ProcAddressJavaMethodBindingEmitter.java

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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
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 * This software is provided "AS IS," without a warranty of any kind. ALL
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package com.jogamp.gluegen.procaddress;

import com.jogamp.gluegen.MethodBinding;
import com.jogamp.gluegen.FunctionEmitter;
import com.jogamp.gluegen.JavaMethodBindingEmitter;

import java.io.*;

/** A specialization of JavaMethodBindingEmitter with knowledge of how
to call through a function pointer. */
public class ProcAddressJavaMethodBindingEmitter extends JavaMethodBindingEmitter {

    protected boolean callThroughProcAddress;
    protected boolean changeNameAndArguments;

    protected String getProcAddressTableExpr;
    protected ProcAddressEmitter emitter;

    public ProcAddressJavaMethodBindingEmitter(final JavaMethodBindingEmitter methodToWrap, final boolean callThroughProcAddress,
            final String getProcAddressTableExpr, final boolean changeNameAndArguments, final ProcAddressEmitter emitter) {

        super(methodToWrap);

        this.callThroughProcAddress = callThroughProcAddress;
        this.getProcAddressTableExpr = getProcAddressTableExpr;
        this.changeNameAndArguments = changeNameAndArguments;
        this.emitter = emitter;

        if (callThroughProcAddress) {
            setCommentEmitter(new WrappedMethodCommentEmitter());
        }

        if (methodToWrap.getBinding().hasContainingType()) {
            throw new IllegalArgumentException(
                    "Cannot create proc. address wrapper; method has containing type: \""
                    + methodToWrap.getBinding() + "\"");
        }
    }

    public ProcAddressJavaMethodBindingEmitter(final ProcAddressJavaMethodBindingEmitter methodToWrap) {
        this(methodToWrap, methodToWrap.callThroughProcAddress, methodToWrap.getProcAddressTableExpr,
             methodToWrap.changeNameAndArguments, methodToWrap.emitter);
    }

    @Override
    public String getImplName() {
        final String res = super.getImplName();
        if (changeNameAndArguments) {
            return ProcAddressEmitter.WRAP_PREFIX + res;
        }
        return res;
    }

    @Override
    protected int emitArguments(final PrintWriter writer) {
        int numEmitted = super.emitArguments(writer);
        if (callThroughProcAddress) {
            if (changeNameAndArguments) {
                if (numEmitted > 0) {
                    writer.print(", ");
                }

                writer.print("long procAddress");
                ++numEmitted;
            }
        }

        return numEmitted;
    }

    @Override
    protected String getNativeImplMethodName() {
        final String name = super.getNativeImplMethodName();
        if (callThroughProcAddress) {
            return ProcAddressEmitter.WRAP_PREFIX + name;
        }
        return name;
    }

    @Override
    protected void emitPreCallSetup(final MethodBinding binding, final PrintWriter writer) {
        super.emitPreCallSetup(binding, writer);

        if (callThroughProcAddress) {
            final String procAddressVariable = ProcAddressEmitter.PROCADDRESS_VAR_PREFIX + binding.getNativeName();
            writer.println("    final long __addr_ = " + getProcAddressTableExpr + "." + procAddressVariable + ";");
            writer.println("    if (__addr_ == 0) {");
            writer.format("      throw new %s(String.format(\"Method \\\"%%s\\\" not available\", \"%s\"));%n",
                          emitter.unsupportedExceptionType(), binding.getName());
            writer.println("    }");
        }
    }

    @Override
    protected int emitCallArguments(final MethodBinding binding, final PrintWriter writer) {
        int numEmitted = super.emitCallArguments(binding, writer);
        if (callThroughProcAddress) {
            if (numEmitted > 0) {
                writer.print(", ");
            }
            writer.print("__addr_");
            ++numEmitted;
        }

        return numEmitted;
    }

    /** This class emits the comment for the wrapper method */
    public class WrappedMethodCommentEmitter extends JavaMethodBindingEmitter.DefaultCommentEmitter {

        @Override
        protected void emitBeginning(final FunctionEmitter methodEmitter, final PrintWriter writer) {
            writer.print("Entry point (through function pointer) to C language function: <br> ");
        }
    }
}