Use copy-and-swap in Tokenizers

Ensures that the classes behave consistently when copied, moved, copy assigned,
and move assigned.

src/tokenizer.cpp

@@ -68,6 +68,28 @@ Tokenizer::Tokenizer(Tokenizer && rhs) :
     reset();
 }
 
+Tokenizer& Tokenizer::operator=(const Tokenizer& other)
+{
+    Tokenizer tmp(other);
+    swap(tmp);
+    return *this;
+}
+
+Tokenizer& Tokenizer::operator=(Tokenizer&& other)
+{
+    Tokenizer tmp(std::move(other));
+    swap(tmp);
+    return *this;
+}
+
+void Tokenizer::swap(Tokenizer& other)
+{
+    std::swap(text, other.text);
+    std::swap(separators, other.separators);
+    std::swap(start, other.start);
+    std::swap(ntokens, other.ntokens);
+}
+
 /*! Re-position the tokenizer state to the first word,
  * i.e. the first non-separator character */
 void Tokenizer::reset() {
@@ -181,6 +203,25 @@ ValueTokenizer::ValueTokenizer(const ValueTokenizer &rhs) : tokens(rhs.tokens) {
 ValueTokenizer::ValueTokenizer(ValueTokenizer &&rhs) : tokens(std::move(rhs.tokens)) {
 }
 
+ValueTokenizer& ValueTokenizer::operator=(const ValueTokenizer& other)
+{
+    ValueTokenizer tmp(other);
+    swap(tmp);
+    return *this;
+}
+
+ValueTokenizer& ValueTokenizer::operator=(ValueTokenizer&& other)
+{
+    ValueTokenizer tmp(std::move(other));
+    swap(tmp);
+    return *this;
+}
+
+void ValueTokenizer::swap(ValueTokenizer& other)
+{
+    std::swap(tokens, other.tokens);
+}
+
 /*! Indicate whether more tokens are available
  *
  * \return   true if there are more tokens, false if not */

src/tokenizer.h

@@ -37,8 +37,9 @@ public:
     Tokenizer(const std::string &str, const std::string &separators = TOKENIZER_DEFAULT_SEPARATORS);
     Tokenizer(Tokenizer &&);
     Tokenizer(const Tokenizer &);
-    Tokenizer& operator=(const Tokenizer&) = default;
-    Tokenizer& operator=(Tokenizer&&) = default;
+    Tokenizer& operator=(const Tokenizer&);
+    Tokenizer& operator=(Tokenizer&&);
+    void swap(Tokenizer &);
 
     void reset();
     void skip(int n=1);
@@ -93,8 +94,9 @@ public:
     ValueTokenizer(const std::string &str, const std::string &separators = TOKENIZER_DEFAULT_SEPARATORS);
     ValueTokenizer(const ValueTokenizer &);
     ValueTokenizer(ValueTokenizer &&);
-    ValueTokenizer& operator=(const ValueTokenizer&) = default;
-    ValueTokenizer& operator=(ValueTokenizer&&) = default;
+    ValueTokenizer& operator=(const ValueTokenizer&);
+    ValueTokenizer& operator=(ValueTokenizer&&);
+    void swap(ValueTokenizer &);
 
     std::string next_string();
     tagint next_tagint();

unittest/utils/test_tokenizer.cpp

@@ -101,6 +101,38 @@ TEST(Tokenizer, move_constructor)
     ASSERT_EQ(u.count(), 3);
 }
 
+TEST(Tokenizer, copy_assignment)
+{
+    Tokenizer t("  test word   ", " ");
+    Tokenizer u("  test2 word2 other2 ", " ");
+    ASSERT_THAT(t.next(), Eq("test"));
+    ASSERT_THAT(t.next(), Eq("word"));
+    ASSERT_EQ(t.count(), 2);
+    Tokenizer v = u;
+    u = t;
+    ASSERT_THAT(u.next(), Eq("test"));
+    ASSERT_THAT(u.next(), Eq("word"));
+    ASSERT_EQ(u.count(), 2);
+
+    ASSERT_THAT(v.next(), Eq("test2"));
+    ASSERT_THAT(v.next(), Eq("word2"));
+    ASSERT_THAT(v.next(), Eq("other2"));
+    ASSERT_EQ(v.count(), 3);
+}
+
+TEST(Tokenizer, move_assignment)
+{
+    Tokenizer t("  test word   ", " ");
+    ASSERT_THAT(t.next(), Eq("test"));
+    ASSERT_THAT(t.next(), Eq("word"));
+    ASSERT_EQ(t.count(), 2);
+    t = Tokenizer("test new word   ", " ");
+    ASSERT_THAT(t.next(), Eq("test"));
+    ASSERT_THAT(t.next(), Eq("new"));
+    ASSERT_THAT(t.next(), Eq("word"));
+    ASSERT_EQ(t.count(), 3);
+}
+
 TEST(Tokenizer, no_separator_path)
 {
     Tokenizer t("one", ":");
@@ -223,6 +255,38 @@ TEST(ValueTokenizer, move_constructor)
     ASSERT_EQ(u.count(), 3);
 }
 
+TEST(ValueTokenizer, copy_assignment)
+{
+    ValueTokenizer t("  test word   ", " ");
+    ValueTokenizer u("  test2 word2 other2 ", " ");
+    ASSERT_THAT(t.next_string(), Eq("test"));
+    ASSERT_THAT(t.next_string(), Eq("word"));
+    ASSERT_EQ(t.count(), 2);
+    ValueTokenizer v = u;
+    u = t;
+    ASSERT_THAT(u.next_string(), Eq("test"));
+    ASSERT_THAT(u.next_string(), Eq("word"));
+    ASSERT_EQ(u.count(), 2);
+
+    ASSERT_THAT(v.next_string(), Eq("test2"));
+    ASSERT_THAT(v.next_string(), Eq("word2"));
+    ASSERT_THAT(v.next_string(), Eq("other2"));
+    ASSERT_EQ(v.count(), 3);
+}
+
+TEST(ValueTokenizer, move_assignment)
+{
+    ValueTokenizer t("  test word   ", " ");
+    ASSERT_THAT(t.next_string(), Eq("test"));
+    ASSERT_THAT(t.next_string(), Eq("word"));
+    ASSERT_EQ(t.count(), 2);
+    t = ValueTokenizer("test new word   ", " ");
+    ASSERT_THAT(t.next_string(), Eq("test"));
+    ASSERT_THAT(t.next_string(), Eq("new"));
+    ASSERT_THAT(t.next_string(), Eq("word"));
+    ASSERT_EQ(t.count(), 3);
+}
+
 TEST(ValueTokenizer, bad_integer)
 {
     ValueTokenizer values("f10 f11 f12");