Add on-the-fly remote repos

Adds a new rule:

new_http_archive(
    name = "whatever",
    url = "http://www.github.com/google/bazel-tools/my-tools.zip",
    sha256 = "...",
    build_file = "my/tools/objc.BUILD",
)

This will download & unzip my-tools.zip, put a WORKSPACE file in its root, and
link the provided BUILD file into its root.

--
MOS_MIGRATED_REVID=88941267

10 files changed, 402 insertions, 24 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java b/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java
index 483103f8c3..988afec114 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java
@@ -20,9 +20,11 @@ import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.analysis.BlazeVersionInfo;
 import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.bazel.repository.HttpArchiveFunction;
+import com.google.devtools.build.lib.bazel.repository.HttpDownloadFunction;
 import com.google.devtools.build.lib.bazel.repository.HttpJarFunction;
 import com.google.devtools.build.lib.bazel.repository.LocalRepositoryFunction;
 import com.google.devtools.build.lib.bazel.repository.MavenJarFunction;
+import com.google.devtools.build.lib.bazel.repository.NewHttpArchiveFunction;
 import com.google.devtools.build.lib.bazel.repository.NewLocalRepositoryFunction;
 import com.google.devtools.build.lib.bazel.repository.RepositoryDelegatorFunction;
 import com.google.devtools.build.lib.bazel.repository.RepositoryFunction;
@@ -30,6 +32,7 @@ import com.google.devtools.build.lib.bazel.rules.workspace.HttpArchiveRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.HttpJarRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.LocalRepositoryRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.MavenJarRule;
+import com.google.devtools.build.lib.bazel.rules.workspace.NewHttpArchiveRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.NewLocalRepositoryRule;
 import com.google.devtools.build.lib.runtime.BlazeModule;
 import com.google.devtools.build.lib.skyframe.SkyFunctions;
@@ -53,12 +56,14 @@ public class BazelRepositoryModule extends BlazeModule {
   private final ImmutableMap<String, RepositoryFunction> repositoryHandlers;
 
   public BazelRepositoryModule() {
-    repositoryHandlers = ImmutableMap.of(
-        LocalRepositoryRule.NAME, new LocalRepositoryFunction(),
-        HttpArchiveRule.NAME, new HttpArchiveFunction(),
-        HttpJarRule.NAME, new HttpJarFunction(),
-        MavenJarRule.NAME, new MavenJarFunction(),
-        NewLocalRepositoryRule.NAME, new NewLocalRepositoryFunction());
+    repositoryHandlers = ImmutableMap.<String, RepositoryFunction>builder()
+        .put(LocalRepositoryRule.NAME, new LocalRepositoryFunction())
+        .put(HttpArchiveRule.NAME, new HttpArchiveFunction())
+        .put(HttpJarRule.NAME, new HttpJarFunction())
+        .put(MavenJarRule.NAME, new MavenJarFunction())
+        .put(NewHttpArchiveRule.NAME, new NewHttpArchiveFunction())
+        .put(NewLocalRepositoryRule.NAME, new NewLocalRepositoryFunction())
+        .build();
   }
 
   @Override
@@ -95,6 +100,9 @@ public class BazelRepositoryModule extends BlazeModule {
     // Create the delegator everything flows through.
     builder.put(SkyFunctions.REPOSITORY,
         new RepositoryDelegatorFunction(repositoryHandlers));
+
+    // Helper SkyFunctions.
+    builder.put(SkyFunctionName.computed(HttpDownloadFunction.NAME), new HttpDownloadFunction());
     return builder.build();
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/DecompressorFactory.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/DecompressorFactory.java
index 3660317148..d3001a40ee 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/DecompressorFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/DecompressorFactory.java
@@ -16,6 +16,7 @@ package com.google.devtools.build.lib.bazel.repository;
 
 import com.google.devtools.build.lib.bazel.rules.workspace.HttpArchiveRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.HttpJarRule;
+import com.google.devtools.build.lib.bazel.rules.workspace.NewHttpArchiveRule;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -55,7 +56,8 @@ public abstract class DecompressorFactory {
       }
     }
 
