1 files changed, 83 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/query2/TargetEdgeErrorObserver.java b/src/main/java/com/google/devtools/build/lib/query2/TargetEdgeErrorObserver.java
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index 0000000000..5a075d2c3c
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+++ b/src/main/java/com/google/devtools/build/lib/query2/TargetEdgeErrorObserver.java
@@ -0,0 +1,83 @@
+// 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.query2;
+
+import com.google.devtools.build.lib.concurrent.ThreadSafety;
+import com.google.devtools.build.lib.packages.Attribute;
+import com.google.devtools.build.lib.packages.NoSuchThingException;
+import com.google.devtools.build.lib.packages.Rule;
+import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.pkgcache.TargetEdgeObserver;
+import com.google.devtools.build.lib.syntax.Label;
+
+/**
+ * Record errors, such as missing package/target or rules containing errors,
+ * encountered during visitation. Emit an error message upon encountering
+ * missing edges
+ *
+ * The accessor {@link #hasErrors}) may not be called until the concurrent phase
+ * is over, i.e. all external calls to visit() methods have completed.
+ *
+ * If you need to report errors to the console during visitation, use the
+ * subclass {@link com.google.devtools.build.lib.query2.ErrorPrintingTargetEdgeErrorObserver}.
+ */
+class TargetEdgeErrorObserver implements TargetEdgeObserver {
+
+  /**
+   * True iff errors were encountered.  Note, may be set to "true" during the
+   * concurrent phase.  Volatile, because it is assigned by worker threads and
+   * read by the main thread without monitor synchronization.
+   */
+  private volatile boolean hasErrors = false;
+
+  /**
+   * Reports an unresolved label error and records the fact that an error was
+   * encountered.
+   * @param target the target that referenced the unresolved label
+   * @param label the label that could not be resolved
+   * @param e the exception that was thrown when the label could not be resolved
+   */
+  @ThreadSafety.ThreadSafe
+  @Override
+  public void missingEdge(Target target, Label label, NoSuchThingException e) {
+    hasErrors = true;
+  }
+
+  /**
+   * Returns true iff any errors (such as missing targets or packages, or rules
+   * with errors) have been encountered during any work.
+   *
+   * <p>Not thread-safe; do not call during visitation.
+   *
+   *  @return true iff no errors (such as missing targets or packages, or rules
+   *              with errors) have been encountered during any work.
+   */
+  public boolean hasErrors() {
+    return hasErrors;
+  }
+
+  @Override
+  public void edge(Target from, Attribute attribute, Target to) {
+    // No-op.
+  }
+
+  @Override
+  public void node(Target node) {
+    if (node.getPackage().containsErrors() ||
+        ((node instanceof Rule) && ((Rule) node).containsErrors())) {
+      this.hasErrors = true;  // Note, this is thread-safe.
+    }
+  }
+}