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/*
 * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
 * Copyright 2004 The Apache Software Foundation
 *
 * 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
 *
 *     http://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.apache.jasper.runtime;

import java.io.IOException;
import java.io.Writer;
import java.security.AccessController;
import java.security.PrivilegedAction;

import jakarta.servlet.ServletResponse;
import jakarta.servlet.jsp.JspWriter;

import org.apache.jasper.Constants;
import org.apache.jasper.compiler.Localizer;
import org.apache.jasper.security.SecurityUtil;

import org.glassfish.jsp.api.ByteWriter;


/**
 * Write text to a character-output stream, buffering characters so as
 * to provide for the efficient writing of single characters, arrays,
 * and strings. 
 *
 * Provide support for discarding for the output that has been 
 * buffered. 
 * 
 * This needs revisiting when the buffering problems in the JSP spec
 * are fixed -akv  What buffering problems? -kmc
 *
 * Add method for writing bytes.  This allows static texts to be pre-encoded,
 * for performance.  Note that this can be done only if the page is unbuffered.
 * -kmc
 *
 * @author Anil K. Vijendran
 * @author Kin-man Chung
 * @author Dongbin Nie
 */
public class JspWriterImpl extends JspWriter {
    
    private static final int MAX_BUFFER_SIZE = Integer.getInteger(
        "org.apache.jasper.runtime.JspWriterImpl.MAX_THREAD_LOCAL_BUFFER_SIZE",
        32 * 1024);
    
    private static final ThreadLocal 
        charBufferPools = new ThreadLocal();

    private Writer out;
    private ServletResponse response;    
    private CharBuffer buf;
    private boolean flushed = false;
    private boolean closed = false;
    protected boolean implementsByteWriter = true;
    protected ByteWriter byteOut;
    
    public JspWriterImpl() {
	super( Constants.DEFAULT_BUFFER_SIZE, true );
    }

    /**
     * Create a buffered character-output stream that uses a default-sized
     * output buffer.
     *
     * @param  response  A Servlet Response
     */
    public JspWriterImpl(ServletResponse response) {
        this(response, Constants.DEFAULT_BUFFER_SIZE, true);
    }

    /**
     * Create a new buffered character-output stream that uses an output
     * buffer of the given size.
     *
     * @param  response A Servlet Response
     * @param  sz   	Output-buffer size, a positive integer
     *
     * @exception  IllegalArgumentException  If sz is <= 0
     */
    public JspWriterImpl(ServletResponse response, int sz, 
                         boolean autoFlush) {
        super(sz, autoFlush);
        if (sz < 0)
            throw new IllegalArgumentException("Buffer size <= 0");
	this.response = response;
        allocateCharBuffer();
        // START OF IASRI 4641975/6172992
        try {
            response.setBufferSize(sz);
        } catch (IllegalStateException ise) {
            // ignore
        }
        // END OF IASRI 4641975/6172992
    }

    void init( ServletResponse response, int sz, boolean autoFlush ) {
	this.response= response;
	this.autoFlush=autoFlush;
	this.bufferSize=sz;
        allocateCharBuffer();
        // START OF IASRI 4641975/6172992
        try {
            response.setBufferSize(sz);
        } catch (IllegalStateException ise) {
            // ignore
        }
        // END OF IASRI 4641975/6172992
    }

    /** Package-level access
     */
    void recycle() {
	flushed = false;
        closed = false;
        out = null;
        byteOut = null;
        releaseCharBuffer();
        response = null;
    }

    /**
     * Flush the output buffer to the underlying character stream, without
     * flushing the stream itself.  This method is non-private only so that it
     * may be invoked by PrintStream.
     */
    protected final void flushBuffer() throws IOException {
        if (bufferSize == 0)
            return;
        flushed = true;
        ensureOpen();
        if (buf.pos == buf.offset)
            return;
        initOut();
        out.write(buf.buf, buf.offset, buf.pos - buf.offset);
        buf.pos = buf.offset;
    }

    private void initOut() throws IOException {
        if (out == null) {
            out = response.getWriter();
	}
    }
	
    private String getLocalizeMessage(final String message){
        if (SecurityUtil.isPackageProtectionEnabled()){
           return AccessController.doPrivileged(
           new PrivilegedAction(){
                public String run(){
                    return Localizer.getMessage(message); 
                }
           });
        } else {
            return Localizer.getMessage(message);
        }
    }

