/*
 * Copyright (c) 2016, Oracle and/or its affiliates.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. Neither the name of the copyright holder nor the names of its 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 THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS 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
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 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.oracle.truffle.llvm.pipe;

import java.io.File;

import java.io.IOException;
import java.nio.file.Files;

public final class CaptureOutput implements AutoCloseable {

    static {
        String pipeLib = System.getProperty("test.pipe.lib");
        if (pipeLib == null) {
            System.loadLibrary("pipe");
        } else {
            System.load(pipeLib);
        }
    }

    private final File captureFile;
    private final int oldStdout;

    private String result;

    public CaptureOutput() throws IOException {
        captureFile = File.createTempFile("capture", ".log");
        captureFile.deleteOnExit();

        oldStdout = startCapturing(captureFile.getAbsolutePath());
        result = null;
    }

    @Override
    public void close() throws IOException {
        if (result == null) {
            stopCapturing(oldStdout);
            result = new String(Files.readAllBytes(captureFile.toPath()));
            captureFile.delete();
        }
    }

    public String getResult() throws IOException {
        close();
        return result;
    }

    private static native int startCapturing(String tempFilename) throws IOException;

    private static native void stopCapturing(int oldStdout) throws IOException;
}