[3747] Addressed review comments.

src/bin/dhcp4/tests/dora_unittest.cc

@@ -726,6 +726,7 @@ TEST_F(DORATest, ignoreChangingClientId) {
     Pkt4Ptr resp = client.getContext().response_;
     // Make sure that the server has responded with DHCPACK.
     ASSERT_EQ(DHCPACK, static_cast<int>(resp->getType()));
+    EXPECT_FALSE(client.config_.lease_.client_id_);
 
     // Remember address which the client has obtained.
     IOAddress leased_address = client.config_.lease_.addr_;
@@ -745,6 +746,8 @@ TEST_F(DORATest, ignoreChangingClientId) {
     // Make sure that the server assigned the same address, even though the
     // client id has changed.
     EXPECT_EQ(leased_address, client.config_.lease_.addr_);
+    // Check that the client id is not present in the lease.
+    EXPECT_FALSE(client.config_.lease_.client_id_);
 }
 
 // This test checks that the match-client-id parameter doesn't have
@@ -762,6 +765,8 @@ TEST_F(DORATest, changingHWAddress) {
     Pkt4Ptr resp = client.getContext().response_;
     // Make sure that the server has responded with DHCPACK.
     ASSERT_EQ(DHCPACK, static_cast<int>(resp->getType()));
+    // Check that the client id is not present in the lease.
+    EXPECT_FALSE(client.config_.lease_.client_id_);
 
     // Remember address which the client has obtained.
     IOAddress leased_address = client.config_.lease_.addr_;
@@ -781,6 +786,8 @@ TEST_F(DORATest, changingHWAddress) {
     // Client must assign different address because the client id is
     // ignored and the HW address was changed.
     EXPECT_NE(client.config_.lease_.addr_, leased_address);
+    // Check that the client id is not present in the lease.
+    EXPECT_FALSE(client.config_.lease_.client_id_);
 }
 
 // This test checks the following scenario:

src/bin/dhcp4/tests/release_unittest.cc

@@ -68,6 +68,11 @@ const char* RELEASE_CONFIGS[] = {
 class ReleaseTest : public Dhcpv4SrvTest {
 public:
 
+    enum ExpectedResult {
+        SHOULD_PASS,
+        SHOULD_FAIL
+    };
+
     /// @brief Constructor.
     ///
     /// Sets up fake interfaces.
@@ -82,27 +87,20 @@ public:
     /// @param client Client to be used to obtain a lease.
     void acquireLease(Dhcp4Client& client);
 
-    /// @brief Test successful release for different identifiers.
+    /// @brief Tests if the acquired lease is or is not released.
     ///
     /// @param hw_address_1 HW Address to be used to acquire the lease.
     /// @param client_id_1 Client id to be used to acquire the lease.
     /// @param hw_address_2 HW Address to be used to release the lease.
     /// @param client_id_2 Client id to be used to release the lease.
-    void successfulRelease(const std::string& hw_address_1,
+    /// @param expected_result SHOULD_PASS if the lease is expected to
+    /// be successfully released, or SHOULD_FAIL if the lease is expected
+    /// to not be released.
+    void acquireAndRelease(const std::string& hw_address_1,
                            const std::string& client_id_1,
                            const std::string& hw_address_2,
-                           const std::string& client_id_2);
-
-    /// @brief Test unsuccessful release for different identifiers.
-    ///
-    /// @param hw_address_1 HW Address to be used to acquire the lease.
-    /// @param client_id_1 Client id to be used to acquire the lease.
-    /// @param hw_address_2 HW Address to be used to release the lease.
-    /// @param client_id_2 Client id to be used to release the lease.
-    void unsuccessfulRelease(const std::string& hw_address_1,
-                             const std::string& client_id_1,
-                             const std::string& hw_address_2,
-                             const std::string& client_id_2);
+                           const std::string& client_id_2,
+                           ExpectedResult expected_result);
 
