1 files changed, 52 insertions, 0 deletions
diff --git a/json/src/com/intellij/json/json5/codeinsight/Json5JsonLiteralChecker.java b/json/src/com/intellij/json/json5/codeinsight/Json5JsonLiteralChecker.java
new file mode 100644
index 00000000..1ed1f273
--- /dev/null
+++ b/json/src/com/intellij/json/json5/codeinsight/Json5JsonLiteralChecker.java
@@ -0,0 +1,52 @@
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.json.json5.codeinsight;
+
+import com.intellij.json.JsonDialectUtil;
+import com.intellij.json.codeinsight.JsonLiteralChecker;
+import com.intellij.json.codeinsight.StandardJsonLiteralChecker;
+import com.intellij.json.json5.Json5Language;
+import com.intellij.json.psi.JsonStringLiteral;
+import com.intellij.openapi.util.Pair;
+import com.intellij.openapi.util.TextRange;
+import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.psi.PsiElement;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.regex.Pattern;
+
+public class Json5JsonLiteralChecker implements JsonLiteralChecker {
+  private static final Pattern VALID_HEX_ESCAPE = Pattern.compile("\\\\(x[0-9a-fA-F]{2})");
+  private static final Pattern INVALID_NUMERIC_ESCAPE = Pattern.compile("\\\\[1-9]");
+  @Nullable
+  @Override
+  public String getErrorForNumericLiteral(String literalText) {
+    return null;
+  }
+
+  @Nullable
+  @Override
+  public Pair<TextRange, String> getErrorForStringFragment(Pair<TextRange, String> fragment, JsonStringLiteral stringLiteral) {
+    String fragmentText = fragment.second;
+    if (fragmentText.startsWith("\\") && fragmentText.length() > 1 && fragmentText.endsWith("\n")) {
+      if (StringUtil.isEmptyOrSpaces(fragmentText.substring(1, fragmentText.length() - 1))) {
+        return null;
+      }
+    }
+
+    if (fragmentText.startsWith("\\x") && VALID_HEX_ESCAPE.matcher(fragmentText).matches()) {
+      return null;
+    }
+
+    if (!StandardJsonLiteralChecker.VALID_ESCAPE.matcher(fragmentText).matches() && !INVALID_NUMERIC_ESCAPE.matcher(fragmentText).matches()) {
+      return null;
+    }
+
+    final String error = StandardJsonLiteralChecker.getStringError(fragmentText);
+    return error == null ? null : Pair.create(fragment.first, error);
+  }
+
+  @Override
+  public boolean isApplicable(PsiElement element) {
+    return JsonDialectUtil.getLanguage(element) == Json5Language.INSTANCE;
+  }
+}