    /**
     * Discard the output buffer.
     */
    public final void clear() throws IOException {
        if ((bufferSize == 0) && (out != null))
            // clear() is illegal after any unbuffered output (JSP.5.5)
            throw new IllegalStateException(
                    getLocalizeMessage("jsp.error.ise_on_clear"));
        if (flushed)
            throw new IOException(
                    getLocalizeMessage("jsp.error.attempt_to_clear_flushed_buffer"));
        ensureOpen();
        if (buf != null)
            buf.pos = buf.offset;
    }

    public void clearBuffer() throws IOException {
        if (bufferSize == 0)
            throw new IllegalStateException(
                    getLocalizeMessage("jsp.error.ise_on_clear"));
        ensureOpen();
        buf.pos = buf.offset;
    }

    private final void bufferOverflow() throws IOException {
        throw new IOException(getLocalizeMessage("jsp.error.overflow"));
    }

    /**
     * Flush the stream.
     *
     */
    public void flush()  throws IOException {
        flushBuffer();
        if (out != null) {
            out.flush();
        }
        // START 6426898
        else {
            // Set the default character encoding if there isn't any present,
            // see CR 6699416
            response.setCharacterEncoding(response.getCharacterEncoding());

            // Cause response headers to be sent
            response.flushBuffer();
        }
        // END 6426898
    }

    /**
     * Close the stream.
     *
     */
    public void close() throws IOException {
        if (response == null || closed)
            // multiple calls to close is OK
            return;
        flush();
        if (out != null)
            out.close();
        out = null;
        byteOut = null;
        closed = true;
    }

    /**
     * @return the number of bytes unused in the buffer
     */
    public int getRemaining() {
        return buf == null ? 0 : buf.lim - buf.pos;
    }

    /** check to make sure that the stream has not been closed */
    private void ensureOpen() throws IOException {
	if (response == null || closed)
	    throw new IOException("Stream closed");
    }


    /**
     * Attempt to write a String pre-encoded with the page encoding.
     *
     * @param bytesOK If true, write out the byte array,
     *                else, write out the String.
     * @param buf     The text encoded with the page encoding
     * @param str     The original text
     */
    public void write(boolean bytesOK, byte buf[], String str)
            throws IOException {

        ensureOpen();
        if (bufferSize == 0 && bytesOK) {
            initByteOut();
            if (implementsByteWriter) {
                write(buf, 0, buf.length);
                return;
            }
        }
        write(str);
    }

    /* Returns true if bytes should be outputted.
     * Used by ServletResponseWrapperInclude.
    */
    boolean shouldOutputBytes() {
        if (bufferSize > 0) {
            return false;
        }
        try {
            initByteOut();
        } catch (IOException ex) {
        }
        return implementsByteWriter;
    }

    private void initByteOut() throws IOException {
        initOut();
        if (byteOut == null) {
            try {
                byteOut = (ByteWriter) out;
                implementsByteWriter = true;
            } catch (ClassCastException ex) {
                implementsByteWriter = false;
            }
        }
    }

    public void write(byte buf[], int off, int len)
            throws IOException {
        byteOut.write(buf, off, len);
    }


    /**
     * Write a single character.
     */
    public void write(int c) throws IOException {
        ensureOpen();
        if (bufferSize == 0) {
            initOut();
            out.write(c);
        }
        else {
            if (getRemaining() == 0)
                if (autoFlush)
                    flushBuffer();
                else
                    bufferOverflow();
            buf.buf[buf.pos++] = (char) c;
        }
    }

    /**
     * Our own little min method, to avoid loading java.lang.Math if we've run
     * out of file descriptors and we're trying to print a stack trace.
     */
    private int min(int a, int b) {
	if (a < b) return a;
	return b;
    }