-    if (targetKind.startsWith(HttpArchiveRule.NAME + " ")) {
+    if (targetKind.startsWith(HttpArchiveRule.NAME + " ")
+        || targetKind.startsWith(NewHttpArchiveRule.NAME + " ")) {
       if (baseName.endsWith(".zip") || baseName.endsWith(".jar")) {
         return new ZipDecompressor(archivePath);
       } else {
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpDownloadFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpDownloadFunction.java
new file mode 100644
index 0000000000..c16f5093ea
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpDownloadFunction.java
@@ -0,0 +1,131 @@
+// 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.bazel.repository;
+
+import com.google.devtools.build.lib.bazel.repository.RepositoryFunction.RepositoryFunctionException;
+import com.google.devtools.build.lib.packages.AggregatingAttributeMapper;
+import com.google.devtools.build.lib.packages.Rule;
+import com.google.devtools.build.lib.packages.Type;
+import com.google.devtools.build.lib.skyframe.FileValue;
+import com.google.devtools.build.lib.skyframe.RepositoryValue;
+import com.google.devtools.build.lib.syntax.EvalException;
+import com.google.devtools.build.lib.vfs.FileSystemUtils;
+import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionException;
+import com.google.devtools.build.skyframe.SkyFunctionName;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.Objects;
+
+import javax.annotation.Nullable;
+
+/**
+ * Downloads an archive file over HTTP.
+ */
+public class HttpDownloadFunction implements SkyFunction {
+  public static final String NAME = "HTTP_DOWNLOAD";
+
+  @Nullable
+  @Override
+  public SkyValue compute(SkyKey skyKey, Environment env) throws RepositoryFunctionException {
+    HttpDescriptor descriptor = (HttpDescriptor) skyKey.argument();
+    try {
+      FileSystemUtils.createDirectoryAndParents(descriptor.outputDirectory);
+    } catch (IOException e) {
+      throw new RepositoryFunctionException(e, SkyFunctionException.Transience.TRANSIENT);
+    }
+    FileValue repositoryValue = RepositoryFunction.getRepositoryDirectory(
+        descriptor.outputDirectory, env);
+    if (repositoryValue == null) {
+      System.out.println("Returning null");
+      return null;
+    }
+
+    Path archive;
+    try {
+      archive = new HttpDownloader(descriptor.url, descriptor.sha256, descriptor.outputDirectory)
+          .download();
+    } catch (IOException e) {
+      throw new RepositoryFunctionException(new IOException("Error downloading from "
+          + descriptor.url + " to " + descriptor.outputDirectory + ": " + e.getMessage()),
+          SkyFunctionException.Transience.TRANSIENT);
+    }
+    return new RepositoryValue(archive, repositoryValue);
+  }
+
+  @Nullable
+  @Override
+  public String extractTag(SkyKey skyKey) {
+    return null;
+  }
+
+  public static SkyKey key(Rule rule, Path outputDirectory)
+      throws RepositoryFunction.RepositoryFunctionException {
+    AggregatingAttributeMapper mapper = AggregatingAttributeMapper.of(rule);
+    URL url = null;
+    try {
+      url = new URL(mapper.get("url", Type.STRING));
+    } catch (MalformedURLException e) {
+      throw new RepositoryFunction.RepositoryFunctionException(
+          new EvalException(rule.getLocation(), "Error parsing URL: " + e.getMessage()),
+          SkyFunctionException.Transience.PERSISTENT);
+    }
+    String sha256 = mapper.get("sha256", Type.STRING);
+    return new SkyKey(
+        SkyFunctionName.computed(NAME),
+        new HttpDownloadFunction.HttpDescriptor(url, sha256, outputDirectory));
+  }
+
+  static final class HttpDescriptor {
+    private URL url;
+    private String sha256;
+    private Path outputDirectory;
+
+    public HttpDescriptor(URL url, String sha256, Path outputDirectory) {
+      this.url = url;
+      this.sha256 = sha256;
+      this.outputDirectory = outputDirectory;
+    }
+
+    @Override
+    public String toString() {
