[2325] Option::equal() method implemented.

src/lib/dhcp/option.cc

@@ -314,6 +314,10 @@ void Option::setData(const OptionBufferConstIter first,
     std::copy(first, last, data_.begin());
 }
 
+bool Option::equal(const OptionPtr& other) const {
+    return ( (getType() == other->getType()) &&
+             (getData() == other->getData()) );
+}
 
 Option::~Option() {
 

src/lib/dhcp/option.h

@@ -197,7 +197,7 @@ public:
     /// Returns option type (0-255 for DHCPv4, 0-65535 for DHCPv6)
     ///
     /// @return option type
-    uint16_t getType() { return (type_); }
+    uint16_t getType() const { return (type_); }
 
     /// Returns length of the complete option (data length + DHCPv4/DHCPv6
     /// option header)
@@ -219,7 +219,7 @@ public:
     ///
     /// @return pointer to actual data (or reference to an empty vector
     ///         if there is no data)
-    virtual const OptionBuffer& getData() { return (data_); }
+    virtual const OptionBuffer& getData() const { return (data_); }
 
     /// Adds a sub-option.
     ///
@@ -303,6 +303,19 @@ public:
     /// just to force that every option has virtual dtor
     virtual ~Option();
 
+    /// @brief Checks if two options are equal
+    ///
+    /// Equality verifies option type and option content. Care should
+    /// be taken when using this method. Implementation for derived
+    /// classes should be provided when this method is expected to be
+    /// used. It is safe in general, as the first check (different types)
+    /// will detect differences between base Option and derived
+    /// objects.
+    ///
+    /// @param other the other option
+    /// @return true if both options are equal
+    virtual bool equal(const OptionPtr& other) const;
+
 protected:
     /// Builds raw (over-wire) buffer of this option, including all
     /// defined suboptions. Version for building DHCPv4 options.

src/lib/dhcp/tests/option_unittest.cc

@@ -524,4 +524,27 @@ TEST_F(OptionTest, setData) {
     EXPECT_TRUE(0 == memcmp(&buf_[0], test_data + opt1->getHeaderLen(),
                             buf_.size()));
 }
+
+// This test verifies that options can be compared using equal() method.
+TEST_F(OptionTest, equal) {
+
+    // five options with varying lengths
+    OptionPtr opt1(new Option(Option::V6, 258, buf_.begin(), buf_.begin() + 1));
+    OptionPtr opt2(new Option(Option::V6, 258, buf_.begin(), buf_.begin() + 2));
+    OptionPtr opt3(new Option(Option::V6, 258, buf_.begin(), buf_.begin() + 3));
+
+    // the same content as opt2, but different type
+    OptionPtr opt4(new Option(Option::V6, 1, buf_.begin(), buf_.begin() + 2));
+
+    // another instance with the same type and content as opt2
+    OptionPtr opt5(new Option(Option::V6, 258, buf_.begin(), buf_.begin() + 2));
+
+    EXPECT_TRUE(opt1->equal(opt1));
+
+    EXPECT_FALSE(opt1->equal(opt2));
+    EXPECT_FALSE(opt1->equal(opt3));
+    EXPECT_FALSE(opt1->equal(opt4));
+
+    EXPECT_TRUE(opt2->equal(opt5));
+}
 }

src/lib/dhcpsrv/subnet.h

@@ -172,7 +172,7 @@ public:
                     // Use option type as the index key. The type is held
                     // in OptionPtr object so we have to call Option::getType
                     // to retrieve this key for each element.
-                    boost::multi_index::mem_fun<
+                    boost::multi_index::const_mem_fun<
                         Option,
                         uint16_t,
                         &Option::getType