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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.TruffleBoundary;
import com.oracle.truffle.api.TruffleLanguage.ContextReference;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Shared;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.interop.InteropException;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.library.CachedLibrary;
import com.oracle.truffle.api.nodes.DirectCallNode;
import com.oracle.truffle.api.nodes.ExplodeLoop;
import com.oracle.truffle.api.nodes.IndirectCallNode;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.nodes.RootNode;
import com.oracle.truffle.nfi.NFIRootNodeFactory.LoadLibraryNodeGen;
import com.oracle.truffle.nfi.NFIRootNodeFactory.LookupAndBindNodeGen;
import com.oracle.truffle.nfi.NativeSource.ParsedLibrary;
import com.oracle.truffle.nfi.spi.NFIBackend;
import com.oracle.truffle.nfi.spi.types.NativeLibraryDescriptor;

class NFIRootNode extends RootNode {

    abstract static class LookupAndBindNode extends Node {

        private final String name;
        private final String signature;

        LookupAndBindNode(String name, String signature) {
            this.name = name;
            this.signature = signature;
        }

        abstract Object execute(Object library);

        @Specialization(limit = "1")
        Object doLookupAndBind(Object library,
                        @CachedLibrary("library") InteropLibrary libInterop,
                        @Shared("symInterop") @CachedLibrary(limit = "1") InteropLibrary symInterop) {
            try {
                Object symbol = libInterop.readMember(library, name);
                return symInterop.invokeMember(symbol, "bind", signature);
            } catch (InteropException ex) {
                CompilerDirectives.transferToInterpreter();
                throw new NFIPreBindException(ex.getMessage(), this);
            }
        }
    }

    abstract static class LoadLibraryNode extends Node {

        private final NativeLibraryDescriptor descriptor;

        LoadLibraryNode(NativeLibraryDescriptor descriptor) {
            this.descriptor = descriptor;
        }

        protected abstract Object execute(NFIBackend backend);

        @TruffleBoundary
        CallTarget parseLibrary(NFIBackend backend) {
            return backend.parse(descriptor);
        }

        @Specialization(limit = "5", guards = "backend == cachedBackend")
        Object doCached(NFIBackend backend,
                        @Cached("backend") NFIBackend cachedBackend,
                        @Cached("create(parseLibrary(cachedBackend))") DirectCallNode callNode) {
            assert backend == cachedBackend;
            return callNode.call();
        }

        @Specialization(replaces = "doCached")
        Object doGeneric(NFIBackend backend,
                        @Cached IndirectCallNode callNode) {
            return callNode.call(parseLibrary(backend));
        }
    }

    @Child LoadLibraryNode loadLibrary;
    @Children LookupAndBindNode[] lookupAndBind;

    private final ContextReference<NFIContext> ctxRef;
    private final String backendId;

    NFIRootNode(NFILanguage language, ParsedLibrary source, String backendId) {
        super(language);
        this.loadLibrary = LoadLibraryNodeGen.create(source.getLibraryDescriptor());
        this.lookupAndBind = new LookupAndBindNode[source.preBoundSymbolsLength()];

        this.ctxRef = lookupContextReference(NFILanguage.class);
        this.backendId = backendId;

        for (int i = 0; i < lookupAndBind.length; i++) {
            lookupAndBind[i] = LookupAndBindNodeGen.create(source.getPreBoundSymbol(i), source.getPreBoundSignature(i));
        }
    }

    @Override
    public boolean isInternal() {
        return true;
    }

    @Override
    @ExplodeLoop
    public Object execute(VirtualFrame frame) {
        NFIBackend backend = ctxRef.get().getBackend(backendId);

        Object library = loadLibrary.execute(backend);
        if (lookupAndBind.length == 0) {
            return library;
        } else {
            NFILibrary ret = new NFILibrary(library);
            for (LookupAndBindNode l : lookupAndBind) {
                ret.preBindSymbol(l.name, l.execute(library));
            }
            return ret;
        }
    }
}