Update documentation

pipeline/includes/web_client/curl_web_client.h

@@ -1,29 +1,70 @@
 #ifndef BIERGARTEN_PIPELINE_WEB_CLIENT_CURL_WEB_CLIENT_H_
 #define BIERGARTEN_PIPELINE_WEB_CLIENT_CURL_WEB_CLIENT_H_
 
+/**
+ * @file web_client/curl_web_client.h
+ * @brief libcurl-based WebClient implementation.
+ */
+
 #include <memory>
 
 #include "web_client/web_client.h"
 
-// RAII for curl_global_init/cleanup.
-// An instance of this class should be created in main() before any curl
-// operations and exist for the lifetime of the application.
+/**
+ * @brief RAII wrapper for curl_global_init and curl_global_cleanup.
+ *
+ * Create one instance in application startup before using libcurl and keep it
+ * alive for application lifetime.
+ */
 class CurlGlobalState {
   public:
+   /// @brief Initializes global libcurl state.
    CurlGlobalState();
+
+   /// @brief Cleans up global libcurl state.
    ~CurlGlobalState();
+
+   /// @brief Non-copyable type.
    CurlGlobalState(const CurlGlobalState&) = delete;
+
+   /// @brief Non-copyable type.
    CurlGlobalState& operator=(const CurlGlobalState&) = delete;
 };
 
+/**
+ * @brief WebClient implementation backed by libcurl.
+ */
 class CURLWebClient : public WebClient {
   public:
+   /// @brief Constructs a CURL web client.
    CURLWebClient();
+
+   /// @brief Destroys the CURL web client.
    ~CURLWebClient() override;
 
+   /**
+    * @brief Downloads URL contents to a file.
+    *
+    * @param url Source URL.
+    * @param file_path Destination file path.
+    */
    void DownloadToFile(const std::string& url,
                        const std::string& file_path) override;
+
+   /**
+    * @brief Executes an HTTP GET request.
+    *
+    * @param url Request URL.
+    * @return Response body.
+    */
    std::string Get(const std::string& url) override;
+
+   /**
+    * @brief URL-encodes a string value.
+    *
+    * @param value Raw value.
+    * @return URL-encoded string.
+    */
    std::string UrlEncode(const std::string& value) override;
 };