nashorn/src/jdk/internal/dynalink/DynamicLinkerFactory.java
changeset 16234 86cb162cec6c
child 16245 6a1c6c8bc113
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/src/jdk/internal/dynalink/DynamicLinkerFactory.java	Thu Feb 14 13:22:26 2013 +0100
@@ -0,0 +1,311 @@
+/*
+ * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file, and Oracle licenses the original version of this file under the BSD
+ * license:
+ */
+/*
+   Copyright 2009-2013 Attila Szegedi
+
+   Licensed under both the Apache License, Version 2.0 (the "Apache License")
+   and the BSD License (the "BSD License"), with licensee being free to
+   choose either of the two at their discretion.
+
+   You may not use this file except in compliance with either the Apache
+   License or the BSD License.
+
+   If you choose to use this file in compliance with the Apache License, the
+   following notice applies to you:
+
+       You may obtain a copy of the Apache 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.
+
+   If you choose to use this file in compliance with the BSD License, the
+   following notice applies to you:
+
+       Redistribution and use in source and binary forms, with or without
+       modification, are permitted provided that the following conditions are
+       met:
+       * Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in the
+         documentation and/or other materials provided with the distribution.
+       * Neither the name of the copyright holder nor the names of
+         contributors may be used to endorse or promote products derived from
+         this software without specific prior written permission.
+
+       THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+       IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+       TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+       PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
+       BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+package jdk.internal.dynalink;
+
+import java.lang.invoke.MutableCallSite;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+import jdk.internal.dynalink.beans.BeansLinker;
+import jdk.internal.dynalink.linker.GuardingDynamicLinker;
+import jdk.internal.dynalink.linker.GuardingTypeConverterFactory;
+import jdk.internal.dynalink.linker.LinkRequest;
+import jdk.internal.dynalink.support.AutoDiscovery;
+import jdk.internal.dynalink.support.BottomGuardingDynamicLinker;
+import jdk.internal.dynalink.support.CompositeGuardingDynamicLinker;
+import jdk.internal.dynalink.support.CompositeTypeBasedGuardingDynamicLinker;
+import jdk.internal.dynalink.support.LinkerServicesImpl;
+import jdk.internal.dynalink.support.TypeConverterFactory;
+
+
+/**
+ * A factory class for creating {@link DynamicLinker}s. The most usual dynamic linker is a linker that is a composition
+ * of all {@link GuardingDynamicLinker}s known and pre-created by the caller as well as any
+ * {@link AutoDiscovery automatically discovered} guarding linkers and the standard fallback {@link BeansLinker}. See
+ * {@link DynamicLinker} documentation for tips on how to use this class.
+ *
+ * @author Attila Szegedi
+ */
+public class DynamicLinkerFactory {
+
+    /**
+     * Default value for {@link #setUnstableRelinkThreshold(int) unstable relink threshold}.
+     */
+    public static final int DEFAULT_UNSTABLE_RELINK_THRESHOLD = 8;
+
+    private ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+    private List<? extends GuardingDynamicLinker> prioritizedLinkers;
+    private List<? extends GuardingDynamicLinker> fallbackLinkers;
+    private int runtimeContextArgCount = 0;
+    private boolean syncOnRelink = false;
+    private int unstableRelinkThreshold = DEFAULT_UNSTABLE_RELINK_THRESHOLD;
+
+    /**
+     * Sets the class loader for automatic discovery of available linkers. If not set explicitly, then the thread
+     * context class loader at the time of the constructor invocation will be used.
+     *
+     * @param classLoader the class loader used for the autodiscovery of available linkers.
+     */
+    public void setClassLoader(ClassLoader classLoader) {
+        this.classLoader = classLoader;
+    }
+
+    /**
+     * Sets the prioritized linkers. Language runtimes using this framework will usually precreate at least the linker
+     * for their own language. These linkers will be consulted first in the resulting dynamic linker, before any
+     * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the prioritized
+     * linkers, it will be ignored and the explicit prioritized instance will be used.
