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.analysis.actions; import com.google.common.collect.ImmutableList; import com.google.common.collect.Iterables; import com.google.devtools.build.lib.actions.ActionOwner; import com.google.devtools.build.lib.actions.Artifact; import com.google.devtools.build.lib.actions.ParameterFile; import com.google.devtools.build.lib.analysis.AnalysisEnvironment; import com.google.devtools.build.lib.analysis.config.BuildConfiguration; import com.google.devtools.build.lib.util.Preconditions; import com.google.devtools.build.lib.vfs.PathFragment; import java.util.List; import javax.annotation.Nullable; import javax.annotation.concurrent.Immutable; /** * A command-line implementation that wraps another command line and puts the arguments in a * parameter file if necessary * * <p>The Linux kernel has a limit for the command line length, and that can be easily reached * if, for example, a command is listing all its inputs on the command line. */ @Immutable public final class ParamFileHelper { /** * Returns a params file artifact or null for a given command description. * * <p>Returns null if parameter files are not to be used according to paramFileInfo, or if the * command line is short enough that a parameter file is not needed. * * <p>Make sure to add the returned artifact (if not null) as an input of the corresponding * action. * * @param executableArgs leading arguments that should never be wrapped in a parameter file * @param arguments arguments to the command (in addition to executableArgs), OR * @param commandLine a {@link CommandLine} that provides the arguments (in addition to * executableArgs) * @param paramFileInfo parameter file information * @param configuration the configuration * @param analysisEnvironment the analysis environment * @param outputs outputs of the action (used to construct a filename for the params file) */ static Artifact getParamsFileMaybe(List<String> executableArgs, @Nullable Iterable<String> arguments, @Nullable CommandLine commandLine, @Nullable ParamFileInfo paramFileInfo, BuildConfiguration configuration, AnalysisEnvironment analysisEnvironment, Iterable<Artifact> outputs) { if (paramFileInfo == null) { return null; } if (!paramFileInfo.always() && getParamFileSize(executableArgs, arguments, commandLine) < configuration.getMinParamFileSize()) { return null; } Artifact output = Iterables.getFirst(outputs, null); Preconditions.checkNotNull(output); PathFragment paramFilePath = ParameterFile.derivePath(output.getRootRelativePath()); return analysisEnvironment.getDerivedArtifact(paramFilePath, output.getRoot()); } /** * Creates a command line using an external params file. * * <p>Call this with the result of {@link #getParamsFileMaybe} if it is not null. * * @param executableArgs leading arguments that should never be wrapped in a parameter file * @param isShellCommand true if this is a shell command * @param paramFileInfo parameter file information * @param parameterFile the output parameter file artifact * @param paramFileWriteAction the action that generates the parameter file */ public static CommandLine createWithParamsFile(List<String> executableArgs, boolean isShellCommand, ParamFileInfo paramFileInfo, Artifact parameterFile, ParameterFileWriteAction paramFileWriteAction) { String pathWithFlag = paramFileInfo.getFlag() + parameterFile.getExecPathString(); Iterable<String> commandArgv = Iterables.concat(executableArgs, ImmutableList.of(pathWithFlag)); return CommandLine.ofInternal(commandArgv, isShellCommand, paramFileWriteAction); } /** * Creates an action to write the parameter file. * * @param arguments arguments to the command (in addition to executableArgs), OR * @param commandLine a {@link CommandLine} that provides the arguments (in addition to * executableArgs) * @param owner owner of the action * @param parameterFile the output parameter file artifact * @param paramFileInfo parameter file information */ public static ParameterFileWriteAction createParameterFileWriteAction(@Nullable Iterable<String> arguments, @Nullable CommandLine commandLine, ActionOwner owner, Artifact parameterFile, ParamFileInfo paramFileInfo) { CommandLine paramFileContents = (commandLine != null) ? commandLine : CommandLine.ofInternal(arguments, false, null); return new ParameterFileWriteAction(owner, parameterFile, paramFileContents, paramFileInfo.getFileType(), paramFileInfo.getCharset()); } /** * Creates a command line without using a params file. * * <p>Call this if {@link #getParamsFileMaybe} returns null. * * @param executableArgs leading arguments that should never be wrapped in a parameter file * @param arguments arguments to the command (in addition to executableArgs), OR * @param commandLine a {@link CommandLine} that provides the arguments (in addition to * executableArgs) * @param isShellCommand true if this is a shell command */ public static CommandLine createWithoutParamsFile(List<String> executableArgs, Iterable<String> arguments, CommandLine commandLine, boolean isShellCommand) { if (commandLine == null) { Iterable<String> commandArgv = Iterables.concat(executableArgs, arguments); return CommandLine.ofInternal(commandArgv, isShellCommand, null); } if (executableArgs.isEmpty()) { return commandLine; } return CommandLine.ofMixed(ImmutableList.copyOf(executableArgs), commandLine, isShellCommand); } /** * Estimates the params file size for the given arguments. */ private static int getParamFileSize(List<String> executableArgs, Iterable<String> arguments, CommandLine commandLine) { Iterable<String> actualArguments = (commandLine != null) ? commandLine.arguments() : arguments; return getParamFileSize(executableArgs) + getParamFileSize(actualArguments); } private static int getParamFileSize(Iterable<String> args) { int size = 0; for (String s : args) { size += s.length() + 1; } return size; } }