empty constructors for lists and maps, and corresponding 'factory' functions Element::createList() and Element::createMap()

git-svn-id: svn://bind10.isc.org/svn/bind10/branches/trac172@2112 e5f2f494-b856-4b98-b285-d166d9295462

9 files changed, 76 insertions, 75 deletions

diff --git a/src/lib/cc/data.cc b/src/lib/cc/data.cc
index ff2b173b78..c9826cfb58 100644
--- a/src/lib/cc/data.cc
+++ b/src/lib/cc/data.cc
@@ -250,19 +250,13 @@ Element::create(const bool b) {
 }
 
 ElementPtr
-Element::create(const std::vector<ElementPtr>& v) {
-    return ElementPtr(new ListElement(v));
+Element::createList() {
+    return ElementPtr(new ListElement());
 }
 
 ElementPtr
-Element::create(const std::map<std::string, ElementPtr>& m) {
-    for (std::map<std::string, ElementPtr>::const_iterator it = m.begin();
-         it != m.end(); ++it) {
-        if ((*it).first.length() > 255) {
-            isc_throw(TypeError, "Map tag is too long");
-        }
-    }
-    return ElementPtr(new MapElement(m));
+Element::createMap() {
+    return ElementPtr(new MapElement());
 }
 
 
@@ -477,27 +471,27 @@ ElementPtr
 from_stringstream_list(std::istream &in, const std::string& file, int& line, int& pos)
 {
     char c = 0;
-    std::vector<ElementPtr> v;
+    ElementPtr list = Element::createList();
     ElementPtr cur_list_element;
 
     skip_chars(in, " \t\n", line, pos);
     while (c != EOF && c != ']') {
         if (in.peek() != ']') {
             cur_list_element = Element::createFromString(in, file, line, pos);
-            v.push_back(cur_list_element);
+            list->add(cur_list_element);
             skip_to(in, file, line, pos, ",]", " \t\n");
         }
         c = in.get();
         pos++;
     }
-    return Element::create(v);
+    return list;
 }
 
 ElementPtr
 from_stringstream_map(std::istream &in, const std::string& file, int& line,
                       int& pos)
 {
-    std::map<std::string, ElementPtr> m;
+    ElementPtr map = Element::createMap();
     skip_chars(in, " \t\n", line, pos);
     char c = in.peek();
     if (c == '}') {
@@ -505,10 +499,8 @@ from_stringstream_map(std::istream &in, const std::string& file, int& line,
         c = in.get();
     } else {
         while (c != EOF && c != '}') {
-            std::pair<std::string, ElementPtr> p;
-
-            p.first = str_from_stringstream(in, file, line, pos);
-            if (p.first.length() > 255) {
+            std::string key = str_from_stringstream(in, file, line, pos);
+            if (key.length() > 255) {
                 // Map tag has one-byte length field in wire format, so the
                 // length cannot exceed 255.
                 throwParseError("Map tag is too long", file, line, pos);
@@ -518,14 +510,16 @@ from_stringstream_map(std::istream &in, const std::string& file, int& line,
             // skip the :
             in.get();
             pos++;
-            p.second = Element::createFromString(in, file, line, pos);
-            m.insert(p);
+
+            ElementPtr value = Element::createFromString(in, file, line, pos);
+            map->set(key, value);
+            
             skip_to(in, file, line, pos, ",}", " \t\n");
             c = in.get();
             pos++;
         }
     }
-    return Element::create(m);
+    return map;
 }
 }
 
@@ -737,6 +731,15 @@ Element::fromWire(std::stringstream& in, int length) {
     return createFromString(in, "<wire>", line, pos);
 }
 
+void
+MapElement::set(const std::string& key, ElementPtr value) {
+    if (key.length() <= 255) {
+        m[key] = value;
+    } else {
+        isc_throw(TypeError, "Map key too long");
+    }
+}
+
 bool
 MapElement::find(const std::string& id, ElementPtr& t) {
     try {
diff --git a/src/lib/cc/data.h b/src/lib/cc/data.h
index a82cd89f5b..b37439eaba 100644
--- a/src/lib/cc/data.h
+++ b/src/lib/cc/data.h
@@ -272,9 +272,12 @@ public:
     static ElementPtr create(const std::string& s);
     // need both std:string and char *, since c++ will match
     // bool before std::string when you pass it a char *
-    static ElementPtr create(const char *s) { return create(std::string(s)); }; 
-    static ElementPtr create(const std::vector<ElementPtr>& v);
-    static ElementPtr create(const std::map<std::string, ElementPtr>& m);
+    static ElementPtr create(const char *s) { return create(std::string(s)); };
+
+    /// \brief Creates an empty ListElement type ElementPtr.
+    static ElementPtr createList();
+    /// \brief Creates an empty MapElement type ElementPtr.
+    static ElementPtr createMap();
     //@}
 