+      return url + " -> " + outputDirectory + " (" + sha256 + ")";
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+      if (obj == this) {
+        return true;
+      }
+      if (!(obj instanceof HttpDescriptor)) {
+        return false;
+      }
+      HttpDescriptor other = (HttpDescriptor) obj;
+      return Objects.equals(url, other.url)
+          && Objects.equals(sha256, other.sha256)
+          && Objects.equals(outputDirectory, other.outputDirectory);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(url, sha256, outputDirectory);
+    }
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
new file mode 100644
index 0000000000..af9ad22996
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
@@ -0,0 +1,88 @@
+// 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.bazel.repository;
+
+import com.google.devtools.build.lib.bazel.rules.workspace.NewHttpArchiveRule;
+import com.google.devtools.build.lib.packages.ExternalPackage;
+import com.google.devtools.build.lib.packages.PackageIdentifier.RepositoryName;
+import com.google.devtools.build.lib.packages.Rule;
+import com.google.devtools.build.lib.skyframe.RepositoryValue;
+import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.skyframe.SkyFunction;
+import com.google.devtools.build.skyframe.SkyFunctionException;
+import com.google.devtools.build.skyframe.SkyFunctionName;
+import com.google.devtools.build.skyframe.SkyKey;
+import com.google.devtools.build.skyframe.SkyValue;
+
+import java.io.IOException;
+
+import javax.annotation.Nullable;
+
+/**
+ * Downloads an archive from a URL, decompresses it, creates a WORKSPACE file, and adds a BUILD
+ * file for it.
+ */
+public class NewHttpArchiveFunction extends HttpArchiveFunction {
+
+  @Override
+  public SkyFunctionName getSkyFunctionName() {
+    return SkyFunctionName.computed(NewHttpArchiveRule.NAME);
+  }
+
+  @Nullable
+  @Override
+  public SkyValue compute(SkyKey skyKey, SkyFunction.Environment env)
+      throws RepositoryFunctionException {
+    RepositoryName repositoryName = (RepositoryName) skyKey.argument();
+    Rule rule = RepositoryFunction.getRule(repositoryName, NewHttpArchiveRule.NAME, env);
+    if (rule == null) {
+      return null;
+    }
+
+    // Download.
+    Path outputDirectory = getOutputBase().getRelative(ExternalPackage.NAME)
+        .getRelative(rule.getName());
+    RepositoryValue downloadedFileValue;
+    try {
+      downloadedFileValue = (RepositoryValue) env.getValueOrThrow(
+          HttpDownloadFunction.key(rule, outputDirectory), IOException.class);
+    } catch (IOException e) {
+      throw new RepositoryFunctionException(e, SkyFunctionException.Transience.PERSISTENT);
+    }
+    if (downloadedFileValue == null) {
+      return null;
+    }
+
+    // Decompress.
+    Path decompressedDirectory;
+    try {
+      decompressedDirectory = DecompressorFactory.create(
+          rule.getTargetKind(), rule.getName(), downloadedFileValue.getPath()).decompress();
+    } catch (DecompressorFactory.DecompressorException e) {
+      throw new RepositoryFunctionException(
+          new IOException(e.getMessage()), SkyFunctionException.Transience.TRANSIENT);
+    }
+
+    // Add WORKSPACE and BUILD files.
+    NewLocalRepositoryFunction.createWorkspaceFile(decompressedDirectory, rule);
+    if (NewLocalRepositoryFunction.createBuildFile(
+        rule, getWorkspace(), decompressedDirectory, env) == null) {
+      return null;
+    }
+
+    return new RepositoryValue(
+        decompressedDirectory, downloadedFileValue.getRepositoryDirectory());
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/NewLocalRepositoryFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewLocalRepositoryFunction.java
index 8f03ac4781..510d36cd60 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/NewLocalRepositoryFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewLocalRepositoryFunction.java
@@ -78,13 +78,7 @@ public class NewLocalRepositoryFunction extends RepositoryFunction {
     }
 
