performance improvement of the ast build cache,

uses an empty no-op root for the cached ASTs since their roots are never queried

Author: douira

glsl-transformer/src/main/java/io/github/douira/glsl_transformer/ast/node/Identifier.java

@@ -27,9 +27,9 @@ public void setName(String name) {
       return;
     }
     validateContents(name);
-    getRoot().identifierIndex.remove(this);
+    getRoot().unregisterIdentifierRename(this);
     this.name = name;
-    getRoot().identifierIndex.add(this);
+    getRoot().registerIdentifierRename(this);
   }
 
   /**

glsl-transformer/src/main/java/io/github/douira/glsl_transformer/ast/query/EmptyRoot.java

@@ -0,0 +1,31 @@
+package io.github.douira.glsl_transformer.ast.query;
+
+import io.github.douira.glsl_transformer.ast.node.Identifier;
+import io.github.douira.glsl_transformer.ast.node.basic.ASTNode;
+
+/**
+ * The empty root overrides a normal root just to do nothing. This allows a root
+ * stub to exist without the performance cost of registering and unregistering
+ * nodes.
+ */
+public class EmptyRoot extends Root {
+  public EmptyRoot() {
+    super(null, null);
+  }
+
+  @Override
+  public void registerIdentifierRename(Identifier identifier) {
+  }
+
+  @Override
+  public void registerNode(ASTNode node) {
+  }
+
+  @Override
+  public void unregisterIdentifierRename(Identifier identifier) {
+  }
+
+  @Override
+  public void unregisterNode(ASTNode node) {
+  }
+}

glsl-transformer/src/main/java/io/github/douira/glsl_transformer/ast/query/Root.java

@@ -33,10 +33,30 @@ public class Root {
    * query capabilities.
    */
   public final IdentifierIndex<?> identifierIndex;
+
+  // internal utility state
+  private static Deque<Root> activeBuildRoots = new ArrayDeque<>();
   private List<? extends ASTNode> nodeList;
   private boolean activity;
 
-  private static Deque<Root> activeBuildRoots = new ArrayDeque<>();
+  /**
+   * Constructs a new root with the given node and identifier indexes.
+   * 
+   * @param nodeIndex       The node index
+   * @param identifierIndex The identifier index
+   */
+  public Root(NodeIndex nodeIndex, IdentifierIndex<?> identifierIndex) {
+    this.nodeIndex = nodeIndex;
+    this.identifierIndex = identifierIndex;
+  }
+
+  /**
+   * Constructs a new root with the default node and identifier indexes which have
+   * the least amount of functionality but are also the most efficient.
+   */
+  public Root() {
+    this(new NodeIndex(), IdentifierIndex.withPrefix());
+  }
 
   /**
    * Returns the currently active build root. When nodes are constructed within a
@@ -194,25 +214,6 @@ public static <NodeType extends ASTNode> void indexSeparateTrees(
     indexSeparateTrees(treeMember.getRoot(), registerer);
   }
 
-  /**
-   * Constructs a new root with the given node and identifier indexes.
-   * 
-   * @param nodeIndex       The node index
-   * @param identifierIndex The identifier index
-   */
-  public Root(NodeIndex nodeIndex, IdentifierIndex<?> identifierIndex) {
-    this.nodeIndex = nodeIndex;
-    this.identifierIndex = identifierIndex;
-  }
-
-  /**
-   * Constructs a new root with the default node and identifier indexes which have
-   * the least amount of functionality but are also the most efficient.
-   */
-  public Root() {
-    this(new NodeIndex(), IdentifierIndex.withPrefix());
-  }
-
   /**
    * Registers the given node with this root.
    * 
@@ -237,15 +238,12 @@ public void unregisterNode(ASTNode node) {
     }
   }
 
-  /**
-   * Merges the given root into this root. This will merge the node index and the
-   * identifier index.
-   * 
-   * @param other The root to merge into this root
-   */
-  public void merge(Root other) {
-    nodeIndex.merge(other.nodeIndex);
-    identifierIndex.merge(other.identifierIndex);
+  public void unregisterIdentifierRename(Identifier identifier) {
+    identifierIndex.remove(identifier);
+  }
+
+  public void registerIdentifierRename(Identifier identifier) {
+    identifierIndex.add(identifier);
   }
 
   private void ensureEmptyNodeList() {

glsl-transformer/src/main/java/io/github/douira/glsl_transformer/ast/query/index/IdentifierIndex.java