     /// @brief Interface Manager's fake configuration control.
     IfaceMgrTestConfig iface_mgr_test_config_;
@@ -130,10 +128,11 @@ ReleaseTest::acquireLease(Dhcp4Client& client) {
 }
 
 void
-ReleaseTest::successfulRelease(const std::string& hw_address_1,
+ReleaseTest::acquireAndRelease(const std::string& hw_address_1,
                                const std::string& client_id_1,
                                const std::string& hw_address_2,
-                               const std::string& client_id_2) {
+                               const std::string& client_id_2,
+                               ExpectedResult expected_result) {
     CfgMgr::instance().clear();
     Dhcp4Client client(Dhcp4Client::SELECTING);
     // Configure DHCP server.
@@ -157,44 +156,23 @@ ReleaseTest::successfulRelease(const std::string& hw_address_1,
     // server.
     ASSERT_NO_THROW(client.doRelease());
     Lease4Ptr lease = LeaseMgrFactory::instance().getLease4(leased_address);
-    ASSERT_FALSE(lease);
-}
 
-void
-ReleaseTest::unsuccessfulRelease(const std::string& hw_address_1,
-                                 const std::string& client_id_1,
-                                 const std::string& hw_address_2,
-                                 const std::string& client_id_2) {
-    Dhcp4Client client(Dhcp4Client::SELECTING);
-    // Configure DHCP server.
-    configure(RELEASE_CONFIGS[0], *client.getServer());
-    // Explicitly set the client id.
-    client.includeClientId(client_id_1);
-    // Explicitly set the HW address.
-    client.setHWAddress(hw_address_1);
-    // Perform 4-way exchange to obtain a new lease.
-    acquireLease(client);
-
-    // Remember the acquired address.
-    IOAddress leased_address = client.config_.lease_.addr_;
-
-    // Explicitly set the client id for DHCPRELEASE.
-    client.includeClientId(client_id_2);
-    // Explicitly set the HW address for DHCPRELEASE.
-    client.setHWAddress(hw_address_2);
+    // We check if the release process was successful by checking if the
+    // lease is in the database. It is expected that it is not present,
+    // i.e. has been deleted with the release.
+    if (expected_result == SHOULD_PASS) {
+        EXPECT_FALSE(lease);
 
-    // Send DHCPRELEASE and make sure it was unsuccessful, i.e. the lease
-    // remains in the database.
-    ASSERT_NO_THROW(client.doRelease());
-    Lease4Ptr lease = LeaseMgrFactory::instance().getLease4(leased_address);
-    ASSERT_TRUE(lease);
+    } else {
+        EXPECT_TRUE(lease);
+    }
 }
 
-
 // This test checks that the client can acquire and release the lease.
 TEST_F(ReleaseTest, releaseNoIdentifierChange) {
-    successfulRelease("01:02:03:04:05:06", "12:14",
-                      "01:02:03:04:05:06", "12:14");
+    acquireAndRelease("01:02:03:04:05:06", "12:14",
+                      "01:02:03:04:05:06", "12:14",
+                      SHOULD_PASS);
 }
 
 // This test verifies the release correctness in the following case:
@@ -203,8 +181,9 @@ TEST_F(ReleaseTest, releaseNoIdentifierChange) {
 //   client identifier.
 // - The server successfully releases the lease.
 TEST_F(ReleaseTest, releaseHWAddressOnly) {
-    successfulRelease("01:02:03:04:05:06", "",
-                      "01:02:03:04:05:06", "");
+    acquireAndRelease("01:02:03:04:05:06", "",
+                      "01:02:03:04:05:06", "",
+                      SHOULD_PASS);
 }
 
 // This test verifies the release correctness in the following case:
@@ -213,8 +192,9 @@ TEST_F(ReleaseTest, releaseHWAddressOnly) {
 //   client identifier.
 // - The server successfully releases the lease.
 TEST_F(ReleaseTest, releaseNoClientId) {
-    successfulRelease("01:02:03:04:05:06", "12:14",
-                      "01:02:03:04:05:06", "");
+    acquireAndRelease("01:02:03:04:05:06", "12:14",
+                      "01:02:03:04:05:06", "",
+                      SHOULD_PASS);
 }
 
 // This test verifies the release correctness in the following case:
@@ -224,8 +204,9 @@ TEST_F(ReleaseTest, releaseNoClientId) {
 // - The server identifies the lease using HW address and releases
 //   this lease.
 TEST_F(ReleaseTest, releaseNoClientId2) {
-    successfulRelease("01:02:03:04:05:06", "",
-                      "01:02:03:04:05:06", "12:14");
+    acquireAndRelease("01:02:03:04:05:06", "",
+                      "01:02:03:04:05:06", "12:14",
+                      SHOULD_PASS);
 }
 