    /**
     * Write a portion of an array of characters.
     *
     * 

Ordinarily this method stores characters from the given array into * this stream's buffer, flushing the buffer to the underlying stream as * needed. If the requested length is at least as large as the buffer, * however, then this method will flush the buffer and write the characters * directly to the underlying stream. Thus redundant * DiscardableBufferedWriters will not copy data unnecessarily. * * @param cbuf A character array * @param off Offset from which to start reading characters * @param len Number of characters to write */ public void write(char cbuf[], int off, int len) throws IOException { ensureOpen(); if (bufferSize == 0) { initOut(); out.write(cbuf, off, len); return; } if ((off < 0) || (off > cbuf.length) || (len < 0) || ((off + len) > cbuf.length) || ((off + len) < 0)) { throw new IndexOutOfBoundsException(); } else if (len == 0) { return; } if (len >= bufferSize) { /* If the request length exceeds the size of the output buffer, flush the buffer and then write the data directly. In this way buffered streams will cascade harmlessly. */ if (autoFlush) flushBuffer(); else bufferOverflow(); initOut(); out.write(cbuf, off, len); return; } int b = off, t = off + len; while (b < t) { int d = min(getRemaining(), t - b); System.arraycopy(cbuf, b, buf.buf, buf.pos, d); b += d; buf.pos += d; if (getRemaining() == 0) if (autoFlush) flushBuffer(); else bufferOverflow(); } } /** * Write an array of characters. This method cannot be inherited from the * Writer class because it must suppress I/O exceptions. */ public void write(char buf[]) throws IOException { write(buf, 0, buf.length); } /** * Write a portion of a String. * * @param s String to be written * @param off Offset from which to start reading characters * @param len Number of characters to be written */ public void write(String s, int off, int len) throws IOException { ensureOpen(); if (bufferSize == 0) { initOut(); out.write(s, off, len); return; } int b = off, t = off + len; while (b < t) { int d = min(getRemaining(), t - b); s.getChars(b, b + d, buf.buf, buf.pos); b += d; buf.pos += d; if (getRemaining() == 0) if (autoFlush) flushBuffer(); else bufferOverflow(); } } /** * Write a string. This method cannot be inherited from the Writer class * because it must suppress I/O exceptions. */ public void write(String s) throws IOException { // Simple fix for Bugzilla 35410 // Calling the other write function so as to init the buffer anyways write(s, 0, (s != null) ? s.length() : 0); } static String lineSeparator = System.getProperty("line.separator"); /** * Write a line separator. The line separator string is defined by the * system property line.separator, and is not necessarily a single * newline ('\n') character. * * @exception IOException If an I/O error occurs */ public void newLine() throws IOException { write(lineSeparator); } /* Methods that do not terminate lines */ /** * Print a boolean value. The string produced by {@link * java.lang.String#valueOf(boolean)} is translated into bytes * according to the platform's default character encoding, and these bytes * are written in exactly the manner of the {@link * #write(int)} method. * * @param b The boolean to be printed */ public void print(boolean b) throws IOException { write(b ? "true" : "false"); } /** * Print a character. The character is translated into one or more bytes * according to the platform's default character encoding, and these bytes * are written in exactly the manner of the {@link * #write(int)} method. * * @param c The char to be printed */ public void print(char c) throws IOException { write(String.valueOf(c)); } /** * Print an integer. The string produced by {@link * java.lang.String#valueOf(int)} is translated into bytes according * to the platform's default character encoding, and these bytes are * written in exactly the manner of the {@link #write(int)} * method. * * @param i The int to be printed */ public void print(int i) throws IOException { write(String.valueOf(i)); } /** * Print a long integer. The string produced by {@link * java.lang.String#valueOf(long)} is translated into bytes * according to the platform's default character encoding, and these bytes * are written in exactly the manner of the {@link #write(int)} * method. * * @param l The long to be printed */ public void print(long l) throws IOException { write(String.valueOf(l)); } /** * Print a floating-point number. The string produced by {@link * java.lang.String#valueOf(float)} is translated into bytes * according to the platform's default character encoding, and these bytes * are written in exactly the manner of the {@link #write(int)} * method. * * @param f The float to be printed */ public void print(float f) throws IOException { write(String.valueOf(f)); } /** * Print a double-precision floating-point number. The string produced by * {@link java.lang.String#valueOf(double)} is translated into * bytes according to the platform's default character encoding, and these * bytes are written in exactly the manner of the {@link * #write(int)} method. * * @param d The double to be printed */ public void print(double d) throws IOException { write(String.valueOf(d)); } /** * Print