Add RuleContext#getPrerequisitesIf and AnalysisUtils#filterByProvider overloads for BuiltinProvider.

PiperOrigin-RevId: 251515875

src/main/java/com/google/devtools/build/lib/analysis/AnalysisUtils.java

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/AnalysisUtils.java b/src/main/java/com/google/devtools/build/lib/analysis/AnalysisUtils.java
index 1e37e93..2bc6b77 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/AnalysisUtils.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/AnalysisUtils.java
@@ -136,6 +136,11 @@
     return Iterables.filter(prerequisites, target -> target.get(provider) != null);
   }
 
+  /** Returns the iterable of collections that have the specified provider. */
+  public static <S extends TransitiveInfoCollection, C extends InfoInterface>
+      Iterable<S> filterByProvider(Iterable<S> prerequisites, final BuiltinProvider<C> provider) {
+    return Iterables.filter(prerequisites, target -> target.get(provider) != null);
+  }
 
   /**
    * Returns the path of the associated manifest file for the path of a Fileset. Works for both

src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
index 7779744..b4ab0d7 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
@@ -1072,6 +1072,15 @@
   }
 
   /**
+   * Returns all the providers of the specified type that are listed under the specified attribute
+   * of this target in the BUILD file, and that contain the specified provider.
+   */
+  public <C extends Info> Iterable<? extends TransitiveInfoCollection> getPrerequisitesIf(
+      String attributeName, Mode mode, final BuiltinProvider<C> classType) {
+    return AnalysisUtils.filterByProvider(getPrerequisites(attributeName, mode), classType);
+  }
+
+  /**
    * Returns the prerequisite referred to by the specified attribute. Also checks whether
    * the attribute is marked as executable and that the target referred to can actually be
    * executed.