 // This test checks the server's behavior in the following case:
@@ -234,8 +215,9 @@ TEST_F(ReleaseTest, releaseNoClientId2) {
 //   client identifier.
 // - The server should not remove the lease.
 TEST_F(ReleaseTest, releaseNonMatchingClientId) {
-    unsuccessfulRelease("01:02:03:04:05:06", "12:14",
-                        "01:02:03:04:05:06", "12:15:16");
+    acquireAndRelease("01:02:03:04:05:06", "12:14",
+                      "01:02:03:04:05:06", "12:15:16",
+                      SHOULD_FAIL);
 }
 
 // This test checks the server's behavior in the following case:
@@ -245,8 +227,9 @@ TEST_F(ReleaseTest, releaseNonMatchingClientId) {
 // - The server uses client identifier to find the client's lease and
 //   releases it.
 TEST_F(ReleaseTest, releaseNonMatchingHWAddress) {
-    successfulRelease("01:02:03:04:05:06", "12:14",
-                      "06:06:06:06:06:06", "12:14");
+    acquireAndRelease("01:02:03:04:05:06", "12:14",
+                      "06:06:06:06:06:06", "12:14",
+                      SHOULD_PASS);
 }
 
 // This test checks the server's behavior in the following case:

src/lib/dhcpsrv/lease.h

@@ -296,28 +296,29 @@ struct Lease4 : public Lease {
     /// cases:
     /// - client didn't generate client identifier and is only using the chaddr
     ///   field to identify itself.
-    /// - server's administrator configured the server to ignore client identifier,
-    ///   the client obtained the new lease, and the administrator reconfigured
-    ///   the server to NOT ignore the client identifier. The client is trying
-    ///   to renew its lease and both the client identifier and HW address is
-    ///   used for matching the lease which doesn't have the record of the
-    ///   client identifier.
+    /// - server's administrator configured the server to NOT match client
+    ///   identifiers, the client obtained the new lease, and the administrator
+    ///   reconfigured the server to match the client identifiers. The client
+    ///   is trying to renew its lease and both the client identifier and HW
+    ///   address is used for matching the lease which doesn't have the record
+    ///   of the client identifier.
     /// - client obtained the lease using the HW address and client identifier,
-    ///   the server's administrator configured the server to ignore the client
-    ///   identifier, and the client returns to renew the lease. This time, the
-    ///   lease has a record of both client identifier and the HW address but
-    ///   only the HW address is used for matching the client to the lease.
+    ///   the server's administrator configured the server to NOT match the
+    ///   client identifiers, and the client returns to renew the lease. This
+    ///   time, the lease has a record of both client identifier and the HW
+    ///   address but only the HW address is used for matching the client to
+    ///   the lease.
     ///
     /// Note that the typical case when the server's administrator may want to
-    /// force ignoring client identifier passed in the client's message is when
-    /// the client is performing multi-stage boot. In such case, the client
-    /// identifiers may change on various stages of the boot, but the HW address
-    /// will remain stable. The server's administrator prefers to use the
-    /// HW address for client identification in this case.
-    ///
-    /// It may also be useful to ignore client identifiers to mitigate the
-    /// problem of broken client implementations which generate new client
-    /// identifiers every time they connect to the network.
+    /// disable matching the client identifier passed in the client's message
+    /// is when the client is performing multi-stage boot. In such case, the
+    /// client identifiers may change on various stages of the boot, but the
+    /// HW address will remain stable. The server's administrator prefers
+    /// using the HW address for client identification in this case.
+    ///
+    /// It may also be useful to disable matching client identifiers to
+    /// mitigate the problem of broken client implementations which generate
+    /// new client identifiers every time they connect to the network.
     ///
     /// @param hw_address Pointer to the HW address of the client.
     /// @param client_id Pointer to the client identifier structure.