@@ -44,17 +44,6 @@ public void remove(Identifier node) {
     }
   }
 
-  public void merge(IdentifierIndex<?> other) {
-    for (var entry : other.index.entrySet()) {
-      var set = index.get(entry.getKey());
-      if (set == null) {
-        set = new HashSet<>();
-        index.put(entry.getKey(), set);
-      }
-      set.addAll(entry.getValue());
-    }
-  }
-
   public Set<Identifier> get(String k) {
     var result = index.get(k);
     return result == null ? Collections.emptySet() : result;

glsl-transformer/src/main/java/io/github/douira/glsl_transformer/ast/query/index/NodeIndex.java

@@ -165,20 +165,4 @@ public boolean hasExact(ASTNode node) {
     var set = get(node);
     return set != null && set.contains(node);
   }
-
-  /**
-   * Merges the given node index into this one.
-   * 
-   * @param other the other index to merge
-   */
-  public void merge(NodeIndex other) {
-    for (var entry : other.index.entrySet()) {
-      var set = (Set<ASTNode>) index.get(entry.getKey());
-      if (set == null) {
-        set = bucketConstructor.get();
-        index.put(entry.getKey(), set);
-      }
-      set.addAll(entry.getValue());
-    }
-  }
 }

glsl-transformer/src/main/java/io/github/douira/glsl_transformer/ast/transform/ASTBuilder.java

@@ -80,6 +80,13 @@ public static <TreeType extends ParseTree, ReturnType extends ASTNode> ReturnTyp
     return Root.indexNodes(() -> buildInternal(ctx, visitMethod));
   }
 
+  public static <TreeType extends ParseTree, ReturnType extends ASTNode> ReturnType build(
+      Root rootInstance,
+      TreeType ctx,
+      BiFunction<ASTBuilder, TreeType, ReturnType> visitMethod) {
+    return Root.indexNodes(rootInstance, () -> buildInternal(ctx, visitMethod));
+  }
+
   /**
    * Builds a subtree that has the same root as the given AST node.
    * 

glsl-transformer/src/main/java/io/github/douira/glsl_transformer/ast/transform/ASTParser.java

@@ -13,6 +13,7 @@
 import io.github.douira.glsl_transformer.ast.node.expression.Expression;
 import io.github.douira.glsl_transformer.ast.node.external_declaration.ExternalDeclaration;
 import io.github.douira.glsl_transformer.ast.node.statement.Statement;
+import io.github.douira.glsl_transformer.ast.query.EmptyRoot;
 import io.github.douira.glsl_transformer.basic.*;
 import io.github.douira.glsl_transformer.basic.EnhancedParser.ParsingStrategy;
 import io.github.douira.glsl_transformer.cst.token_filter.TokenFilter;
@@ -106,7 +107,7 @@ public <RuleType extends ExtendedContext, ReturnType extends ASTNode> ReturnType
     } else {
       // cache and possibly build, always clone to return new trees
       return (ReturnType) buildCache.cachedGet(input, ruleType,
-          () -> ASTBuilder.build(parser.parse(input, ruleType, parseMethod), visitMethod))
+          () -> ASTBuilder.build(new EmptyRoot(), parser.parse(input, ruleType, parseMethod), visitMethod))
           .cloneInto(parentTreeMember);
     }
   }
@@ -123,7 +124,7 @@ public <RuleType extends ExtendedContext, ReturnType extends ASTNode> ReturnType
       return ASTBuilder.build(parser.parse(input, ruleType, parseMethod), visitMethod);
     } else {
       return (ReturnType) buildCache.cachedGet(input, ruleType,
-          () -> ASTBuilder.build(parser.parse(input, ruleType, parseMethod), visitMethod))
+          () -> ASTBuilder.build(new EmptyRoot(), parser.parse(input, ruleType, parseMethod), visitMethod))
           .cloneSeparate();
     }
   }

glsl-transformer/src/test/java/io/github/douira/glsl_transformer/ast/query/NodeIndexTest.java

@@ -90,19 +90,6 @@ void testHasExact() {
     assertFalse(index.hasExact(new Identifier("e")));
   }
 
-  @Test
-  void testMerge() {
-    var other = new NodeIndex();
-    other.add(a);
-    other.add(b);
-    var e = new Identifier("e");
-    other.add(e);
-    index.add(a);
-    index.add(c);
-    index.merge(other);
-    assertEquals(Set.of(a, b, e, c), index.get(Identifier.class));
-  }
-
   @Test
   void testRemove() {
     index.add(a);