Restore build scope script class cache

This cache was useful when a script was applied
multiple times during a build. It avoids checking
the hash of the script again, as we can safely
assume that a build script will not change during
a single build.

subprojects/core/src/main/java/org/gradle/groovy/scripts/internal/BuildScopeInMemoryCachingScriptClassCompiler.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2010 the original author or authors.
+ *
+ * Licensed 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.gradle.groovy.scripts.internal;
+
+import com.google.common.collect.Maps;
+import groovy.lang.Script;
+import org.codehaus.groovy.ast.ClassNode;
+import org.gradle.api.Action;
+import org.gradle.api.internal.initialization.loadercache.ClassLoaderId;
+import org.gradle.groovy.scripts.ScriptSource;
+import org.gradle.internal.Cast;
+
+import java.util.Map;
+
+/**
+ * This in-memory cache is responsible for caching compiled build scripts during a build.
+ * If the compiled script is not found in this cache, it will try to find it in the global cache,
+ * which will use the delegate script class compiler in case of a miss. The lookup in this cache is
+ * more efficient than looking in the global cache, as we do not check the script's hash code here,
+ * assuming that it did not change during the build.
+ */
+public class BuildScopeInMemoryCachingScriptClassCompiler implements ScriptClassCompiler {
+    private final CrossBuildInMemoryCachingScriptClassCache cache;
+    private final ScriptClassCompiler scriptClassCompiler;
+    private final Map<ScriptCacheKey, CompiledScript<?, ?>> cachedCompiledScripts = Maps.newHashMap();
+
+    public BuildScopeInMemoryCachingScriptClassCompiler(CrossBuildInMemoryCachingScriptClassCache cache, ScriptClassCompiler scriptClassCompiler) {
+        this.cache = cache;
+        this.scriptClassCompiler = scriptClassCompiler;
+    }
+
+    @Override
+    public <T extends Script, M> CompiledScript<T, M> compile(ScriptSource source, ClassLoader classLoader, ClassLoaderId classLoaderId, CompileOperation<M> operation, Class<T> scriptBaseClass, Action<? super ClassNode> verifier) {
+        ScriptCacheKey key = new ScriptCacheKey(source.getClassName(), classLoader, operation.getId());
+        CompiledScript<T, M> compiledScript = Cast.uncheckedCast(cachedCompiledScripts.get(key));
+        if (compiledScript == null) {
+            compiledScript = cache.getOrCompile(source, classLoader, classLoaderId, operation, scriptBaseClass, verifier, scriptClassCompiler);
+            cachedCompiledScripts.put(key, compiledScript);
+        }
+        return compiledScript;
+    }
+
+}

subprojects/core/src/main/java/org/gradle/internal/service/scopes/BuildScopeServices.java

@@ -97,7 +97,7 @@
 import org.gradle.groovy.scripts.DefaultScriptCompilerFactory;
 import org.gradle.groovy.scripts.ScriptCompilerFactory;
 import org.gradle.groovy.scripts.ScriptExecutionListener;
-import org.gradle.groovy.scripts.internal.BuildScopeScriptClassCompiler;
+import org.gradle.groovy.scripts.internal.BuildScopeInMemoryCachingScriptClassCompiler;
 import org.gradle.groovy.scripts.internal.CrossBuildInMemoryCachingScriptClassCache;
 import org.gradle.groovy.scripts.internal.DefaultScriptCompilationHandler;
 import org.gradle.groovy.scripts.internal.DefaultScriptRunnerFactory;
@@ -262,7 +262,7 @@ protected ScriptCompilerFactory createScriptCompileFactory(ListenerManager liste
                                                                CrossBuildInMemoryCachingScriptClassCache cache) {
         ScriptExecutionListener scriptExecutionListener = listenerManager.getBroadcaster(ScriptExecutionListener.class);
         return new DefaultScriptCompilerFactory(
-            new BuildScopeScriptClassCompiler(cache, scriptCompiler),
+            new BuildScopeInMemoryCachingScriptClassCompiler(cache, scriptCompiler),
             new DefaultScriptRunnerFactory(
                 scriptExecutionListener,
                 DirectInstantiator.INSTANCE