1 files changed, 150 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/packages/PackageSpecification.java b/src/main/java/com/google/devtools/build/lib/packages/PackageSpecification.java
new file mode 100644
index 0000000000..20524aa411
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/packages/PackageSpecification.java
@@ -0,0 +1,150 @@
+// 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.packages;
+
+import com.google.devtools.build.lib.cmdline.LabelValidator;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.lib.vfs.PathFragment;
+
+/**
+ * A class that represents some packages that are included in the visibility list of a rule.
+ */
+public abstract class PackageSpecification {
+  private static final String PACKAGE_LABEL = "__pkg__";
+  private static final String SUBTREE_LABEL = "__subpackages__";
+  private static final String ALL_BENEATH_SUFFIX = "/...";
+  public static final PackageSpecification EVERYTHING =
+      new AllPackagesBeneath(new PathFragment(""));
+
+  public abstract boolean containsPackage(PathFragment packageName);
+
+  @Override
+  public int hashCode() {
+    return toString().hashCode();
+  }
+
+  @Override
+  public boolean equals(Object that) {
+    if (this == that) {
+      return true;
+    }
+
+    if (!(that instanceof PackageSpecification)) {
+      return false;
+    }
+
+    return this.toString().equals(that.toString());
+  }
+
+  /**
+   * Parses a string as a visibility specification.
+   * Throws {@link InvalidPackageSpecificationException} if the label cannot be parsed.
+   *
+   * <p>Note that these strings are different from what {@link #fromLabel} understands.
+   */
+  public static PackageSpecification fromString(final String spec)
+      throws InvalidPackageSpecificationException {
+    String result = spec;
+    boolean allBeneath = false;
+
+    if (result.startsWith("//")) {
+      result = spec.substring(2);
+    } else {
+      throw new InvalidPackageSpecificationException("invalid package label: " + spec);
+    }
+
+    if (result.indexOf(':') >= 0) {
+      throw new InvalidPackageSpecificationException("invalid package label: " + spec);
+    }
+
+    if (result.equals("...")) {
+      // Special case: //... will not end in /...
+      return EVERYTHING;
+    }
+
+    if (result.endsWith(ALL_BENEATH_SUFFIX)) {
+      allBeneath = true;
+      result = result.substring(0, result.length() - ALL_BENEATH_SUFFIX.length());
+    }
+
+    String errorMessage = LabelValidator.validatePackageName(result);
+    if (errorMessage == null) {
+      return allBeneath ?
+          new AllPackagesBeneath(new PathFragment(result)) :
+          new SinglePackage(new PathFragment(result));
+    } else {
+      throw new InvalidPackageSpecificationException(errorMessage);
+    }
+  }
+
+  /**
+   * Parses a label as a visibility specification. returns null if the label cannot be parsed.
+   *
+   * <p>Note that these strings are different from what {@link #fromString} understands.
+   */
+  public static PackageSpecification fromLabel(Label label) {
+    if (label.getName().equals(PACKAGE_LABEL)) {
+      return new SinglePackage(label.getPackageFragment());
+    } else if (label.getName().equals(SUBTREE_LABEL)) {
+      return new AllPackagesBeneath(label.getPackageFragment());
+    } else {
+      return null;
+    }
+  }
+
+  private static class SinglePackage extends PackageSpecification {
+    private PathFragment singlePackageName;
+
+    public SinglePackage(PathFragment packageName) {
+      this.singlePackageName = packageName;
+    }
+
+    @Override
+    public boolean containsPackage(PathFragment packageName) {
+      return this.singlePackageName.equals(packageName);
+    }
+
+    @Override
+    public String toString() {
+      return singlePackageName.toString();
+    }
+  }
+
+  private static class AllPackagesBeneath extends PackageSpecification {
+    private PathFragment prefix;
+
+    public AllPackagesBeneath(PathFragment prefix) {
+      this.prefix = prefix;
+    }
+
+    @Override
+    public boolean containsPackage(PathFragment packageName) {
+      return packageName.startsWith(prefix);
+    }
+
+    @Override
+    public String toString() {
+      return prefix.equals(new PathFragment("")) ? "..." : prefix.toString() + "/...";
+    }
+  }
+
+  /**
+   * Exception class to be thrown when a specification cannot be parsed.
+   */
+  public static class InvalidPackageSpecificationException extends Exception {
+    public InvalidPackageSpecificationException(String message) {
+      super(message);
+    }
+  }
+}