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Closure Compiler is a JavaScript optimizing compiler. It parses your
JavaScript, analyzes it, removes dead code and rewrites and minimizes
what's left. It also checks syntax, variable references, and types, and
warns about common JavaScript pitfalls. It is used in many of Google's
JavaScript apps, including Gmail, Google Web Search, Google Maps, and
Google Docs.
This binary checks for style issues such as incorrect or missing JSDoc
usage, and missing goog.require() statements. It does not do more advanced
checks such as typechecking.
/*
* Copyright 2008 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp.deps;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.CharMatcher;
import com.google.javascript.jscomp.CheckLevel;
import com.google.javascript.jscomp.DiagnosticType;
import com.google.javascript.jscomp.ErrorManager;
import com.google.javascript.jscomp.JSError;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Base class for classes that parse JavaScript sources on a line-by-line basis. Strips comments
* from files and records all parsing errors.
*/
@GwtIncompatible("java.io")
public abstract class JsFileLineParser {
static final DiagnosticType PARSE_WARNING = DiagnosticType.warning(
"DEPS_PARSE_WARNING", "{0}\n{1}");
public static final DiagnosticType PARSE_ERROR = DiagnosticType.error(
"DEPS_PARSE_ERROR", "{0}\n{1}");
boolean shortcutMode = false;
/**
* Thrown by base classes to signify a problem parsing a line.
*/
static class ParseException extends Exception {
public static final long serialVersionUID = 1L;
private final boolean fatal;
/**
* Constructor.
*
* @param message A description of what caused the exception.
* @param fatal Whether the exception is recoverable.
*/
public ParseException(String message, boolean fatal) {
super(message);
this.fatal = fatal;
}
public boolean isFatal() {
return fatal;
}
}
/** Pattern for matching JavaScript string literals. */
private static final Pattern STRING_LITERAL_PATTERN = Pattern.compile(
"\\s*(?:'((?:\\\\'|[^'])*?)'|\"((?:\\\\\"|[^\"])*?)\")\\s*");
/** Matcher used in the parsing string literals. */
private final Matcher valueMatcher = STRING_LITERAL_PATTERN.matcher("");
/** Path of the file currently being parsed. */
String filePath;
/** The line number of the line currently being parsed. */
int lineNum;
/** Handles error messages. */
ErrorManager errorManager;
/** Did our parse succeed. */
boolean parseSucceeded;
/**
* Constructor.
*
* @param errorManager Parse error handler.
*/
public JsFileLineParser(ErrorManager errorManager) {
this.errorManager = errorManager;
}
/**
* In shortcut mode, the file line parser can stop reading early if
* it thinks it found enough information.
*
* For example, many parsers assume that dependency information never
* shows up after "real" code.
*/
public void setShortcutMode(boolean mode) {
this.shortcutMode = mode;
}
public boolean didParseSucceed() {
return parseSucceeded;
}
/**
* Performs the line-by-line parsing of the given fileContents. This method
* strips out JavaScript comments and then uses the abstract parseLine()
* method to do the line parsing.
*
* @param filePath The path to the file being parsed. Used for reporting parse
* exceptions.
* @param fileContents A reader for the contents of the file.
*/
void doParse(String filePath, Reader fileContents) {
this.filePath = filePath;
parseSucceeded = true;
BufferedReader lineBuffer = new BufferedReader(fileContents);
// Parse all lines.
String line = null;
lineNum = 0;
boolean inMultilineComment = false;
boolean inJsDocComment = false;
try {
while (null != (line = lineBuffer.readLine())) {
++lineNum;
try {
String revisedLine = line;
String revisedJsDocCommentLine = "";
if (inMultilineComment) {
int endOfComment = revisedLine.indexOf("*/");
if (endOfComment != -1) {
if (inJsDocComment) {
revisedJsDocCommentLine = revisedLine.substring(0, endOfComment + 2);
inJsDocComment = false;
}
revisedLine = revisedLine.substring(endOfComment + 2);
inMultilineComment = false;
} else {
if (inJsDocComment) {
revisedJsDocCommentLine = line;
}
revisedLine = "";
}
}
if (!inMultilineComment) {
while (true) {
int startOfLineComment = revisedLine.indexOf("//");
int startOfMultilineComment = revisedLine.indexOf("/*");
if (startOfLineComment != -1 &&
(startOfMultilineComment == -1 ||
startOfLineComment < startOfMultilineComment)) {
revisedLine = revisedLine.substring(0, startOfLineComment);
break;
} else if (startOfMultilineComment != -1) {
// If comment is in a string (single or double quoted), don't parse as a comment.
