Add static methods to return target kinds for built-in targets

Add static methods to return target kinds of InputFile and OutFile, as well as
suffix of target kind of Rule.

RELNOTES: None
PiperOrigin-RevId: 154866926

src/main/java/com/google/devtools/build/lib/packages/InputFile.java

@@ -109,7 +109,7 @@ public PathFragment getExecPath() {
 
   @Override
   public String getTargetKind() {
-    return "source file";
+    return targetKind();
   }
 
   @Override
@@ -121,4 +121,9 @@ public Rule getAssociatedRule() {
   public Location getLocation() {
     return location;
   }
+
+  /** Returns the target kind for all input files. */
+  public static String targetKind() {
+    return "source file";
+  }
 }

src/main/java/com/google/devtools/build/lib/packages/OutputFile.java

@@ -52,7 +52,7 @@ public Rule getGeneratingRule() {
 
   @Override
   public String getTargetKind() {
-    return "generated file";
+    return targetKind();
   }
 
   @Override
@@ -64,4 +64,9 @@ public Rule getAssociatedRule() {
   public Location getLocation() {
     return generatingRule.getLocation();
   }
+
+  /** Returns the target kind for all output files. */
+  public static String targetKind() {
+    return "generated file";
+  }
 }

src/main/java/com/google/devtools/build/lib/packages/Rule.java

@@ -730,4 +730,9 @@ public Collection<? extends Label> getAspectLabelsSuperset(DependencyFilter pred
   public RepositoryName getRepository() {
     return getLabel().getPackageIdentifier().getRepository();
   }
+
+  /** Returns the suffix of target kind for all rules. */
+  public static String targetKindSuffix() {
+    return " rule";
+  }
 }

src/main/java/com/google/devtools/build/lib/packages/RuleClass.java

@@ -1168,7 +1168,7 @@ public Attribute.Builder<?> copy(String name) {
       Attribute... attributes) {
     this.name = name;
     this.isSkylark = isSkylark;
-    this.targetKind = name + " rule";
+    this.targetKind = name + Rule.targetKindSuffix();
     this.skylarkExecutable = skylarkExecutable;
     this.skylarkTestable = skylarkTestable;
     this.documented = documented;

src/main/java/com/google/devtools/build/lib/query2/FakeSubincludeTarget.java

@@ -56,7 +56,7 @@ public Package getPackage() {
 
   @Override
   public String getTargetKind() {
-    return "source file";
+    return targetKind();
   }
 
   @Override
@@ -107,4 +107,9 @@ public boolean equals(Object obj) {
     FakeSubincludeTarget other = (FakeSubincludeTarget) obj;
     return label.equals(other.label) && pkg.equals(other.pkg);
   }
+
+  /** Returns the target kind for all fake sub-include targets. */
+  public static String targetKind() {
+    return "source file";
+  }
 }