com.google.errorprone.bugpatterns.UnicodeDirectionalityCharacters Maven / Gradle / Ivy
/*
* Copyright 2021 The Error Prone 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.errorprone.bugpatterns;
import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.CompilationUnitTreeMatcher;
import com.google.errorprone.fixes.FixedPosition;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.sun.source.tree.CompilationUnitTree;
/** Bans, without the possibility of suppression, the use of direction-changing Unicode escapes. */
@BugPattern(
severity = ERROR,
summary = "Unicode directionality modifiers can be used to conceal code in many editors.",
disableable = false)
public final class UnicodeDirectionalityCharacters extends BugChecker
implements CompilationUnitTreeMatcher {
@Override
public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState state) {
CharSequence source = state.getSourceCode();
for (int i = 0; i < source.length(); ++i) {
char c = source.charAt(i);
// Do not extract this switch to a method. It's ugly as-is, but profiling suggests this
// checker is expensive for large files, and also that the method-call overhead would
// double the time spent in this loop.
switch (c) {
case 0x202A: // Left-to-Right Embedding
case 0x202B: // Right-to-Left Embedding
case 0x202C: // Pop Directional Formatting
case 0x202D: // Left-to-Right Override
case 0x202E: // Right-to-Left Override
case 0x2066: // Left-to-Right Isolate
case 0x2067: // Right-to-Left Isolate
case 0x2068: // First Strong Isolate
case 0x2069: // Pop Directional Isolate
state.reportMatch(
describeMatch(
new FixedPosition(tree, i),
SuggestedFix.replace(i, i + 1, String.format("\\u%04x", (int) c))));
break;
default:
break;
}
}
return NO_MATCH;
}
}