From 4162d5df19ab1298844413b9218c2f0d8a35205e Mon Sep 17 00:00:00 2001
From: Stuart Douglas <stuart.w.douglas@gmail.com>
Date: Tue, 21 Sep 2021 13:36:00 +1000
Subject: [PATCH] ArC build time perf improvement

This removes the need to iterate over all beans when performing
resolution. For a project with 2k injection points this saves close to
0.5s on my desktop.
---
 .../quarkus/arc/processor/BeanDeployment.java | 24 +++++++++++++++++++
 .../arc/processor/BeanResolverImpl.java       | 12 ++++++++--
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanDeployment.java b/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanDeployment.java
index 0a814bda4d486..365210f050fe2 100644
--- a/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanDeployment.java
+++ b/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanDeployment.java
@@ -68,6 +68,7 @@ public class BeanDeployment {
     private final Map<DotName, StereotypeInfo> stereotypes;
 
     private final List<BeanInfo> beans;
+    private volatile Map<Type, List<BeanInfo>> beansByType = null;
 
     private final List<InterceptorInfo> interceptors;
     private final List<DecoratorInfo> decorators;
@@ -248,6 +249,7 @@ void init(Consumer<BytecodeTransformer> bytecodeTransformerConsumer,
             List<Predicate<BeanInfo>> additionalUnusedBeanExclusions) {
         long start = System.nanoTime();
 
+        initBeanByTypeMap();
         // Collect dependency resolution errors
         List<Throwable> errors = new ArrayList<>();
         for (BeanInfo bean : beans) {
@@ -279,11 +281,25 @@ void init(Consumer<BytecodeTransformer> bytecodeTransformerConsumer,
             LOGGER.debugf("Removed %s beans, %s interceptors and %s decorators in %s ms", removedBeans.size(),
                     removedInterceptors.size(), removedDecorators.size(),
                     TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - removalStart));
+            //we need to re-initialize it, so it does not contain removed beans
+            initBeanByTypeMap();
         }
         buildContext.putInternal(BuildExtension.Key.REMOVED_BEANS.asString(), Collections.unmodifiableSet(removedBeans));
         LOGGER.debugf("Bean deployment initialized in %s ms", TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start));
     }
 
+    private void initBeanByTypeMap() {
+        beansByType = new HashMap<>();
+        for (var bean : beans) {
+            for (var beanType : bean.types) {
+                beansByType.computeIfAbsent(beanType, (s) -> new ArrayList<>()).add(bean);
+            }
+        }
+        for (var e : beansByType.entrySet()) {
+            e.setValue(Collections.unmodifiableList(e.getValue()));
+        }
+    }
+
     private void removeUnusedComponents(Set<BeanInfo> declaresObserver,
             List<Predicate<BeanInfo>> allUnusedExclusions, Set<DecoratorInfo> removedDecorators,
             Set<InterceptorInfo> removedInterceptors) {
@@ -407,6 +423,14 @@ public Collection<BeanInfo> getBeans() {
         return Collections.unmodifiableList(beans);
     }
 
+    public Collection<BeanInfo> getBeansByType(Type type) {
+        var ret = beansByType.get(type);
+        if (ret == null) {
+            return Collections.emptyList();
+        }
+        return ret;
+    }
+
     public Collection<BeanInfo> getRemovedBeans() {
         return Collections.unmodifiableSet(removedBeans);
     }
diff --git a/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanResolverImpl.java b/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanResolverImpl.java
index a085f58197861..3229791511537 100644
--- a/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanResolverImpl.java
+++ b/independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/BeanResolverImpl.java
@@ -9,6 +9,7 @@
 
 import io.quarkus.arc.processor.InjectionPointInfo.TypeAndQualifiers;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
@@ -81,7 +82,11 @@ List<BeanInfo> resolve(TypeAndQualifiers typeAndQualifiers) {
 
     private List<BeanInfo> findMatching(TypeAndQualifiers typeAndQualifiers) {
         List<BeanInfo> resolved = new ArrayList<>();
-        for (BeanInfo b : beanDeployment.getBeans()) {
+        //optimisation for the simple class case
+        Collection<BeanInfo> potentialBeans = typeAndQualifiers.type.kind() == CLASS
+                ? beanDeployment.getBeansByType(typeAndQualifiers.type)
+                : beanDeployment.getBeans();
+        for (BeanInfo b : potentialBeans) {
             if (Beans.matches(b, typeAndQualifiers)) {
                 resolved.add(b);
             }
@@ -91,7 +96,10 @@ private List<BeanInfo> findMatching(TypeAndQualifiers typeAndQualifiers) {
 
     List<BeanInfo> findTypeMatching(Type type) {
         List<BeanInfo> resolved = new ArrayList<>();
-        for (BeanInfo b : beanDeployment.getBeans()) {
+        //optimisation for the simple class case
+        Collection<BeanInfo> potentialBeans = type.kind() == CLASS ? beanDeployment.getBeansByType(type)
+                : beanDeployment.getBeans();
+        for (BeanInfo b : potentialBeans) {
             if (Beans.matchesType(b, type)) {
                 resolved.add(b);
             }