Painless: Add PainlessClassBuilder (#32141)

Several pieces of data in PainlessClass cannot be passed in at the time the
PainlessClass is created so it must be "frozen" after all the data is collected. This means
PainlessClass is currently serving two functions as both a builder and a set of data. This
separates the two pieces into clearly distinct values.

This change also removes the PainlessMethodKey in favor of a simple String. The goal is
to have the painless method key be completely internal to the PainlessLookup eventually
and this simplifies the way there. Note that this was added since PainlessClass and
PainlessClassBuilder were already being changed instead of a follow up PR.

modules/lang-painless/src/main/java/org/elasticsearch/painless/Def.java

@@ -23,7 +23,6 @@
 import org.elasticsearch.painless.lookup.PainlessLookup;
 import org.elasticsearch.painless.lookup.PainlessLookupUtility;
 import org.elasticsearch.painless.lookup.PainlessMethod;
-import org.elasticsearch.painless.lookup.PainlessMethodKey;
 
 import java.lang.invoke.CallSite;
 import java.lang.invoke.MethodHandle;
@@ -185,7 +184,7 @@ static MethodHandle arrayLengthGetter(Class<?> arrayType) {
      * @throws IllegalArgumentException if no matching whitelisted method was found.
      */
     static PainlessMethod lookupMethodInternal(PainlessLookup painlessLookup, Class<?> receiverClass, String name, int arity) {
-        PainlessMethodKey key = new PainlessMethodKey(name, arity);
+        String key = PainlessLookupUtility.buildPainlessMethodKey(name, arity);
         // check whitelist for matching method
         for (Class<?> clazz = receiverClass; clazz != null; clazz = clazz.getSuperclass()) {
             PainlessClass struct = painlessLookup.getPainlessStructFromJavaClass(clazz);

modules/lang-painless/src/main/java/org/elasticsearch/painless/FunctionRef.java

@@ -23,7 +23,6 @@
 import org.elasticsearch.painless.lookup.PainlessLookup;
 import org.elasticsearch.painless.lookup.PainlessLookupUtility;
 import org.elasticsearch.painless.lookup.PainlessMethod;
-import org.elasticsearch.painless.lookup.PainlessMethodKey;
 import org.objectweb.asm.Type;
 
 import java.lang.invoke.MethodType;
@@ -177,10 +176,11 @@ private static PainlessMethod lookup(PainlessLookup painlessLookup, Class<?> exp
         final PainlessMethod impl;
         // ctor ref
         if ("new".equals(call)) {
-            impl = struct.constructors.get(new PainlessMethodKey("<init>", method.arguments.size()));
+            impl = struct.constructors.get(PainlessLookupUtility.buildPainlessMethodKey("<init>", method.arguments.size()));
         } else {
             // look for a static impl first
-            PainlessMethod staticImpl = struct.staticMethods.get(new PainlessMethodKey(call, method.arguments.size()));
+            PainlessMethod staticImpl =
+                    struct.staticMethods.get(PainlessLookupUtility.buildPainlessMethodKey(call, method.arguments.size()));
             if (staticImpl == null) {
                 // otherwise a virtual impl
                 final int arity;
@@ -191,7 +191,7 @@ private static PainlessMethod lookup(PainlessLookup painlessLookup, Class<?> exp
                     // receiver passed
                     arity = method.arguments.size() - 1;
                 }
-                impl = struct.methods.get(new PainlessMethodKey(call, arity));
+                impl = struct.methods.get(PainlessLookupUtility.buildPainlessMethodKey(call, arity));
             } else {
                 impl = staticImpl;
             }

modules/lang-painless/src/main/java/org/elasticsearch/painless/Locals.java

@@ -23,7 +23,6 @@
 import org.elasticsearch.painless.lookup.PainlessLookup;
 import org.elasticsearch.painless.lookup.PainlessLookupUtility;
 import org.elasticsearch.painless.lookup.PainlessMethod;
-import org.elasticsearch.painless.lookup.PainlessMethodKey;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -144,7 +143,7 @@ public Variable getVariable(Location location, String name) {
     }
 
     /** Looks up a method. Returns null if the method does not exist. */
-    public PainlessMethod getMethod(PainlessMethodKey key) {
+    public PainlessMethod getMethod(String key) {
         PainlessMethod method = lookupMethod(key);
         if (method != null) {
             return method;
@@ -200,7 +199,7 @@ public PainlessLookup getPainlessLookup() {
     // variable name -> variable
     private Map<String,Variable> variables;
     // method name+arity -> methods
-    private Map<PainlessMethodKey,PainlessMethod> methods;
+    private Map<String,PainlessMethod> methods;
 
     /**
      * Create a new Locals
@@ -238,7 +237,7 @@ private Variable lookupVariable(Location location, String name) {
     }
 
     /** Looks up a method at this scope only. Returns null if the method does not exist. */
-    private PainlessMethod lookupMethod(PainlessMethodKey key) {
+    private PainlessMethod lookupMethod(String key) {
         if (methods == null) {
             return null;
         }
@@ -261,7 +260,7 @@ private void addMethod(PainlessMethod method) {
         if (methods == null) {
             methods = new HashMap<>();
         }
-        methods.put(new PainlessMethodKey(method.name, method.arguments.size()), method);
+        methods.put(PainlessLookupUtility.buildPainlessMethodKey(method.name, method.arguments.size()), method);
         // TODO: check result
     }
 

modules/lang-painless/src/main/java/org/elasticsearch/painless/lookup/PainlessClass.java

