Java tutorial
// 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.rules.java; import static java.nio.charset.StandardCharsets.UTF_8; import com.google.common.annotations.VisibleForTesting; import com.google.common.collect.ImmutableList; import com.google.common.collect.Iterables; import com.google.devtools.build.lib.actions.ActionExecutionContext; import com.google.devtools.build.lib.actions.ActionOwner; import com.google.devtools.build.lib.actions.Artifact; import com.google.devtools.build.lib.analysis.WorkspaceStatusAction; import com.google.devtools.build.lib.analysis.WorkspaceStatusAction.Key; import com.google.devtools.build.lib.analysis.actions.AbstractFileWriteAction; import com.google.devtools.build.lib.util.Fingerprint; import com.google.devtools.build.lib.util.Preconditions; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.Writer; import java.util.Collection; import java.util.HashMap; import java.util.LinkedHashMap; import java.util.Map; import java.util.Properties; /** * An action that creates a Java properties file containing the build informations. */ public class WriteBuildInfoPropertiesAction extends AbstractFileWriteAction { private static final String GUID = "922949ca-1391-4046-a300-74810618dcdc"; private final ImmutableList<Artifact> valueArtifacts; private final BuildInfoPropertiesTranslator keyTranslations; private final boolean includeVolatile; private final boolean includeNonVolatile; private final TimestampFormatter timestampFormatter; /** * An interface to format a timestamp. We are using our custom one to avoid external dependency. */ public static interface TimestampFormatter { /** * Return a human readable string for the given {@code timestamp}. {@code timestamp} is given * in milliseconds since 1st of January 1970 at 0am UTC. */ public String format(long timestamp); } /** * A wrapper around a {@link Writer} that skips the first line assuming the line is pure ASCII. It * can be used to strip the timestamp comment that {@link Properties#store(Writer, String)} adds. */ @VisibleForTesting static class StripFirstLineWriter extends Writer { private final Writer writer; private boolean newlineFound = false; StripFirstLineWriter(OutputStream out) { this.writer = new OutputStreamWriter(out, UTF_8); } @Override public void write(char[] cbuf, int off, int len) throws IOException { if (!newlineFound) { while (len > 0 && cbuf[off] != '\n') { off++; len--; } if (len > 0) { newlineFound = true; off++; len--; } } if (len > 0) { writer.write(cbuf, off, len); } } @Override public void flush() throws IOException { writer.flush(); } @Override public void close() throws IOException { writer.close(); } } /** * Creates an action that writes a Java property files with build information. * * <p>It reads the set of build info keys from an action context that is usually contributed to * Blaze by the workspace status module, and the value associated with said keys from the * workspace status files (stable and volatile) written by the workspace status action. The files * generated by this action serve as input to the * {@link com.google.devtools.build.singlejar.SingleJar} program. * * <p>Without input artifacts, this action uses redacted build information. * * @param inputs Artifacts that contain build information, or an empty collection to use redacted * build information * @param output output the properties file Artifact created by this action * @param keyTranslations how to translates available keys. See * {@link BuildInfoPropertiesTranslator}. * @param includeVolatile whether the set of key to write are giving volatile keys or not * @param includeNonVolatile whether the set of key to write are giving non-volatile keys or not * @param timestampFormatter formats dates printed in the properties file */ public WriteBuildInfoPropertiesAction(Collection<Artifact> inputs, Artifact output, BuildInfoPropertiesTranslator keyTranslations, boolean includeVolatile, boolean includeNonVolatile, TimestampFormatter timestampFormatter) { super(ActionOwner.SYSTEM_ACTION_OWNER, inputs, output, /* makeExecutable= */ false); this.keyTranslations = keyTranslations; this.includeVolatile = includeVolatile; this.includeNonVolatile = includeNonVolatile; this.timestampFormatter = timestampFormatter; valueArtifacts = ImmutableList.copyOf(inputs); if (!inputs.isEmpty()) { // With non-empty inputs we should not generate both volatile and non-volatile data // in the same properties file. Preconditions.checkState(includeVolatile ^ includeNonVolatile); } Preconditions.checkState(output.isConstantMetadata() == (includeVolatile && !inputs.isEmpty())); } @Override public DeterministicWriter newDeterministicWriter(final ActionExecutionContext ctx) { final long timestamp = System.currentTimeMillis(); return new DeterministicWriter() { @Override public void writeOutputFile(OutputStream out) throws IOException { WorkspaceStatusAction.Context context = ctx.getExecutor() .getContext(WorkspaceStatusAction.Context.class); Map<String, String> values = new LinkedHashMap<>(); for (Artifact valueFile : valueArtifacts) { values.putAll(WorkspaceStatusAction.parseValues(valueFile.getPath())); } Map<String, String> keys = new HashMap<>(); if (includeVolatile) { addValues(keys, values, context.getVolatileKeys()); keys.put("BUILD_TIMESTAMP", Long.toString(timestamp / 1000)); keys.put("BUILD_TIME", timestampFormatter.format(timestamp)); } addValues(keys, values, context.getStableKeys()); Properties properties = new Properties(); keyTranslations.translate(keys, properties); properties.store(new StripFirstLineWriter(out), null); } }; } private void addValues(Map<String, String> result, Map<String, String> values, Map<String, Key> keys) { boolean redacted = values.isEmpty(); for (Map.Entry<String, WorkspaceStatusAction.Key> key : keys.entrySet()) { if (key.getValue().isInLanguage("Java")) { result.put(key.getKey(), gePropertyValue(values, redacted, key)); } } } private static String gePropertyValue(Map<String, String> values, boolean redacted, Map.Entry<String, WorkspaceStatusAction.Key> key) { return redacted ? key.getValue().getRedactedValue() : values.containsKey(key.getKey()) ? values.get(key.getKey()) : key.getValue().getDefaultValue(); } @Override protected String computeKey() { Fingerprint f = new Fingerprint(); f.addString(GUID); f.addString(keyTranslations.computeKey()); f.addBoolean(includeVolatile); f.addBoolean(includeNonVolatile); return f.hexDigestAndReset(); } @Override public boolean executeUnconditionally() { return isVolatile(); } @Override public boolean isVolatile() { return includeVolatile && !Iterables.isEmpty(getInputs()); } }