Add a custom interface for cache hit processing in actions

The new interface mirrors ActionExecutionContext, but is restricted to exactly
the parts used right now. I did consider using ActionExecutionContext, but it
contains some parts that we don't want to make available for cache hits.

The end goal is to allow the build event stream access to artifact metadata,
in particular for TestResult and TestSummary events, which in turn requires
making artifact metadata available when the TestRunnerAction is a cache hit.

PiperOrigin-RevId: 155612573

1 files changed, 32 insertions, 2 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/actions/NotifyOnActionCacheHit.java b/src/main/java/com/google/devtools/build/lib/actions/NotifyOnActionCacheHit.java
index ac58b89f4a..89c9a20c2e 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/NotifyOnActionCacheHit.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/NotifyOnActionCacheHit.java
@@ -14,17 +14,47 @@
 
 package com.google.devtools.build.lib.actions;
 
+import com.google.common.eventbus.EventBus;
+import com.google.devtools.build.lib.actions.Executor.ActionContext;
+import com.google.devtools.build.lib.events.EventHandler;
+import com.google.devtools.build.lib.vfs.Path;
+
 /**
  * An action which must know when it is skipped due to an action cache hit.
  *
  * Use should be rare, as the action graph is a functional model.
  */
 public interface NotifyOnActionCacheHit extends Action {
+  /**
+   * A custom interface similar to {@link ActionExecutionContext}, but specific to cache hits.
+   */
+  public interface ActionCachedContext {
+    /**
+     * An event listener to report messages to. Errors that signal a action failure should
+     * use ActionExecutionException.
+     */
+    EventHandler getEventHandler();
+
+    /** The EventBus for the current build. */
+    EventBus getEventBus();
+
+    /**
+     * Returns the execution root. This is the directory underneath which Blaze builds its entire
+     * output working tree, including the source symlink forest. All build actions are executed
+     * relative to this directory.
+     */
+    Path getExecRoot();
+
+    /**
+     * Looks up and returns an action context implementation of the given interface type.
+     */
+    <T extends ActionContext> T getContext(Class<? extends T> type);
+  }
 
   /**
    * Called when action has "cache hit", and therefore need not be executed.
    *
-   * @param executor the executor
+   * @param context the action context for a cache hit
    */
-  void actionCacheHit(Executor executor);
+  void actionCacheHit(ActionCachedContext context);
 }