Add InternetAddress.tryParse

Closes #40692

Allows a better pattern for parsing user input than catching an
`ArgumentError`.

- Add a new static method to InternetAddress and implement it in all
  patch files.
- Add tests which match the tests for the constructor.

Change-Id: Idc76fc4875578f7a381219c0e7e12d1931d98fd8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136406
Commit-Queue: Nate Bosch <nbosch@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
Auto-Submit: Nate Bosch <nbosch@google.com>

CHANGELOG.md

@@ -15,6 +15,7 @@
 
 *   Class `OSError` now implements `Exception`. This change means `OSError` will
     now be caught in catch clauses catching `Exception`s.
+*   Added `InternetAddress.tryParse`.
 
 ### Tools
 

sdk/lib/_internal/js_dev_runtime/patch/io_patch.dart

@@ -427,6 +427,11 @@ class InternetAddress {
       InternetAddress address, String host) {
     throw UnsupportedError("InternetAddress._cloneWithNewHost");
   }
+
+  @patch
+  static InternetAddress tryParse(String address) {
+    throw UnsupportedError("InternetAddress.tryParse");
+  }
 }
 
 @patch

sdk/lib/_internal/js_runtime/lib/io_patch.dart

@@ -427,6 +427,11 @@ class InternetAddress {
       InternetAddress address, String host) {
     throw new UnsupportedError("InternetAddress._cloneWithNewHost");
   }
+
+  @patch
+  static InternetAddress tryParse(String address) {
+    throw new UnsupportedError("InternetAddress.tryParse");
+  }
 }
 
 @patch

sdk/lib/_internal/vm/bin/socket_patch.dart

@@ -92,6 +92,11 @@ class InternetAddress {
       InternetAddress address, String host) {
     return (address as _InternetAddress)._cloneWithNewHost(host);
   }
+
+  @patch
+  static InternetAddress tryParse(String address) {
+    return _InternetAddress.tryParse(address);
+  }
 }
 
 @patch
@@ -253,6 +258,18 @@ class _InternetAddress implements InternetAddress {
     }
   }
 
+  static _InternetAddress tryParse(String address) {
+    if (address == null) {
+      throw ArgumentError("Invalid internet address $address");
+    }
+    var addressBytes = _parse(address);
+    if (addressBytes == null) return null;
+    var type = addressBytes.length == _IPv4AddrLength
+        ? InternetAddressType.IPv4
+        : InternetAddressType.IPv6;
+    return _InternetAddress(type, address, null, addressBytes);
+  }
+
   factory _InternetAddress.fixed(int id) {
     switch (id) {
       case _addressLoopbackIPv4:

sdk/lib/io/socket.dart

@@ -215,6 +215,12 @@ abstract class InternetAddress {
    */
   external static InternetAddress _cloneWithNewHost(
       InternetAddress address, String host);
+
+  /// Attempts to parse [address] as a numeric address.
+  ///
+  /// Returns `null` if [address] is not a numeric IPv4 (dotted-decimal
+  /// notation) or IPv6 (hexadecimal representation) address.
+  external static InternetAddress tryParse(String address);
 }
 
 /**

sdk_nnbd/lib/_internal/js_dev_runtime/patch/io_patch.dart

@@ -425,6 +425,11 @@ class InternetAddress {
       InternetAddress address, String host) {
     throw UnsupportedError("InternetAddress._cloneWithNewHost");
   }
+
+  @patch
+  static InternetAddress? tryParse(String address) {
+    throw UnsupportedError("InternetAddress.tryParse");
+  }
 }
 
 @patch

sdk_nnbd/lib/_internal/js_runtime/lib/io_patch.dart

@@ -425,6 +425,11 @@ class InternetAddress {
       InternetAddress address, String host) {
     throw new UnsupportedError("InternetAddress._cloneWithNewHost");
   }
+
+  @patch
+  static InternetAddress? tryParse(String address) {
+    throw UnsupportedError("InternetAddress.tryParse");
+  }
 }
 
 @patch

sdk_nnbd/lib/_internal/vm/bin/common_patch.dart

@@ -7,7 +7,7 @@
 /// patches of that library. We plan to change this when we have a shared front
 /// end and simply use parts.
 
