1 files changed, 41 insertions, 0 deletions
diff --git a/json/src/com/jetbrains/jsonSchema/impl/CachedValueProviderOnPsiFile.java b/json/src/com/jetbrains/jsonSchema/impl/CachedValueProviderOnPsiFile.java
new file mode 100644
index 00000000..b069841a
--- /dev/null
+++ b/json/src/com/jetbrains/jsonSchema/impl/CachedValueProviderOnPsiFile.java
@@ -0,0 +1,41 @@
+// 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.jetbrains.jsonSchema.impl;
+
+import com.intellij.openapi.application.ReadAction;
+import com.intellij.openapi.util.Key;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.util.CachedValue;
+import com.intellij.psi.util.CachedValueProvider;
+import com.intellij.psi.util.CachedValuesManager;
+import com.intellij.util.Function;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public abstract class CachedValueProviderOnPsiFile<T> implements CachedValueProvider<T> {
+  private final PsiFile myPsiFile;
+
+  public CachedValueProviderOnPsiFile(@NotNull PsiFile psiFile) {
+    myPsiFile = psiFile;
+  }
+
+  @Nullable
+  @Override
+  public Result<T> compute() {
+    return CachedValueProvider.Result.create(evaluate(myPsiFile), myPsiFile);
+  }
+
+  @Nullable
+  public abstract T evaluate(@NotNull PsiFile psiFile);
+
+  @Nullable
+  public static <T> T getOrCompute(@NotNull PsiFile psiFile, @NotNull Function<? super PsiFile, ? extends T> eval, @NotNull Key<CachedValue<T>> key) {
+    final CachedValueProvider<T> provider = new CachedValueProviderOnPsiFile<T>(psiFile) {
+      @Override
+      @Nullable
+      public T evaluate(@NotNull PsiFile psiFile) {
+        return eval.fun(psiFile);
+      }
+    };
+    return ReadAction.compute(() -> CachedValuesManager.getCachedValue(psiFile, key, provider));
+  }
+}