| // 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.skyframe; |
| |
| import java.io.Serializable; |
| import java.util.Objects; |
| |
| /** |
| * In case we can't get a fast digest from the filesystem, we store this metadata as a proxy to |
| * the file contents. Currently it is a pair of the mtime and "value id" (which is right now just |
| * the ivalue number). We may wish to augment this object with the following data: |
| * a. the device number |
| * b. the ctime, which cannot be tampered with in userspace |
| * |
| * <p>For an example of why mtime alone is insufficient, note that 'mv' preserves timestamps. So if |
| * files 'a' and 'b' initially have the same timestamp, then we would think 'b' is unchanged after |
| * the user executes `mv a b` between two builds. |
| */ |
| public final class FileContentsProxy implements Serializable { |
| private final long mtime; |
| private final long valueId; |
| |
| public FileContentsProxy(long mtime, long valueId) { |
| this.mtime = mtime; |
| this.valueId = valueId; |
| } |
| |
| public static FileContentsProxy create(long mtime, long valueId) { |
| return new FileContentsProxy(mtime, valueId); |
| } |
| |
| public long getMtime() { |
| return mtime; |
| } |
| |
| public long getValueId() { |
| return valueId; |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (other == this) { |
| return true; |
| } |
| |
| if (!(other instanceof FileContentsProxy)) { |
| return false; |
| } |
| |
| FileContentsProxy that = (FileContentsProxy) other; |
| return mtime == that.mtime && valueId == that.valueId; |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(mtime, valueId); |
| } |
| |
| @Override |
| public String toString() { |
| return prettyPrint(); |
| } |
| |
| public String prettyPrint() { |
| return String.format("mtime of %d and nodeId of %d", mtime, valueId); |
| } |
| } |