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// Copyright 2018 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.runfiles;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* Runfiles lookup library for Bazel-built Java binaries and tests.
*
* <p>USAGE:
*
* <p>1. Depend on this runfiles library from your build rule:
*
* <pre>
* java_binary(
* name = "my_binary",
* ...
* deps = ["@bazel_tools//tools/java/runfiles"],
* )
* </pre>
*
* <p>2. Import the runfiles library.
*
* <pre>
* import com.google.devtools.build.runfiles.Runfiles;
* </pre>
*
* <p>3. Create a Runfiles object and use rlocation to look up runfile paths:
*
* <pre>
* public void myFunction() {
* Runfiles runfiles = Runfiles.create();
* String path = runfiles.rlocation("my_workspace/path/to/my/data.txt");
* ...
* </pre>
*
* <p>If you want to start subprocesses that also need runfiles, you need to set the right
* environment variables for them:
*
* <pre>
* String path = r.rlocation("path/to/binary");
* ProcessBuilder pb = new ProcessBuilder(path);
* pb.environment().putAll(r.getEnvVars());
* ...
* Process p = pb.start();
* </pre>
*/
public abstract class Runfiles {
// Package-private constructor, so only package-private classes may extend it.
private Runfiles() {}
/**
* Returns a new {@link Runfiles} instance.
*
* <p>This method passes the JVM's environment variable map to {@link #create(Map)}.
*/
public static Runfiles create() throws IOException {
return create(System.getenv());
}
/**
* Returns a new {@link Runfiles} instance.
*
* <p>The returned object is either:
*
* <ul>
* <li>manifest-based, meaning it looks up runfile paths from a manifest file, or
* <li>directory-based, meaning it looks up runfile paths under a given directory path
* </ul>
*
* <p>If {@code env} contains "RUNFILES_MANIFEST_ONLY" with value "1", this method returns a
* manifest-based implementation. The manifest's path is defined by the "RUNFILES_MANIFEST_FILE"
* key's value in {@code env}.
*
* <p>Otherwise this method returns a directory-based implementation. The directory's path is
* defined by the value in {@code env} under the "RUNFILES_DIR" key, or if absent, then under the
* "JAVA_RUNFILES" key.
*
* <p>Note about performance: the manifest-based implementation eagerly reads and caches the whole
* manifest file upon instantiation.
*
* @throws IOException if RUNFILES_MANIFEST_ONLY=1 is in {@code env} but there's no
* "RUNFILES_MANIFEST_FILE", "RUNFILES_DIR", or "JAVA_RUNFILES" key in {@code env} or their
* values are empty, or some IO error occurs
*/
public static Runfiles create(Map<String, String> env) throws IOException {
if (isManifestOnly(env)) {
// On Windows, Bazel sets RUNFILES_MANIFEST_ONLY=1.
// On every platform, Bazel also sets RUNFILES_MANIFEST_FILE, but on Linux and macOS it's
// faster to use RUNFILES_DIR.
return new ManifestBased(getManifestPath(env));
} else {
return new DirectoryBased(getRunfilesDir(env));
}
}
/**
* Returns the runtime path of a runfile (a Bazel-built binary's/test's data-dependency).
*
* <p>The returned path may not be valid. The caller should check the path's validity and that the
* path exists.
*
* <p>The function may return null. In that case the caller can be sure that the rule does not
* know about this data-dependency.
*
* @param path runfiles-root-relative path of the runfile
* @throws IllegalArgumentException if {@code path} fails validation, for example if it's null or
* empty, or not normalized (contains "./", "../", or "//")
*/
public final String rlocation(String path) {
Util.checkArgument(path != null);
Util.checkArgument(!path.isEmpty());
Util.checkArgument(
!path.startsWith("../")
&& !path.contains("/..")
&& !path.startsWith("./")
&& !path.contains("/./")
&& !path.endsWith("/.")
&& !path.contains("//"),
"path is not normalized: \"%s\"",
path);
Util.checkArgument(
!path.startsWith("\\"), "path is absolute without a drive letter: \"%s\"", path);
if (new File(path).isAbsolute()) {
return path;
}
return rlocationChecked(path);
}
/**
* Returns environment variables for subprocesses.
*
* <p>The caller should add the returned key-value pairs to the environment of subprocesses in
* case those subprocesses are also Bazel-built binaries that need to use runfiles.
