Move the runfiles for external repositories to under the x.runfiles/ directory

This also sets the Bazel workspace name to io_bazel_source.

Fixes #848.

Relevant to #1116, #1124,

RELNOTES[INC]: All repositories are now directly under the x.runfiles directory in the runfiles tree (previously, external repositories were at x.runfiles/main-repo/external/other-repo. This simplifies handling remote repository runfiles considerably, but will break existing references to external repository runfiles.
---
Furthermore, if a Bazel project does not provide a workspace name in the WORKSPACE file, Bazel will now default to using __main__ as the workspace name (instead of "", as previously). The repository's runfiles will appear under x.runfiles/__main__/.

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MOS_MIGRATED_REVID=120224534

1 files changed, 15 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/actions/Artifact.java b/src/main/java/com/google/devtools/build/lib/actions/Artifact.java
index f28683b451..9a132faa08 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/Artifact.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/Artifact.java
@@ -498,6 +498,21 @@ public class Artifact
   }
 
   /**
+   * For targets in external repositories, this returns the path the artifact live at in the
+   * runfiles tree. For local targets, it returns the rootRelativePath.
+   */
+  public final PathFragment getRunfilesPath() {
+    PathFragment relativePath = rootRelativePath;
+    if (relativePath.segmentCount() > 1
+        && relativePath.getSegment(0).equals(Label.EXTERNAL_PATH_PREFIX)) {
+      // Turn external/repo/foo into ../repo/foo.
+      relativePath = relativePath.relativeTo(Label.EXTERNAL_PATH_PREFIX);
+      relativePath = new PathFragment("..").getRelative(relativePath);
+    }
+    return relativePath;
+  }
+
+  /**
    * Returns this.getExecPath().getPathString().
    */
   @Override