Allow to set buffer size for client; don't auto adjust reading buffer size; refine the global definitions.

webcc/utility.h

@@ -9,9 +9,8 @@
 
 namespace webcc {
 
-// Adjust buffer size according to content length.
-// This is to avoid reading too many times.
-void AdjustBufferSize(std::size_t content_length, std::vector<char>* buffer);
+// If |port| is empty, try to extract it from |host| (separated by ':').
+void AdjustHostPort(std::string& host, std::string& port);
 
 void PrintEndpoint(std::ostream& ostream,
                    const boost::asio::ip::tcp::endpoint& endpoint);
@@ -27,6 +26,25 @@ std::string EndpointToString(const boost::asio::ip::tcp::endpoint& endpoint);
 // See: https://tools.ietf.org/html/rfc7231#section-7.1.1.2
 std::string GetHttpDateTimestamp();
 
+// Resize a buffer in ctor and restore its original size in dtor.
+struct BufferResizer {
+  BufferResizer(std::vector<char>* buffer, std::size_t new_size)
+    : buffer_(buffer), old_size_(buffer->size()) {
+    if (new_size != 0 && new_size != old_size_) {
+      buffer_->resize(new_size);
+    }
+  }
+
+  ~BufferResizer() {
+    if (buffer_->size() != old_size_) {
+      buffer_->resize(old_size_);
+    }
+  }
+
+  std::vector<char>* buffer_;
+  std::size_t old_size_;
+};
+
 }  // namespace webcc
 
 #endif  // WEBCC_UTILITY_H_