     /// \name Compound factory functions
@@ -404,7 +407,7 @@ class ListElement : public Element {
     std::vector<ElementPtr> l;
 
 public:
-    ListElement(std::vector<ElementPtr> v) : Element(list), l(v) {};
+    ListElement() : Element(list), l(std::vector<ElementPtr>()) {};
     const std::vector<ElementPtr>& listValue() { return l; }
     using Element::getValue;
     bool getValue(std::vector<ElementPtr>& t) { t = l; return true; };
@@ -426,7 +429,8 @@ class MapElement : public Element {
     std::map<std::string, ElementPtr> m;
 
 public:
-    MapElement(const std::map<std::string, ElementPtr>& v) : Element(map), m(v) {};
+    MapElement() : Element(map), m(std::map<std::string, ElementPtr>()) {};
+    // TODO: should we have direct iterators instead of exposing the std::map here?
     const std::map<std::string, ElementPtr>& mapValue() { return m; }
     using Element::getValue;
     bool getValue(std::map<std::string, ElementPtr>& t) { t = m; return true; };
@@ -435,7 +439,7 @@ public:
     using Element::get;
     ElementPtr get(const std::string& s) { if (contains(s)) { return m[s]; } else { return ElementPtr();} };
     using Element::set;
-    void set(const std::string& s, ElementPtr p) { m[s] = p; };
+    void set(const std::string& key, ElementPtr value);
     using Element::remove;
     void remove(const std::string& s) { m.erase(s); }
     bool contains(const std::string& s) { return m.find(s) != m.end(); }
diff --git a/src/lib/cc/data_unittests.cc b/src/lib/cc/data_unittests.cc
index ebb8bd3314..8470ea084a 100644
--- a/src/lib/cc/data_unittests.cc
+++ b/src/lib/cc/data_unittests.cc
@@ -40,11 +40,9 @@ TEST(Element, type) {
     EXPECT_EQ(bool_el.getType(), Element::boolean);
     StringElement str_el = StringElement("foo");
     EXPECT_EQ(str_el.getType(), Element::string);
-    std::vector<ElementPtr> v;
-    ListElement list_el = ListElement(v);
+    ListElement list_el = ListElement();
     EXPECT_EQ(list_el.getType(), Element::list);
-    std::map<std::string, ElementPtr> m;
-    MapElement map_el = MapElement(m);
+    MapElement map_el = MapElement();
     EXPECT_EQ(map_el.getType(), Element::map);
 }
 
@@ -139,16 +137,14 @@ TEST(Element, create_and_value_throws) {
     EXPECT_THROW(el->listValue(), TypeError);
     EXPECT_THROW(el->mapValue(), TypeError);
 
-    std::vector<ElementPtr> v;
-    el = Element::create(v);
+    el = Element::createList();
     EXPECT_THROW(el->intValue(), TypeError);
     EXPECT_THROW(el->doubleValue(), TypeError);
     EXPECT_THROW(el->boolValue(), TypeError);
     EXPECT_THROW(el->stringValue(), TypeError);
     EXPECT_THROW(el->mapValue(), TypeError);
 
-    std::map<std::string, ElementPtr> m;
-    el = Element::create(m);
+    el = Element::createMap();
     EXPECT_THROW(el->intValue(), TypeError);
     EXPECT_THROW(el->doubleValue(), TypeError);
     EXPECT_THROW(el->boolValue(), TypeError);
@@ -222,14 +218,13 @@ TEST(Element, MapElement) {
                        "9123456789abcdefa123456789abcdefb123456789abcdef"
                        "c123456789abcdefd123456789abcdefe123456789abcdef"
                        "f123456789abcde");
-    std::map<std::string, ElementPtr> long_maptag_map;
     
     EXPECT_EQ(255, long_maptag.length()); // check prerequisite
     el = Element::createFromString("{ \"" + long_maptag + "\": \"bar\"}");
     EXPECT_EQ("bar", el->find(long_maptag)->stringValue());
 
