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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.
The newest version!
/*
* Copyright 2007 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;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.javascript.jscomp.SourceExcerptProvider.SourceExcerpt.LINE;
import com.google.common.base.Strings;
import com.google.debugging.sourcemap.proto.Mapping.OriginalMapping;
import com.google.javascript.jscomp.SourceExcerptProvider.ExcerptFormatter;
import com.google.javascript.jscomp.SourceExcerptProvider.SourceExcerpt;
import com.google.javascript.rhino.TokenUtil;
/**
* Lightweight message formatter. The format of messages this formatter
* produces is very compact and to the point.
*
*/
public final class LightweightMessageFormatter extends AbstractMessageFormatter {
private final SourceExcerpt excerpt;
private static final ExcerptFormatter excerptFormatter =
new LineNumberingFormatter();
private boolean includeLocation = true;
private boolean includeLevel = true;
/**
* A constructor for when the client doesn't care about source information.
*/
private LightweightMessageFormatter() {
super(null);
this.excerpt = LINE;
}
public LightweightMessageFormatter(SourceExcerptProvider source) {
this(source, LINE);
}
public LightweightMessageFormatter(SourceExcerptProvider source,
SourceExcerpt excerpt) {
super(source);
checkNotNull(source);
this.excerpt = excerpt;
}
public static LightweightMessageFormatter withoutSource() {
return new LightweightMessageFormatter();
}
public LightweightMessageFormatter setIncludeLocation(boolean includeLocation) {
this.includeLocation = includeLocation;
return this;
}
public LightweightMessageFormatter setIncludeLevel(boolean includeLevel) {
this.includeLevel = includeLevel;
return this;
}
@Override
public String formatError(JSError error) {
return format(error, false);
}
@Override
public String formatWarning(JSError warning) {
return format(warning, true);
}
private String format(JSError error, boolean warning) {
SourceExcerptProvider source = getSource();
String sourceName = error.sourceName;
int lineNumber = error.lineNumber;
int charno = error.getCharno();
// Format the non-reverse-mapped position.
StringBuilder b = new StringBuilder();
StringBuilder boldLine = new StringBuilder();
String nonMappedPosition = formatPosition(sourceName, lineNumber);
// Check if we can reverse-map the source.
if (includeLocation) {
OriginalMapping mapping = source == null ? null : source.getSourceMapping(
error.sourceName, error.lineNumber, error.getCharno());
if (mapping == null) {
boldLine.append(nonMappedPosition);
} else {
sourceName = mapping.getOriginalFile();
lineNumber = mapping.getLineNumber();
charno = mapping.getColumnPosition();
b.append(nonMappedPosition);
b.append("\nOriginally at:\n");
boldLine.append(formatPosition(sourceName, lineNumber));
}
}
if (includeLevel) {
boldLine.append(getLevelName(warning ? CheckLevel.WARNING : CheckLevel.ERROR));
boldLine.append(" - ");
}
boldLine.append(error.description);
b.append(maybeEmbolden(boldLine.toString()));
b.append('\n');
String sourceExcerptWithPositionIndicator =
getExcerptWithPosition(error, sourceName, lineNumber, charno);
if (sourceExcerptWithPositionIndicator != null) {
b.append(sourceExcerptWithPositionIndicator);
}
return b.toString();
}
String getExcerptWithPosition(JSError error) {
return getExcerptWithPosition(error, error.sourceName, error.lineNumber, error.getCharno());
}
String getExcerptWithPosition(JSError error, String sourceName, int lineNumber, int charno) {
StringBuilder b = new StringBuilder();
SourceExcerptProvider source = getSource();
String sourceExcerpt =
source == null ? null : excerpt.get(source, sourceName, lineNumber, excerptFormatter);
if (sourceExcerpt != null) {
b.append(sourceExcerpt);
b.append('\n');
// padding equal to the excerpt and arrow at the end
// charno == sourceExcerpt.length() means something is missing
// at the end of the line
if (excerpt.equals(LINE) && 0 <= charno && charno <= sourceExcerpt.length()) {
for (int i = 0; i < charno; i++) {
char c = sourceExcerpt.charAt(i);
if (TokenUtil.isWhitespace(c)) {
b.append(c);
} else {
b.append(' ');
}
}
if (error.node == null) {
b.append("^");
} else {
int length =
Math.max(1, Math.min(error.node.getLength(), sourceExcerpt.length() - charno));
for (int i = 0; i < length; i++) {
b.append("^");
}
}
b.append("\n");
}
}
return b.toString();
}
private static String formatPosition(String sourceName, int lineNumber) {
StringBuilder b = new StringBuilder();
if (sourceName != null) {
b.append(sourceName);
if (lineNumber > 0) {
b.append(':');
b.append(lineNumber);
}
b.append(": ");
}
return b.toString();
}
/**
* Formats a region by appending line numbers in front, e.g.
*
*
* 9| if (foo) {
* 10| alert('bar');
* 11| }
*
*
* and return line excerpt without any modification.
*/
static class LineNumberingFormatter implements ExcerptFormatter {
@Override
public String formatLine(String line, int lineNumber) {
return line;
}
@Override
public String formatRegion(Region region) {
if (region == null) {
return null;
}
String code = region.getSourceExcerpt();
if (code.isEmpty()) {
return null;
}
// max length of the number display
int numberLength = Integer.toString(region.getEndingLineNumber())
.length();
// formatting
StringBuilder builder = new StringBuilder(code.length() * 2);
int start = 0;
int end = code.indexOf('\n', start);
int lineNumber = region.getBeginningLineNumber();
while (start >= 0) {
// line extraction
String line;
if (end < 0) {
line = code.substring(start);
if (line.isEmpty()) {
return builder.substring(0, builder.length() - 1);
}
} else {
line = code.substring(start, end);
}
builder.append(" ");
// nice spaces for the line number
int spaces = numberLength - Integer.toString(lineNumber).length();
builder.append(Strings.repeat(" ", spaces));
builder.append(lineNumber);
builder.append("| ");
// end & update
if (end < 0) {
builder.append(line);
start = -1;
} else {
builder.append(line);
builder.append('\n');
start = end + 1;
end = code.indexOf('\n', start);
lineNumber++;
}
}
return builder.toString();
}
}
}