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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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 com.google.devtools.build.lib.util;
import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableList;
import com.google.common.escape.CharEscaperBuilder;
import com.google.common.escape.Escaper;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
/**
* Various utility methods operating on strings.
*/
public class StringUtilities {
private static final Joiner NEWLINE_JOINER = Joiner.on('\n');
private static final Escaper KEY_ESCAPER = new CharEscaperBuilder()
.addEscape('!', "!!")
.addEscape('<', "!<")
.addEscape('>', "!>")
.toEscaper();
private static final Escaper CONTROL_CHAR_ESCAPER = new CharEscaperBuilder()
.addEscape('\r', "\\r")
.addEscapes(new char[] {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, /*13=\r*/
14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 127}, "<?>")
.toEscaper();
/**
* Java doesn't have multiline string literals, so having to join a bunch
* of lines is a very common problem. So, here's a static method that we
* can static import in such situations.
*/
public static String joinLines(String... lines) {
return NEWLINE_JOINER.join(lines);
}
/**
* A corollary to {@link #joinLines(String[])} for collections.
*/
public static String joinLines(Collection<String> lines) {
return NEWLINE_JOINER.join(lines);
}
/**
* combineKeys(x1, ..., xn):
* Computes a string that encodes the sequence
* x1, ..., xn. Distinct sequences map to distinct strings.
*
* The encoding is intended to be vaguely human-readable.
*/
public static String combineKeys(Iterable<String> parts) {
final StringBuilder buf = new StringBuilder(128);
for (String part : parts) {
// We enclose each part in angle brackets to separate them. Some
// trickiness is required to ensure that the result is unique (distinct
// sequences map to distinct strings): we escape any angle bracket
// characters in the parts by preceding them with an escape character
// (we use "!") and we also need to escape any escape characters.
buf.append('<');
buf.append(KEY_ESCAPER.escape(part));
buf.append('>');
}
return buf.toString();
}
/**
* combineKeys(x1, ..., xn):
* Computes a string that encodes the sequence
* x1, ..., xn. Distinct sequences map to distinct strings.
*
* The encoding is intended to be vaguely human-readable.
*/
public static String combineKeys(String... parts) {
return combineKeys(ImmutableList.copyOf(parts));
}
/**
* Replaces all occurrences of 'literal' in 'input' with 'replacement'.
* Like {@link String#replaceAll(String, String)} but for literal Strings
* instead of regular expression patterns.
*
* @param input the input String
* @param literal the literal String to replace in 'input'.
* @param replacement the replacement String to replace 'literal' in 'input'.
* @return the 'input' String with all occurrences of 'literal' replaced with
* 'replacement'.
*/
public static String replaceAllLiteral(String input, String literal,
String replacement) {
int literalLength = literal.length();
if (literalLength == 0) {
return input;
}
StringBuilder result = new StringBuilder(
input.length() + replacement.length());
int start = 0;
int index = 0;
while ((index = input.indexOf(literal, start)) >= 0) {
result.append(input, start, index);
result.append(replacement);
start = index + literalLength;
}
result.append(input.substring(start));
return result.toString();
}
/**
* Creates a simple key-value table of the form
*
* <pre>
* key: some value
* another key: some other value
* yet another key: and so on ...
* </pre>
*
* The return value will not include a final {@code "\n"}.
*/
public static String layoutTable(Map<String, String> data) {
List<String> tableLines = new ArrayList<>();
for (Map.Entry<String, String> entry : data.entrySet()) {
tableLines.add(entry.getKey() + ": " + entry.getValue());
}
return NEWLINE_JOINER.join(tableLines);
}
/**
* Returns an easy-to-read string approximation of a number of bytes,
* e.g. "21MB". Note, these are IEEE units, i.e. decimal not binary powers.
*/
public static String prettyPrintBytes(long bytes) {
if (bytes < 1E4) { // up to 10KB
return bytes + "B";
} else if (bytes < 1E7) { // up to 10MB
return ((int) (bytes / 1E3)) + "KB";
} else if (bytes < 1E11) { // up to 100GB
return ((int) (bytes / 1E6)) + "MB";
} else {
return ((int) (bytes / 1E9)) + "GB";
}
}
/**
* Returns true if 'source' contains 'target' as a sub-array.
*/
public static boolean containsSubarray(char[] source, char[] target) {
if (target.length > source.length) {
return false;
}
for (int i = 0; i < source.length - target.length + 1; i++) {
boolean matches = true;
for (int j = 0; j < target.length; j++) {
if (source[i + j] != target[j]) {
matches = false;
break;
}
}
if (matches) {
return true;
}
}
return false;
}
/**
* Replace control characters with visible strings.
* @return the sanitized string.
*/
public static String sanitizeControlChars(String message) {
return CONTROL_CHAR_ESCAPER.escape(message);
}
/**
* Converts a Java style function name to a Python style function name the following way:
* every upper case character gets replaced with an underscore and its lower case counterpart.
* <p>E.g. fooBar --> foo_bar
*/
public static String toPythonStyleFunctionName(String javaStyleFunctionName) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < javaStyleFunctionName.length(); i++) {
char c = javaStyleFunctionName.charAt(i);
if (Character.isUpperCase(c)) {
sb.append('_').append(Character.toLowerCase(c));
} else {
sb.append(c);
}
}
return sb.toString();
}
}
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