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- /*
- * Copyright (C) 2017, Google Inc.
- * 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.internal.storage.dfs;
-
- import java.io.EOFException;
- import java.io.IOException;
- import java.nio.ByteBuffer;
- import java.text.MessageFormat;
-
- import org.eclipse.jgit.annotations.Nullable;
- import org.eclipse.jgit.errors.PackInvalidException;
- import org.eclipse.jgit.internal.storage.pack.PackExt;
-
- /** Block based file stored in {@link DfsBlockCache}. */
- abstract class BlockBasedFile {
- /** Cache that owns this file and its data. */
- final DfsBlockCache cache;
-
- /** Unique identity of this file while in-memory. */
- final DfsStreamKey key;
-
- /** Description of the associated pack file's storage. */
- final DfsPackDescription desc;
- final PackExt ext;
-
- /**
- * Preferred alignment for loading blocks from the backing file.
- * <p>
- * It is initialized to 0 and filled in on the first read made from the
- * file. Block sizes may be odd, e.g. 4091, caused by the underling DFS
- * storing 4091 user bytes and 5 bytes block metadata into a lower level
- * 4096 byte block on disk.
- */
- volatile int blockSize;
-
- /**
- * Total number of bytes in this pack file.
- * <p>
- * This field initializes to -1 and gets populated when a block is loaded.
- */
- volatile long length;
-
- /** True once corruption has been detected that cannot be worked around. */
- volatile boolean invalid;
-
- /** Exception that caused the packfile to be flagged as invalid */
- protected volatile Exception invalidatingCause;
-
- BlockBasedFile(DfsBlockCache cache, DfsPackDescription desc, PackExt ext) {
- this.cache = cache;
- this.key = desc.getStreamKey(ext);
- this.desc = desc;
- this.ext = ext;
- }
-
- String getFileName() {
- return desc.getFileName(ext);
- }
-
- boolean invalid() {
- return invalid;
- }
-
- void setInvalid() {
- invalid = true;
- }
-
- void setBlockSize(int newSize) {
- blockSize = newSize;
- }
-
- long alignToBlock(long pos) {
- int size = blockSize;
- if (size == 0)
- size = cache.getBlockSize();
- return (pos / size) * size;
- }
-
- int blockSize(ReadableChannel rc) {
- // If the block alignment is not yet known, discover it. Prefer the
- // larger size from either the cache or the file itself.
- int size = blockSize;
- if (size == 0) {
- size = rc.blockSize();
- if (size <= 0)
- size = cache.getBlockSize();
- else if (size < cache.getBlockSize())
- size = (cache.getBlockSize() / size) * size;
- blockSize = size;
- }
- return size;
- }
-
- DfsBlock getOrLoadBlock(long pos, DfsReader ctx) throws IOException {
- return cache.getOrLoad(this, pos, ctx, null);
- }
-
- DfsBlock readOneBlock(long pos, DfsReader ctx,
- @Nullable ReadableChannel fileChannel) throws IOException {
- if (invalid) {
- throw new PackInvalidException(getFileName(), invalidatingCause);
- }
-
- ctx.stats.readBlock++;
- long start = System.nanoTime();
- ReadableChannel rc = fileChannel != null ? fileChannel
- : ctx.db.openFile(desc, ext);
- try {
- int size = blockSize(rc);
- pos = (pos / size) * size;
-
- // If the size of the file is not yet known, try to discover it.
- // Channels may choose to return -1 to indicate they don't
- // know the length yet, in this case read up to the size unit
- // given by the caller, then recheck the length.
- long len = length;
- if (len < 0) {
- len = rc.size();
- if (0 <= len)
- length = len;
- }
-
- if (0 <= len && len < pos + size)
- size = (int) (len - pos);
- if (size <= 0)
- throw new EOFException(MessageFormat.format(
- DfsText.get().shortReadOfBlock, Long.valueOf(pos),
- getFileName(), Long.valueOf(0), Long.valueOf(0)));
-
- byte[] buf = new byte[size];
- rc.position(pos);
- int cnt = read(rc, ByteBuffer.wrap(buf, 0, size));
- ctx.stats.readBlockBytes += cnt;
- if (cnt != size) {
- if (0 <= len) {
- throw new EOFException(MessageFormat.format(
- DfsText.get().shortReadOfBlock, Long.valueOf(pos),
- getFileName(), Integer.valueOf(size),
- Integer.valueOf(cnt)));
- }
-
- // Assume the entire thing was read in a single shot, compact
- // the buffer to only the space required.
- byte[] n = new byte[cnt];
- System.arraycopy(buf, 0, n, 0, n.length);
- buf = n;
- } else if (len < 0) {
- // With no length at the start of the read, the channel should
- // have the length available at the end.
- length = len = rc.size();
- }
-
- return new DfsBlock(key, pos, buf);
- } finally {
- if (rc != fileChannel) {
- rc.close();
- }
- ctx.stats.readBlockMicros += elapsedMicros(start);
- }
- }
-
- static int read(ReadableChannel rc, ByteBuffer buf) throws IOException {
- int n;
- do {
- n = rc.read(buf);
- } while (0 < n && buf.hasRemaining());
- return buf.position();
- }
-
- static long elapsedMicros(long start) {
- return (System.nanoTime() - start) / 1000L;
- }
- }
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