     // Add x/WORKSPACE.
-    try {
-      Path workspaceFile = repositoryDirectory.getRelative("WORKSPACE");
-      FileSystemUtils.writeContent(workspaceFile, Charset.forName("UTF-8"),
-          "# DO NOT EDIT: automatically generated WORKSPACE file for " + rule + "\n");
-    } catch (IOException e) {
-      throw new RepositoryFunctionException(e, Transience.TRANSIENT);
-    }
+    createWorkspaceFile(repositoryDirectory, rule);
 
     AggregatingAttributeMapper mapper = AggregatingAttributeMapper.of(rule);
     String path = mapper.get("path", Type.STRING);
@@ -112,24 +106,52 @@ public class NewLocalRepositoryFunction extends RepositoryFunction {
     }
 
     // Link x/BUILD to <build_root>/x.BUILD.
+    if (createBuildFile(rule, getWorkspace(), repositoryDirectory, env) == null) {
+      return null;
+    }
+
+    return new RepositoryValue(repositoryDirectory, directoryValue);
+  }
+
+  public static void createWorkspaceFile(Path repositoryDirectory, Rule rule)
+      throws RepositoryFunctionException {
+    try {
+      Path workspaceFile = repositoryDirectory.getRelative("WORKSPACE");
+      FileSystemUtils.writeContent(workspaceFile, Charset.forName("UTF-8"),
+          "# DO NOT EDIT: automatically generated WORKSPACE file for " + rule + "\n");
+    } catch (IOException e) {
+      throw new RepositoryFunctionException(e, Transience.TRANSIENT);
+    }
+  }
+
+  /**
+   * Symlinks a BUILD file from the local filesystem into the external repository's root.
+   * @param rule the rule that declares the build_file path.
+   * @param workspaceDirectory the workspace root for the build.
+   * @param repositoryDirectory the external repository's root directory.
+   * @param env the Skyframe environment.
+   * @return the file value of the symlink created.
+   * @throws RepositoryFunctionException if the BUILD file specified does not exist or cannot be
+   * linked.
+   */
+  public static FileValue createBuildFile(Rule rule, Path workspaceDirectory,
+                                          Path repositoryDirectory, Environment env)
+      throws RepositoryFunctionException {
+    AggregatingAttributeMapper mapper = AggregatingAttributeMapper.of(rule);
     PathFragment buildFile = new PathFragment(mapper.get("build_file", Type.STRING));
-    Path buildFileTarget = getWorkspace().getRelative(buildFile);
+    Path buildFileTarget = workspaceDirectory.getRelative(buildFile);
     if (!buildFileTarget.exists()) {
       throw new RepositoryFunctionException(
           new EvalException(rule.getLocation(), "In " + rule
               + " the 'build_file' attribute does not specify an existing file ("
-              + buildFile + " does not exist)"),
+              + buildFileTarget + " does not exist)"),
           Transience.PERSISTENT);
     }
     Path buildFilePath = repositoryDirectory.getRelative("BUILD");
-    if (createSymbolicLink(buildFilePath, buildFileTarget, env) == null) {
-      return null;
-    }
-
-    return new RepositoryValue(repositoryDirectory, directoryValue);
+    return createSymbolicLink(buildFilePath, buildFileTarget, env);
   }
 
-  private FileValue createSymbolicLink(Path from, Path to, Environment env)
+  private static FileValue createSymbolicLink(Path from, Path to, Environment env)
       throws RepositoryFunctionException {
     try {
       if (!from.exists()) {
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
index 1eaf6a210d..0a43d80d6e 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
@@ -52,6 +52,7 @@ import com.google.devtools.build.lib.bazel.rules.workspace.HttpArchiveRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.HttpJarRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.LocalRepositoryRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.MavenJarRule;
+import com.google.devtools.build.lib.bazel.rules.workspace.NewHttpArchiveRule;
 import com.google.devtools.build.lib.bazel.rules.workspace.NewLocalRepositoryRule;
 import com.google.devtools.build.lib.packages.Attribute;
 import com.google.devtools.build.lib.packages.PackageGroup;
@@ -274,6 +275,7 @@ public class BazelRuleClassProvider {
     builder.addRuleDefinition(HttpJarRule.class);
     builder.addRuleDefinition(LocalRepositoryRule.class);
     builder.addRuleDefinition(MavenJarRule.class);
+    builder.addRuleDefinition(NewHttpArchiveRule.class);
     builder.addRuleDefinition(NewLocalRepositoryRule.class);
 
     builder.addConfigurationFragment(new BazelConfiguration.Loader());
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/HttpArchiveRule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/HttpArchiveRule.java
index a2d5a35473..5da1ae9966 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/HttpArchiveRule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/HttpArchiveRule.java
@@ -42,7 +42,7 @@ public class HttpArchiveRule implements RuleDefinition {
         A URL to an archive file containing a Bazel repository.
         ${SYNOPSIS}
 
