Address review: containsTraceComment takes a SubSequence; callers build the view

Per review on #11737: move SubSequence.of to the call sites (SQLCommenter builds
the comment-region view; the String overload wraps the whole content) and make
SharedDBCommenter.containsTraceComment take a SubSequence instead of (String,
from, to). Behavior unchanged (SubSequence.contains -> Strings.regionContains);
test + dup-comment-benchmark Javadoc updated to the new shape.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: dougqh

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/dbm/SharedDBCommenter.java

@@ -58,16 +58,15 @@ public class SharedDBCommenter {
   // passes the already-extracted comment body; SQLCommenter uses the range overload to check it
   // in place. Both run the same nine "<key>=" needle checks.
   public static boolean containsTraceComment(String commentContent) {
-    return containsTraceComment(commentContent, 0, commentContent.length());
+    return containsTraceComment(SubSequence.of(commentContent, 0));
   }
 
   /**
-   * Range overload: true if {@code sql} contains a trace-comment needle fully within {@code [from,
-   * to)} -- checks the comment body in place, with no substring allocation of the region.
+   * True if {@code comment} contains a trace-comment needle. Callers pass a zero-copy {@link
+   * SubSequence} view of the comment body, so the check runs in place with no substring allocation
+   * of the region.
    */
-  public static boolean containsTraceComment(String sql, int from, int to) {
-    // Zero-copy view of the comment body; reads like ordinary String.contains, no substring.
-    SubSequence comment = SubSequence.of(sql, from, to);
+  public static boolean containsTraceComment(SubSequence comment) {
     return comment.contains(PARENT_SERVICE_EQ)
         || comment.contains(DATABASE_SERVICE_EQ)
         || comment.contains(DD_HOSTNAME_EQ)

dd-java-agent/agent-bootstrap/src/test/java/datadog/trace/bootstrap/instrumentation/dbm/SharedDBCommenterContainsTraceCommentTest.java

@@ -4,12 +4,14 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import datadog.trace.util.SubSequence;
 import org.junit.jupiter.api.Test;
 
 /**
  * DB-level behavior of {@link SharedDBCommenter#containsTraceComment}: the nine "<key>=" needle
- * set, the {@code String} delegate, and the range overload checking the comment body in place. (The
- * {@code [from, to)} boundary semantics are unit-tested on {@code Strings.regionContains}.)
+ * set, the {@code String} delegate, and the {@link SubSequence} overload checking the comment body
+ * in place. (The {@code [from, to)} boundary semantics are unit-tested on {@code
+ * Strings.regionContains}.)
  */
 class SharedDBCommenterContainsTraceCommentTest {
 
@@ -25,15 +27,15 @@ void range_needleInsideCommentBody() {
     String sql = "SELECT 1 /*ddps='svc',dde='test'*/";
     int from = sql.indexOf("/*") + 2;
     int to = sql.indexOf("*/");
-    assertTrue(containsTraceComment(sql, from, to));
+    assertTrue(containsTraceComment(SubSequence.of(sql, from, to)));
   }
 
   @Test
   void range_nonDdCommentBody() {
     String sql = "SELECT 1 /* just a customer comment */";
     int from = sql.indexOf("/*") + 2;
     int to = sql.indexOf("*/");
-    assertFalse(containsTraceComment(sql, from, to));
+    assertFalse(containsTraceComment(SubSequence.of(sql, from, to)));
   }
 
   @Test
@@ -43,6 +45,6 @@ void range_ddNeedleOutsideCommentRegionNotMatched() {
     String sql = "ddps='x' /* clean */";
     int from = sql.indexOf("/*") + 2;
     int to = sql.indexOf("*/");
-    assertFalse(containsTraceComment(sql, from, to));
+    assertFalse(containsTraceComment(SubSequence.of(sql, from, to)));
   }
 }

dd-java-agent/instrumentation/jdbc/src/jmh/java/datadog/trace/instrumentation/jdbc/SQLCommenterDuplicateCommentBenchmark.java

@@ -14,8 +14,8 @@
  *
  * <p><b>What we're measuring.</b> The guard used to materialize {@code sql.substring(commentStart,
  * commentEnd)} (the comment body) just to scan it for trace-comment needles. (B) checks the comment
- * region in place via {@code SharedDBCommenter.containsTraceComment(sql, from, to)} -- no
- * substring.
+ * region in place via {@code SharedDBCommenter.containsTraceComment(SubSequence.of(sql, from, to))}
+ * -- no substring.
  *
  * <p><b>Isolation.</b> The substring only happens when the SQL already carries a comment in the
  * checked position; for a DD comment {@code inject} then returns early. Passing {@code dbType=null}

dd-java-agent/instrumentation/jdbc/src/main/java/datadog/trace/instrumentation/jdbc/SQLCommenter.java

@@ -1,6 +1,7 @@
 package datadog.trace.instrumentation.jdbc;
 
 import datadog.trace.bootstrap.instrumentation.dbm.SharedDBCommenter;
+import datadog.trace.util.SubSequence;
 
 public class SQLCommenter {
   // SQL-specific constants, rest defined in SharedDBCommenter
@@ -122,8 +123,9 @@ private static boolean hasDDComment(String sql, boolean appendComment) {
       endIdx = sql.indexOf(CLOSE_COMMENT);
     }
     if (startIdx != -1 && endIdx != -1 && endIdx > startIdx) {
-      // Check the comment body in place -- no substring of the comment region.
-      return SharedDBCommenter.containsTraceComment(sql, startIdx + OPEN_COMMENT_LEN, endIdx);
+      // Check the comment body in place via a zero-copy view -- no substring of the comment region.
+      return SharedDBCommenter.containsTraceComment(
+          SubSequence.of(sql, startIdx + OPEN_COMMENT_LEN, endIdx));
     }
     return false;
   }