-    long_maptag_map[long_maptag] = Element::create("bar");
-    el = Element::create(long_maptag_map);
+    el = Element::createMap();
+    el->set(long_maptag, Element::create("bar"));
     EXPECT_EQ("bar", el->find(long_maptag)->stringValue());
 
     // A one-byte longer tag should trigger an exception.
@@ -238,8 +233,7 @@ TEST(Element, MapElement) {
                                            "\": \"bar\"}"),
                  ParseError);
 
-    long_maptag_map[long_maptag] = Element::create("bar");
-    EXPECT_THROW(Element::create(long_maptag_map), TypeError);
+    EXPECT_THROW(el->set(long_maptag, Element::create("bar")), TypeError);
 
 }
 
@@ -314,27 +308,27 @@ TEST(Element, equals) {
 }
 
 TEST(Element, removeIdentical) {
-    ElementPtr a = Element::createFromString("{}");
-    ElementPtr b = Element::createFromString("{}");
-    ElementPtr c = Element::createFromString("{}");
+    ElementPtr a = Element::createMap();
+    ElementPtr b = Element::createMap();
+    ElementPtr c = Element::createMap();
     removeIdentical(a, b);
     EXPECT_TRUE(a == c);
 
     a = Element::createFromString("{ \"a\": 1 }");
     b = Element::createFromString("{ \"a\": 1 }");
-    c = Element::createFromString("{}");
+    c = Element::createMap();
     removeIdentical(a, b);
     EXPECT_TRUE(a == c);
 
     a = Element::createFromString("{ \"a\": 1, \"b\": [ 1, 2 ] }");
-    b = Element::createFromString("{}");
+    b = Element::createMap();
     c = Element::createFromString("{ \"a\": 1, \"b\": [ 1, 2 ] }");
     removeIdentical(a, b);
     EXPECT_TRUE(a == c);
 
     a = Element::createFromString("{ \"a\": 1, \"b\": [ 1, 2 ] }");
     b = Element::createFromString("{ \"a\": 1, \"b\": [ 1, 2 ] }");
-    c = Element::createFromString("{}");
+    c = Element::createMap();
     removeIdentical(a, b);
     EXPECT_TRUE(a == c);
 
@@ -345,14 +339,14 @@ TEST(Element, removeIdentical) {
     EXPECT_TRUE(a == c);
 
     a = Element::createFromString("{ \"a\": { \"b\": \"c\" } }");
-    b = Element::createFromString("{}");
+    b = Element::createMap();
     c = Element::createFromString("{ \"a\": { \"b\": \"c\" } }");
     removeIdentical(a, b);
     EXPECT_TRUE(a == c);
 
     a = Element::createFromString("{ \"a\": { \"b\": \"c\" } }");
     b = Element::createFromString("{ \"a\": { \"b\": \"c\" } }");
-    c = Element::createFromString("{}");
+    c = Element::createMap();
     removeIdentical(a, b);
     EXPECT_TRUE(a == c);
 
@@ -365,17 +359,17 @@ TEST(Element, removeIdentical) {
 
 TEST(Element, merge)
 {
-    ElementPtr a = Element::createFromString("{}");
-    ElementPtr b = Element::createFromString("{}");
-    ElementPtr c = Element::createFromString("{}");
+    ElementPtr a = Element::createMap();
+    ElementPtr b = Element::createMap();
+    ElementPtr c = Element::createMap();
     merge(a, b);
     EXPECT_TRUE(a == c);
 
     a = Element::createFromString("1");
-    b = Element::createFromString("{}");
+    b = Element::createMap();
     EXPECT_THROW(merge(a, b), TypeError);
 
-    a = Element::createFromString("{}");
+    a = Element::createMap();
     b = Element::createFromString("{ \"a\": 1 }");
     c = Element::createFromString("{ \"a\": 1 }");
     merge(a, b);
diff --git a/src/lib/cc/session.cc b/src/lib/cc/session.cc
index 66bc2717ab..1394ea8e79 100644
--- a/src/lib/cc/session.cc
+++ b/src/lib/cc/session.cc
@@ -56,7 +56,7 @@ namespace cc {
 
 class SessionImpl {
 public:
-    SessionImpl() : sequence_(-1) { queue_ = Element::createFromString("[]"); }
+    SessionImpl() : sequence_(-1) { queue_ = Element::createList(); }
     virtual ~SessionImpl() {}
     virtual void establish(const char& socket_file) = 0;
     virtual int getSocket() = 0;
@@ -422,7 +422,7 @@ Session::recvmsg(ElementPtr& env, ElementPtr& msg,
         msg = l_msg;
         return true;
     } else {
-        ElementPtr q_el = Element::createFromString("[]");
+        ElementPtr q_el = Element::createList();
         q_el->add(l_env);
         q_el->add(l_msg);
         impl_->queue_->add(q_el);
@@ -433,7 +433,7 @@ Session::recvmsg(ElementPtr& env, ElementPtr& msg,
 
