1 files changed, 104 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaHelper.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaHelper.java
new file mode 100644
index 0000000000..b2a7ca0504
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+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaHelper.java
@@ -0,0 +1,104 @@
+// Copyright 2014 Google Inc. 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 com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.packages.Type;
+import com.google.devtools.build.lib.shell.ShellUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Utility methods for use by Java-related parts of Bazel.
+ */
+// TODO(bazel-team): Merge with JavaUtil.
+public abstract class JavaHelper {
+
+  private JavaHelper() {}
+
+  /**
+   * Returns the java launcher implementation for the given target, if any.
+   * A null return value means "use the JDK launcher".
+   */
+  public static TransitiveInfoCollection launcherForTarget(JavaSemantics semantics,
+      RuleContext ruleContext) {
+    String launcher = filterLauncherForTarget(semantics, ruleContext);
+    return (launcher == null) ? null : ruleContext.getPrerequisite(launcher, Mode.TARGET);
+  }
+
+  /**
+   * Returns the java launcher artifact for the given target, if any.
+   * A null return value means "use the JDK launcher".
+   */
+  public static Artifact launcherArtifactForTarget(JavaSemantics semantics,
+      RuleContext ruleContext) {
+    String launcher = filterLauncherForTarget(semantics, ruleContext);
+    return (launcher == null) ? null : ruleContext.getPrerequisiteArtifact(launcher, Mode.TARGET);
+  }
+
+  /**
+   * Control structure abstraction for safely extracting a prereq from the launcher attribute
+   * or --java_launcher flag.
+   */
+  private static String filterLauncherForTarget(JavaSemantics semantics, RuleContext ruleContext) {
+    // BUILD rule "launcher" attribute
+    if (ruleContext.getRule().isAttrDefined("launcher", Type.LABEL)
+        && ruleContext.attributes().get("launcher", Type.LABEL) != null) {
+      if (ruleContext.attributes().get("launcher", Type.LABEL)
+          .equals(JavaSemantics.JDK_LAUNCHER_LABEL)) {
+        return null;
+      }
+      return "launcher";
+    }
+    // Blaze flag --java_launcher
+    JavaConfiguration javaConfig = ruleContext.getFragment(JavaConfiguration.class);
+    if (ruleContext.getRule().isAttrDefined(":java_launcher", Type.LABEL)
+        && ((javaConfig.getJavaLauncherLabel() != null
+                && !javaConfig.getJavaLauncherLabel().equals(JavaSemantics.JDK_LAUNCHER_LABEL))
+            || semantics.forceUseJavaLauncherTarget(ruleContext))) {
+      return ":java_launcher";
+    }
+    return null;
+  }
+
+  /**
+   * Javac options require special processing - People use them and expect the
+   * options to be tokenized.
+   */
+  public static List<String> tokenizeJavaOptions(Iterable<String> inOpts) {
+    // Ideally, this would be in the options parser. Unfortunately,
+    // the options parser can't handle a converter that expands
+    // from a value X into a List<X> and allow-multiple at the
+    // same time.
+    List<String> result = new ArrayList<>();
+    for (String current : inOpts) {
+      try {
+        ShellUtils.tokenize(result, current);
+      } catch (ShellUtils.TokenizationException ex) {
+        // Tokenization failed; this likely means that the user
+        // did not want tokenization to happen on his argument.
+        // (Any tokenization where we should produce an error
+        // has already been done by the shell that invoked
+        // blaze). Therefore, pass the argument through to
+        // the tool, so that we can see the original error.
+        result.add(current);
+      }
+    }
+    return result;
+  }
+}