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/*
*
* Copyright 2016 jshook
* 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 io.nosqlbench.nb.api.config;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* Synopsis
*
* This is a multi-purpose special parser for parameters in a command or
* other map. It is called special because it does take a few liberties which are not
* commonly found in regular languages, but which may be desirable for casual use.
* This is done in a very specific way such that interpretation is unambiguous.
*
*
* Basic Format
*
* The input line consists of a sequence of names and values, called assignments.
* These occur as {@code name=value}, and may be delimited by spaces or semicolons, like
* {@code name1=value1 name2=value2} or {@code name1=value1;name2=value2}.
* Values can even contain spaces, even though space is a possible delimiter.
* Thus, {@code name1= value foo bar
* name2=baz} works, with the values {@code value foo bar} and {@code baz}.
*
*
* Names
* The name of a parameter must appear in raw literal form, with no escaping. A name may not
* contain spaces, semicolons or equals signs, and may not start with quotes of any kind.
* Otherwise, there are no restrictions placed on the characters that may appear in
* a name. Even escaped characters are allowed.
*
* Values
* Values can appear as single quoted values, double quoted values, or literal values.
* The way the value is parsed is determined by the leading character, respectively.
*
* Single Quoted
* If the leading character is a single quote, then all following characters up to the next single quote
* are taken as the value, except for escape characters which work as expected. Double quotes,
* spaces, equals or any other characters have no special meaning within a single quoted value.
*
*
* Double Quoted
* If the leading character is a double quote, then all following characters up to the next double quote
* are taken as the value, except for escape characters which work as expected. Single quotes,
* spaces, equals or other characters have no special meaning within double quotes.
*
* Literal
* Otherwise, the value is taken as every single character, including spaces, single quotes,
* and double quotes, up to the end of the command line or the next parameter assignment.
* Any occurrence of semicolons which is not escaped will be treated as a delimiter. The next occurrence
* of a name and equals pattern after a space will be taken as the next named parameter. Otherwise, all
* spaces and partial word are included in the last value assigment found. Leading spaces on literal
* values are skipped unless escaped.
*
*/
public class ParamsParser {
public final static String ASSIGN_CHARS = "=:";
private final static Logger logger = LogManager.getLogger(ParamsParser.class);
public static Map parse(String input, boolean canonicalize) {
return parse(input, ASSIGN_CHARS, canonicalize);
}
public static boolean hasValues(String input) {
return hasValues(input, ASSIGN_CHARS);
}
public static boolean hasValues(String input, String assignChars) {
for (int i = 0; i < assignChars.length(); i++) {
if (input.contains(assignChars.substring(i, i + 1))) {
return true;
}
}
return false;
}
/**
* Parse a string input as a loose-form param=value list, and be reasonable about formatting
* conventions that most users would follow in the absence of detailed rules.
* See {@link ParamsParser} for more details on how this works.
*
* @param input The string form containing the parameter names and values to be extracted.
* @param canonicalize Whether or not to replace synonyms with modern forms and to warn when old forms are used
* @return A map of extracted keys and values
*/
public static Map parse(String input, String assignmentCharacters, boolean canonicalize) {
ParseState s = ParseState.expectingName;
Map parms = new LinkedHashMap<>();
StringBuilder varname = new StringBuilder(512);
StringBuilder value = new StringBuilder(512);
String lastVarname = null;
boolean isEscaped = false;
for (int i = 0; i < input.length(); i++) {
char c = input.charAt(i);
if (isEscaped) {
switch (s) {
case expectingVal:
case readingDquotedVal:
case readingSquotedVal:
case readingRawVal:
value.append(c);
break;
case readingName:
varname.append(c);
break;
default:
throw new RuntimeException("invalid position for escape:" + i + ", in " + input);
}
isEscaped = false;
continue;
}
switch (s) {
case expectingName:
if (c =='\'' || c=='"') {
throw new RuntimeException("Unable to parse a name starting with character '" + c + "'. Names" +
" must be literal values.");
} else if (c != ' ' && c != ';') {
s = ParseState.readingName;
varname.append(c);
}
break;
case readingName:
if (c == '\\') {
isEscaped = true;
} else if (c == ' ') {
String partial = parms.get(lastVarname);
if (partial == null) {
throw new RuntimeException("space continuation while reading name or value, but no prior " +
"for " + lastVarname + " exists");
}
parms.put(lastVarname, partial + " " + varname);
varname.setLength(0);
} else if (assignmentCharacters.indexOf(c) == -1) {
varname.append(c);
} else {
s = ParseState.expectingVal;
}
break;
case expectingVal:
if (c == ' ') {
} else if (c == '\\') {
isEscaped = true;
} else if (c == '\'') {
s = ParseState.readingSquotedVal;
} else if (c == '"') {
s = ParseState.readingDquotedVal;
} else if (c == ';') {
parms.put(varname.toString(), null);
varname.setLength(0);
s = ParseState.expectingName;
} else {
s = ParseState.readingRawVal;
value.append(c);
}
break;
case readingRawVal:
if (c == '\\') {
isEscaped = true;
} else if (c != ';' && c != ' ') {
value.append(c);
} else {
parms.put(varname.toString(), value.toString());
lastVarname=varname.toString();
varname.setLength(0);
value.setLength(0);
s = ParseState.expectingName;
}
break;
case readingSquotedVal:
if (c == '\\') {
isEscaped = true;
} else if (c != '\'') {
value.append(c);
} else {
parms.put(varname.toString(), value.toString());
varname.setLength(0);
value.setLength(0);
s = ParseState.expectingName;
}
break;
case readingDquotedVal:
if (c == '\\') {
isEscaped = true;
} else if (c != '"') {
value.append(c);
} else {
parms.put(varname.toString(), value.toString());
varname.setLength(0);
value.setLength(0);
s = ParseState.expectingName;
}
break;
default:
throw new RuntimeException("Unmatched parse state. This should be impossible.");
}
}
if (isEscaped) {
throw new RuntimeException("an unfinished escape sequence at the end is not valid");
}
switch (s) {
case expectingVal:
parms.put(varname.toString(), null);
varname.setLength(0);
s = ParseState.expectingName;
break;
case readingRawVal:
parms.put(varname.toString(), value.toString());
varname.setLength(0);
s = ParseState.expectingName;
break;
case readingName:
parms.put(lastVarname,parms.get(lastVarname)+' '+varname.toString());
varname.setLength(0);
break;
default:
}
if (input.length()>0 && parms.size()==0) {
throw new RuntimeException("Unable to parse input:" + input);
}
if (canonicalize) {
List keys= new ArrayList<>(parms.keySet());
for (String key : keys) {
String properkey= Synonyms.canonicalize(key,logger);
if (!key.equals(properkey)) {
parms.put(properkey,parms.get(key));
parms.remove(key);
}
}
}
return parms;
}
private enum ParseState {
expectingName,
readingName,
expectingVal,
readingRawVal,
readingSquotedVal,
readingDquotedVal
}
}