 void
 Session::subscribe(std::string group, std::string instance) {
-    ElementPtr env = Element::create(std::map<std::string, ElementPtr>());
+    ElementPtr env = Element::createMap();
 
     env->set("type", Element::create("subscribe"));
     env->set("group", Element::create(group));
@@ -444,7 +444,7 @@ Session::subscribe(std::string group, std::string instance) {
 
 void
 Session::unsubscribe(std::string group, std::string instance) {
-    ElementPtr env = Element::create(std::map<std::string, ElementPtr>());
+    ElementPtr env = Element::createMap();
 
     env->set("type", Element::create("unsubscribe"));
     env->set("group", Element::create(group));
@@ -457,7 +457,7 @@ int
 Session::group_sendmsg(ElementPtr msg, std::string group,
                        std::string instance, std::string to)
 {
-    ElementPtr env = Element::create(std::map<std::string, ElementPtr>());
+    ElementPtr env = Element::createMap();
     int nseq = ++impl_->sequence_;
     
     env->set("type", Element::create("send"));
@@ -481,7 +481,7 @@ Session::group_recvmsg(ElementPtr& envelope, ElementPtr& msg,
 
 int
 Session::reply(ElementPtr& envelope, ElementPtr& newmsg) {
-    ElementPtr env = Element::create(std::map<std::string, ElementPtr>());
+    ElementPtr env = Element::createMap();
     int nseq = ++impl_->sequence_;
     
     env->set("type", Element::create("send"));
diff --git a/src/lib/config/ccsession.cc b/src/lib/config/ccsession.cc
index e0020ab2eb..c72f624e1b 100644
--- a/src/lib/config/ccsession.cc
+++ b/src/lib/config/ccsession.cc
@@ -125,8 +125,8 @@ createCommand(const std::string& command)
 ElementPtr
 createCommand(const std::string& command, ElementPtr arg)
 {
-    ElementPtr cmd = Element::createFromString("{}");
-    ElementPtr cmd_parts = Element::createFromString("[]");
+    ElementPtr cmd = Element::createMap();
+    ElementPtr cmd_parts = Element::createList();
     cmd_parts->add(Element::create(command));
     if (arg) {
         cmd_parts->add(arg);
@@ -274,7 +274,7 @@ ElementPtr
 ModuleCCSession::handleConfigUpdate(ElementPtr new_config)
 {
     ElementPtr answer;
-    ElementPtr errors = Element::createFromString("[]");
+    ElementPtr errors = Element::createList();
     if (!config_handler_) {
         answer = createAnswer(1, module_name_ + " does not have a config handler");
     } else if (!module_specification_.validate_config(new_config, false, errors)) {
diff --git a/src/lib/config/config_data.cc b/src/lib/config/config_data.cc
index 1dcffdb20a..9ce2f151b0 100644
--- a/src/lib/config/config_data.cc
+++ b/src/lib/config/config_data.cc
@@ -158,7 +158,7 @@ ConfigData::getValue(bool& is_default, const std::string& identifier)
 ElementPtr
 ConfigData::getItemList(const std::string& identifier, bool recurse)
 {
-    ElementPtr result = Element::createFromString("[]");
+    ElementPtr result = Element::createList();
     ElementPtr spec_part = getModuleSpec().getConfigSpec();
     if (identifier != "" && identifier != "/") {
         spec_part = find_spec_part(spec_part, identifier);
@@ -172,7 +172,7 @@ ConfigData::getItemList(const std::string& identifier, bool recurse)
 ElementPtr
 ConfigData::getFullConfig()
 {
-    ElementPtr result = Element::createFromString("{}");
+    ElementPtr result = Element::createMap();
     ElementPtr items = getItemList("", true);
     BOOST_FOREACH(ElementPtr item, items->listValue()) {
         result->set(item->stringValue(), getValue(item->stringValue()));
diff --git a/src/lib/config/config_data.h b/src/lib/config/config_data.h
index 359a6e154d..a38c209d69 100644
--- a/src/lib/config/config_data.h
+++ b/src/lib/config/config_data.h
@@ -39,12 +39,12 @@ class ConfigData {
 public:
     /// Constructs a ConfigData option with no specification and an
     /// empty configuration.
-    ConfigData() { _config = Element::createFromString("{}"); };
+    ConfigData() { _config = Element::createMap(); };
     