*/
public abstract Map<String, String> getEnvVars();
/** Returns true if the platform supports runfiles only via manifests. */
private static boolean isManifestOnly(Map<String, String> env) {
return "1".equals(env.get("RUNFILES_MANIFEST_ONLY"));
}
private static String getManifestPath(Map<String, String> env) throws IOException {
String value = env.get("RUNFILES_MANIFEST_FILE");
if (Util.isNullOrEmpty(value)) {
throw new IOException(
"Cannot load runfiles manifest: $RUNFILES_MANIFEST_ONLY is 1 but"
+ " $RUNFILES_MANIFEST_FILE is empty or undefined");
}
return value;
}
private static String getRunfilesDir(Map<String, String> env) throws IOException {
String value = env.get("RUNFILES_DIR");
if (Util.isNullOrEmpty(value)) {
value = env.get("JAVA_RUNFILES");
}
if (Util.isNullOrEmpty(value)) {
throw new IOException(
"Cannot find runfiles: $RUNFILES_DIR and $JAVA_RUNFILES are both unset or empty");
}
return value;
}
abstract String rlocationChecked(String path);
/** {@link Runfiles} implementation that parses a runfiles-manifest file to look up runfiles. */
private static final class ManifestBased extends Runfiles {
private final Map<String, String> runfiles;
private final String manifestPath;
ManifestBased(String manifestPath) throws IOException {
Util.checkArgument(manifestPath != null);
Util.checkArgument(!manifestPath.isEmpty());
this.manifestPath = manifestPath;
this.runfiles = loadRunfiles(manifestPath);
}
private static Map<String, String> loadRunfiles(String path) throws IOException {
HashMap<String, String> result = new HashMap<>();
try (BufferedReader r =
new BufferedReader(
new InputStreamReader(new FileInputStream(path), StandardCharsets.UTF_8))) {
String line = null;
while ((line = r.readLine()) != null) {
int index = line.indexOf(' ');
String runfile = (index == -1) ? line : line.substring(0, index);
String realPath = (index == -1) ? line : line.substring(index + 1);
result.put(runfile, realPath);
}
}
return Collections.unmodifiableMap(result);
}
private static String findRunfilesDir(String manifest) {
if (manifest.endsWith("/MANIFEST")
|| manifest.endsWith("\\MANIFEST")
|| manifest.endsWith(".runfiles_manifest")) {
String path = manifest.substring(0, manifest.length() - 9);
if (new File(path).isDirectory()) {
return path;
}
}
return "";
}
@Override
public String rlocationChecked(String path) {
String exactMatch = runfiles.get(path);
if (exactMatch != null) {
return exactMatch;
}
// If path references a runfile that lies under a directory that itself is a runfile, then
// only the directory is listed in the manifest. Look up all prefixes of path in the manifest
// and append the relative path from the prefix if there is a match.
int prefixEnd = path.length();
while ((prefixEnd = path.lastIndexOf('/', prefixEnd - 1)) != -1) {
String prefixMatch = runfiles.get(path.substring(0, prefixEnd));
if (prefixMatch != null) {
return prefixMatch + '/' + path.substring(prefixEnd + 1);
}
}
return null;
}
@Override
public Map<String, String> getEnvVars() {
HashMap<String, String> result = new HashMap<>(4);
result.put("RUNFILES_MANIFEST_ONLY", "1");
result.put("RUNFILES_MANIFEST_FILE", manifestPath);
String runfilesDir = findRunfilesDir(manifestPath);
result.put("RUNFILES_DIR", runfilesDir);
// TODO(laszlocsomor): remove JAVA_RUNFILES once the Java launcher can pick up RUNFILES_DIR.
result.put("JAVA_RUNFILES", runfilesDir);
return result;
}
}
/** {@link Runfiles} implementation that appends runfiles paths to the runfiles root. */
private static final class DirectoryBased extends Runfiles {
private final String runfilesRoot;
DirectoryBased(String runfilesDir) {
Util.checkArgument(!Util.isNullOrEmpty(runfilesDir));
Util.checkArgument(new File(runfilesDir).isDirectory());
this.runfilesRoot = runfilesDir;
}
@Override
String rlocationChecked(String path) {
return runfilesRoot + "/" + path;
}
@Override
public Map<String, String> getEnvVars() {
HashMap<String, String> result = new HashMap<>(2);
result.put("RUNFILES_DIR", runfilesRoot);
// TODO(laszlocsomor): remove JAVA_RUNFILES once the Java launcher can pick up RUNFILES_DIR.
result.put("JAVA_RUNFILES", runfilesRoot);
return result;
}
}
static Runfiles createManifestBasedForTesting(String manifestPath) throws IOException {
return new ManifestBased(manifestPath);
}
static Runfiles createDirectoryBasedForTesting(String runfilesDir) {
return new DirectoryBased(runfilesDir);
}
}