From bed035b0ad23e511518ace0e76d0c9c7facea9d1 Mon Sep 17 00:00:00 2001
From: Alexandr Evstigneev <Alexandr.Evstigneev@jetbrains.com>
Date: Mon, 8 Oct 2018 19:50:25 +0300
Subject: [PATCH] Abstract handler move to the platform

---
 .../AbstractCodeBlockSupportHandler.java      | 116 ++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 platform/lang-impl/src/com/intellij/codeInsight/highlighting/AbstractCodeBlockSupportHandler.java

diff --git a/platform/lang-impl/src/com/intellij/codeInsight/highlighting/AbstractCodeBlockSupportHandler.java b/platform/lang-impl/src/com/intellij/codeInsight/highlighting/AbstractCodeBlockSupportHandler.java
new file mode 100644
index 000000000000..b065474ff5ec
--- /dev/null
+++ b/platform/lang-impl/src/com/intellij/codeInsight/highlighting/AbstractCodeBlockSupportHandler.java
@@ -0,0 +1,116 @@
+// 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.codeInsight.highlighting;
+
+import com.intellij.openapi.util.TextRange;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.tree.IElementType;
+import com.intellij.psi.tree.TokenSet;
+import com.intellij.psi.util.PsiUtilCore;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * This implementation collects specific direct children of top level elements and specific direct children of specific composite elements.
+ * This covers all of the ruby PSI structure
+ */
+public abstract class AbstractCodeBlockSupportHandler implements CodeBlockSupportHandler {
+
+  /**
+   * @return top-level elements tokens to be handled, e.g. IF_STATEMENT, UNLESS_STATEMENT
+   */
+  @NotNull
+  protected abstract TokenSet getTopLevelElementTypes();
+
+  /**
+   * @return direct tokens of {@code parentElementType} to be handled.
+   * e.g IF_STATEMENT => [kwIF, kwUNLESS, kwEND]
+   */
+  @NotNull
+  protected abstract TokenSet getDirectChildrenElementTypes(@Nullable IElementType parentElementType);
+
+  /**
+   * @return map of direct composite child elements to tokens to extract from them.
+   * E.g.: IF_STATEMENT => {ELSE_BRANCH => kwELSE, ELSIF_BRANCH => kwELSIF, ...}
+   */
+  @NotNull
+  protected abstract Map<IElementType, IElementType> getIndirectChildrenMap(@Nullable IElementType parentElementType);
+
+  @NotNull
+  @Override
+  public List<TextRange> getCodeBlockMarkerRanges(@NotNull PsiElement elementAtCursor) {
+    PsiElement parentElement = elementAtCursor.getParent();
+    if (parentElement == null) {
+      return Collections.emptyList();
+    }
+
+    IElementType elementType = PsiUtilCore.getElementType(elementAtCursor);
+    IElementType parentElementType = PsiUtilCore.getElementType(parentElement);
+    TokenSet directChildrenElementTypes = getDirectChildrenElementTypes(parentElementType);
+
+    if (directChildrenElementTypes.contains(elementType)) {
+      return computeMarkersRanges(parentElement);
+    }
+
+    PsiElement grandParentElement = parentElement.getParent();
+    if (grandParentElement == null) {
+      return Collections.emptyList();
+    }
+    Map<IElementType, IElementType> indirectChildrenMap = getIndirectChildrenMap(PsiUtilCore.getElementType(grandParentElement));
+
+    if (elementType == indirectChildrenMap.get(parentElementType)) {
+      return computeMarkersRanges(grandParentElement);
+    }
+
+    return Collections.emptyList();
+  }
+
+  @NotNull
+  private List<TextRange> computeMarkersRanges(@NotNull PsiElement rootElement) {
+    IElementType rootElementType = PsiUtilCore.getElementType(rootElement);
+    TokenSet directChildrenTypes = getDirectChildrenElementTypes(rootElementType);
+    Map<IElementType, IElementType> indirectChildrenMap = getIndirectChildrenMap(rootElementType);
+
+    List<TextRange> result = new ArrayList<>();
+    PsiElement currentElement = rootElement.getFirstChild();
+    while (currentElement != null) {
+      IElementType currentElementType = PsiUtilCore.getElementType(currentElement);
+      if (directChildrenTypes.contains(currentElementType)) {
+        result.add(currentElement.getTextRange());
+      }
+      else {
+        if (indirectChildrenMap.containsKey(currentElementType)) {
+          PsiElement firstChild = currentElement.getFirstChild();
+          if (PsiUtilCore.getElementType(firstChild) == indirectChildrenMap.get(currentElementType)) {
+            result.add(firstChild.getTextRange());
+          }
+        }
+      }
+      currentElement = currentElement.getNextSibling();
+    }
+    return result;
+  }
+
+  @NotNull
+  @Override
+  public TextRange getCodeBlockRange(@NotNull PsiElement elementAtCursor) {
+    PsiElement run = elementAtCursor;
+    while (run != null && !(run instanceof PsiFile)) {
+      IElementType currentElementType = PsiUtilCore.getElementType(run);
+      if (getTopLevelElementTypes().contains(currentElementType)) {
+        return run.getTextRange();
+      }
+      IElementType parentElementType = PsiUtilCore.getElementType(run.getParent());
+      if (getIndirectChildrenMap(parentElementType).containsKey(currentElementType)) {
+        return run.getTextRange();
+      }
+      run = run.getParent();
+    }
+    return TextRange.EMPTY_RANGE;
+  }
+}