@@ -19,19 +19,20 @@
 
 package org.elasticsearch.painless.lookup;
 
+import org.objectweb.asm.Type;
+
 import java.lang.invoke.MethodHandle;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.Map;
 
 public final class PainlessClass {
     public final String name;
     public final Class<?> clazz;
-    public final org.objectweb.asm.Type type;
+    public final Type type;
 
-    public final Map<PainlessMethodKey, PainlessMethod> constructors;
-    public final Map<PainlessMethodKey, PainlessMethod> staticMethods;
-    public final Map<PainlessMethodKey, PainlessMethod> methods;
+    public final Map<String, PainlessMethod> constructors;
+    public final Map<String, PainlessMethod> staticMethods;
+    public final Map<String, PainlessMethod> methods;
 
     public final Map<String, PainlessField> staticMembers;
     public final Map<String, PainlessField> members;
@@ -41,63 +42,25 @@ public final class PainlessClass {
 
     public final PainlessMethod functionalMethod;
 
-    PainlessClass(String name, Class<?> clazz, org.objectweb.asm.Type type) {
+    PainlessClass(String name, Class<?> clazz, Type type,
+                  Map<String, PainlessMethod> constructors, Map<String, PainlessMethod> staticMethods, Map<String, PainlessMethod> methods,
+                  Map<String, PainlessField> staticMembers, Map<String, PainlessField> members,
+                  Map<String, MethodHandle> getters, Map<String, MethodHandle> setters,
+                  PainlessMethod functionalMethod) {
         this.name = name;
         this.clazz = clazz;
         this.type = type;
 
-        constructors = new HashMap<>();
-        staticMethods = new HashMap<>();
-        methods = new HashMap<>();
-
-        staticMembers = new HashMap<>();
-        members = new HashMap<>();
-
-        getters = new HashMap<>();
-        setters = new HashMap<>();
-
-        functionalMethod = null;
-    }
-
-    private PainlessClass(PainlessClass struct, PainlessMethod functionalMethod) {
-        name = struct.name;
-        clazz = struct.clazz;
-        type = struct.type;
+        this.constructors = Collections.unmodifiableMap(constructors);
+        this.staticMethods = Collections.unmodifiableMap(staticMethods);
+        this.methods = Collections.unmodifiableMap(methods);
 
-        constructors = Collections.unmodifiableMap(struct.constructors);
-        staticMethods = Collections.unmodifiableMap(struct.staticMethods);
-        methods = Collections.unmodifiableMap(struct.methods);
+        this.staticMembers = Collections.unmodifiableMap(staticMembers);
+        this.members = Collections.unmodifiableMap(members);
 
-        staticMembers = Collections.unmodifiableMap(struct.staticMembers);
-        members = Collections.unmodifiableMap(struct.members);
-
-        getters = Collections.unmodifiableMap(struct.getters);
-        setters = Collections.unmodifiableMap(struct.setters);
+        this.getters = Collections.unmodifiableMap(getters);
+        this.setters = Collections.unmodifiableMap(setters);
 
         this.functionalMethod = functionalMethod;
     }
-
-    public PainlessClass freeze(PainlessMethod functionalMethod) {
-        return new PainlessClass(this, functionalMethod);
-    }
-
-    @Override
-    public boolean equals(Object object) {
-        if (this == object) {
-            return true;
-        }
-
-        if (object == null || getClass() != object.getClass()) {
-            return false;
-        }
-
-        PainlessClass struct = (PainlessClass)object;
-
-        return name.equals(struct.name);
-    }
-
-    @Override
-    public int hashCode() {
-        return name.hashCode();
-    }
 }

modules/lang-painless/src/main/java/org/elasticsearch/painless/lookup/PainlessClassBuilder.java

@@ -0,0 +1,70 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.painless.lookup;
+
+import org.objectweb.asm.Type;
+
+import java.lang.invoke.MethodHandle;
+import java.util.HashMap;
+import java.util.Map;
+
+final class PainlessClassBuilder {
+    final String name;
+    final Class<?> clazz;
+    final Type type;
+
+    final Map<String, PainlessMethod> constructors;
+    final Map<String, PainlessMethod> staticMethods;
+    final Map<String, PainlessMethod> methods;
+
+    final Map<String, PainlessField> staticMembers;
+    final Map<String, PainlessField> members;
+
+    final Map<String, MethodHandle> getters;
+    final Map<String, MethodHandle> setters;
+
+    PainlessMethod functionalMethod;
+
+    PainlessClassBuilder(String name, Class<?> clazz, Type type) {
+        this.name = name;
+        this.clazz = clazz;
+        this.type = type;
+
+        constructors = new HashMap<>();
+        staticMethods = new HashMap<>();
+        methods = new HashMap<>();
+
+        staticMembers = new HashMap<>();
+        members = new HashMap<>();
+
+        getters = new HashMap<>();
+        setters = new HashMap<>();
+
+        functionalMethod = null;
+    }
+
+    PainlessClass build() {
+        return new PainlessClass(name, clazz, type,
+            constructors, staticMethods, methods,
+            staticMembers, members,
+            getters, setters,
+            functionalMethod);
+    }
+}