src/lib/dhcpsrv/tests/alloc_engine4_unittest.cc

@@ -554,6 +554,7 @@ TEST_F(AllocEngine4Test, identifyClientLease) {
     EXPECT_EQ("192.0.2.101", identified_lease->addr_.toText());
 
     ctx.hwaddr_ = hwaddr2_;
+    ctx.clientid_ = clientid_;
     identified_lease = engine.allocateLease4(ctx);
     ASSERT_TRUE(identified_lease);
     EXPECT_EQ("192.0.2.101", identified_lease->addr_.toText());
@@ -564,12 +565,14 @@ TEST_F(AllocEngine4Test, identifyClientLease) {
     ASSERT_TRUE(identified_lease);
     EXPECT_NE(identified_lease->addr_.toText(), "192.0.2.101");
 
+    ctx.hwaddr_ = hwaddr_;
     ctx.clientid_.reset();
     identified_lease = engine.allocateLease4(ctx);
     ASSERT_TRUE(identified_lease);
     EXPECT_EQ("192.0.2.101", identified_lease->addr_.toText());
 
     ctx.hwaddr_ = hwaddr2_;
+    ctx.clientid_.reset();
     identified_lease = engine.allocateLease4(ctx);
     ASSERT_TRUE(identified_lease);
     EXPECT_NE(identified_lease->addr_.toText(), "192.0.2.101");
@@ -583,13 +586,14 @@ TEST_F(AllocEngine4Test, identifyClientLease) {
     ASSERT_TRUE(identified_lease);
     EXPECT_EQ("192.0.2.101", identified_lease->addr_.toText());
 
+    ctx.hwaddr_ = hwaddr_;
     ctx.clientid_.reset();
     identified_lease = engine.allocateLease4(ctx);
     ASSERT_TRUE(identified_lease);
     EXPECT_EQ("192.0.2.101", identified_lease->addr_.toText());
 
-    ctx.clientid_ = clientid_;
     ctx.hwaddr_ = hwaddr2_;
+    ctx.clientid_ = clientid_;
     identified_lease = engine.allocateLease4(ctx);
     ASSERT_TRUE(identified_lease);
     EXPECT_NE(identified_lease->addr_.toText(), "192.0.2.101");

src/lib/dhcpsrv/tests/lease_unittest.cc

@@ -1,4 +1,4 @@
-// Copyright (C) 2013-2014 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2013-2015 Internet Systems Consortium, Inc. ("ISC")
 //
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
@@ -16,6 +16,7 @@
 #include <asiolink/io_address.h>
 #include <dhcp/duid.h>
 #include <dhcpsrv/lease.h>
+#include <util/pointer_util.h>
 #include <gtest/gtest.h>
 #include <vector>
 #include <sstream>
@@ -96,8 +97,8 @@ TEST_F(Lease4Test, constructor) {
 
         EXPECT_EQ(ADDRESS[i], static_cast<uint32_t>(lease.addr_));
         EXPECT_EQ(0, lease.ext_);
-        EXPECT_TRUE(hwaddr_ == lease.hwaddr_);
-        EXPECT_TRUE(*clientid_ == *lease.client_id_);
+        EXPECT_TRUE(util::equalValues(hwaddr_, lease.hwaddr_));
+        EXPECT_TRUE(util::equalValues(clientid_, lease.client_id_));
         EXPECT_EQ(0, lease.t1_);
         EXPECT_EQ(0, lease.t2_);
         EXPECT_EQ(VALID_LIFETIME, lease.valid_lft_);
@@ -188,90 +189,62 @@ TEST_F(Lease4Test, operatorAssign) {
 // belongs to the particular client identified by the client identifier
 // and hw address.
 TEST_F(Lease4Test, leaseBelongsToClient) {
+    // Client identifier that matches the one in the lease.
+    ClientIdPtr matching_client_id = ClientId::fromText("01:02:03:04");
+    // Client identifier that doesn't match the one in the lease.
+    ClientIdPtr diff_client_id = ClientId::fromText("01:02:03:05");
+    // Null (no) client identifier.
+    ClientIdPtr null_client_id;
+
+    // HW Address that matches the one in the lease.
+    HWAddrPtr matching_hw(new HWAddr(HWAddr::fromText("00:01:02:03:04:05",
+                                                      HTYPE_ETHER)));
+    // HW Address that doesn't match the one in the lease.
+    HWAddrPtr diff_hw(new HWAddr(HWAddr::fromText("00:01:02:03:04:06",
+                                                  HTYPE_ETHER)));
+    // Null HW Address.
+    HWAddrPtr null_hw;
+
     // Create the lease with MAC address and Client Identifier.
-    Lease4 lease(IOAddress("192.0.2.1"),
-                 HWAddrPtr(new HWAddr(HWAddr::fromText("00:01:02:03:04:05", HTYPE_ETHER))),
-                 ClientId::fromText("01:02:03:04"),
+    Lease4 lease(IOAddress("192.0.2.1"), matching_hw, matching_client_id,
                  60, time(NULL), 0, 0, 1);
 