+     *
+     * @param prioritizedLinkers the list of prioritized linkers. Null can be passed to indicate no prioritized linkers
+     * (this is also the default value).
+     */
+    public void setPrioritizedLinkers(List<? extends GuardingDynamicLinker> prioritizedLinkers) {
+        this.prioritizedLinkers =
+                prioritizedLinkers == null ? null : new ArrayList<>(prioritizedLinkers);
+    }
+
+    /**
+     * Sets the prioritized linkers. Language runtimes using this framework will usually precreate at least the linker
+     * for their own language. These linkers will be consulted first in the resulting dynamic linker, before any
+     * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the prioritized
+     * linkers, it will be ignored and the explicit prioritized instance will be used.
+     *
+     * @param prioritizedLinkers a list of prioritized linkers.
+     */
+    public void setPrioritizedLinkers(GuardingDynamicLinker... prioritizedLinkers) {
+        setPrioritizedLinkers(Arrays.asList(prioritizedLinkers));
+    }
+
+    /**
+     * Sets a single prioritized linker. Identical to calling {@link #setPrioritizedLinkers(List)} with a single-element
+     * list.
+     *
+     * @param prioritizedLinker the single prioritized linker. Must not be null.
+     * @throws IllegalArgumentException if null is passed.
+     */
+    public void setPrioritizedLinker(GuardingDynamicLinker prioritizedLinker) {
+        if(prioritizedLinker == null) {
+            throw new IllegalArgumentException("prioritizedLinker == null");
+        }
+        this.prioritizedLinkers = Collections.singletonList(prioritizedLinker);
+    }
+
+    /**
+     * Sets the fallback linkers. These linkers will be consulted last in the resulting composite linker, after any
+     * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the fallback
+     * linkers, it will be ignored and the explicit fallback instance will be used.
+     *
+     * @param fallbackLinkers the list of fallback linkers. Can be empty to indicate the caller wishes to set no
+     * fallback linkers.
+     */
+    public void setFallbackLinkers(List<? extends GuardingDynamicLinker> fallbackLinkers) {
+        this.fallbackLinkers = fallbackLinkers == null ? null : new ArrayList<>(fallbackLinkers);
+    }
+
+    /**
+     * Sets the fallback linkers. These linkers will be consulted last in the resulting composite linker, after any
+     * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the fallback
+     * linkers, it will be ignored and the explicit fallback instance will be used.
+     *
+     * @param fallbackLinkers the list of fallback linkers. Can be empty to indicate the caller wishes to set no
+     * fallback linkers. If it is left as null, the standard fallback {@link BeansLinker} will be used.
+     */
+    public void setFallbackLinkers(GuardingDynamicLinker... fallbackLinkers) {
+        setFallbackLinkers(Arrays.asList(fallbackLinkers));
+    }
+
+    /**
+     * Sets the number of arguments in the call sites that represent the stack context of the language runtime creating
+     * the linker. If the language runtime uses no context information passed on stack, then it should be zero
+     * (the default value). If it is set to nonzero value, then every dynamic call site emitted by this runtime must
+     * have the argument list of the form: {@code (this, contextArg1[, contextArg2[, ...]], normalArgs)}. It is
+     * advisable to only pass one context-specific argument, though, of an easily recognizable, runtime specific type
+     * encapsulating the runtime thread local state.
+     *
+     * @param runtimeContextArgCount the number of language runtime context arguments in call sites.
+     */
+    public void setRuntimeContextArgCount(int runtimeContextArgCount) {
+        if(runtimeContextArgCount < 0) {
+            throw new IllegalArgumentException("runtimeContextArgCount < 0");
+        }
+        this.runtimeContextArgCount = runtimeContextArgCount;
+    }
+
+    /**
+     * Sets whether the linker created by this factory will invoke {@link MutableCallSite#syncAll(MutableCallSite[])}
+     * after a call site is relinked. Defaults to false. You probably want to set it to true if your runtime supports
+     * multithreaded execution of dynamically linked code.
