Support custom hosts file size (#349)

flaming-archer · web-flow · commit 036a16f5d934 · 2024-11-25T19:06:47.000+01:00
diff --git a/README.adoc b/README.adoc
@@ -103,6 +103,12 @@ Do NOT use it.
 |true
 |false
 
+.2+|dnsjava.hostsfile.max_size_bytes
+3+|Set the size of the hosts file to be loaded at a time, in bytes.
+|Integer
+|16384
+|1000000
+
 .2+|dnsjava.nio.selector_timeout
 3+|Set selector timeout in milliseconds. Default/Max 1000, Min 1.
 |Integer
diff --git a/src/main/java/org/xbill/DNS/hosts/HostsFileParser.java b/src/main/java/org/xbill/DNS/hosts/HostsFileParser.java
@@ -29,7 +29,8 @@
  */
 @Slf4j
 public final class HostsFileParser {
-  private static final int MAX_FULL_CACHE_FILE_SIZE_BYTES = 16384;
+  private final int MAX_FULL_CACHE_FILE_SIZE_BYTES = Integer.parseInt(
+    System.getProperty("dnsjava.hostsfile.max_size_bytes", "16384"));
 
   private final Map<String, InetAddress> hostsCache = new HashMap<>();
   private final Path path;
diff --git a/src/test/java/org/xbill/DNS/hosts/HostsFileParserTest.java b/src/test/java/org/xbill/DNS/hosts/HostsFileParserTest.java
@@ -171,6 +171,19 @@ void testBigFileIsNotCompletelyCachedA() throws IOException {
     assertEquals(1, hostsFileParser.cacheSize());
   }
 
+  @Test
+  void testBigFileCompletelyCachedA() throws IOException {
+    try {
+      System.setProperty("dnsjava.hostsfile.max_size_bytes", 1024 * 1024 * 1024 + "");
+      HostsFileParser hostsFileParser = generateLargeHostsFile("testBigFileCompletelyCachedA");
+      hostsFileParser.getAddressForHost(Name.fromConstantString("localhost-10."), Type.A)
+        .orElseThrow(() -> new IllegalStateException("Host entry not found"));
+      assertEquals(1280, hostsFileParser.cacheSize());
+    } finally {
+      System.clearProperty("dnsjava.hostsfile.max_size_bytes");
+    }
+  }
+
   @Test
   void testBigFileIsNotCompletelyCachedAAAA() throws IOException {
     HostsFileParser hostsFileParser =
