/*
* Copyright (C) 2009, Google Inc.
* Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.diff;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.eclipse.jgit.util.IO;
import org.eclipse.jgit.util.IntList;
import org.eclipse.jgit.util.RawParseUtils;
/**
* A Sequence supporting UNIX formatted text in byte[] format.
* <p>
* Elements of the sequence are the lines of the file, as delimited by the UNIX
* newline character ('\n'). The file content is treated as 8 bit binary text,
* with no assumptions or requirements on character encoding.
* <p>
* Note that the first line of the file is element 0, as defined by the Sequence
* interface API. Traditionally in a text editor a patch file the first line is
* line number 1. Callers may need to subtract 1 prior to invoking methods if
* they are converting from "line number" to "element index".
*/
public class RawText extends Sequence {
/** A Rawtext of length 0 */
public static final RawText EMPTY_TEXT = new RawText(new byte[0]);
/** Number of bytes to check for heuristics in {@link #isBinary(byte[])} */
private static final int FIRST_FEW_BYTES = 8000;
/** The file content for this sequence. */
protected final byte[] content;
/** Map of line number to starting position within {@link #content}. */
protected final IntList lines;
/**
* Create a new sequence from an existing content byte array.
* <p>
* The entire array (indexes 0 through length-1) is used as the content.
*
* @param input
* the content array. The array is never modified, so passing
* through cached arrays is safe.
*/
public RawText(final byte[] input) {
content = input;
lines = RawParseUtils.lineMap(content, 0, content.length);
}
/**
* Create a new sequence from a file.
* <p>
* The entire file contents are used.
*
* @param file
* the text file.
* @throws IOException
* if Exceptions occur while reading the file
*/
public RawText(File file) throws IOException {
this(IO.readFully(file));
}
/** @return total number of items in the sequence. */
public int size() {
// The line map is always 2 entries larger than the number of lines in
// the file. Index 0 is padded out/unused. The last index is the total
// length of the buffer, and acts as a sentinel.
//
return lines.size() - 2;
}
/**
* Write a specific line to the output stream, without its trailing LF.
* <p>
* The specified line is copied as-is, with no character encoding
* translation performed.
* <p>
* If the specified line ends with an LF ('\n'), the LF is <b>not</b>
* copied. It is up to the caller to write the LF, if desired, between
* output lines.
*
* @param out
* stream to copy the line data onto.
* @param i
* index of the line to extract. Note this is 0-based, so line
* number 1 is actually index 0.
* @throws IOException
* the stream write operation failed.
*/
public void writeLine(final OutputStream out, final int i)
throws IOException {
int start = getStart(i);
int end = getEnd(i);
if (content[end - 1] == '\n')
end--;
out.write(content, start, end - start);
}
/**
* Determine if the file ends with a LF ('\n').
*
* @return true if the last line has an LF; false otherwise.
*/
public boolean isMissingNewlineAtEnd() {
final int end = lines.get(lines.size() - 1);
if (end == 0)
return true;
return content[end - 1] != '\n';
}
/**
* Get the text for a single line.
*
* @param i
* index of the line to extract. Note this is 0-based, so line
* number 1 is actually index 0.
* @return the text for the line, without a trailing LF.
*/
public String getString(int i) {
return getString(i, i + 1, true);
}
/**
* Get the text for a region of lines.
*
* @param begin
* index of the first line to extract. Note this is 0-based, so
* line number 1 is actually index 0.
* @param end
* index of one past the last line to extract.
* @param dropLF
* if true the trailing LF ('\n') of the last returned line is
* dropped, if present.
* @return the text for lines {@code [begin, end)}.
*/
public String getString(int begin, int end, boolean dropLF) {
if (begin == end)
return ""; //$NON-NLS-1$
int s = getStart(begin);
int e = getEnd(end - 1);
if (dropLF && content[e - 1] == '\n')
e--;
return decode(s, e);
}
/**
* Decode a region of the text into a String.
*
* The default implementation of this method tries to guess the character
* set by considering UTF-8, the platform default, and falling back on
* ISO-8859-1 if neither of those can correctly decode the region given.
*
* @param start
* first byte of the content to decode.
* @param end
* one past the last byte of the content to decode.
* @return the region {@code [start, end)} decoded as a String.
*/
protected String decode(int start, int end) {
return RawParseUtils.decode(content, start, end);
}
private int getStart(final int i) {
return lines.get(i + 1);
}
private int getEnd(final int i) {
return lines.get(i + 2);
}
/**
* Determine heuristically whether a byte array represents binary (as
* opposed to text) content.
*
* @param raw
* the raw file content.
* @return true if raw is likely to be a binary file, false otherwise
*/
public static boolean isBinary(byte[] raw) {
return isBinary(raw, raw.length);
}
/**
* Determine heuristically whether the bytes contained in a stream
* represents binary (as opposed to text) content.
*
* Note: Do not further use this stream after having called this method! The
* stream may not be fully read and will be left at an unknown position
* after consuming an unknown number of bytes. The caller is responsible for
* closing the stream.
*
* @param raw
* input stream containing the raw file content.
* @return true if raw is likely to be a binary file, false otherwise
* @throws IOException
* if input stream could not be read
*/
public static boolean isBinary(InputStream raw) throws IOException {
final byte[] buffer = new byte[FIRST_FEW_BYTES];
int cnt = 0;
while (cnt < buffer.length) {
final int n = raw.read(buffer, cnt, buffer.length - cnt);
if (n == -1)
break;
cnt += n;
}
return isBinary(buffer, cnt);
}
/**
* Determine heuristically whether a byte array represents binary (as
* opposed to text) content.
*
* @param raw
* the raw file content.
* @param length
* number of bytes in {@code raw} to evaluate. This should be
* {@code raw.length} unless {@code raw} was over-allocated by
* the caller.
* @return true if raw is likely to be a binary file, false otherwise
*/
public static boolean isBinary(byte[] raw, int length) {
// Same heuristic as C Git
if (length > FIRST_FEW_BYTES)
length = FIRST_FEW_BYTES;
for (int ptr = 0; ptr < length; ptr++)
if (raw[ptr] == '\0')
return true;
return false;
}
/**
* Get the line delimiter for the first line.
*
* @since 2.0
* @return the line delimiter or <code>null</code>
*/
public String getLineDelimiter() {
if (size() == 0)
return null;
int e = getEnd(0);
if (content[e - 1] != '\n')
return null;
if (content.length > 1 && e > 1 && content[e - 2] == '\r')
return "\r\n"; //$NON-NLS-1$
else
return "\n"; //$NON-NLS-1$
}
}