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Grace Framework : Grace Web Common
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/*
 * Copyright 2004-2023 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://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.
 */
package org.grails.web.util;

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.nio.charset.CharacterCodingException;
import java.util.Locale;

import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.WriteListener;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpServletResponseWrapper;

import org.grails.buffer.GrailsPrintWriterAdapter;
import org.grails.buffer.StreamByteBuffer;
import org.grails.buffer.StreamCharBuffer;

/**
 * Response wrapper used to capture the content of a response (such as within in an include).
 *
 * @author Graeme Rocher
 * @since 1.2.1
 */
public class IncludeResponseWrapper extends HttpServletResponseWrapper {

    private StreamCharBuffer charBuffer;

    private PrintWriter pw;

    private StreamByteBuffer byteBuffer;

    private OutputStream os;

    private ServletOutputStream sos;

    private boolean usingStream;

    private boolean usingWriter;

    private int status;

    private String contentType;

    private boolean committed;

    private String redirectURL;

    public IncludeResponseWrapper(HttpServletResponse httpServletResponse) {
        super(httpServletResponse);
    }

    public String getRedirectURL() {
        return this.redirectURL;
    }

    @Override
    public String getContentType() {
        return this.contentType;
    }

    @Override
    public void setStatus(int i) {
        this.status = i;
    }

    @Override
    public boolean isCommitted() {
        return this.committed;
    }

    @Override
    public void sendRedirect(String s) throws IOException {
        this.committed = true;
        this.redirectURL = s;
        super.sendRedirect(s);
    }

    // don't add @Override since it's only a method as of Servlet 3.0
    public int getStatus() {
        return this.status;
    }

    @Override
    public void setContentType(String s) {
        this.contentType = s;
    }

    @Override
    public void setLocale(Locale locale) {
        // do nothing
    }

    @Override
    public void sendError(int i, String s) {
        if (isCommitted()) {
            throw new IllegalStateException("Response already committed");
        }
        setStatus(i);
        flushBuffer();
    }

    @Override
    public void sendError(int i) {
        if (isCommitted()) {
            throw new IllegalStateException("Response already committed");
        }
        setStatus(i);
        flushBuffer();
    }

    @Override
    public ServletOutputStream getOutputStream() {
        if (this.usingWriter) {
            throw new IllegalStateException("Method getWriter() already called");
        }

        if (!this.usingStream) {
            this.usingStream = true;
            this.byteBuffer = new StreamByteBuffer();
            this.os = this.byteBuffer.getOutputStream();
            this.sos = new ServletOutputStream() {

                @Override
                public void write(byte[] b, int off, int len) throws IOException {
                    IncludeResponseWrapper.this.os.write(b, off, len);
                }

                @Override
                public void write(byte[] b) throws IOException {
                    IncludeResponseWrapper.this.os.write(b);
                }

                @Override
                public void write(int b) throws IOException {
                    IncludeResponseWrapper.this.os.write(b);
                }

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

                @Override
                public void setWriteListener(WriteListener writeListener) {
                    //no op
                }

            };
        }

        return this.sos;
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        if (this.usingStream) {
            throw new IllegalStateException("Method getOutputStream() already called");
        }

        if (!this.usingWriter) {
            this.usingWriter = true;
            this.charBuffer = new StreamCharBuffer();
            this.charBuffer.setNotifyParentBuffersEnabled(false);
            this.pw = GrailsPrintWriterAdapter.newInstance(this.charBuffer.getWriter());
        }
        return this.pw;
    }

    public Object getContent() throws CharacterCodingException {
        return getContent("UTF-8");
    }

    public Object getContent(String encoding) throws CharacterCodingException {
        if (this.usingWriter) {
            return this.charBuffer;
        }

        if (this.usingStream) {
            return this.byteBuffer.readAsString(encoding);
        }

        return "";
    }

    @Override
    public void resetBuffer() {
        if (isCommitted()) {
            throw new IllegalStateException("Response already committed");
        }
        if (this.usingWriter) {
            this.charBuffer.reset();
        }

        if (this.usingStream) {
            this.byteBuffer.reset();
        }
    }

    @Override
    public void reset() {
        resetBuffer();
    }

    @Override
    public void setContentLength(int len) {
        // do nothing
    }

    @Override
    public void flushBuffer() {
        // do nothing
    }

}