if (isCommentQuoted(revisedLine, startOfMultilineComment, '\'')) {
break;
}
if (isCommentQuoted(revisedLine, startOfMultilineComment, '"')) {
break;
}
if (startOfMultilineComment == revisedLine.indexOf("/**")) {
inJsDocComment = true;
}
int endOfMultilineComment = revisedLine.indexOf("*/", startOfMultilineComment + 2);
if (endOfMultilineComment == -1) {
if (inJsDocComment) {
revisedJsDocCommentLine = revisedLine.substring(startOfMultilineComment);
}
revisedLine = revisedLine.substring(0, startOfMultilineComment);
inMultilineComment = true;
break;
} else {
if (inJsDocComment) {
String jsDocComment =
revisedLine.substring(startOfMultilineComment, endOfMultilineComment + 2);
if (!parseJsDocCommentLine(jsDocComment) && shortcutMode) {
break;
}
inJsDocComment = false;
}
revisedLine =
revisedLine.substring(0, startOfMultilineComment) +
revisedLine.substring(endOfMultilineComment + 2);
}
} else {
break;
}
}
}
if (!revisedJsDocCommentLine.isEmpty()) {
if (!parseJsDocCommentLine(revisedJsDocCommentLine) && shortcutMode) {
break;
}
}
if (!revisedLine.isEmpty()) {
// This check for shortcut mode should be redundant, but
// it's done for safety reasons.
if (!parseLine(revisedLine) && shortcutMode) {
break;
}
}
} catch (ParseException e) {
// Inform the error handler of the exception.
errorManager.report(
e.isFatal() ? CheckLevel.ERROR : CheckLevel.WARNING,
JSError.make(filePath, lineNum, 0 /* char offset */,
e.isFatal() ? PARSE_ERROR : PARSE_WARNING,
e.getMessage(), line));
parseSucceeded = parseSucceeded && !e.isFatal();
}
}
} catch (IOException e) {
errorManager.report(CheckLevel.ERROR,
JSError.make(filePath, 0, 0 /* char offset */,
PARSE_ERROR, "Error reading file: " + filePath));
parseSucceeded = false;
}
}
private boolean isCommentQuoted(String line, int startOfMultilineComment, char quoteChar) {
int startQuoteIndex = line.indexOf(quoteChar);
// Loop in case there are multiple strings between start of line and start of the comment.
while (startQuoteIndex != -1 && startQuoteIndex < startOfMultilineComment) {
int closingQuoteIndex = line.indexOf(quoteChar, startQuoteIndex + 1);
if (closingQuoteIndex == -1) {
return false;
}
;
// Skip escaped quotes
while (isEscaped(line, closingQuoteIndex)) {
closingQuoteIndex = line.indexOf(quoteChar, closingQuoteIndex + 1);
if (closingQuoteIndex == -1) {
return false;
}
}
if (closingQuoteIndex > startOfMultilineComment) {
return true;
}
startQuoteIndex = line.indexOf(quoteChar, closingQuoteIndex + 1);
}
return false;
}
private boolean isEscaped(String line, int closingQuoteIndex) {
int escapeCharCount = 0;
int index = closingQuoteIndex - 1;
while (line.charAt(index) == '\\') {
index--;
escapeCharCount++;
}
// Odd number of backslashes means one is actually escaping the quote. Otherwise they are
// literal backslashes which are being escaped by another backslash.
return escapeCharCount % 2 == 1;
}
/**
* Called for each line of the file being parsed.
*
* @param line The line to parse.
* @return true to keep going, false otherwise.
* @throws ParseException Should be thrown to signify a problem with the line.
