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RESTHeart Commons - Common classes for core components and plugins.
/**
* ---------------------- Minify.java 2015-10-04 ----------------------
*
* Copyright (c) 2015 Charles Bihis (www.whoischarles.com)
*
* This work is an adaptation of JSMin.java published by John Reilly which is a
* translation from C to Java of jsmin.c published by Douglas Crockford.
* Permission is hereby granted to use this Java version under the same
* conditions as the original jsmin.c on which all of these derivatives are
* based.
*
*
*
* --------------------- JSMin.java 2006-02-13 ---------------------
*
* Copyright (c) 2006 John Reilly (www.inconspicuous.org)
*
* This work is a translation from C to Java of jsmin.c published by Douglas
* Crockford. Permission is hereby granted to use the Java version under the
* same conditions as the jsmin.c on which it is based.
*
*
*
* ------------------ jsmin.c 2003-04-21 ------------------
*
* Copyright (c) 2002 Douglas Crockford (www.crockford.com)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* The Software shall be used for Good, not Evil.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/**
* Minify.java is written by Charles Bihis (www.whoischarles.com) and is adapted
* from JSMin.java written by John Reilly (www.inconspicuous.org) which is
* itself a translation of jsmin.c written by Douglas Crockford
* (www.crockford.com).
*
* See
* http://www.unl.edu/ucomm/templatedependents/JSMin.java
* See
* http://www.crockford.com/javascript/jsmin.c
*/
package org.restheart.utils;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PushbackInputStream;
import java.nio.charset.StandardCharsets;
public class Minify {
private static final int EOF = -1;
private PushbackInputStream in;
private OutputStream out;
private int currChar;
private int nextChar;
private int line;
private int column;
/**
*
*/
public Minify() {
this.in = null;
this.out = null;
}
/**
* Minifies the input JSON string.
*
* Takes the input JSON string and deletes the characters which are
* insignificant to JavaScipt. Comments will be removed, tabs will be
* replaced with spaces, carriage returns will be replaced with line feeds,
* and most spaces and line feeds will be removed. The result will be
* returned.
*
* @param json The JSON string for which to minify
* @return A minified, yet functionally identical, version of the input JSON
* string
*/
public StringBuilder minify(String json) {
var ret = new StringBuilder();
var ins = new ByteArrayInputStream(json.getBytes(StandardCharsets.UTF_8));
var bout = new StringBufferOutputStream(ret);
try {
minify(ins, bout);
} catch (Exception e) {
return null;
}
return ret;
}
private static class StringBufferOutputStream extends OutputStream {
protected StringBuilder sb;
public StringBufferOutputStream(StringBuilder sb) {
this.sb = sb;
}
@Override
public void write(int ch) throws IOException {
this.sb.append((char)ch);
}
}
/**
* Takes an input stream to a JSON string and outputs minified JSON to the
* output stream.
*
* Takes the input JSON via the input stream and deletes the characters
* which are insignificant to JavaScript. Comments will be removed, tabs
* will be replaced with spaaces, carriage returns will be replaced with
* line feeds, and most spaces and line feeds will be removed. The result is
* streamed to the output stream.
*
* @param in The InputStream from which to get the un-minified
* JSON
* @param out The OutputStream where the resulting minified
* JSON will be streamed to
* @throws java.io.IOException
* @throws UnterminatedRegExpLiteralException
* @throws UnterminatedCommentException
* @throws UnterminatedStringLiteralException
*/
public void minify(InputStream in, OutputStream out) throws IOException, UnterminatedRegExpLiteralException, UnterminatedCommentException, UnterminatedStringLiteralException {
// Initialize
this.in = new PushbackInputStream(in);
this.out = out;
this.line = 0;
this.column = 0;
var onFirstChar = true;
currChar = '\n';
action(Action.DELETE_NEXT);
// Process input
while (currChar != EOF) {
switch (currChar) {
case ' ':
if (isAlphanum(nextChar)) {
action(Action.OUTPUT_CURR);
} else {
action(Action.DELETE_CURR);
}
break;
case '\n':
switch (nextChar) {
case '{':
case '[':
case '(':
case '+':
case '-':
if (!onFirstChar) {
action(Action.OUTPUT_CURR);
} else {
action(Action.DELETE_CURR);
onFirstChar = false;
}
break;
case ' ':
action(Action.DELETE_NEXT);
break;
default:
if (isAlphanum(nextChar)) {
if (!onFirstChar) {
action(Action.OUTPUT_CURR);
} else {
action(Action.DELETE_CURR);
onFirstChar = false;
}
} else {
action(Action.DELETE_CURR);
onFirstChar = false;
}
}
break;
default:
switch (nextChar) {
case ' ':
if (isAlphanum(currChar)) {
action(Action.OUTPUT_CURR);
break;
}
action(Action.DELETE_NEXT);
break;
case '\n':
switch (currChar) {
case '}':
case ']':
case ')':
case '+':
case '-':
case '"':
case '\'':
action(Action.OUTPUT_CURR);
break;
default:
if (isAlphanum(currChar)) {
action(Action.OUTPUT_CURR);
} else {
action(Action.DELETE_NEXT);
}
}
break;
default:
action(Action.OUTPUT_CURR);
break;
}
}
}
out.flush();
}
/**
* Process the current character with an appropriate action.