+     * @param syncOnRelink true for invoking sync on relink, false otherwise.
+     */
+    public void setSyncOnRelink(boolean syncOnRelink) {
+        this.syncOnRelink = syncOnRelink;
+    }
+
+    /**
+     * Sets the unstable relink threshold; the number of times a call site is relinked after which it will be
+     * considered unstable, and subsequent link requests for it will indicate this.
+     * @param unstableRelinkThreshold the new threshold. Must not be less than zero. The value of zero means that
+     * call sites will never be considered unstable.
+     * @see LinkRequest#isCallSiteUnstable()
+     */
+    public void setUnstableRelinkThreshold(int unstableRelinkThreshold) {
+        if(unstableRelinkThreshold < 0) {
+            throw new IllegalArgumentException("unstableRelinkThreshold < 0");
+        }
+        this.unstableRelinkThreshold = unstableRelinkThreshold;
+    }
+
+    /**
+     * Creates a new dynamic linker consisting of all the prioritized, autodiscovered, and fallback linkers.
+     *
+     * @return the new dynamic Linker
+     */
+    public DynamicLinker createLinker() {
+        // Treat nulls appropriately
+        if(prioritizedLinkers == null) {
+            prioritizedLinkers = Collections.emptyList();
+        }
+        if(fallbackLinkers == null) {
+            fallbackLinkers = Collections.singletonList(new BeansLinker());
+        }
+
+        // Gather classes of all precreated (prioritized and fallback) linkers.
+        // We'll filter out any discovered linkers of the same class.
+        final Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses = new HashSet<>();
+        addClasses(knownLinkerClasses, prioritizedLinkers);
+        addClasses(knownLinkerClasses, fallbackLinkers);
+
+        final List<GuardingDynamicLinker> discovered = AutoDiscovery.loadLinkers(classLoader);
+        // Now, concatenate ...
+        final List<GuardingDynamicLinker> linkers = new ArrayList<>(prioritizedLinkers.size() + discovered.size()
+                + fallbackLinkers.size());
+        // ... prioritized linkers, ...
+        linkers.addAll(prioritizedLinkers);
+        // ... filtered discovered linkers, ...
+        for(GuardingDynamicLinker linker: discovered) {
+            if(!knownLinkerClasses.contains(linker.getClass())) {
+                linkers.add(linker);
+            }
+        }
+        // ... and finally fallback linkers.
+        linkers.addAll(fallbackLinkers);
+        final List<GuardingDynamicLinker> optimized = CompositeTypeBasedGuardingDynamicLinker.optimize(linkers);
+        final GuardingDynamicLinker composite;
+        switch(linkers.size()) {
+            case 0: {
+                composite = BottomGuardingDynamicLinker.INSTANCE;
+                break;
+            }
+            case 1: {
+                composite = optimized.get(0);
+                break;
+            }
+            default: {
+                composite = new CompositeGuardingDynamicLinker(optimized);
+                break;
+            }
+        }
+
+        final List<GuardingTypeConverterFactory> typeConverters = new LinkedList<>();
+        for(GuardingDynamicLinker linker: linkers) {
+            if(linker instanceof GuardingTypeConverterFactory) {
+                typeConverters.add((GuardingTypeConverterFactory)linker);
+            }
+        }
+
+        return new DynamicLinker(new LinkerServicesImpl(new TypeConverterFactory(typeConverters), composite),
+                runtimeContextArgCount, syncOnRelink, unstableRelinkThreshold);
+    }
+
+    private static void addClasses(Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses,
+            List<? extends GuardingDynamicLinker> linkers) {
+        for(GuardingDynamicLinker linker: linkers) {
+            knownLinkerClasses.add(linker.getClass());
+        }
+    }
+}
\ No newline at end of file