Implement ctx.actions.expand_template.

It also changes the return value of ctx.template_action to None, so a
very minor breaking change.  There are no internal usages at least.

RELNOTES: None.
PiperOrigin-RevId: 160825636

3 files changed, 91 insertions, 41 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java b/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java
index 4474a76cd3..26a68a5c7e 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java
@@ -580,8 +580,8 @@ public abstract class AbstractAction implements Action, SkylarkValue {
   @SkylarkCallable(
       name = "content",
       doc = "For actions created by <a href=\"actions.html#write\">ctx.actions.write()</a> or "
-          + "<a href=\"ctx.html#template_action\">ctx.template_action()</a>, the contents of the "
-          + "file to be written.",
+          + "<a href=\"actions.html#expand_template\">ctx.actions.expand_template()</a>,"
+          + " the contents of the file to be written.",
       structField = true,
       allowReturnNones = true)
   public String getSkylarkContent() throws IOException {
@@ -590,8 +590,9 @@ public abstract class AbstractAction implements Action, SkylarkValue {
 
   @SkylarkCallable(
       name = "substitutions",
-      doc = "For actions created by <a href=\"ctx.html#template_action\">"
-          + "ctx.template_action()</a>, an immutable dict holding the substitution mapping.",
+      doc = "For actions created by "
+          + "<a href=\"actions.html#expand_template\">ctx.actions.expand_template()</a>,"
+          + " an immutable dict holding the substitution mapping.",
       structField = true,
       allowReturnNones = true)
   public SkylarkDict<String, String> getSkylarkSubstitutions() {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/SkylarkActionFactory.java b/src/main/java/com/google/devtools/build/lib/rules/SkylarkActionFactory.java
index 2fad61119a..20f1fb18c4 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/SkylarkActionFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/SkylarkActionFactory.java
@@ -25,6 +25,8 @@ import com.google.devtools.build.lib.analysis.PseudoAction;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.actions.FileWriteAction;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
+import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction;
+import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction.Substitution;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.skylarkinterface.Param;
@@ -43,6 +45,7 @@ import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 
 /**
@@ -623,6 +626,82 @@ public class SkylarkActionFactory implements SkylarkValue {
     ruleContext.registerAction(builder.build(ruleContext));
   }
 
+  @SkylarkCallable(
+      name = "expand_template",
+      doc = "Creates a template expansion action.",
+      parameters = {
+          @Param(
+              name = "template",
+              type = Artifact.class,
+              named = true,
+              positional = false,
+              doc = "the template file, which is a UTF-8 encoded text file."
+          ),
+          @Param(
+              name = "output",
+              type = Artifact.class,
+              named = true,
+              positional = false,
+              doc = "the output file, which is a UTF-8 encoded text file."
+          ),
+          @Param(
+              name = "substitutions",
+              type = SkylarkDict.class,
+              named = true,
+              positional = false,
+              doc = "substitutions to make when expanding the template."
+          ),
+          @Param(
+              name = "executable",
+              type = Boolean.class,
+              defaultValue = "False",
+              named = true,
+              positional = false,
+              doc = "whether the output file should be executable (default is False)."
+          )
+      }
+  )
+  public void expandTemplate(
+            Artifact template,
+            Artifact output,
+            SkylarkDict<?, ?> substitutionsUnchecked,
+            Boolean executable)
+            throws EvalException {
+    context.checkMutable("actions.expand_template");
+    ImmutableList.Builder<Substitution> substitutionsBuilder = ImmutableList.builder();
+    for (Map.Entry<String, String> substitution :
+        substitutionsUnchecked
+            .getContents(String.class, String.class, "substitutions")
+            .entrySet()) {
+      // ParserInputSource.create(Path) uses Latin1 when reading BUILD files, which might
+      // contain UTF-8 encoded symbols as part of template substitution.
+      // As a quick fix, the substitution values are corrected before being passed on.
+      // In the long term, fixing ParserInputSource.create(Path) would be a better approach.
+      substitutionsBuilder.add(
+          Substitution.of(
+              substitution.getKey(), convertLatin1ToUtf8(substitution.getValue())));
+    }
+    TemplateExpansionAction action =
+        new TemplateExpansionAction(
+            ruleContext.getActionOwner(),
+            template,
+            output,
+            substitutionsBuilder.build(),
+            executable);
+    ruleContext.registerAction(action);
+  }
+
+  /**
+   * Returns the proper UTF-8 representation of a String that was erroneously read using Latin1.
+   * @param latin1 Input string
+   * @return The input string, UTF8 encoded
+   */
+  private static String convertLatin1ToUtf8(String latin1) {
+    return new String(latin1.getBytes(StandardCharsets.ISO_8859_1), StandardCharsets.UTF_8);
+  }
+
+
+
   @Override
   public boolean isImmutable() {
     return context.isImmutable();
diff --git a/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java b/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java
index 1be40eb9d4..5b316bc5ff 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/SkylarkRuleImplementationFunctions.java
@@ -24,8 +24,6 @@ import com.google.devtools.build.lib.analysis.LocationExpander;
 import com.google.devtools.build.lib.analysis.Runfiles;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
-import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction;
-import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction.Substitution;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.skylarkinterface.Param;
@@ -46,7 +44,6 @@ import com.google.devtools.build.lib.syntax.SkylarkSignatureProcessor;
 import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.syntax.Type.ConversionException;
 import com.google.devtools.build.lib.vfs.PathFragment;
-import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -403,9 +400,11 @@ public class SkylarkRuleImplementationFunctions {
 