-        <p>This must be an http URL that ends with .zip. There is no support for authentication or
+        <p>This must be an HTTP URL that ends with .zip. There is no support for authentication or
           redirection.</p>
         <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
         .add(attr("url", STRING).mandatory())
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/NewHttpArchiveRule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/NewHttpArchiveRule.java
new file mode 100644
index 0000000000..131bbac910
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/NewHttpArchiveRule.java
@@ -0,0 +1,121 @@
+// 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.bazel.rules.workspace;
+
+import static com.google.devtools.build.lib.packages.Attribute.attr;
+import static com.google.devtools.build.lib.packages.Type.STRING;
+
+import com.google.devtools.build.lib.analysis.BlazeRule;
+import com.google.devtools.build.lib.analysis.RuleDefinition;
+import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
+import com.google.devtools.build.lib.packages.RuleClass;
+
+/**
+ * Rule definition for the new_http_archive rule.
+ */
+@BlazeRule(name = NewHttpArchiveRule.NAME,
+    type = RuleClass.Builder.RuleClassType.WORKSPACE,
+    ancestors = { WorkspaceBaseRule.class },
+    factoryClass = WorkspaceConfiguredTargetFactory.class)
+public class NewHttpArchiveRule implements RuleDefinition {
+  public static final String NAME = "new_http_archive";
+
+  @Override
+  public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment environment) {
+    return builder
+        /* <!-- #BLAZE_RULE(new_http_archive).ATTRIBUTE(url) -->
+        A URL to an archive file containing a Bazel repository.
+        ${SYNOPSIS}
+
+        <p>This must be an HTTP URL that ends with .zip. There is no support for authentication or
+          redirection.</p>
+        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
+        .add(attr("url", STRING).mandatory())
+        /* <!-- #BLAZE_RULE(new_http_archive).ATTRIBUTE(sha256) -->
+        The expected SHA-256 hash of the file downloaded.
+        ${SYNOPSIS}
+
+        <p>This must match the SHA-256 hash of the file downloaded.</p>
+        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
+        .add(attr("sha256", STRING).mandatory())
+        /* <!-- #BLAZE_RULE(new_http_archive).ATTRIBUTE(build_file) -->
+        A file to use as a BUILD file for this directory.
+        ${SYNOPSIS}
+
+        <p>This path is relative to the build's workspace. The file does not need to be named
+        BUILD, but can be (something like BUILD.new-repo-name may work well for distinguishing it
+        from the repository's actual BUILD files.</p>
+        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
+        .add(attr("build_file", STRING).mandatory())
+        .setWorkspaceOnly()
+        .build();
+  }
+}
+
+/*<!-- #BLAZE_RULE (NAME = new_http_archive, TYPE = OTHER, FAMILY = General)[GENERIC_RULE] -->
+
+${ATTRIBUTE_SIGNATURE}
+
+<p>Downloads a compressed archive file, decompresses it, and creates a Bazel repository by
+combining the archive with the provided BUILD file.</p>
+
+<p>Only Zip-formatted archives with the .zip extension are supported.</p>
+
+${ATTRIBUTE_DEFINITION}
+
+<h4 id="new_http_archive_examples">Examples</h4>
+
+<p>Suppose the current repository contains the source code for a chat program, rooted at the
+  directory <i>~/chat-app</i>. It needs to depend on an SSL library which is available from
+  <i>http://example.com/openssl.zip</i>. This .zip file contains the following directory
+  structure:</p>
+
+<pre class="code">
+src/
+  openssl.cc
+  openssl.h
+</pre>
+
+<p>In the local repository, the user creates a <i>ssl.BUILD</i> file which contains the following
+target definition:</p>
+
+<pre class="code">
+cc_library(
+    name = "openssl-lib",
+    srcs = ["src/openssl.cc"],
+    hdrs = ["src/openssl.h"],
+)
+</pre>
+
+<p>Targets in the <i>~/chat-app</i> repository can depend on this target if the following lines are
+  added to <i>~/chat-app/WORKSPACE</i>:</p>
+
+<pre class="code">
+new_http_archive(
+    name = "my-ssl",
+    url = "http://example.com/openssl.zip",
+    sha256 = "03a58ac630e59778f328af4bcc4acb4f80208ed4",
+    build_file = "ssl.BUILD",
+)
+
+bind(
+    name = "openssl",
+    actual = "@my-ssl//:openssl-lib",
+)
+</pre>
+
+<p>See <a href="#bind_examples">Bind</a> for how to use bound targets.</p>
+
+<!-- #END_BLAZE_RULE -->*/
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/NewLocalRepositoryRule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/NewLocalRepositoryRule.java
index 96438fed8d..f8f8b85baf 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/NewLocalRepositoryRule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/NewLocalRepositoryRule.java
@@ -48,7 +48,7 @@ public class NewLocalRepositoryRule implements RuleDefinition {
         A file to use as a BUILD file for this directory.
         ${SYNOPSIS}
 
-        <p>This path must be relative to the build's workspace. The file does not need to be named
+        <p>This path is relative to the build's workspace. The file does not need to be named
         BUILD, but can be (something like BUILD.new-repo-name may work well for distinguishing it
         from the repository's actual BUILD files.</p>
         <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/RepositoryValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/RepositoryValue.java
index 3183953e77..8272e6726a 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/RepositoryValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/RepositoryValue.java
@@ -47,6 +47,10 @@ public class RepositoryValue implements SkyValue {
     return path;
   }
 
+  public FileValue getRepositoryDirectory() {
+    return details;
+  }
+
   @Override
   public boolean equals(Object other) {
     if (this == other) {