-import "dart:_internal" show VMLibraryHooks, patch;
+import "dart:_internal" show VMLibraryHooks, patch, checkNotNullable;
 
 import "dart:async"
     show

sdk_nnbd/lib/_internal/vm/bin/socket_patch.dart

@@ -89,6 +89,11 @@ class InternetAddress {
       InternetAddress address, String host) {
     return (address as _InternetAddress)._cloneWithNewHost(host);
   }
+
+  @patch
+  static InternetAddress? tryParse(String address) {
+    return _InternetAddress.tryParse(address);
+  }
 }
 
 @patch
@@ -255,6 +260,16 @@ class _InternetAddress implements InternetAddress {
     }
   }
 
+  static _InternetAddress? tryParse(String address) {
+    checkNotNullable(address, "address");
+    var addressBytes = _parse(address);
+    if (addressBytes == null) return null;
+    var type = addressBytes.length == _IPv4AddrLength
+        ? InternetAddressType.IPv4
+        : InternetAddressType.IPv6;
+    return _InternetAddress(type, address, null, addressBytes);
+  }
+
   factory _InternetAddress.fixed(int id) {
     switch (id) {
       case _addressLoopbackIPv4:

sdk_nnbd/lib/io/socket.dart

@@ -213,6 +213,12 @@ abstract class InternetAddress {
    */
   external static InternetAddress _cloneWithNewHost(
       InternetAddress address, String host);
+
+  /// Attempts to parse [address] as a numeric address.
+  ///
+  /// Returns `null` If [address] is not a numeric IPv4 (dotted-decimal
+  /// notation) or IPv6 (hexadecimal representation) address.
+  external static InternetAddress? tryParse(String address);
 }
 
 /**

tests/standalone/io/internet_address_test.dart

@@ -74,6 +74,56 @@ void testConstructor() {
   Expect.throwsArgumentError(() => new InternetAddress("::FFFF::1"));
 }
 
+void testTryParse() {
+  var loopback4 = InternetAddress.tryParse("127.0.0.1")!;
+  Expect.equals(InternetAddressType.IPv4, loopback4.type);
+  Expect.equals("127.0.0.1", loopback4.host);
+  Expect.equals("127.0.0.1", loopback4.address);
+  Expect.isFalse(loopback4.isMulticast);
+
+  var loopback6 = InternetAddress.tryParse("::1")!;
+  Expect.equals(InternetAddressType.IPv6, loopback6.type);
+  Expect.equals("::1", loopback6.host);
+  Expect.equals("::1", loopback6.address);
+  Expect.isFalse(loopback6.isMulticast);
+
+  var ip4 = InternetAddress.tryParse("10.20.30.40")!;
+  Expect.equals(InternetAddressType.IPv4, ip4.type);
+  Expect.equals("10.20.30.40", ip4.host);
+  Expect.equals("10.20.30.40", ip4.address);
+  Expect.isFalse(ip4.isMulticast);
+
+  var ip6 = InternetAddress.tryParse("10:20::30:40")!;
+  Expect.equals(InternetAddressType.IPv6, ip6.type);
+  Expect.equals("10:20::30:40", ip6.host);
+  Expect.equals("10:20::30:40", ip6.address);
+  Expect.isFalse(ip6.isMulticast);
+
+  var multicast4 = InternetAddress.tryParse("224.1.2.3")!;
+  Expect.equals(InternetAddressType.IPv4, multicast4.type);
+  Expect.isTrue(multicast4.isMulticast);
+
+  var multicast6 = InternetAddress.tryParse("FF00::1:2:3")!;
+  Expect.equals(InternetAddressType.IPv6, multicast6.type);
+  Expect.isTrue(multicast6.isMulticast);
+
+  var lowercase = InternetAddress.tryParse("ff00::1:2:3")!;
+  Expect.equals(InternetAddressType.IPv6, lowercase.type);
+  Expect.equals("ff00::1:2:3", lowercase.host);
+  Expect.equals("ff00::1:2:3", lowercase.address);
+
+  Expect.isNull(InternetAddress.tryParse("1.2.3"));
+  Expect.isNull(InternetAddress.tryParse("1.2.3.4.5"));
+  Expect.isNull(InternetAddress.tryParse("192.168.256.0"));
+  Expect.isNull(InternetAddress.tryParse("192.168.999.0"));
+  Expect.isNull(InternetAddress.tryParse("1.-2.3.4"));
+  Expect.isNull(InternetAddress.tryParse("01.02.03.04"));
+  Expect.isNull(InternetAddress.tryParse(""));
+  Expect.isNull(InternetAddress.tryParse("FFFG::0"));
+  Expect.isNull(InternetAddress.tryParse("FFF@::0"));
+  Expect.isNull(InternetAddress.tryParse("::FFFF::1"));
+}
+
 void testEquality() {
   Expect.equals(
       new InternetAddress("127.0.0.1"), new InternetAddress("127.0.0.1"));
@@ -163,6 +213,7 @@ void testRawPath() {
 void main() {
   testDefaultAddresses();
   testConstructor();
+  testTryParse();
   testEquality();
   testLookup();
   testReverseLookup();