-    // Create HW address and Client Id objects which match those held by the
-    // lease. This is a full match, so the lease belongs to the client.
-    HWAddrPtr hwaddr(new HWAddr(HWAddr::fromText("00:01:02:03:04:05", HTYPE_ETHER)));
-    ClientIdPtr clientid = ClientId::fromText("01:02:03:04");
-    EXPECT_TRUE(lease.belongsToClient(hwaddr, clientid));
-
-    // Modify the HW address. The lease should still belong to the client
-    // because the client identifier matches.
-    hwaddr.reset(new HWAddr(HWAddr::fromText("00:01:02:03:04:06", HTYPE_ETHER)));
-    EXPECT_TRUE(lease.belongsToClient(hwaddr, clientid));
-
-    // Use the correct HW address, but modify the client identifier. The client
-    // identifier must match if present. If it doesn't match, the lease doesn't
-    // belong to the client.
-    hwaddr.reset(new HWAddr(HWAddr::fromText("00:01:02:03:04:05", HTYPE_ETHER)));
-    clientid = ClientId::fromText("01:02:03:05");
-    EXPECT_FALSE(lease.belongsToClient(hwaddr, clientid));
-
-    // Set client id to null and leave only HW address. It coveres the case when
-    // the client id is ignored by the server (e.g. multi-stage boot case), but
-    // the client has a lease already.
-    clientid.reset();
-    EXPECT_TRUE(lease.belongsToClient(hwaddr, clientid));
-
-    // Now use the correct client id and the null HW address. The client id
-    // should be sufficient to match the lease.
-    clientid = ClientId::fromText("01:02:03:04");
-    hwaddr.reset();
-    EXPECT_TRUE(lease.belongsToClient(hwaddr, clientid));
-
-    // Use both HW address and client id set to null. There must be no match.
-    hwaddr.reset();
-    clientid.reset();
-    EXPECT_FALSE(lease.belongsToClient(hwaddr, clientid));
-
-    // This time both HW address and client identifier are different than
-    // those held by the lease. There should be no match.
-    hwaddr.reset(new HWAddr(HWAddr::fromText("00:01:02:03:04:06", HTYPE_ETHER)));
-    clientid = ClientId::fromText("01:02:03:05");
-    EXPECT_FALSE(lease.belongsToClient(hwaddr, clientid));
-
-    // Use the correct HW address and client id to match the lease, but set the
-    // client id for the lease to null. This covers the case when the lease
-    // has been acquired without client identifier but then the client is
-    // renewing using some client identifier (or server is configured to
-    // not ignore the client identifier). The client should obtain the lease.
-    hwaddr.reset(new HWAddr(HWAddr::fromText("00:01:02:03:04:05", HTYPE_ETHER)));
-    lease.client_id_.reset();
-    EXPECT_TRUE(lease.belongsToClient(hwaddr, clientid));
-
-    // Change HW address. This time, the HW address doesn't match and client id
-    // can't be compared so it is considered as no match.
-    hwaddr.reset(new HWAddr(HWAddr::fromText("00:01:02:03:04:06", HTYPE_ETHER)));
-    EXPECT_FALSE(lease.belongsToClient(hwaddr, clientid));
-
-    // The lease now holds the client id by the HW address is null for the lease.
-    // Also, we're using correct client id to match the lease and some HW address.
-    // There should be a match because client id is ok.
-    lease.client_id_ = ClientId::fromText("01:02:03:04");
-    lease.hwaddr_.reset();
-    clientid = ClientId::fromText("01:02:03:04");
-    hwaddr.reset(new HWAddr(HWAddr::fromText("00:01:02:03:04:05", HTYPE_ETHER)));
-    EXPECT_TRUE(lease.belongsToClient(hwaddr, clientid));
-
-    // If client id is wrong, there should be no match.