*
* The action that occurs is determined by the current character. The
* options are:
*
* 1. Output currChar: output currChar, copy nextChar to currChar, get the
* next character and save it to nextChar 2. Delete currChar: copy nextChar
* to currChar, get the next character and save it to nextChar 3. Delete
* nextChar: get the next character and save it to nextChar
*
* This method essentially treats a string as a single character. Also
* recognizes regular expressions if they are preceded by '(', ',', or '='.
*
* @param action The action to perform
* @throws java.io.IOException
* @throws UnterminatedRegExpLiteralException
* @throws UnterminatedCommentException
* @throws UnterminatedStringLiteralException
*/
private void action(Action action) throws IOException, UnterminatedRegExpLiteralException, UnterminatedCommentException, UnterminatedStringLiteralException {
// Process action
switch (action) {
case OUTPUT_CURR:
out.write(currChar);
case DELETE_CURR:
currChar = nextChar;
if (currChar == '\'' || currChar == '"') {
for (;;) {
out.write(currChar);
currChar = get();
if (currChar == nextChar) {
break;
}
if (currChar <= '\n') {
throw new UnterminatedStringLiteralException(line, column);
}
if (currChar == '\\') {
out.write(currChar);
currChar = get();
}
}
}
case DELETE_NEXT:
nextChar = next();
if (nextChar == '/' && (currChar == '(' || currChar == ',' || currChar == '=' || currChar == ':')) {
out.write(currChar);
out.write(nextChar);
for (;;) {
currChar = get();
if (currChar == '/') {
break;
} else if (currChar == '\\') {
out.write(currChar);
currChar = get();
} else if (currChar <= '\n') {
throw new UnterminatedRegExpLiteralException(line, column);
}
out.write(currChar);
}
nextChar = next();
}
}
}
/**
* Determines whether a given character is a letter, digit, underscore,
* dollar sign, or non-ASCII character.
*
* @param c The character to compare
* @return True if the character is a letter, digit, underscore, dollar
* sign, or non-ASCII character. False otherwise.
*/
private boolean isAlphanum(int c) {
return ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z')
|| c == '_' || c == '$' || c == '\\' || c > 126);
}
/**
* Returns the next character from the input stream.
*
* Will pop the next character from the input stack. If the character is a
* control character, translate it to a space or line feed.
*
* @return The next character from the input stream
* @throws java.io.IOException
*/
private int get() throws IOException {
int c = in.read();
if (c == '\n') {
line++;
column = 0;
} else {
column++;
}
if (c >= ' ' || c == '\n' || c == EOF) {
return c;
}
if (c == '\r') {
column = 0;
return '\n';
}
return ' ';
}
/**
* Returns the next character from the input stream without popping it from
* the stack.
*
* @return The next character from the input stream
* @throws java.io.IOException
*/
private int peek() throws IOException {
int lookaheadChar = in.read();
in.unread(lookaheadChar);
return lookaheadChar;
}
/**
* Get the next character from the input stream, excluding comments.
*
* Will read from the input stream via the get() method. Will
* exclude characters that are part of comments. peek() is used
* to se if a '/' is followed by a '/' or a '*' for the purpose of
* identifying comments.
*
* @return The next character from the input stream, excluding characters
* from comments
* @throws java.io.IOException
* @throws UnterminatedCommentException
*/
private int next() throws IOException, UnterminatedCommentException {
int c = get();
if (c == '/') {
switch (peek()) {
case '/':
for (;;) {
c = get();
if (c <= '\n') {
return c;
}
}
case '*':
get();
for (;;) {
switch (get()) {
case '*':
if (peek() == '/') {
get();
return ' ';
}
break;
case EOF:
throw new UnterminatedCommentException(line, column);
}
}
default:
return c;
}
}
return c;
}
/**
*
*/
public static enum Action {
/**
*
*/
OUTPUT_CURR,
/**
*
*/
DELETE_CURR,
/**
*
*/
DELETE_NEXT
}
/**
* Exception to be thrown when an unterminated comment appears in the input.
*/
public static class UnterminatedCommentException extends Exception {
/**
*
*/
private static final long serialVersionUID = -6883462093707704791L;
/**
*
* @param line
* @param column
*/
public UnterminatedCommentException(int line, int column) {
super("Unterminated comment at line " + line + " and column " + column);
}
}
/**
* Exception to be thrown when an unterminated string literal appears in the
* input.
*/
public static class UnterminatedStringLiteralException extends Exception {
/**
*
*/
private static final long serialVersionUID = 4074245780159866501L;
/**
*
* @param line
* @param column
*/
public UnterminatedStringLiteralException(int line, int column) {
super("Unterminated string literal at line " + line + " and column " + column);
}
}
/**
* Exception to be thrown when an unterminated regular expression literal
* appears in the input.
*/
public static class UnterminatedRegExpLiteralException extends Exception {
/**
*
*/
private static final long serialVersionUID = -3296214957230186243L;
/**
*
* @param line
* @param column
*/
public UnterminatedRegExpLiteralException(int line, int column) {
super("Unterminated regular expression at line " + line + " and column " + column);
}
}
}
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