an array of characters. The characters are converted into bytes * according to the platform's default character encoding, and these bytes * are written in exactly the manner of the {@link #write(int)} * method. * * @param s The array of chars to be printed * * @throws NullPointerException If s is null */ public void print(char s[]) throws IOException { write(s); } /** * Print a string. If the argument is null then the string * "null" is printed. Otherwise, the string's characters are * converted into bytes according to the platform's default character * encoding, and these bytes are written in exactly the manner of the * {@link #write(int)} method. * * @param s The String to be printed */ public void print(String s) throws IOException { if (s == null) { s = "null"; } write(s); } /** * Print an object. The string produced by the {@link * java.lang.String#valueOf(Object)} method is translated into bytes * according to the platform's default character encoding, and these bytes * are written in exactly the manner of the {@link #write(int)} * method. * * @param obj The Object to be printed */ public void print(Object obj) throws IOException { write(String.valueOf(obj)); } /* Methods that do terminate lines */ /** * Terminate the current line by writing the line separator string. The * line separator string is defined by the system property * line.separator, and is not necessarily a single newline * character ('\n'). * * Need to change this from PrintWriter because the default * println() writes to the sink directly instead of through the * write method... */ public void println() throws IOException { newLine(); } /** * Print a boolean value and then terminate the line. This method behaves * as though it invokes {@link #print(boolean)} and then * {@link #println()}. */ public void println(boolean x) throws IOException { print(x); println(); } /** * Print a character and then terminate the line. This method behaves as * though it invokes {@link #print(char)} and then {@link * #println()}. */ public void println(char x) throws IOException { print(x); println(); } /** * Print an integer and then terminate the line. This method behaves as * though it invokes {@link #print(int)} and then {@link * #println()}. */ public void println(int x) throws IOException { print(x); println(); } /** * Print a long integer and then terminate the line. This method behaves * as though it invokes {@link #print(long)} and then * {@link #println()}. */ public void println(long x) throws IOException { print(x); println(); } /** * Print a floating-point number and then terminate the line. This method * behaves as though it invokes {@link #print(float)} and then * {@link #println()}. */ public void println(float x) throws IOException { print(x); println(); } /** * Print a double-precision floating-point number and then terminate the * line. This method behaves as though it invokes {@link * #print(double)} and then {@link #println()}. */ public void println(double x) throws IOException { print(x); println(); } /** * Print an array of characters and then terminate the line. This method * behaves as though it invokes {@link #print(char[])} and then * {@link #println()}. */ public void println(char x[]) throws IOException { print(x); println(); } /** * Print a String and then terminate the line. This method behaves as * though it invokes {@link #print(String)} and then * {@link #println()}. */ public void println(String x) throws IOException { print(x); println(); } /** * Print an Object and then terminate the line. This method behaves as * though it invokes {@link #print(Object)} and then * {@link #println()}. */ public void println(Object x) throws IOException { print(x); println(); } // START PWC 6512276 public boolean hasData() { if (bufferSize != 0 && buf.pos != buf.offset) { return true; } return false; } // END PWC 6512276 private void allocateCharBuffer() { if (bufferSize == 0) return; if (bufferSize > MAX_BUFFER_SIZE) { buf = new CharBuffer(new char[bufferSize], 0, bufferSize); } else { buf = getCharBufferThreadLocalPool().allocate(bufferSize); } } private void releaseCharBuffer() { if (buf == null) return; if ((buf.lim - buf.offset) <= MAX_BUFFER_SIZE) { getCharBufferThreadLocalPool().release(buf); } buf = null; } private CharBufferThreadLocalPool getCharBufferThreadLocalPool() { CharBufferThreadLocalPool pool = charBufferPools.get(); if (pool == null) { pool = new CharBufferThreadLocalPool(); charBufferPools.set(pool); } return pool; } private static class CharBuffer { char[] buf; int offset; int pos; int lim; CharBuffer(char[] buffer, int offset, int length) { this.buf = buffer; this.offset = offset; this.pos = offset; this.lim = offset + length; } } private static class CharBufferThreadLocalPool { private char[] pool; private int pos; public CharBuffer allocate(int size) { if (remaining() < size) { pool = new char[MAX_BUFFER_SIZE]; pos = 0; } CharBuffer allocated = new CharBuffer(pool, pos, size); pos += size; return allocated; } public void release(CharBuffer buffer) { if (buffer.buf == pool && buffer.lim == pos) { pos = buffer.offset; } } public int remaining() { return pool == null ? 0 : pool.length - pos; } } }





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