NFILanguage.java

/*
 * Copyright (c) 2017, 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
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package com.oracle.truffle.nfi;

import com.oracle.truffle.api.CallTarget;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.Truffle;
import com.oracle.truffle.api.TruffleLanguage;
import com.oracle.truffle.api.TruffleLanguage.Env;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.RootNode;
import com.oracle.truffle.nfi.types.NativeLibraryDescriptor;
import com.oracle.truffle.nfi.types.Parser;

@TruffleLanguage.Registration(name = "TruffleNFI", version = "0.1", mimeType = NFILanguage.MIME_TYPE)
public class NFILanguage extends TruffleLanguage<Env> {

    public static final String MIME_TYPE = "application/x-native";

    @Override
    protected Env createContext(Env env) {
        return env;
    }

    private static class LoadLibraryNode extends RootNode {

        private final String name;
        private final int flags;

        @CompilationFinal private LibFFILibrary cached;

        LoadLibraryNode(String name, int flags) {
            super(null);
            this.name = name;
            this.flags = flags;
        }

        @Override
        public Object execute(VirtualFrame frame) {
            if (cached == null) {
                CompilerDirectives.transferToInterpreterAndInvalidate();
                cached = LibFFILibrary.create(NativeAccess.loadLibrary(name, flags));
            }
            return cached;
        }
    }

    private static class GetDefaultLibraryNode extends RootNode {

        GetDefaultLibraryNode() {
            super(null);
        }

        @Override
        public Object execute(VirtualFrame frame) {
            return LibFFILibrary.DEFAULT;
        }
    }

    @Override
    protected CallTarget parse(ParsingRequest request) throws Exception {
        String library = request.getSource().getCode();
        NativeLibraryDescriptor descriptor = Parser.parseLibraryDescriptor(library);

        RootNode root;
        if (descriptor.isDefaultLibrary()) {
            root = new GetDefaultLibraryNode();
        } else {
            int flags = 0;
            boolean lazyOrNow = false;
            if (descriptor.getFlags() != null) {
                for (String flag : descriptor.getFlags()) {
                    switch (flag) {
                        case "RTLD_GLOBAL":
                            flags |= NativeAccess.RTLD_GLOBAL;
                            break;
                        case "RTLD_LOCAL":
                            flags |= NativeAccess.RTLD_LOCAL;
                            break;
                        case "RTLD_LAZY":
                            flags |= NativeAccess.RTLD_LAZY;
                            lazyOrNow = true;
                            break;
                        case "RTLD_NOW":
                            flags |= NativeAccess.RTLD_NOW;
                            lazyOrNow = true;
                            break;
                    }
                }
            }
            if (!lazyOrNow) {
                // default to 'RTLD_NOW' if neither 'RTLD_LAZY' nor 'RTLD_NOW' was specified
                flags |= NativeAccess.RTLD_NOW;
            }
            root = new LoadLibraryNode(descriptor.getFilename(), flags);
        }
        return Truffle.getRuntime().createCallTarget(root);
    }

    @Override
    protected Object findExportedSymbol(Env context, String globalName, boolean onlyExplicit) {
        return null;
    }

    @Override
    protected Object getLanguageGlobal(Env context) {
        return null;
    }

    @Override
    protected boolean isObjectOfLanguage(Object object) {
        return object instanceof LibFFIFunction || object instanceof LibFFILibrary || object instanceof NativePointer || object instanceof NativeString;
    }
}