     /// Constructs a ConfigData option with the given specification
     /// and an empty configuration.
     /// \param module_spec A ModuleSpec for the relevant module
-    ConfigData(const ModuleSpec& module_spec) : _module_spec(module_spec) { _config = Element::createFromString("{}"); }
+    ConfigData(const ModuleSpec& module_spec) : _module_spec(module_spec) { _config = Element::createMap(); }
 
     virtual ~ConfigData() {};
 
diff --git a/src/lib/config/tests/fake_session.cc b/src/lib/config/tests/fake_session.cc
index cad2e054d4..c88c29d871 100644
--- a/src/lib/config/tests/fake_session.cc
+++ b/src/lib/config/tests/fake_session.cc
@@ -92,12 +92,12 @@ getFirstMessage(std::string& group, std::string& to)
 void
 addMessage(ElementPtr msg, const std::string& group, const std::string& to)
 {
-    ElementPtr m_el = Element::createFromString("[]");
+    ElementPtr m_el = Element::createList();
     m_el->add(Element::create(group));
     m_el->add(Element::create(to));
     m_el->add(msg);
     if (!msg_queue) {
-        msg_queue = Element::createFromString("[]");
+        msg_queue = Element::createList();
     }
     msg_queue->add(m_el);
 }
@@ -108,8 +108,8 @@ haveSubscription(const std::string& group, const std::string& instance)
     if (!subscriptions) {
         return false;
     }
-    ElementPtr s1 = Element::createFromString("[]");
-    ElementPtr s2 = Element::createFromString("[]");
+    ElementPtr s1 = Element::createList();
+    ElementPtr s2 = Element::createList();
     s1->add(Element::create(group));
     s1->add(Element::create(instance));
     s2->add(Element::create(group));
@@ -206,7 +206,7 @@ Session::recvmsg(ElementPtr& env, ElementPtr& msg, bool nonblock UNUSED_PARAM, i
         BOOST_FOREACH(ElementPtr c_m, msg_queue->listValue()) {
             ElementPtr to_remove = ElementPtr();
             if (haveSubscription(c_m->get(0), c_m->get(1))) {
-                env = Element::createFromString("{}");
+                env = Element::createMap();
                 env->set("group", c_m->get(0));
                 env->set("to", c_m->get(1));
                 msg = c_m->get(2);
@@ -226,11 +226,11 @@ Session::recvmsg(ElementPtr& env, ElementPtr& msg, bool nonblock UNUSED_PARAM, i
 void
 Session::subscribe(std::string group, std::string instance) {
     //cout << "[XX] client subscribes to " << group << " . " << instance << endl;
-    ElementPtr s_el = Element::createFromString("[]");
+    ElementPtr s_el = Element::createList();
     s_el->add(Element::create(group));
     s_el->add(Element::create(instance));
     if (!subscriptions) {
-        subscriptions = Element::createFromString("[]");
+        subscriptions = Element::createList();
     }
     subscriptions->add(s_el);
 }
@@ -238,7 +238,7 @@ Session::subscribe(std::string group, std::string instance) {
 void
 Session::unsubscribe(std::string group, std::string instance) {
     //cout << "[XX] client unsubscribes from " << group << " . " << instance << endl;
-    ElementPtr s_el = Element::createFromString("[]");
+    ElementPtr s_el = Element::createList();
     s_el->add(Element::create(group));
     s_el->add(Element::create(instance));
     if (!subscriptions) {
diff --git a/src/lib/config/tests/module_spec_unittests.cc b/src/lib/config/tests/module_spec_unittests.cc
index 23869bf6e5..2265094dfe 100644
--- a/src/lib/config/tests/module_spec_unittests.cc
+++ b/src/lib/config/tests/module_spec_unittests.cc
@@ -169,7 +169,7 @@ TEST(ModuleSpec, DataValidation) {
     EXPECT_TRUE(data_test(dd, "data22_7.data"));
     EXPECT_FALSE(data_test(dd, "data22_8.data"));
 
-    ElementPtr errors = Element::createFromString("[]");
+    ElementPtr errors = Element::createList();
     EXPECT_FALSE(data_test_with_errors(dd, "data22_8.data", errors));
     EXPECT_EQ("[ \"Type mismatch\" ]", errors->str());
 }