/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.felix.gogo.shell;
import java.text.CharacterIterator;
import java.text.StringCharacterIterator;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.ListIterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class History {
private static final int SIZE_DEFAULT = 100;
private LinkedList<String> commands;
private int limit;
public History() {
this.limit = SIZE_DEFAULT;
this.commands = new LinkedList<String>();
}
CharSequence evaluate(final CharSequence commandLine) {
/*
* <pre>
* hist = ( '!' spec ) | ( '^' subst ) .
* spec = '!' ( '!' | idx | '?' find | string ) [ ':' [ 'a' | 'g' ] 's' regex ] . idx = [ '-' ] { 0..9 } .
* find = string ( '?' | EOL ) .
* subst = pat '^' repl '^' EOL .
* regex = str pat str repl str EOL .
* </pre>
*/
final CharacterIterator ci = new StringCharacterIterator(commandLine.toString());
String event;
char c = ci.current();
if (c == '!') {
c = ci.next();
if (c == '!') {
event = this.commands.getLast();
ci.next();
} else if ((c >= '0' && c <= '9') || c == '-') {
event = getCommand(ci);
} else if (c == '?') {
event = findContains(ci);
ci.next();
} else {
ci.previous();
event = findStartsWith(ci);
}
} else if (c == '^') {
event = subst(ci, c, false, this.commands.getLast());
} else {
throw new IllegalArgumentException(commandLine + ": Unsupported event");
}
if (ci.current() == ':') {
c = ci.next();
boolean global = (c == 'a' || c == 'g');
if (global) {
c = ci.next();
}
if (c == 's') {
event = subst(ci, ci.next(), global, event);
}
}
return event;
}
/**
* Returns the command history, oldest command first
*/
Iterator<String> getHistory() {
return this.commands.iterator();
}
void append(final CharSequence commandLine) {
commands.add(commandLine.toString());
if (commands.size() > this.limit) {
commands.removeFirst();
}
}
private String getCommand(final CharacterIterator ci) {
final StringBuilder s = new StringBuilder();
char c = ci.current();
do {
s.append(c);
c = ci.next();
} while (c >= '0' && c <= '9');
final int n = Integer.parseInt(s.toString());
final int pos = ((n < 0) ? this.commands.size() : -1) + n;
if (pos >= 0 && pos < this.commands.size()) {
return this.commands.get(pos);
}
throw new IllegalArgumentException("!" + n + ": event not found");
}
private String findContains(final CharacterIterator ci) {
CharSequence part = findDelimiter(ci, '?');
final ListIterator<String> iter = this.commands.listIterator(this.commands.size());
while (iter.hasPrevious()) {
String value = iter.previous();
if (value.contains(part)) {
return value;
}
}
throw new IllegalArgumentException("No command containing '" + part + "' in the history");
}
private String findStartsWith(final CharacterIterator ci) {
String part = findDelimiter(ci, ':').toString();
final ListIterator<String> iter2 = this.commands.listIterator(this.commands.size());
while (iter2.hasPrevious()) {
String value = iter2.previous();
if (value.startsWith(part)) {
return value;
}
}
throw new IllegalArgumentException("No command containing '" + part + "' in the history");
}
private String subst(final CharacterIterator ci, final char delimiter, final boolean replaceAll, final String event) {
final String pattern = findDelimiter(ci, delimiter).toString();
final String repl = findDelimiter(ci, delimiter).toString();
if (pattern.length() == 0) {
throw new IllegalArgumentException(":s" + event + ": substitution failed");
}
final Pattern regex = Pattern.compile(pattern);
final Matcher m = regex.matcher(event);
final StringBuffer res = new StringBuffer();
if (!m.find()) {
throw new IllegalArgumentException(":s" + event + ": substitution failed");
}
do {
m.appendReplacement(res, repl);
} while (replaceAll && m.find());
m.appendTail(res);
return res.toString();
}
private CharSequence findDelimiter(final CharacterIterator ci, char delimiter) {
final StringBuilder b = new StringBuilder();
for (char c = ci.next(); c != CharacterIterator.DONE && c != delimiter; c = ci.next()) {
if (c == '\\') {
c = ci.next();
}
b.append(c);
}
return b;
}
}