Add a framework for prefetching input files (in case they come from remote file systems).

--
MOS_MIGRATED_REVID=131280794

2 files changed, 27 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/runtime/BlazeModule.java b/src/main/java/com/google/devtools/build/lib/runtime/BlazeModule.java
index 55e7440303..4a487607f3 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/BlazeModule.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/BlazeModule.java
@@ -22,6 +22,7 @@ import com.google.devtools.build.lib.analysis.BlazeVersionInfo;
 import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.analysis.ServerDirectories;
 import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.exec.ActionInputPrefetcher;
 import com.google.devtools.build.lib.exec.OutputService;
 import com.google.devtools.build.lib.packages.NoSuchThingException;
 import com.google.devtools.build.lib.packages.Package;
@@ -171,15 +172,24 @@ public abstract class BlazeModule {
   }
 
   /**
-   * Does any handling of options needed by the command.
+   * Returns an implementation of {@link ActionInputPrefetcher}.
    *
    * <p>This method will be called at the beginning of each command (after #beforeCommand).
    */
   @SuppressWarnings("unused")
-  public void handleOptions(OptionsProvider optionsProvider) {
+  public ActionInputPrefetcher getPrefetcher() throws AbruptExitException {
+    return null;
   }
 
   /**
+   * Does any handling of options needed by the command.
+   *
+   * <p>This method will be called at the beginning of each command (after #beforeCommand).
+   */
+  @SuppressWarnings("unused")
+  public void handleOptions(OptionsProvider optionsProvider) {}
+
+  /**
    * Returns extra options this module contributes to a specific command. Note that option
    * inheritance applies: if this method returns a non-empty list, then the returned options are
    * added to every command that depends on this command.
@@ -187,11 +197,13 @@ public abstract class BlazeModule {
    * <p>This method may be called at any time, and the returned value may be cached. Implementations
    * must be thread-safe and never return different lists for the same command object. Typical
    * implementations look like this:
+   *
    * <pre>
    * return "build".equals(command.name())
    *     ? ImmutableList.<Class<? extends OptionsBase>>of(MyOptions.class)
    *     : ImmutableList.<Class<? extends OptionsBase>>of();
    * </pre>
+   *
    * Note that this example adds options to all commands that inherit from the build command.
    *
    * <p>This method is also used to generate command-line documentation; in order to avoid
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java b/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java
index c3fec79170..9786f0f1e7 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java
@@ -29,10 +29,10 @@ import com.google.devtools.build.lib.analysis.SkyframePackageRootResolver;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.analysis.config.BuildConfigurationCollection;
 import com.google.devtools.build.lib.analysis.config.BuildOptions;
-import com.google.devtools.build.lib.analysis.config.DefaultsPackage;
 import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.events.Reporter;
+import com.google.devtools.build.lib.exec.ActionInputPrefetcher;
 import com.google.devtools.build.lib.exec.OutputService;
 import com.google.devtools.build.lib.packages.NoSuchThingException;
 import com.google.devtools.build.lib.packages.Target;
@@ -54,7 +54,6 @@ import com.google.devtools.common.options.OptionPriority;
 import com.google.devtools.common.options.OptionsParser;
 import com.google.devtools.common.options.OptionsParsingException;
 import com.google.devtools.common.options.OptionsProvider;
-
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Collections;
@@ -86,6 +85,7 @@ public final class CommandEnvironment {
   private PathFragment relativeWorkingDirectory = PathFragment.EMPTY_FRAGMENT;
   private long commandStartTime;
   private OutputService outputService;
+  private ImmutableList<ActionInputPrefetcher> actionInputPrefetchers = ImmutableList.of();
   private Path workingDirectory;
 
   private AtomicReference<AbruptExitException> pendingException = new AtomicReference<>();
@@ -308,6 +308,10 @@ public final class CommandEnvironment {
     return outputService;
   }
 
+  public ImmutableList<ActionInputPrefetcher> getActionInputPrefetchers() {
+    return actionInputPrefetchers;
+  }
+
   public ActionCache getPersistentActionCache() throws IOException {
     return workspace.getPersistentActionCache(reporter);
   }
@@ -441,6 +445,7 @@ public final class CommandEnvironment {
 
     outputService = null;
     BlazeModule outputModule = null;
+    ImmutableList.Builder<ActionInputPrefetcher> prefetchersBuilder = ImmutableList.builder();
     for (BlazeModule module : runtime.getBlazeModules()) {
       OutputService moduleService = module.getOutputService();
       if (moduleService != null) {
@@ -452,7 +457,13 @@ public final class CommandEnvironment {
         outputService = moduleService;
         outputModule = module;
       }
+
+      ActionInputPrefetcher actionInputPrefetcher = module.getPrefetcher();
+      if (actionInputPrefetcher != null) {
+        prefetchersBuilder.add(actionInputPrefetcher);
+      }
     }
+    actionInputPrefetchers = prefetchersBuilder.build();
 
     SkyframeExecutor skyframeExecutor = getSkyframeExecutor();
     skyframeExecutor.setOutputService(outputService);