1 files changed, 31 insertions, 27 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java b/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java
index e4bc250333..d5a612efa5 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/PackageDeserializer.java
@@ -34,7 +34,6 @@ import com.google.devtools.build.lib.syntax.GlobCriteria;
 import com.google.devtools.build.lib.syntax.GlobList;
 import com.google.devtools.build.lib.syntax.Label;
 import com.google.devtools.build.lib.syntax.Label.SyntaxException;
-import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
 
@@ -55,11 +54,23 @@ public class PackageDeserializer {
 
   private static final Logger LOG = Logger.getLogger(PackageDeserializer.class.getName());
 
-  // Workaround for Java serialization not allowing to pass in a context manually.
+  /**
+   * Provides the deserializer with tools it needs to build a package from its serialized form.
+   */
+  public interface PackageDeserializationEnvironment {
+
+    /** Converts the serialized package's path string into a {@link Path} object. */
+    Path getPath(String buildFilePath);
+
+    /** Returns a {@link RuleClass} object for the serialized rule. */
+    RuleClass getRuleClass(Build.Rule rulePb, Location ruleLocation);
+  }
+
+  // Workaround for Java serialization making it tough to pass in a deserialization environment
+  // manually.
   // volatile is needed to ensure that the objects are published safely.
-  // TODO(bazel-team): Subclass ObjectOutputStream to pass through environment variables.
-  public static volatile RuleClassProvider defaultRuleClassProvider;
-  public static volatile FileSystem defaultDeserializerFileSystem;
+  // TODO(bazel-team): Subclass ObjectOutputStream to pass this through instead.
+  public static volatile PackageDeserializationEnvironment defaultPackageDeserializationEnvironment;
 
   private class Context {
     private final Package.Builder packageBuilder;
@@ -120,15 +131,9 @@ public class PackageDeserializer {
       }
     }
 
-    void deserializeRule(Build.Rule rulePb)
-        throws PackageDeserializationException {
-      String ruleClassName = rulePb.getRuleClass();
-      RuleClass ruleClass = ruleClassProvider.getRuleClassMap().get(ruleClassName);
-      if (ruleClass == null) {
-        throw new PackageDeserializationException(
-            String.format("Invalid rule class '%s'", ruleClassName));
-      }
-
+    void deserializeRule(Build.Rule rulePb) throws PackageDeserializationException {
+      Location ruleLocation = deserializeLocation(rulePb.getParseableLocation());
+      RuleClass ruleClass = packageDeserializationEnvironment.getRuleClass(rulePb, ruleLocation);
       Map<String, ParsedAttributeValue> attributeValues = new HashMap<>();
       for (Build.Attribute attrPb : rulePb.getAttributeList()) {
         Type<?> type = ruleClass.getAttributeByName(attrPb.getName()).getType();
@@ -136,7 +141,6 @@ public class PackageDeserializer {
       }
 
       Label ruleLabel = deserializeLabel(rulePb.getName());
-      Location ruleLocation = deserializeLocation(rulePb.getParseableLocation());
       try {
         Rule rule = ruleClass.createRuleWithParsedAttributeValues(
             ruleLabel, packageBuilder, ruleLocation, attributeValues,
@@ -150,8 +154,7 @@ public class PackageDeserializer {
     }
   }
 
-  private final FileSystem fileSystem;
-  private final RuleClassProvider ruleClassProvider;
+  private final PackageDeserializationEnvironment packageDeserializationEnvironment;
 
   @Immutable
   private static final class ExplicitLocation extends Location {
@@ -196,15 +199,16 @@ public class PackageDeserializer {
     }
   }
 
-  public PackageDeserializer(FileSystem fileSystem, RuleClassProvider ruleClassProvider) {
-    if (fileSystem == null) {
-      fileSystem = defaultDeserializerFileSystem;
-    }
-    this.fileSystem = Preconditions.checkNotNull(fileSystem);
-    if (ruleClassProvider == null) {
-      ruleClassProvider = defaultRuleClassProvider;
-    }
-    this.ruleClassProvider = Preconditions.checkNotNull(ruleClassProvider);
+  /**
+   * Creates a {@link PackageDeserializer} using {@link #defaultPackageDeserializationEnvironment}.
+   */
+  public PackageDeserializer() {
+    this.packageDeserializationEnvironment = defaultPackageDeserializationEnvironment;
+  }
+
+  public PackageDeserializer(PackageDeserializationEnvironment packageDeserializationEnvironment) {
+    this.packageDeserializationEnvironment =
+        Preconditions.checkNotNull(packageDeserializationEnvironment);
   }
 
   /**
@@ -310,7 +314,7 @@ public class PackageDeserializer {
    */
   private void deserializeInternal(Build.Package packagePb, StoredEventHandler eventHandler,
       Package.Builder builder, InputStream in) throws PackageDeserializationException, IOException {
-    Path buildFile = fileSystem.getPath(packagePb.getBuildFilePath());
+    Path buildFile = packageDeserializationEnvironment.getPath(packagePb.getBuildFilePath());
     Preconditions.checkNotNull(buildFile);
     Context context = new Context(buildFile, builder);
     builder.setFilename(buildFile);