org.gwtproject.safehtml.shared.SafeHtmlHostedModeUtils Maven / Gradle / Ivy
/*
* Copyright © 2019 The GWT Project 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 org.gwtproject.safehtml.shared;
import com.google.streamhtmlparser.HtmlParser;
import com.google.streamhtmlparser.HtmlParserFactory;
import com.google.streamhtmlparser.ParseException;
import org.gwtproject.safehtml.shared.annotations.GwtIncompatible;
/**
* SafeHtml utilities whose implementation differs between Development and Production Mode.
*
* This class has a super-source peer that provides the Production Mode implementation.
*/
public class SafeHtmlHostedModeUtils {
/**
* Name of system property that if set, enables checks in server-side code (even if assertions are
* disabled).
*/
public static final String FORCE_CHECK_COMPLETE_HTML =
"com.google.gwt.safehtml.ForceCheckCompleteHtml";
private static final JreImpl impl = new JreImpl();
private static boolean forceCheckCompleteHtml;
static {
setForceCheckCompleteHtmlFromProperty();
}
/**
* Returns whether the provided HTML string is complete (ends in "inner HTML" context).
*
*
This method parses the provided string as HTML and determines the HTML context at the end of
* the string. This method returns true if and only if the context is "inner HTML text".
*
*
For example, this method returns true for the following strings:
*
*
{@code
* blah
* bazfoo hello
* }
*
* This method returns false for the following strings:
*
*
{@code
* bazfoo foo
*
* Note that the parser is lenient and this method will return true for HTML that is not
* well-formed, or contains invalid tags, as long as the parser can determine the HTML context at
* the end of the string.
*
* @param html the HTML to check.
* @return true if the provided HTML string is complete.
*/
public static boolean isCompleteHtml(String html) {
return impl.isCompleteHtml(html);
}
/**
* Conditionally checks if the provided HTML string is complete (ends in "inner HTML" context).
*
*
This check is intended to assert a convention-of-use constraint of {@link
* SafeHtmlBuilder#appendHtmlConstant(String)} and {@link SafeHtmlUtils#fromSafeConstant(String)}.
* Since the check is somewhat expensive, it is intended to run only in the context of unit-tests
* or test environments, and not in production environments. Hence this check will only execute
* under the following conditions, and will be short-circuited otherwise:
*
*
* - In client-side code in Development Mode,
*
- In server-side code if assertions are enabled,
*
- In server-side code if the property {@code
* com.google.gwt.safehtml.ForceCheckCompleteHtml} is set.
*
- In server-side code if {@link #setForceCheckCompleteHtml(boolean)} has been called with a
* {@code true} argument.
*
*
* @param html the HTML to check
* @see #isCompleteHtml(String)
*/
public static void maybeCheckCompleteHtml(String html) {
impl.maybeCheckCompleteHtml(html);
}
/**
* Sets a global flag that controls whether or not {@link #maybeCheckCompleteHtml(String)} should
* perform its check in a server-side environment.
*
* @param check if true, perform server-side checks.
*/
public static void setForceCheckCompleteHtml(boolean check) {
forceCheckCompleteHtml = check;
}
/**
* Sets a global flag that controls whether or not {@link #maybeCheckCompleteHtml(String)} should
* perform its check in a server-side environment from the value of the {@value
* FORCE_CHECK_COMPLETE_HTML} property.
*/
// The following annotation causes javadoc to crash on Mac OS X 10.5.8,
// using java 1.5.0_24.
//
// See http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6442982
//
// @VisibleForTesting
public static void setForceCheckCompleteHtmlFromProperty() {
forceCheckCompleteHtml = impl.getForceCheckCompleteHtmlFromProperty();
}
private static class JsImpl {
public boolean isCompleteHtml(String html) {
return true;
}
public void maybeCheckCompleteHtml(String html) {}
public boolean getForceCheckCompleteHtmlFromProperty() {
return false;
}
}
private static class JreImpl extends JsImpl {
@GwtIncompatible
@Override
public boolean isCompleteHtml(String html) {
HtmlParser htmlParser = HtmlParserFactory.createParser();
try {
htmlParser.parse(html);
} catch (ParseException e) {
return false;
}
return htmlParser.getState() == HtmlParser.STATE_TEXT
&& !htmlParser.inJavascript()
&& !htmlParser.inCss();
}
@GwtIncompatible
@Override
public void maybeCheckCompleteHtml(String html) {
if (forceCheckCompleteHtml) {
checkArgument(
isCompleteHtml(html),
"String is not complete HTML (ends in non-inner-HTML context): " + html);
} else {
assert isCompleteHtml(html)
: "String is not complete HTML (ends in non-inner-HTML context): " + html;
}
}
private static void checkArgument(boolean completeHtml, String message) {
if (!completeHtml) {
throw new IllegalArgumentException(message);
}
}
@GwtIncompatible
@Override
public boolean getForceCheckCompleteHtmlFromProperty() {
return System.getProperty(FORCE_CHECK_COMPLETE_HTML) != null;
}
}
}