Make impl of ClassPathResourceIndex#getResourceKey() faster

Previous implementation: Warmup Iteration 7: 63202.300 ops/ms Warmup Iteration 8: 64074.043 ops/ms Warmup Iteration 9: 63297.222 ops/ms Warmup Iteration 10: 63905.908 ops/ms New implementation: Warmup Iteration 6: 234089.005 ops/ms Warmup Iteration 7: 234372.742 ops/ms Warmup Iteration 8: 235722.737 ops/ms Warmup Iteration 9: 233265.148 ops/ms Also added a test to make sure we don't break it.
gsmet · Aug 16, 2024 · 34631a0 · 34631a0
1 parent 1318543
commit 34631a0
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Showing 2 changed files with 39 additions and 19 deletions.
diff --git a/...ootstrap/core/src/main/java/io/quarkus/bootstrap/classloading/ClassPathResourceIndex.java b/...ootstrap/core/src/main/java/io/quarkus/bootstrap/classloading/ClassPathResourceIndex.java
@@ -38,6 +38,9 @@ public class ClassPathResourceIndex {
     // let's go with default max segments + 3 for the META-INF/versions/<version> part
     private static final int MAX_SEGMENTS_META_INF_VERSIONS = MAX_SEGMENTS_DEFAULT + 3;
 
+    private static final char SLASH = '/';
+    private static final char DOT = '.';
+
     /**
      * This map is mapped by prefixes.
      */
@@ -132,7 +135,7 @@ public static Builder builder() {
      * <p>
      * Probably something we will have to tweak for corner cases but let's try to keep it fast.
      */
-    private static String getResourceKey(String resource) {
+    static String getResourceKey(String resource) {
         // we don't really care about this part, it can be slower
         if (resource.startsWith(META_INF_MAVEN)) {
             return META_INF_MAVEN;
@@ -141,7 +144,6 @@ private static String getResourceKey(String resource) {
             // for services, we want to reference the full path
             return resource;
         }
-        StringBuilder prefix = new StringBuilder();
 
         int maxSegments;
         if (resource.startsWith(IO_QUARKUS)) {
@@ -152,27 +154,21 @@ private static String getResourceKey(String resource) {
             maxSegments = MAX_SEGMENTS_DEFAULT;
         }
 
-        char[] charArray = resource.toCharArray();
-        int segmentCount = 0;
-        for (char c : charArray) {
-            if (c == '/') {
-                segmentCount++;
-                if (segmentCount == maxSegments) {
-                    return prefix.toString();
+        int position = 0;
+        for (int i = 0; i < maxSegments; i++) {
+            int slashPosition = resource.indexOf(SLASH, position);
+            if (slashPosition > 0) {
+                position = slashPosition + 1;
+            } else {
+                if (i > 0 && resource.substring(position).indexOf(DOT) >= 0) {
+                    break;
+                } else {
+                    return resource;
                 }
             }
-            prefix.append(c);
-        }
-
-        // let's drop the file name if we haven't truncated anything and we detect it's a file
-        if (segmentCount > 0 && segmentCount < maxSegments) {
-            int lastSlash = prefix.lastIndexOf("/");
-            if (prefix.substring(lastSlash).contains(".")) {
-                prefix.setLength(lastSlash);
-            }
         }
 
-        return prefix.toString();
+        return resource.substring(0, position - 1);
     }
 
     public static class Builder {

diff --git a/.../core/src/test/java/io/quarkus/bootstrap/classloading/ClassPathResourceIndexTestCase.java b/.../core/src/test/java/io/quarkus/bootstrap/classloading/ClassPathResourceIndexTestCase.java
@@ -0,0 +1,24 @@
+package io.quarkus.bootstrap.classloading;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class ClassPathResourceIndexTestCase {
+
+    @Test
+    public void testGetResourceKey() {
+        assertEquals("io/quarkus/core/deployment",
+                ClassPathResourceIndex.getResourceKey("io/quarkus/core/deployment/MyClass.class"));
+        assertEquals("io/quarkus/core/deployment",
+                ClassPathResourceIndex.getResourceKey("io/quarkus/core/deployment/package/MyClass.class"));
+        assertEquals("org/apache/commons",
+                ClassPathResourceIndex.getResourceKey("org/apache/commons/codec/MyClass.class"));
+        assertEquals("test.properties", ClassPathResourceIndex.getResourceKey("test.properties"));
+        assertEquals("META-INF/maven/", ClassPathResourceIndex.getResourceKey("META-INF/maven/commons-codec/file.properties"));
+        assertEquals("io/quarkus", ClassPathResourceIndex.getResourceKey("io/quarkus/MyClass.class"));
+        assertEquals("META-INF/services/my-service", ClassPathResourceIndex.getResourceKey("META-INF/services/my-service"));
+        assertEquals("META-INF/versions/17/io/quarkus/core",
+                ClassPathResourceIndex.getResourceKey("META-INF/versions/17/io/quarkus/core/deployment"));
+    }
+}