-    clientid = ClientId::fromText("01:02:03:05");
-    EXPECT_FALSE(lease.belongsToClient(hwaddr, clientid));
-
-    // Setting HW address to null shouldn't matter and we should still have a
-    // match if the client id is correct.
-    clientid = ClientId::fromText("01:02:03:04");
-    hwaddr.reset();
-    EXPECT_TRUE(lease.belongsToClient(hwaddr, clientid));
-
-    // But with the null HW address and non-matching client id there should be
-    // no match whatsoever.
-    clientid = ClientId::fromText("01:02:03:06");
-    EXPECT_FALSE(lease.belongsToClient(hwaddr, clientid));
+    // Verify cases for lease that has both hw address and client identifier.
+    EXPECT_TRUE(lease.belongsToClient(matching_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(matching_hw, diff_client_id));
+    EXPECT_TRUE(lease.belongsToClient(matching_hw, null_client_id));
+    EXPECT_TRUE(lease.belongsToClient(diff_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(diff_hw, diff_client_id));
+    EXPECT_FALSE(lease.belongsToClient(diff_hw, null_client_id));
+    EXPECT_TRUE(lease.belongsToClient(null_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(null_hw, diff_client_id));
+    EXPECT_FALSE(lease.belongsToClient(null_hw, null_client_id));
+
+
+    // Verify cases for lease that has only HW address.
+    lease.client_id_ = null_client_id;
+    EXPECT_TRUE(lease.belongsToClient(matching_hw, matching_client_id));
+    EXPECT_TRUE(lease.belongsToClient(matching_hw, diff_client_id));
+    EXPECT_TRUE(lease.belongsToClient(matching_hw, null_client_id));
+    EXPECT_FALSE(lease.belongsToClient(diff_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(diff_hw, diff_client_id));
+    EXPECT_FALSE(lease.belongsToClient(diff_hw, null_client_id));
+    EXPECT_FALSE(lease.belongsToClient(null_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(null_hw, diff_client_id));
+    EXPECT_FALSE(lease.belongsToClient(null_hw, null_client_id));
+
+    // Verify cases for lease that has only client identifier.
+    lease.client_id_ = matching_client_id;
+    lease.hwaddr_ = null_hw;
+    EXPECT_TRUE(lease.belongsToClient(matching_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(matching_hw, diff_client_id));
+    EXPECT_FALSE(lease.belongsToClient(matching_hw, null_client_id));
+    EXPECT_TRUE(lease.belongsToClient(diff_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(diff_hw, diff_client_id));
+    EXPECT_FALSE(lease.belongsToClient(diff_hw, null_client_id));
+    EXPECT_TRUE(lease.belongsToClient(null_hw, matching_client_id));
+    EXPECT_FALSE(lease.belongsToClient(null_hw, diff_client_id));
+    EXPECT_FALSE(lease.belongsToClient(null_hw, null_client_id));
 }
 
 /// @brief Lease4 Equality Test

src/lib/util/pointer_util.h

@@ -32,7 +32,7 @@ namespace util {
 /// @return true only if both pointers are non-null and the values which they
 /// point to are equal.
 template<typename T>
-bool equalValues(const T& ptr1, const T& ptr2) {
+inline bool equalValues(const T& ptr1, const T& ptr2) {
     return (ptr1 && ptr2 && (*ptr1 == *ptr2));
 }
 
@@ -47,7 +47,7 @@ bool equalValues(const T& ptr1, const T& ptr2) {
 /// @return true if both pointers are null or if they are both non-null
 /// and the values pointed to are equal.
 template<typename T>
-bool nullOrEqualValues(const T& ptr1, const T& ptr2) {
+inline bool nullOrEqualValues(const T& ptr1, const T& ptr2) {
     return ((!ptr1 && !ptr2) || equalValues(ptr1, ptr2));
 }