Add API for individual actions

This exposes action inputs, outputs, argv, content, and substitutions (if applicable).

--
MOS_MIGRATED_REVID=135226123

src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java

@@ -21,12 +21,19 @@
 import com.google.devtools.build.lib.actions.extra.ExtraActionInfo;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.CollectionUtils;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.events.EventHandler;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
 import com.google.devtools.build.lib.syntax.Printer;
+import com.google.devtools.build.lib.syntax.SkylarkDict;
+import com.google.devtools.build.lib.syntax.SkylarkList;
+import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.util.Preconditions;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
@@ -42,6 +49,10 @@
  * immutable - see the documentation on {@link Action}.
  */
 @Immutable @ThreadSafe
+@SkylarkModule(
+    name = "Action",
+    doc = "Base class for actions.",
+    documented = false)
 public abstract class AbstractAction implements Action, SkylarkValue {
 
   /**
@@ -455,4 +466,52 @@ public Iterable<Artifact> getInputFilesForExtraAction(
     return getInputs();
   }
 
+  @SkylarkCallable(
+      name = "inputs",
+      doc = "A set of the input files of this action.",
+      structField = true)
+  public SkylarkNestedSet getSkylarkInputs() {
+    return SkylarkNestedSet.of(Artifact.class, NestedSetBuilder.wrap(
+        Order.STABLE_ORDER, getInputs()));
+  }
+
+  @SkylarkCallable(
+      name = "outputs",
+      doc = "A set of the output files of this action.",
+      structField = true)
+  public SkylarkNestedSet getSkylarkOutputs() {
+    return SkylarkNestedSet.of(Artifact.class, NestedSetBuilder.wrap(
+        Order.STABLE_ORDER, getOutputs()));
+  }
+
+  @SkylarkCallable(
+      name = "argv",
+      doc = "For actions created by <a href=\"ctx.html#action\">ctx.action()</a>, an immutable "
+          + "list of the command line arguments. For all other actions, None.",
+      structField = true,
+      allowReturnNones = true)
+  public SkylarkList<String> getSkylarkArgv() {
+    return null;
+  }
+
+  @SkylarkCallable(
+      name = "content",
+      doc = "For actions created by <a href=\"ctx.html#file_action\">ctx.file_action()</a> or "
+          + "<a href=\"ctx.html#template_action\">ctx.template_action()</a>, the contents of the "
+          + "file to be written. For all other actions, None.",
+      structField = true,
+      allowReturnNones = true)
+  public String getSkylarkContent() throws IOException {
+    return null;
+  }
+
+  @SkylarkCallable(
+      name = "substitutions",
+      doc = "For actions created by <a href=\"ctx#template_action\">ctx.template_action()</a>, "
+          + "an immutable dict holding the substitution mapping. For all other actions, None.",
+      structField = true,
+      allowReturnNones = true)
+  public SkylarkDict<String, String> getSkylarkSubstitutions() {
+    return null;
+  }
 }

src/main/java/com/google/devtools/build/lib/analysis/actions/FileWriteAction.java

@@ -23,7 +23,6 @@
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.util.Fingerprint;
 import com.google.devtools.build.lib.util.LazyString;
-
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Collection;
@@ -113,6 +112,11 @@ public String getFileContents() {
     return fileContents.toString();
   }
 
+  @Override
+  public String getSkylarkContent() {
+    return getFileContents();
+  }
+
   /**
    * Create a DeterministicWriter for the content of the output file as provided by
    * {@link #getFileContents()}.

src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java

@@ -48,6 +48,7 @@
 import com.google.devtools.build.lib.collect.IterablesChain;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.syntax.SkylarkList;
 import com.google.devtools.build.lib.util.Fingerprint;
 import com.google.devtools.build.lib.util.Preconditions;
 import com.google.devtools.build.lib.util.ShellEscaper;
@@ -65,7 +66,7 @@
 
 /** An Action representing an arbitrary subprocess to be forked and exec'd. */
 public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifier, CommandAction {
-  
+
   /** Sets extensions on ExtraActionInfo **/
   protected static class ExtraActionInfoSupplier<T> {
     private final GeneratedExtension<ExtraActionInfo, T> extension;
@@ -205,6 +206,11 @@ public List<String> getArguments() {
     return ImmutableList.copyOf(argv.arguments());
   }
 