   @SkylarkSignature(
     name = "template_action",
-    doc = "Creates a template expansion action.",
+    doc = "DEPRECATED. "
+        + "Use <a href=\"actions.html#expand_template\">ctx.actions.expand_template()</a> instead."
+        + "<br>Creates a template expansion action.",
     objectType = SkylarkRuleContext.class,
-    returnType = TemplateExpansionAction.class,
+    returnType = Runtime.NoneType.class,
     parameters = {
       @Param(name = "self", type = SkylarkRuleContext.class, doc = "this context."),
       @Param(
@@ -441,7 +440,7 @@ public class SkylarkRuleImplementationFunctions {
   )
   private static final BuiltinFunction createTemplateAction =
       new BuiltinFunction("template_action", Arrays.<Object>asList(false)) {
-        public TemplateExpansionAction invoke(
+        public Runtime.NoneType invoke(
             SkylarkRuleContext ctx,
             Artifact template,
             Artifact output,
@@ -449,40 +448,11 @@ public class SkylarkRuleImplementationFunctions {
             Boolean executable)
             throws EvalException, ConversionException {
           ctx.checkMutable("template_action");
-          ImmutableList.Builder<Substitution> substitutionsBuilder = ImmutableList.builder();
-          for (Map.Entry<String, String> substitution :
-              substitutionsUnchecked
-                  .getContents(String.class, String.class, "substitutions")
-                  .entrySet()) {
-            // ParserInputSource.create(Path) uses Latin1 when reading BUILD files, which might
-            // contain UTF-8 encoded symbols as part of template substitution.
-            // As a quick fix, the substitution values are corrected before being passed on.
-            // In the long term, fixing ParserInputSource.create(Path) would be a better approach.
-            substitutionsBuilder.add(
-                Substitution.of(
-                    substitution.getKey(), convertLatin1ToUtf8(substitution.getValue())));
-          }
-          TemplateExpansionAction action =
-              new TemplateExpansionAction(
-                  ctx.getRuleContext().getActionOwner(),
-                  template,
-                  output,
-                  substitutionsBuilder.build(),
-                  executable);
-          ctx.getRuleContext().registerAction(action);
-          return action;
+          ctx.actions().expandTemplate(template, output, substitutionsUnchecked, executable);
+          return Runtime.NONE;
         }
       };
 
-  /**
-   * Returns the proper UTF-8 representation of a String that was erroneously read using Latin1.
-   * @param latin1 Input string
-   * @return The input string, UTF8 encoded
-   */
-  private static String convertLatin1ToUtf8(String latin1) {
-    return new String(latin1.getBytes(StandardCharsets.ISO_8859_1), StandardCharsets.UTF_8);
-  }
-
   // TODO(bazel-team): Remove runfile states from Skylark.
   @SkylarkSignature(name = "runfiles",
       doc = "Creates a runfiles object.",