*/
abstract boolean parseLine(String line) throws ParseException;
/**
* Called for each JSDoc line of the file being parsed.
*
* @param line The JSDoc comment line to parse.
* @return true to keep going, false otherwise.
*/
boolean parseJsDocCommentLine(String line) {
return true;
}
/**
* Parses a JS string literal.
*
* @param jsStringLiteral The literal. Must look like "asdf" or 'asdf'
* @throws ParseException Thrown if there is a string literal that cannot be parsed.
*/
String parseJsString(String jsStringLiteral) throws ParseException {
valueMatcher.reset(jsStringLiteral);
if (!valueMatcher.matches()) {
throw new ParseException("Syntax error in JS String literal", true /* fatal */);
}
return valueMatcher.group(1) != null ? valueMatcher.group(1) : valueMatcher.group(2);
}
/**
* Parses a JavaScript array of string literals. (eg: ['a', 'b', "c"]).
* @param input A string containing a JavaScript array of string literals.
* @return A list of parsed string literals.
* @throws ParseException Thrown if there is a syntax error with the input.
*/
List parseJsStringArray(String input)
throws ParseException {
List results = new ArrayList<>();
int indexStart = input.indexOf('[');
int indexEnd = input.lastIndexOf(']');
if ((indexStart == -1) || (indexEnd == -1)) {
throw new ParseException("Syntax error when parsing JS array", true /* fatal */);
}
String innerValues = input.substring(indexStart + 1, indexEnd);
if (!innerValues.trim().isEmpty()) {
valueMatcher.reset(innerValues);
for (;;) {
// Parse the current string literal.
if (!valueMatcher.lookingAt()) {
throw new ParseException("Syntax error in JS String literal", true /* fatal */);
}
// Add it to the results.
results.add(valueMatcher.group(1) != null ?
valueMatcher.group(1) : valueMatcher.group(2));
if (valueMatcher.hitEnd()) {
break;
}
// Ensure there is a comma after the value.
if (innerValues.charAt(valueMatcher.end()) != ',') {
throw new ParseException("Missing comma in string array", true /* fatal */);
}
// Move to the next value.
valueMatcher.region(valueMatcher.end() + 1, valueMatcher.regionEnd());
}
}
return results;
}
// TODO(sdh): Consider simplifying this by reusing the parser or a separate JSON library.
/**
* Parses a JavaScript map of string literals. (eg: {'a': 'b', "c": "d"}).
* @param input A string containing a JavaScript map of string literals.
* @return A map of parsed string literals.
* @throws ParseException Thrown if there is a syntax error with the input.
*/
Map parseJsStringMap(String input) throws ParseException {
input = CharMatcher.whitespace().trimFrom(input);
check(
!input.isEmpty() && input.charAt(0) == '{' && input.charAt(input.length() - 1) == '}',
"Syntax error when parsing JS object");
input = input.substring(1, input.length() - 1).trim();
Map results = new LinkedHashMap<>();
boolean done = input.isEmpty();
valueMatcher.reset(input);
while (!done) {
// Parse the next key (TODO(sdh): need to support non-quoted keys?).
check(valueMatcher.lookingAt(), "Bad key in JS object literal");
String key = valueMatcher.group(1) != null ? valueMatcher.group(1) : valueMatcher.group(2);
check(!valueMatcher.hitEnd(), "Missing value in JS object literal");
check(input.charAt(valueMatcher.end()) == ':', "Missing colon in JS object literal");
valueMatcher.region(valueMatcher.end() + 1, valueMatcher.regionEnd());
// Parse the corresponding value.
check(valueMatcher.lookingAt(), "Bad value in JS object literal");
String val = valueMatcher.group(1) != null ? valueMatcher.group(1) : valueMatcher.group(2);
results.put(key, val);
if (!valueMatcher.hitEnd()) {
check(input.charAt(valueMatcher.end()) == ',', "Missing comma in JS object literal");
valueMatcher.region(valueMatcher.end() + 1, valueMatcher.regionEnd());
} else {
done = true;
}
}
return results;
}
private static void check(boolean condition, String message) throws ParseException {
if (!condition) {
throw new ParseException(message, true /* fatal */);
}
}
}