements), end: tryResult.end };
const catchResult = handleBlock(node.catchClause.block, checker);
return {
statements: tryResult.statements
// remove all throw statements and throwing function calls from the list of control flow statements inside tryBlock
.filter((s) => s.kind !== ts.SyntaxKind.ThrowStatement && s.kind !== ts.SyntaxKind.ExpressionStatement)
.concat(catchResult.statements, finallyResult === undefined ? [] : finallyResult.statements),
end: tryResult.end && catchResult.end, // only ends control flow if try AND catch definitely end control flow
};
}
/** Dotted name as TypeScript requires it for assertion signatures to affect control flow. */
function isDottedNameWithExplicitTypeAnnotation(node, checker) {
while (true) {
switch (node.kind) {
case ts.SyntaxKind.Identifier: {
const symbol = checker.getExportSymbolOfSymbol(checker.getSymbolAtLocation(node));
return isExplicitlyTypedSymbol(util_1.isSymbolFlagSet(symbol, ts.SymbolFlags.Alias) ? checker.getAliasedSymbol(symbol) : symbol, checker);
}
case ts.SyntaxKind.ThisKeyword:
return isExplicitlyTypedThis(node);
case ts.SyntaxKind.SuperKeyword:
return true;
case ts.SyntaxKind.PropertyAccessExpression:
if (!isExplicitlyTypedSymbol(checker.getSymbolAtLocation(node), checker))
return false;
// falls through
case ts.SyntaxKind.ParenthesizedExpression:
node = node.expression;
continue;
default:
return false;
}
}
}
function isExplicitlyTypedSymbol(symbol, checker) {
if (symbol === undefined)
return false;
if (util_1.isSymbolFlagSet(symbol, ts.SymbolFlags.Function | ts.SymbolFlags.Method | ts.SymbolFlags.Class | ts.SymbolFlags.ValueModule))
return true;
if (!util_1.isSymbolFlagSet(symbol, ts.SymbolFlags.Variable | ts.SymbolFlags.Property))
return false;
if (symbol.valueDeclaration === undefined)
return false;
if (declarationHasExplicitTypeAnnotation(symbol.valueDeclaration))
return true;
return node_1.isVariableDeclaration(symbol.valueDeclaration) &&
symbol.valueDeclaration.parent.parent.kind === ts.SyntaxKind.ForOfStatement &&
isDottedNameWithExplicitTypeAnnotation(symbol.valueDeclaration.parent.parent.expression, checker);
}
function declarationHasExplicitTypeAnnotation(node) {
if (ts.isJSDocPropertyLikeTag(node))
return node.typeExpression !== undefined;
return (node_1.isVariableDeclaration(node) ||
node_1.isParameterDeclaration(node) ||
node_1.isPropertyDeclaration(node) ||
node_1.isPropertySignature(node)) && (util_1.isNodeFlagSet(node, ts.NodeFlags.JavaScriptFile)
? ts.getJSDocType(node)
: node.type) !== undefined;
}
function isExplicitlyTypedThis(node) {
var _a;
do {
node = node.parent;
if (node_1.isDecorator(node)) {
// `this` in decorators always resolves outside of the containing class
if (node.parent.kind === ts.SyntaxKind.Parameter && node_1.isClassLikeDeclaration(node.parent.parent.parent)) {
node = node.parent.parent.parent.parent;
}
else if (node_1.isClassLikeDeclaration(node.parent.parent)) {
node = node.parent.parent.parent;
}
else if (node_1.isClassLikeDeclaration(node.parent)) {
node = node.parent.parent;
}
}
} while (util_1.isFunctionScopeBoundary(node) !== 1 /* Function */ || node.kind === ts.SyntaxKind.ArrowFunction);
return util_1.isFunctionWithBody(node) &&
(util_1.isNodeFlagSet(node, ts.NodeFlags.JavaScriptFile)
? ((_a = ts.getJSDocThisTag(node)) === null || _a === void 0 ? void 0 : _a.typeExpression) !== undefined
: node.parameters.length !== 0 && util_1.isThisParameter(node.parameters[0]) && node.parameters[0].type !== undefined) ||
node_1.isClassLikeDeclaration(node.parent);
}
var SignatureEffect;
(function (SignatureEffect) {
SignatureEffect[SignatureEffect["Never"] = 1] = "Never";
SignatureEffect[SignatureEffect["Asserts"] = 2] = "Asserts";
})(SignatureEffect = exports.SignatureEffect || (exports.SignatureEffect = {}));
/**
* Dermines whether a top level CallExpression has a control flow effect according to TypeScript's rules.
* This handles functions returning `never` and `asserts`.
*/
function callExpressionAffectsControlFlow(node, checker) {
var _a, _b, _c;
if (!node_1.isExpressionStatement(node.parent) ||
ts.isOptionalChain(node) ||
!isDottedNameWithExplicitTypeAnnotation(node.expression, checker))
return;
const signature = checker.getResolvedSignature(node);
if ((signature === null || signature === void 0 ? void 0 : signature.declaration) === undefined)
return;
const typeNode = ts.isJSDocSignature(signature.declaration)
? (_b = (_a = signature.declaration.type) === null || _a === void 0 ? void 0 : _a.typeExpression) === null || _b === void 0 ? void 0 : _b.type
: (_c = signature.declaration.type) !== null && _c !== void 0 ? _c : (util_1.isNodeFlagSet(signature.declaration, ts.NodeFlags.JavaScriptFile)
? ts.getJSDocReturnType(signature.declaration)
: undefined);
if (typeNode === undefined)
return;
if (node_1.isTypePredicateNode(typeNode) && typeNode.assertsModifier !== undefined)
return 2 /* Asserts */;
return util_1.isTypeFlagSet(checker.getTypeFromTypeNode(typeNode), ts.TypeFlags.Never) ? 1 /* Never */ : undefined;
}
exports.callExpressionAffectsControlFlow = callExpressionAffectsControlFlow;
function handleExpressionStatement(node, checker) {
if (!node_1.isCallExpression(node.expression))
return defaultControlFlowEnd;
switch (callExpressionAffectsControlFlow(node.expression, checker)) {
case 2 /* Asserts */:
return { statements: [node], end: false };
case 1 /* Never */:
return { statements: [node], end: true };
case undefined:
return defaultControlFlowEnd;
}
}
function matchBreakOrContinue(current, pred) {
const result = {
statements: [],
end: current.end,
};
for (const statement of current.statements) {
if (pred(statement) && statement.label === undefined) {
result.end = false;
continue;
}
result.statements.push(statement);
}
return result;
}
function matchLabel(current, label) {
const result = {
statements: [],
end: current.end,
};
const labelText = label.text;
for (const statement of current.statements) {
switch (statement.kind) {
case ts.SyntaxKind.BreakStatement:
case ts.SyntaxKind.ContinueStatement:
if (statement.label !== undefined && statement.label.text === labelText) {
result.end = false;
continue;
}
}
result.statements.push(statement);
}
return result;
}
//# sourceMappingURL=control-flow.js.map
Zerion Mini Shell 1.0