tests/standalone_2/io/internet_address_test.dart

@@ -74,6 +74,56 @@ void testConstructor() {
   Expect.throwsArgumentError(() => new InternetAddress("::FFFF::1"));
 }
 
+void testTryParse() {
+  var loopback4 = InternetAddress.tryParse("127.0.0.1");
+  Expect.equals(InternetAddressType.IPv4, loopback4.type);
+  Expect.equals("127.0.0.1", loopback4.host);
+  Expect.equals("127.0.0.1", loopback4.address);
+  Expect.isFalse(loopback4.isMulticast);
+
+  var loopback6 = InternetAddress.tryParse("::1");
+  Expect.equals(InternetAddressType.IPv6, loopback6.type);
+  Expect.equals("::1", loopback6.host);
+  Expect.equals("::1", loopback6.address);
+  Expect.isFalse(loopback6.isMulticast);
+
+  var ip4 = InternetAddress.tryParse("10.20.30.40");
+  Expect.equals(InternetAddressType.IPv4, ip4.type);
+  Expect.equals("10.20.30.40", ip4.host);
+  Expect.equals("10.20.30.40", ip4.address);
+  Expect.isFalse(ip4.isMulticast);
+
+  var ip6 = InternetAddress.tryParse("10:20::30:40");
+  Expect.equals(InternetAddressType.IPv6, ip6.type);
+  Expect.equals("10:20::30:40", ip6.host);
+  Expect.equals("10:20::30:40", ip6.address);
+  Expect.isFalse(ip6.isMulticast);
+
+  var multicast4 = InternetAddress.tryParse("224.1.2.3");
+  Expect.equals(InternetAddressType.IPv4, multicast4.type);
+  Expect.isTrue(multicast4.isMulticast);
+
+  var multicast6 = InternetAddress.tryParse("FF00::1:2:3");
+  Expect.equals(InternetAddressType.IPv6, multicast6.type);
+  Expect.isTrue(multicast6.isMulticast);
+
+  var lowercase = InternetAddress.tryParse("ff00::1:2:3");
+  Expect.equals(InternetAddressType.IPv6, lowercase.type);
+  Expect.equals("ff00::1:2:3", lowercase.host);
+  Expect.equals("ff00::1:2:3", lowercase.address);
+
+  Expect.isNull(InternetAddress.tryParse("1.2.3"));
+  Expect.isNull(InternetAddress.tryParse("1.2.3.4.5"));
+  Expect.isNull(InternetAddress.tryParse("192.168.256.0"));
+  Expect.isNull(InternetAddress.tryParse("192.168.999.0"));
+  Expect.isNull(InternetAddress.tryParse("1.-2.3.4"));
+  Expect.isNull(InternetAddress.tryParse("01.02.03.04"));
+  Expect.isNull(InternetAddress.tryParse(""));
+  Expect.isNull(InternetAddress.tryParse("FFFG::0"));
+  Expect.isNull(InternetAddress.tryParse("FFF@::0"));
+  Expect.isNull(InternetAddress.tryParse("::FFFF::1"));
+}
+
 void testEquality() {
   Expect.equals(
       new InternetAddress("127.0.0.1"), new InternetAddress("127.0.0.1"));
@@ -162,6 +212,7 @@ void testRawPath() {
 void main() {
   testDefaultAddresses();
   testConstructor();
+  testTryParse();
   testEquality();
   testLookup();
   testReverseLookup();