Add iterator support to url_search_params

include/ada/url_search_params-inl.h

@@ -165,6 +165,48 @@ inline void url_search_params::sort() {
                    });
 }
 
+inline url_search_params_keys_iter url_search_params::get_keys() {
+  return url_search_params_keys_iter(*this);
+}
+
+/**
+ * @see https://url.spec.whatwg.org/#interface-urlsearchparams
+ */
+inline url_search_params_values_iter url_search_params::get_values() {
+  return url_search_params_values_iter(*this);
+}
+
+/**
+ * @see https://url.spec.whatwg.org/#interface-urlsearchparams
+ */
+inline url_search_params_entries_iter url_search_params::get_entries() {
+  return url_search_params_entries_iter(*this);
+}
+
+template <typename T, url_search_params_iter_type Type>
+inline bool url_search_params_iter<T, Type>::is_done() {
+  return pos >= params.params.size();
+}
+
+template <>
+inline std::optional<std::string> url_search_params_keys_iter::next() {
+  if (is_done()) return std::nullopt;
+  return params.params[pos++].first;
+}
+
+template <>
+inline std::optional<std::string> url_search_params_values_iter::next() {
+  if (is_done()) return std::nullopt;
+  return params.params[pos++].second;
+}
+
+template <>
+inline std::optional<std::pair<std::string, std::string>>
+url_search_params_entries_iter::next() {
+  if (is_done()) return std::nullopt;
+  return params.params[pos++];
+}
+
 }  // namespace ada
 
 #endif  // ADA_URL_SEARCH_PARAMS_INL_H

include/ada/url_search_params.h

@@ -12,6 +12,23 @@
 
 namespace ada {
 
+enum class url_search_params_iter_type {
+  keys,
+  values,
+  entries,
+};
+
+template <typename T, url_search_params_iter_type Type>
+struct url_search_params_iter;
+
+using url_search_params_keys_iter =
+    url_search_params_iter<std::string, url_search_params_iter_type::keys>;
+using url_search_params_values_iter =
+    url_search_params_iter<std::string, url_search_params_iter_type::values>;
+using url_search_params_entries_iter =
+    url_search_params_iter<std::pair<std::string, std::string>,
+                           url_search_params_iter_type::entries>;
+
 /**
  * @see https://url.spec.whatwg.org/#interface-urlsearchparams
  */
@@ -74,6 +91,21 @@ struct url_search_params {
    */
   inline std::string to_string();
 
+  /**
+   * @see https://url.spec.whatwg.org/#interface-urlsearchparams
+   */
+  inline url_search_params_keys_iter get_keys();
+
+  /**
+   * @see https://url.spec.whatwg.org/#interface-urlsearchparams
+   */
+  inline url_search_params_values_iter get_values();
+
+  /**
+   * @see https://url.spec.whatwg.org/#interface-urlsearchparams
+   */
+  inline url_search_params_entries_iter get_entries();
+
  private:
   typedef std::pair<std::string, std::string> key_value_pair;
   std::vector<key_value_pair> params{};
@@ -82,7 +114,31 @@ struct url_search_params {
    * @see https://url.spec.whatwg.org/#concept-urlencoded-parser
    */
   void initialize(std::string_view init);
+
+  template <typename T, url_search_params_iter_type Type>
+  friend struct url_search_params_iter;
 };  // url_search_params
 
+template <typename T, url_search_params_iter_type Type>
+struct url_search_params_iter {
+  url_search_params_iter(const url_search_params_iter &u) = default;
+  url_search_params_iter(url_search_params_iter &&u) noexcept = default;
+  url_search_params_iter &operator=(url_search_params_iter &&u) noexcept =
+      default;
+  url_search_params_iter &operator=(const url_search_params_iter &u) = default;
+  ~url_search_params_iter() = default;
+
+  inline std::optional<T> next();
+  inline bool is_done();
+
+ private:
+  inline url_search_params_iter(url_search_params &params_) : params(params_) {}
+
+  url_search_params &params;
+  size_t pos = 0;
+
+  friend struct url_search_params;
+};
+
 }  // namespace ada
 #endif

tests/url_search_params.cpp

@@ -166,4 +166,40 @@ TEST(url_search_params, has) {
   ASSERT_TRUE(!search_params.has("key1", "value2"));
   ASSERT_TRUE(!search_params.has("key3", "value3"));
   SUCCEED();
-}
+}
+
+TEST(url_search_params, iterators) {
+  auto search_params =
+      ada::url_search_params("key1=value1&key1=value2&key2=value3");
+  auto keys = search_params.get_keys();
+  ASSERT_EQ(keys.next(), "key1");
+  ASSERT_EQ(keys.next(), "key1");
+  ASSERT_EQ(keys.next(), "key2");
+  ASSERT_FALSE(keys.next().has_value());
+
+  auto values = search_params.get_values();
+  ASSERT_EQ(values.next(), "value1");
+  ASSERT_EQ(values.next(), "value2");
+  ASSERT_EQ(values.next(), "value3");
+  ASSERT_FALSE(keys.next().has_value());
+
+  auto entries = search_params.get_entries();
+  auto next = entries.next();
+  ASSERT_EQ(next->first, "key1");
+  ASSERT_EQ(next->second, "value1");
+  next = entries.next();
+  ASSERT_EQ(next->first, "key1");
+  ASSERT_EQ(next->second, "value2");
+  next = entries.next();
+  ASSERT_EQ(next->first, "key2");
+  ASSERT_EQ(next->second, "value3");
+  // At this point we can add a new entry and the iterator will pick it up.
+  search_params.append("foo", "bar");
+  next = entries.next();
+  ASSERT_EQ(next->first, "foo");
+  ASSERT_EQ(next->second, "bar");
+
+  ASSERT_FALSE(entries.next().has_value());
+
+  SUCCEED();
+}