From 1caa7f0908e69741c35c0ae7d8256cb5184beb72 Mon Sep 17 00:00:00 2001
From: Ron Shapiro <ronshapiro@google.com>
Date: Sun, 7 Mar 2021 00:13:42 -0800
Subject: [PATCH] Index the first-matching component method instead of
 filtering on each request.

RELNOTES=Build performance improvements
PiperOrigin-RevId: 361389870
---
 .../codegen/binding/ComponentDescriptor.java  | 22 +++++++++----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/java/dagger/internal/codegen/binding/ComponentDescriptor.java b/java/dagger/internal/codegen/binding/ComponentDescriptor.java
index a7e4cc4f343..f6ea62c77d5 100644
--- a/java/dagger/internal/codegen/binding/ComponentDescriptor.java
+++ b/java/dagger/internal/codegen/binding/ComponentDescriptor.java
@@ -45,6 +45,8 @@
 import dagger.model.Scope;
 import dagger.producers.CancellationPolicy;
 import dagger.producers.ProductionComponent;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.stream.Stream;
@@ -240,19 +242,17 @@ final ComponentDescriptor getChildComponentWithBuilderType(TypeElement builderTy
 
   /** Returns the first component method associated with this binding request, if one exists. */
   public Optional<ComponentMethodDescriptor> firstMatchingComponentMethod(BindingRequest request) {
-    return componentMethods().stream()
-        .filter(method -> doesComponentMethodMatch(method, request))
-        .findFirst();
+    return Optional.ofNullable(firstMatchingComponentMethods().get(request));
   }
 
-  /** Returns true if the component method matches the binding request. */
-  private static boolean doesComponentMethodMatch(
-      ComponentMethodDescriptor componentMethod, BindingRequest request) {
-    return componentMethod
-        .dependencyRequest()
-        .map(BindingRequest::bindingRequest)
-        .filter(request::equals)
-        .isPresent();
+  @Memoized
+  ImmutableMap<BindingRequest, ComponentMethodDescriptor>
+      firstMatchingComponentMethods() {
+    Map<BindingRequest, ComponentMethodDescriptor> methods = new HashMap<>();
+    for (ComponentMethodDescriptor method : entryPointMethods()) {
+      methods.putIfAbsent(BindingRequest.bindingRequest(method.dependencyRequest().get()), method);
+    }
+    return ImmutableMap.copyOf(methods);
   }
 
   /** The entry point methods on the component type. Each has a {@link DependencyRequest}. */