+  @Override
+  public SkylarkList<String> getSkylarkArgv() {
+    return SkylarkList.createImmutable(getArguments());
+  }
+
   /**
    * Returns the list of options written to the parameter file. Don't use this method outside tests.
    * The list is often huge, resulting in significant garbage collection overhead.

src/main/java/com/google/devtools/build/lib/analysis/actions/TemplateExpansionAction.java

@@ -24,12 +24,12 @@
 import com.google.devtools.build.lib.actions.ActionOwner;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.syntax.SkylarkDict;
 import com.google.devtools.build.lib.util.Fingerprint;
 import com.google.devtools.build.lib.util.ResourceFileLoader;
 import com.google.devtools.build.lib.util.StringUtilities;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
-
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.charset.Charset;
@@ -97,7 +97,7 @@ public String getValue() {
         }
       };
     }
-    
+
     /**
      * Returns an immutable Substitution instance for the key and map of values.  Corresponding
      * values in the map will be joined with "=", and pairs will be joined by spaces before
@@ -119,7 +119,7 @@ public String getValue() {
         }
       };
     }
-    
+
     @Override
     public boolean equals(Object object) {
       if (this == object) {
@@ -346,6 +346,11 @@ public String getFileContents() throws IOException {
     return expandTemplate(template.getContent());
   }
 
+  @Override
+  public String getSkylarkContent() throws IOException {
+    return getFileContents();
+  }
+
   @Override
   public DeterministicWriter newDeterministicWriter(ActionExecutionContext ctx) throws IOException {
     final byte[] bytes = getFileContents().getBytes(Template.DEFAULT_CHARSET);
@@ -384,4 +389,13 @@ protected String getRawProgressMessage() {
   public List<Substitution> getSubstitutions() {
     return substitutions;
   }
+
+  @Override
+  public SkylarkDict<String, String> getSkylarkSubstitutions() {
+    ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
+    for (Substitution entry : substitutions) {
+      builder.put(entry.getKey(), entry.getValue());
+    }
+    return SkylarkDict.copyOf(null, builder.build());
+  }
 }

src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleContext.java

@@ -11,6 +11,7 @@
 // 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.rules;
 
 import com.google.common.base.Function;

src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java

@@ -291,9 +291,9 @@ public Runtime.NoneType invoke(
           // input file that is in HOST configuration to the action as a precaution.
           addRequiredIndirectRunfiles(ctx, builder);
 
-          if (mnemonicUnchecked != Runtime.NONE) {
-            builder.setMnemonic((String) mnemonicUnchecked);
-          }
+          String mnemonic = mnemonicUnchecked == Runtime.NONE
+              ? "Generating" : (String) mnemonicUnchecked;
+          builder.setMnemonic(mnemonic);
           if (envUnchecked != Runtime.NONE) {
             builder.setEnvironment(
                 ImmutableMap.copyOf(

src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java

@@ -208,13 +208,6 @@ public FuncallException(String msg) {
 
   private final int numPositionalArgs;
 
-  /**
-   * Note: the grammar definition restricts the function value in a function
-   * call expression to be a global identifier; however, the representation of
-   * values in the interpreter is flexible enough to allow functions to be
-   * arbitrary expressions. In any case, the "func" expression is always
-   * evaluated, so functions and variables share a common namespace.
-   */
   public FuncallExpression(@Nullable Expression obj, Identifier func,
                            List<Argument.Passed> args) {
     this.obj = obj;
@@ -223,13 +216,6 @@ public FuncallExpression(@Nullable Expression obj, Identifier func,
     this.numPositionalArgs = countPositionalArguments();
   }
 
-  /**
-   * Note: the grammar definition restricts the function value in a function
-   * call expression to be a global identifier; however, the representation of
-   * values in the interpreter is flexible enough to allow functions to be
-   * arbitrary expressions. In any case, the "func" expression is always
-   * evaluated, so functions and variables share a common namespace.
-   */
   public FuncallExpression(Identifier func, List<Argument.Passed> args) {
     this(null, func, args);
   }